Add mitogen plugin

mitogen/ansible_mitogen/affinity.py

@@ -0,0 +1,286 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+"""
+As Mitogen separates asynchronous IO out to a broker thread, communication
+necessarily involves context switching and waking that thread. When application
+threads and the broker share a CPU, this can be almost invisibly fast - around
+25 microseconds for a full A->B->A round-trip.
+
+However when threads are scheduled on different CPUs, round-trip delays
+regularly vary wildly, and easily into milliseconds. Many contributing factors
+exist, not least scenarios like:
+
+1. A is preempted immediately after waking B, but before releasing the GIL.
+2. B wakes from IO wait only to immediately enter futex wait.
+3. A may wait 10ms or more for another timeslice, as the scheduler on its CPU
+   runs threads unrelated to its transaction (i.e. not B), wake only to release
+   its GIL, before entering IO sleep waiting for a reply from B, which cannot
+   exist yet.
+4. B wakes, acquires GIL, performs work, and sends reply to A, causing it to
+   wake. B is preempted before releasing GIL.
+5. A wakes from IO wait only to immediately enter futex wait.
+6. B may wait 10ms or more for another timeslice, wake only to release its GIL,
+   before sleeping again.
+7. A wakes, acquires GIL, finally receives reply.
+
+Per above if we are unlucky, on an even moderately busy machine it is possible
+to lose milliseconds just in scheduling delay, and the effect is compounded
+when pairs of threads in process A are communicating with pairs of threads in
+process B using the same scheme, such as when Ansible WorkerProcess is
+communicating with ContextService in the connection multiplexer. In the worst
+case it could involve 4 threads working in lockstep spread across 4 busy CPUs.
+
+Since multithreading in Python is essentially useless except for waiting on IO
+due to the presence of the GIL, at least in Ansible there is no good reason for
+threads in the same process to run on distinct CPUs - they always operate in
+lockstep due to the GIL, and are thus vulnerable to issues like above.
+
+Linux lacks any natural API to describe what we want, it only permits
+individual threads to be constrained to run on specific CPUs, and for that
+constraint to be inherited by new threads and forks of the constrained thread.
+
+This module therefore implements a CPU pinning policy for Ansible processes,
+providing methods that should be called early in any new process, either to
+rebalance which CPU it is pinned to, or in the case of subprocesses, to remove
+the pinning entirely. It is likely to require ongoing tweaking, since pinning
+necessarily involves preventing the scheduler from making load balancing
+decisions.
+"""
+
+from __future__ import absolute_import
+import ctypes
+import logging
+import mmap
+import multiprocessing
+import os
+import struct
+
+import mitogen.core
+import mitogen.parent
+
+
+LOG = logging.getLogger(__name__)
+
+
+try:
+    _libc = ctypes.CDLL(None, use_errno=True)
+    _strerror = _libc.strerror
+    _strerror.restype = ctypes.c_char_p
+    _sem_init = _libc.sem_init
+    _sem_wait = _libc.sem_wait
+    _sem_post = _libc.sem_post
+    _sched_setaffinity = _libc.sched_setaffinity
+except (OSError, AttributeError):
+    _libc = None
+    _strerror = None
+    _sem_init = None
+    _sem_wait = None
+    _sem_post = None
+    _sched_setaffinity = None
+
+
+class sem_t(ctypes.Structure):
+    """
+    Wrap sem_t to allow storing a lock in shared memory.
+    """
+    _fields_ = [
+        ('data', ctypes.c_uint8 * 128),
+    ]
+
+    def init(self):
+        if _sem_init(self.data, 1, 1):
+            raise Exception(_strerror(ctypes.get_errno()))
+
+    def acquire(self):
+        if _sem_wait(self.data):
+            raise Exception(_strerror(ctypes.get_errno()))
+
+    def release(self):
+        if _sem_post(self.data):
+            raise Exception(_strerror(ctypes.get_errno()))
+
+
+class State(ctypes.Structure):
+    """
+    Contents of shared memory segment. This allows :meth:`Manager.assign` to be
+    called from any child, since affinity assignment must happen from within
+    the context of the new child process.
+    """
+    _fields_ = [
+        ('lock', sem_t),
+        ('counter', ctypes.c_uint8),
+    ]
+
+
+class Policy(object):
+    """
+    Process affinity policy.
+    """
+    def assign_controller(self):
+        """
+        Assign the Ansible top-level policy to this process.
+        """
+
+    def assign_muxprocess(self, index):
+        """
+        Assign the MuxProcess policy to this process.
+        """
+
+    def assign_worker(self):
+        """
+        Assign the WorkerProcess policy to this process.
+        """
+
+    def assign_subprocess(self):
+        """
+        Assign the helper subprocess policy to this process.
+        """
+
+class FixedPolicy(Policy):
+    """
+    :class:`Policy` for machines where the only control method available is
+    fixed CPU placement. The scheme here was tested on an otherwise idle 16
+    thread machine.
+
+    - The connection multiplexer is pinned to CPU 0.
+    - The Ansible top-level (strategy) is pinned to CPU 1.
+    - WorkerProcesses are pinned sequentually to 2..N, wrapping around when no
+      more CPUs exist.
+    - Children such as SSH may be scheduled on any CPU except 0/1.
+
+    If the machine has less than 4 cores available, the top-level and workers
+    are pinned between CPU 2..N, i.e. no CPU is reserved for the top-level
+    process.
+
+    This could at least be improved by having workers pinned to independent
+    cores, before reusing the second hyperthread of an existing core.
+
+    A hook is installed that causes :meth:`reset` to run in the child of any
+    process created with :func:`mitogen.parent.popen`, ensuring CPU-intensive
+    children like SSH are not forced to share the same core as the (otherwise
+    potentially very busy) parent.
+    """
+    def __init__(self, cpu_count=None):
+        #: For tests.
+        self.cpu_count = cpu_count or multiprocessing.cpu_count()
+        self.mem = mmap.mmap(-1, 4096)
+        self.state = State.from_buffer(self.mem)
+        self.state.lock.init()
+
+        if self.cpu_count < 2:
+            # uniprocessor
+            self._reserve_mux = False
+            self._reserve_controller = False
+            self._reserve_mask = 0
+            self._reserve_shift = 0
+        elif self.cpu_count < 4:
+            # small SMP
+            self._reserve_mux = True
+            self._reserve_controller = False
+            self._reserve_mask = 1
+            self._reserve_shift = 1
+        else:
+            # big SMP
+            self._reserve_mux = True
+            self._reserve_controller = True
+            self._reserve_mask = 3
+            self._reserve_shift = 2
+
+    def _set_affinity(self, descr, mask):
+        if descr:
+            LOG.debug('CPU mask for %s: %#08x', descr, mask)
+        mitogen.parent._preexec_hook = self._clear
+        self._set_cpu_mask(mask)
+
+    def _balance(self, descr):
+        self.state.lock.acquire()
+        try:
+            n = self.state.counter
+            self.state.counter += 1
+        finally:
+            self.state.lock.release()
+
+        self._set_cpu(descr, self._reserve_shift + (
+            (n % (self.cpu_count - self._reserve_shift))
+        ))
+
+    def _set_cpu(self, descr, cpu):
+        self._set_affinity(descr, 1 << (cpu % self.cpu_count))
+
+    def _clear(self):
+        all_cpus = (1 << self.cpu_count) - 1
+        self._set_affinity(None, all_cpus & ~self._reserve_mask)
+
+    def assign_controller(self):
+        if self._reserve_controller:
+            self._set_cpu('Ansible top-level process', 1)
+        else:
+            self._balance('Ansible top-level process')
+
+    def assign_muxprocess(self, index):
+        self._set_cpu('MuxProcess %d' % (index,), index)
+
+    def assign_worker(self):
+        self._balance('WorkerProcess')
+
+    def assign_subprocess(self):
+        self._clear()
+
+
+class LinuxPolicy(FixedPolicy):
+    def _mask_to_bytes(self, mask):
+        """
+        Convert the (type long) mask to a cpu_set_t.
+        """
+        chunks = []
+        shiftmask = (2 ** 64) - 1
+        for x in range(16):
+            chunks.append(struct.pack('<Q', mask & shiftmask))
+            mask >>= 64
+        return mitogen.core.b('').join(chunks)
+
+    def _get_thread_ids(self):
+        try:
+            ents = os.listdir('/proc/self/task')
+        except OSError:
+            LOG.debug('cannot fetch thread IDs for current process')
+            return [os.getpid()]
+
+        return [int(s) for s in ents if s.isdigit()]
+
+    def _set_cpu_mask(self, mask):
+        s = self._mask_to_bytes(mask)
+        for tid in self._get_thread_ids():
+            _sched_setaffinity(tid, len(s), s)
+
+
+if _sched_setaffinity is not None:
+    policy = LinuxPolicy()
+else:
+    policy = Policy()

mitogen/ansible_mitogen/compat/simplejson/__init__.py

@@ -0,0 +1,318 @@
+r"""JSON (JavaScript Object Notation) <http://json.org> is a subset of
+JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data
+interchange format.
+
+:mod:`simplejson` exposes an API familiar to users of the standard library
+:mod:`marshal` and :mod:`pickle` modules. It is the externally maintained
+version of the :mod:`json` library contained in Python 2.6, but maintains
+compatibility with Python 2.4 and Python 2.5 and (currently) has
+significant performance advantages, even without using the optional C
+extension for speedups.
+
+Encoding basic Python object hierarchies::
+
+    >>> import simplejson as json
+    >>> json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])
+    '["foo", {"bar": ["baz", null, 1.0, 2]}]'
+    >>> print json.dumps("\"foo\bar")
+    "\"foo\bar"
+    >>> print json.dumps(u'\u1234')
+    "\u1234"
+    >>> print json.dumps('\\')
+    "\\"
+    >>> print json.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True)
+    {"a": 0, "b": 0, "c": 0}
+    >>> from StringIO import StringIO
+    >>> io = StringIO()
+    >>> json.dump(['streaming API'], io)
+    >>> io.getvalue()
+    '["streaming API"]'
+
+Compact encoding::
+
+    >>> import simplejson as json
+    >>> json.dumps([1,2,3,{'4': 5, '6': 7}], separators=(',',':'))
+    '[1,2,3,{"4":5,"6":7}]'
+
+Pretty printing::
+
+    >>> import simplejson as json
+    >>> s = json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4)
+    >>> print '\n'.join([l.rstrip() for l in  s.splitlines()])
+    {
+        "4": 5,
+        "6": 7
+    }
+
+Decoding JSON::
+
+    >>> import simplejson as json
+    >>> obj = [u'foo', {u'bar': [u'baz', None, 1.0, 2]}]
+    >>> json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]') == obj
+    True
+    >>> json.loads('"\\"foo\\bar"') == u'"foo\x08ar'
+    True
+    >>> from StringIO import StringIO
+    >>> io = StringIO('["streaming API"]')
+    >>> json.load(io)[0] == 'streaming API'
+    True
+
+Specializing JSON object decoding::
+
+    >>> import simplejson as json
+    >>> def as_complex(dct):
+    ...     if '__complex__' in dct:
+    ...         return complex(dct['real'], dct['imag'])
+    ...     return dct
+    ...
+    >>> json.loads('{"__complex__": true, "real": 1, "imag": 2}',
+    ...     object_hook=as_complex)
+    (1+2j)
+    >>> import decimal
+    >>> json.loads('1.1', parse_float=decimal.Decimal) == decimal.Decimal('1.1')
+    True
+
+Specializing JSON object encoding::
+
+    >>> import simplejson as json
+    >>> def encode_complex(obj):
+    ...     if isinstance(obj, complex):
+    ...         return [obj.real, obj.imag]
+    ...     raise TypeError(repr(o) + " is not JSON serializable")
+    ...
+    >>> json.dumps(2 + 1j, default=encode_complex)
+    '[2.0, 1.0]'
+    >>> json.JSONEncoder(default=encode_complex).encode(2 + 1j)
+    '[2.0, 1.0]'
+    >>> ''.join(json.JSONEncoder(default=encode_complex).iterencode(2 + 1j))
+    '[2.0, 1.0]'
+
+
+Using simplejson.tool from the shell to validate and pretty-print::
+
+    $ echo '{"json":"obj"}' | python -m simplejson.tool
+    {
+        "json": "obj"
+    }
+    $ echo '{ 1.2:3.4}' | python -m simplejson.tool
+    Expecting property name: line 1 column 2 (char 2)
+"""
+__version__ = '2.0.9'
+__all__ = [
+    'dump', 'dumps', 'load', 'loads',
+    'JSONDecoder', 'JSONEncoder',
+]
+
+__author__ = 'Bob Ippolito <bob@redivi.com>'
+
+from decoder import JSONDecoder
+from encoder import JSONEncoder
+
+_default_encoder = JSONEncoder(
+    skipkeys=False,
+    ensure_ascii=True,
+    check_circular=True,
+    allow_nan=True,
+    indent=None,
+    separators=None,
+    encoding='utf-8',
+    default=None,
+)
+
+def dump(obj, fp, skipkeys=False, ensure_ascii=True, check_circular=True,
+        allow_nan=True, cls=None, indent=None, separators=None,
+        encoding='utf-8', default=None, **kw):
+    """Serialize ``obj`` as a JSON formatted stream to ``fp`` (a
+    ``.write()``-supporting file-like object).
+
+    If ``skipkeys`` is true then ``dict`` keys that are not basic types
+    (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
+    will be skipped instead of raising a ``TypeError``.
+
+    If ``ensure_ascii`` is false, then the some chunks written to ``fp``
+    may be ``unicode`` instances, subject to normal Python ``str`` to
+    ``unicode`` coercion rules. Unless ``fp.write()`` explicitly
+    understands ``unicode`` (as in ``codecs.getwriter()``) this is likely
+    to cause an error.
+
+    If ``check_circular`` is false, then the circular reference check
+    for container types will be skipped and a circular reference will
+    result in an ``OverflowError`` (or worse).
+
+    If ``allow_nan`` is false, then it will be a ``ValueError`` to
+    serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``)
+    in strict compliance of the JSON specification, instead of using the
+    JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
+
+    If ``indent`` is a non-negative integer, then JSON array elements and object
+    members will be pretty-printed with that indent level. An indent level
+    of 0 will only insert newlines. ``None`` is the most compact representation.
+
+    If ``separators`` is an ``(item_separator, dict_separator)`` tuple
+    then it will be used instead of the default ``(', ', ': ')`` separators.
+    ``(',', ':')`` is the most compact JSON representation.
+
+    ``encoding`` is the character encoding for str instances, default is UTF-8.
+
+    ``default(obj)`` is a function that should return a serializable version
+    of obj or raise TypeError. The default simply raises TypeError.
+
+    To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
+    ``.default()`` method to serialize additional types), specify it with
+    the ``cls`` kwarg.
+
+    """
+    # cached encoder
+    if (not skipkeys and ensure_ascii and
+        check_circular and allow_nan and
+        cls is None and indent is None and separators is None and
+        encoding == 'utf-8' and default is None and not kw):
+        iterable = _default_encoder.iterencode(obj)
+    else:
+        if cls is None:
+            cls = JSONEncoder
+        iterable = cls(skipkeys=skipkeys, ensure_ascii=ensure_ascii,
+            check_circular=check_circular, allow_nan=allow_nan, indent=indent,
+            separators=separators, encoding=encoding,
+            default=default, **kw).iterencode(obj)
+    # could accelerate with writelines in some versions of Python, at
+    # a debuggability cost
+    for chunk in iterable:
+        fp.write(chunk)
+
+
+def dumps(obj, skipkeys=False, ensure_ascii=True, check_circular=True,
+        allow_nan=True, cls=None, indent=None, separators=None,
+        encoding='utf-8', default=None, **kw):
+    """Serialize ``obj`` to a JSON formatted ``str``.
+
+    If ``skipkeys`` is false then ``dict`` keys that are not basic types
+    (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
+    will be skipped instead of raising a ``TypeError``.
+
+    If ``ensure_ascii`` is false, then the return value will be a
+    ``unicode`` instance subject to normal Python ``str`` to ``unicode``
+    coercion rules instead of being escaped to an ASCII ``str``.
+
+    If ``check_circular`` is false, then the circular reference check
+    for container types will be skipped and a circular reference will
+    result in an ``OverflowError`` (or worse).
+
+    If ``allow_nan`` is false, then it will be a ``ValueError`` to
+    serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in
+    strict compliance of the JSON specification, instead of using the
+    JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
+
+    If ``indent`` is a non-negative integer, then JSON array elements and
+    object members will be pretty-printed with that indent level. An indent
+    level of 0 will only insert newlines. ``None`` is the most compact
+    representation.
+
+    If ``separators`` is an ``(item_separator, dict_separator)`` tuple
+    then it will be used instead of the default ``(', ', ': ')`` separators.
+    ``(',', ':')`` is the most compact JSON representation.
+
+    ``encoding`` is the character encoding for str instances, default is UTF-8.
+
+    ``default(obj)`` is a function that should return a serializable version
+    of obj or raise TypeError. The default simply raises TypeError.
+
+    To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
+    ``.default()`` method to serialize additional types), specify it with
+    the ``cls`` kwarg.
+
+    """
+    # cached encoder
+    if (not skipkeys and ensure_ascii and
+        check_circular and allow_nan and
+        cls is None and indent is None and separators is None and
+        encoding == 'utf-8' and default is None and not kw):
+        return _default_encoder.encode(obj)
+    if cls is None:
+        cls = JSONEncoder
+    return cls(
+        skipkeys=skipkeys, ensure_ascii=ensure_ascii,
+        check_circular=check_circular, allow_nan=allow_nan, indent=indent,
+        separators=separators, encoding=encoding, default=default,
+        **kw).encode(obj)
+
+
+_default_decoder = JSONDecoder(encoding=None, object_hook=None)
+
+
+def load(fp, encoding=None, cls=None, object_hook=None, parse_float=None,
+        parse_int=None, parse_constant=None, **kw):
+    """Deserialize ``fp`` (a ``.read()``-supporting file-like object containing
+    a JSON document) to a Python object.
+
+    If the contents of ``fp`` is encoded with an ASCII based encoding other
+    than utf-8 (e.g. latin-1), then an appropriate ``encoding`` name must
+    be specified. Encodings that are not ASCII based (such as UCS-2) are
+    not allowed, and should be wrapped with
+    ``codecs.getreader(fp)(encoding)``, or simply decoded to a ``unicode``
+    object and passed to ``loads()``
+
+    ``object_hook`` is an optional function that will be called with the
+    result of any object literal decode (a ``dict``). The return value of
+    ``object_hook`` will be used instead of the ``dict``. This feature
+    can be used to implement custom decoders (e.g. JSON-RPC class hinting).
+
+    To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
+    kwarg.
+
+    """
+    return loads(fp.read(),
+        encoding=encoding, cls=cls, object_hook=object_hook,
+        parse_float=parse_float, parse_int=parse_int,
+        parse_constant=parse_constant, **kw)
+
+
+def loads(s, encoding=None, cls=None, object_hook=None, parse_float=None,
+        parse_int=None, parse_constant=None, **kw):
+    """Deserialize ``s`` (a ``str`` or ``unicode`` instance containing a JSON
+    document) to a Python object.
+
+    If ``s`` is a ``str`` instance and is encoded with an ASCII based encoding
+    other than utf-8 (e.g. latin-1) then an appropriate ``encoding`` name
+    must be specified. Encodings that are not ASCII based (such as UCS-2)
+    are not allowed and should be decoded to ``unicode`` first.
+
+    ``object_hook`` is an optional function that will be called with the
+    result of any object literal decode (a ``dict``). The return value of
+    ``object_hook`` will be used instead of the ``dict``. This feature
+    can be used to implement custom decoders (e.g. JSON-RPC class hinting).
+
+    ``parse_float``, if specified, will be called with the string
+    of every JSON float to be decoded. By default this is equivalent to
+    float(num_str). This can be used to use another datatype or parser
+    for JSON floats (e.g. decimal.Decimal).
+
+    ``parse_int``, if specified, will be called with the string
+    of every JSON int to be decoded. By default this is equivalent to
+    int(num_str). This can be used to use another datatype or parser
+    for JSON integers (e.g. float).
+
+    ``parse_constant``, if specified, will be called with one of the
+    following strings: -Infinity, Infinity, NaN, null, true, false.
+    This can be used to raise an exception if invalid JSON numbers
+    are encountered.
+
+    To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
+    kwarg.
+
+    """
+    if (cls is None and encoding is None and object_hook is None and
+            parse_int is None and parse_float is None and
+            parse_constant is None and not kw):
+        return _default_decoder.decode(s)
+    if cls is None:
+        cls = JSONDecoder
+    if object_hook is not None:
+        kw['object_hook'] = object_hook
+    if parse_float is not None:
+        kw['parse_float'] = parse_float
+    if parse_int is not None:
+        kw['parse_int'] = parse_int
+    if parse_constant is not None:
+        kw['parse_constant'] = parse_constant
+    return cls(encoding=encoding, **kw).decode(s)

mitogen/ansible_mitogen/compat/simplejson/decoder.py

@@ -0,0 +1,354 @@
+"""Implementation of JSONDecoder
+"""
+import re
+import sys
+import struct
+
+from simplejson.scanner import make_scanner
+try:
+    from simplejson._speedups import scanstring as c_scanstring
+except ImportError:
+    c_scanstring = None
+
+__all__ = ['JSONDecoder']
+
+FLAGS = re.VERBOSE | re.MULTILINE | re.DOTALL
+
+def _floatconstants():
+    _BYTES = '7FF80000000000007FF0000000000000'.decode('hex')
+    if sys.byteorder != 'big':
+        _BYTES = _BYTES[:8][::-1] + _BYTES[8:][::-1]
+    nan, inf = struct.unpack('dd', _BYTES)
+    return nan, inf, -inf
+
+NaN, PosInf, NegInf = _floatconstants()
+
+
+def linecol(doc, pos):
+    lineno = doc.count('\n', 0, pos) + 1
+    if lineno == 1:
+        colno = pos
+    else:
+        colno = pos - doc.rindex('\n', 0, pos)
+    return lineno, colno
+
+
+def errmsg(msg, doc, pos, end=None):
+    # Note that this function is called from _speedups
+    lineno, colno = linecol(doc, pos)
+    if end is None:
+        #fmt = '{0}: line {1} column {2} (char {3})'
+        #return fmt.format(msg, lineno, colno, pos)
+        fmt = '%s: line %d column %d (char %d)'
+        return fmt % (msg, lineno, colno, pos)
+    endlineno, endcolno = linecol(doc, end)
+    #fmt = '{0}: line {1} column {2} - line {3} column {4} (char {5} - {6})'
+    #return fmt.format(msg, lineno, colno, endlineno, endcolno, pos, end)
+    fmt = '%s: line %d column %d - line %d column %d (char %d - %d)'
+    return fmt % (msg, lineno, colno, endlineno, endcolno, pos, end)
+
+
+_CONSTANTS = {
+    '-Infinity': NegInf,
+    'Infinity': PosInf,
+    'NaN': NaN,
+}
+
+STRINGCHUNK = re.compile(r'(.*?)(["\\\x00-\x1f])', FLAGS)
+BACKSLASH = {
+    '"': u'"', '\\': u'\\', '/': u'/',
+    'b': u'\b', 'f': u'\f', 'n': u'\n', 'r': u'\r', 't': u'\t',
+}
+
+DEFAULT_ENCODING = "utf-8"
+
+def py_scanstring(s, end, encoding=None, strict=True, _b=BACKSLASH, _m=STRINGCHUNK.match):
+    """Scan the string s for a JSON string. End is the index of the
+    character in s after the quote that started the JSON string.
+    Unescapes all valid JSON string escape sequences and raises ValueError
+    on attempt to decode an invalid string. If strict is False then literal
+    control characters are allowed in the string.
+    
+    Returns a tuple of the decoded string and the index of the character in s
+    after the end quote."""
+    if encoding is None:
+        encoding = DEFAULT_ENCODING
+    chunks = []
+    _append = chunks.append
+    begin = end - 1
+    while 1:
+        chunk = _m(s, end)
+        if chunk is None:
+            raise ValueError(
+                errmsg("Unterminated string starting at", s, begin))
+        end = chunk.end()
+        content, terminator = chunk.groups()
+        # Content is contains zero or more unescaped string characters
+        if content:
+            if not isinstance(content, unicode):
+                content = unicode(content, encoding)
+            _append(content)
+        # Terminator is the end of string, a literal control character,
+        # or a backslash denoting that an escape sequence follows
+        if terminator == '"':
+            break
+        elif terminator != '\\':
+            if strict:
+                msg = "Invalid control character %r at" % (terminator,)
+                #msg = "Invalid control character {0!r} at".format(terminator)
+                raise ValueError(errmsg(msg, s, end))
+            else:
+                _append(terminator)
+                continue
+        try:
+            esc = s[end]
+        except IndexError:
+            raise ValueError(
+                errmsg("Unterminated string starting at", s, begin))
+        # If not a unicode escape sequence, must be in the lookup table
+        if esc != 'u':
+            try:
+                char = _b[esc]
+            except KeyError:
+                msg = "Invalid \\escape: " + repr(esc)
+                raise ValueError(errmsg(msg, s, end))
+            end += 1
+        else:
+            # Unicode escape sequence
+            esc = s[end + 1:end + 5]
+            next_end = end + 5
+            if len(esc) != 4:
+                msg = "Invalid \\uXXXX escape"
+                raise ValueError(errmsg(msg, s, end))
+            uni = int(esc, 16)
+            # Check for surrogate pair on UCS-4 systems
+            if 0xd800 <= uni <= 0xdbff and sys.maxunicode > 65535:
+                msg = "Invalid \\uXXXX\\uXXXX surrogate pair"
+                if not s[end + 5:end + 7] == '\\u':
+                    raise ValueError(errmsg(msg, s, end))
+                esc2 = s[end + 7:end + 11]
+                if len(esc2) != 4:
+                    raise ValueError(errmsg(msg, s, end))
+                uni2 = int(esc2, 16)
+                uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00))
+                next_end += 6
+            char = unichr(uni)
+            end = next_end
+        # Append the unescaped character
+        _append(char)
+    return u''.join(chunks), end
+
+
+# Use speedup if available
+scanstring = c_scanstring or py_scanstring
+
+WHITESPACE = re.compile(r'[ \t\n\r]*', FLAGS)
+WHITESPACE_STR = ' \t\n\r'
+
+def JSONObject((s, end), encoding, strict, scan_once, object_hook, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
+    pairs = {}
+    # Use a slice to prevent IndexError from being raised, the following
+    # check will raise a more specific ValueError if the string is empty
+    nextchar = s[end:end + 1]
+    # Normally we expect nextchar == '"'
+    if nextchar != '"':
+        if nextchar in _ws:
+            end = _w(s, end).end()
+            nextchar = s[end:end + 1]
+        # Trivial empty object
+        if nextchar == '}':
+            return pairs, end + 1
+        elif nextchar != '"':
+            raise ValueError(errmsg("Expecting property name", s, end))
+    end += 1
+    while True:
+        key, end = scanstring(s, end, encoding, strict)
+
+        # To skip some function call overhead we optimize the fast paths where
+        # the JSON key separator is ": " or just ":".
+        if s[end:end + 1] != ':':
+            end = _w(s, end).end()
+            if s[end:end + 1] != ':':
+                raise ValueError(errmsg("Expecting : delimiter", s, end))
+
+        end += 1
+
+        try:
+            if s[end] in _ws:
+                end += 1
+                if s[end] in _ws:
+                    end = _w(s, end + 1).end()
+        except IndexError:
+            pass
+
+        try:
+            value, end = scan_once(s, end)
+        except StopIteration:
+            raise ValueError(errmsg("Expecting object", s, end))
+        pairs[key] = value
+
+        try:
+            nextchar = s[end]
+            if nextchar in _ws:
+                end = _w(s, end + 1).end()
+                nextchar = s[end]
+        except IndexError:
+            nextchar = ''
+        end += 1
+
+        if nextchar == '}':
+            break
+        elif nextchar != ',':
+            raise ValueError(errmsg("Expecting , delimiter", s, end - 1))
+
+        try:
+            nextchar = s[end]
+            if nextchar in _ws:
+                end += 1
+                nextchar = s[end]
+                if nextchar in _ws:
+                    end = _w(s, end + 1).end()
+                    nextchar = s[end]
+        except IndexError:
+            nextchar = ''
+
+        end += 1
+        if nextchar != '"':
+            raise ValueError(errmsg("Expecting property name", s, end - 1))
+
+    if object_hook is not None:
+        pairs = object_hook(pairs)
+    return pairs, end
+
+def JSONArray((s, end), scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
+    values = []
+    nextchar = s[end:end + 1]
+    if nextchar in _ws:
+        end = _w(s, end + 1).end()
+        nextchar = s[end:end + 1]
+    # Look-ahead for trivial empty array
+    if nextchar == ']':
+        return values, end + 1
+    _append = values.append
+    while True:
+        try:
+            value, end = scan_once(s, end)
+        except StopIteration:
+            raise ValueError(errmsg("Expecting object", s, end))
+        _append(value)
+        nextchar = s[end:end + 1]
+        if nextchar in _ws:
+            end = _w(s, end + 1).end()
+            nextchar = s[end:end + 1]
+        end += 1
+        if nextchar == ']':
+            break
+        elif nextchar != ',':
+            raise ValueError(errmsg("Expecting , delimiter", s, end))
+
+        try:
+            if s[end] in _ws:
+                end += 1
+                if s[end] in _ws:
+                    end = _w(s, end + 1).end()
+        except IndexError:
+            pass
+
+    return values, end
+
+class JSONDecoder(object):
+    """Simple JSON <http://json.org> decoder
+
+    Performs the following translations in decoding by default:
+
+    +---------------+-------------------+
+    | JSON          | Python            |
+    +===============+===================+
+    | object        | dict              |
+    +---------------+-------------------+
+    | array         | list              |
+    +---------------+-------------------+
+    | string        | unicode           |
+    +---------------+-------------------+
+    | number (int)  | int, long         |
+    +---------------+-------------------+
+    | number (real) | float             |
+    +---------------+-------------------+
+    | true          | True              |
+    +---------------+-------------------+
+    | false         | False             |
+    +---------------+-------------------+
+    | null          | None              |
+    +---------------+-------------------+
+
+    It also understands ``NaN``, ``Infinity``, and ``-Infinity`` as
+    their corresponding ``float`` values, which is outside the JSON spec.
+
+    """
+
+    def __init__(self, encoding=None, object_hook=None, parse_float=None,
+            parse_int=None, parse_constant=None, strict=True):
+        """``encoding`` determines the encoding used to interpret any ``str``
+        objects decoded by this instance (utf-8 by default).  It has no
+        effect when decoding ``unicode`` objects.
+
+        Note that currently only encodings that are a superset of ASCII work,
+        strings of other encodings should be passed in as ``unicode``.
+
+        ``object_hook``, if specified, will be called with the result
+        of every JSON object decoded and its return value will be used in
+        place of the given ``dict``.  This can be used to provide custom
+        deserializations (e.g. to support JSON-RPC class hinting).
+
+        ``parse_float``, if specified, will be called with the string
+        of every JSON float to be decoded. By default this is equivalent to
+        float(num_str). This can be used to use another datatype or parser
+        for JSON floats (e.g. decimal.Decimal).
+
+        ``parse_int``, if specified, will be called with the string
+        of every JSON int to be decoded. By default this is equivalent to
+        int(num_str). This can be used to use another datatype or parser
+        for JSON integers (e.g. float).
+
+        ``parse_constant``, if specified, will be called with one of the
+        following strings: -Infinity, Infinity, NaN.
+        This can be used to raise an exception if invalid JSON numbers
+        are encountered.
+
+        """
+        self.encoding = encoding
+        self.object_hook = object_hook
+        self.parse_float = parse_float or float
+        self.parse_int = parse_int or int
+        self.parse_constant = parse_constant or _CONSTANTS.__getitem__
+        self.strict = strict
+        self.parse_object = JSONObject
+        self.parse_array = JSONArray
+        self.parse_string = scanstring
+        self.scan_once = make_scanner(self)
+
+    def decode(self, s, _w=WHITESPACE.match):
+        """Return the Python representation of ``s`` (a ``str`` or ``unicode``
+        instance containing a JSON document)
+
+        """
+        obj, end = self.raw_decode(s, idx=_w(s, 0).end())
+        end = _w(s, end).end()
+        if end != len(s):
+            raise ValueError(errmsg("Extra data", s, end, len(s)))
+        return obj
+
+    def raw_decode(self, s, idx=0):
+        """Decode a JSON document from ``s`` (a ``str`` or ``unicode`` beginning
+        with a JSON document) and return a 2-tuple of the Python
+        representation and the index in ``s`` where the document ended.
+
+        This can be used to decode a JSON document from a string that may
+        have extraneous data at the end.
+
+        """
+        try:
+            obj, end = self.scan_once(s, idx)
+        except StopIteration:
+            raise ValueError("No JSON object could be decoded")
+        return obj, end

mitogen/ansible_mitogen/compat/simplejson/encoder.py

@@ -0,0 +1,440 @@
+"""Implementation of JSONEncoder
+"""
+import re
+
+try:
+    from simplejson._speedups import encode_basestring_ascii as c_encode_basestring_ascii
+except ImportError:
+    c_encode_basestring_ascii = None
+try:
+    from simplejson._speedups import make_encoder as c_make_encoder
+except ImportError:
+    c_make_encoder = None
+
+ESCAPE = re.compile(r'[\x00-\x1f\\"\b\f\n\r\t]')
+ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')
+HAS_UTF8 = re.compile(r'[\x80-\xff]')
+ESCAPE_DCT = {
+    '\\': '\\\\',
+    '"': '\\"',
+    '\b': '\\b',
+    '\f': '\\f',
+    '\n': '\\n',
+    '\r': '\\r',
+    '\t': '\\t',
+}
+for i in range(0x20):
+    #ESCAPE_DCT.setdefault(chr(i), '\\u{0:04x}'.format(i))
+    ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))
+
+# Assume this produces an infinity on all machines (probably not guaranteed)
+INFINITY = float('1e66666')
+FLOAT_REPR = repr
+
+def encode_basestring(s):
+    """Return a JSON representation of a Python string
+
+    """
+    def replace(match):
+        return ESCAPE_DCT[match.group(0)]
+    return '"' + ESCAPE.sub(replace, s) + '"'
+
+
+def py_encode_basestring_ascii(s):
+    """Return an ASCII-only JSON representation of a Python string
+
+    """
+    if isinstance(s, str) and HAS_UTF8.search(s) is not None:
+        s = s.decode('utf-8')
+    def replace(match):
+        s = match.group(0)
+        try:
+            return ESCAPE_DCT[s]
+        except KeyError:
+            n = ord(s)
+            if n < 0x10000:
+                #return '\\u{0:04x}'.format(n)
+                return '\\u%04x' % (n,)
+            else:
+                # surrogate pair
+                n -= 0x10000
+                s1 = 0xd800 | ((n >> 10) & 0x3ff)
+                s2 = 0xdc00 | (n & 0x3ff)
+                #return '\\u{0:04x}\\u{1:04x}'.format(s1, s2)
+                return '\\u%04x\\u%04x' % (s1, s2)
+    return '"' + str(ESCAPE_ASCII.sub(replace, s)) + '"'
+
+
+encode_basestring_ascii = c_encode_basestring_ascii or py_encode_basestring_ascii
+
+class JSONEncoder(object):
+    """Extensible JSON <http://json.org> encoder for Python data structures.
+
+    Supports the following objects and types by default:
+
+    +-------------------+---------------+
+    | Python            | JSON          |
+    +===================+===============+
+    | dict              | object        |
+    +-------------------+---------------+
+    | list, tuple       | array         |
+    +-------------------+---------------+
+    | str, unicode      | string        |
+    +-------------------+---------------+
+    | int, long, float  | number        |
+    +-------------------+---------------+
+    | True              | true          |
+    +-------------------+---------------+
+    | False             | false         |
+    +-------------------+---------------+
+    | None              | null          |
+    +-------------------+---------------+
+
+    To extend this to recognize other objects, subclass and implement a
+    ``.default()`` method with another method that returns a serializable
+    object for ``o`` if possible, otherwise it should call the superclass
+    implementation (to raise ``TypeError``).
+
+    """
+    item_separator = ', '
+    key_separator = ': '
+    def __init__(self, skipkeys=False, ensure_ascii=True,
+            check_circular=True, allow_nan=True, sort_keys=False,
+            indent=None, separators=None, encoding='utf-8', default=None):
+        """Constructor for JSONEncoder, with sensible defaults.
+
+        If skipkeys is false, then it is a TypeError to attempt
+        encoding of keys that are not str, int, long, float or None.  If
+        skipkeys is True, such items are simply skipped.
+
+        If ensure_ascii is true, the output is guaranteed to be str
+        objects with all incoming unicode characters escaped.  If
+        ensure_ascii is false, the output will be unicode object.
+
+        If check_circular is true, then lists, dicts, and custom encoded
+        objects will be checked for circular references during encoding to
+        prevent an infinite recursion (which would cause an OverflowError).
+        Otherwise, no such check takes place.
+
+        If allow_nan is true, then NaN, Infinity, and -Infinity will be
+        encoded as such.  This behavior is not JSON specification compliant,
+        but is consistent with most JavaScript based encoders and decoders.
+        Otherwise, it will be a ValueError to encode such floats.
+
+        If sort_keys is true, then the output of dictionaries will be
+        sorted by key; this is useful for regression tests to ensure
+        that JSON serializations can be compared on a day-to-day basis.
+
+        If indent is a non-negative integer, then JSON array
+        elements and object members will be pretty-printed with that
+        indent level.  An indent level of 0 will only insert newlines.
+        None is the most compact representation.
+
+        If specified, separators should be a (item_separator, key_separator)
+        tuple.  The default is (', ', ': ').  To get the most compact JSON
+        representation you should specify (',', ':') to eliminate whitespace.
+
+        If specified, default is a function that gets called for objects
+        that can't otherwise be serialized.  It should return a JSON encodable
+        version of the object or raise a ``TypeError``.
+
+        If encoding is not None, then all input strings will be
+        transformed into unicode using that encoding prior to JSON-encoding.
+        The default is UTF-8.
+
+        """
+
+        self.skipkeys = skipkeys
+        self.ensure_ascii = ensure_ascii
+        self.check_circular = check_circular
+        self.allow_nan = allow_nan
+        self.sort_keys = sort_keys
+        self.indent = indent
+        if separators is not None:
+            self.item_separator, self.key_separator = separators
+        if default is not None:
+            self.default = default
+        self.encoding = encoding
+
+    def default(self, o):
+        """Implement this method in a subclass such that it returns
+        a serializable object for ``o``, or calls the base implementation
+        (to raise a ``TypeError``).
+
+        For example, to support arbitrary iterators, you could
+        implement default like this::
+
+            def default(self, o):
+                try:
+                    iterable = iter(o)
+                except TypeError:
+                    pass
+                else:
+                    return list(iterable)
+                return JSONEncoder.default(self, o)
+
+        """
+        raise TypeError(repr(o) + " is not JSON serializable")
+
+    def encode(self, o):
+        """Return a JSON string representation of a Python data structure.
+
+        >>> JSONEncoder().encode({"foo": ["bar", "baz"]})
+        '{"foo": ["bar", "baz"]}'
+
+        """
+        # This is for extremely simple cases and benchmarks.
+        if isinstance(o, basestring):
+            if isinstance(o, str):
+                _encoding = self.encoding
+                if (_encoding is not None
+                        and not (_encoding == 'utf-8')):
+                    o = o.decode(_encoding)
+            if self.ensure_ascii:
+                return encode_basestring_ascii(o)
+            else:
+                return encode_basestring(o)
+        # This doesn't pass the iterator directly to ''.join() because the
+        # exceptions aren't as detailed.  The list call should be roughly
+        # equivalent to the PySequence_Fast that ''.join() would do.
+        chunks = self.iterencode(o, _one_shot=True)
+        if not isinstance(chunks, (list, tuple)):
+            chunks = list(chunks)
+        return ''.join(chunks)
+
+    def iterencode(self, o, _one_shot=False):
+        """Encode the given object and yield each string
+        representation as available.
+
+        For example::
+
+            for chunk in JSONEncoder().iterencode(bigobject):
+                mysocket.write(chunk)
+
+        """
+        if self.check_circular:
+            markers = {}
+        else:
+            markers = None
+        if self.ensure_ascii:
+            _encoder = encode_basestring_ascii
+        else:
+            _encoder = encode_basestring
+        if self.encoding != 'utf-8':
+            def _encoder(o, _orig_encoder=_encoder, _encoding=self.encoding):
+                if isinstance(o, str):
+                    o = o.decode(_encoding)
+                return _orig_encoder(o)
+
+        def floatstr(o, allow_nan=self.allow_nan, _repr=FLOAT_REPR, _inf=INFINITY, _neginf=-INFINITY):
+            # Check for specials.  Note that this type of test is processor- and/or
+            # platform-specific, so do tests which don't depend on the internals.
+
+            if o != o:
+                text = 'NaN'
+            elif o == _inf:
+                text = 'Infinity'
+            elif o == _neginf:
+                text = '-Infinity'
+            else:
+                return _repr(o)
+
+            if not allow_nan:
+                raise ValueError(
+                    "Out of range float values are not JSON compliant: " +
+                    repr(o))
+
+            return text
+
+
+        if _one_shot and c_make_encoder is not None and not self.indent and not self.sort_keys:
+            _iterencode = c_make_encoder(
+                markers, self.default, _encoder, self.indent,
+                self.key_separator, self.item_separator, self.sort_keys,
+                self.skipkeys, self.allow_nan)
+        else:
+            _iterencode = _make_iterencode(
+                markers, self.default, _encoder, self.indent, floatstr,
+                self.key_separator, self.item_separator, self.sort_keys,
+                self.skipkeys, _one_shot)
+        return _iterencode(o, 0)
+
+def _make_iterencode(markers, _default, _encoder, _indent, _floatstr, _key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,
+        ## HACK: hand-optimized bytecode; turn globals into locals
+        False=False,
+        True=True,
+        ValueError=ValueError,
+        basestring=basestring,
+        dict=dict,
+        float=float,
+        id=id,
+        int=int,
+        isinstance=isinstance,
+        list=list,
+        long=long,
+        str=str,
+        tuple=tuple,
+    ):
+
+    def _iterencode_list(lst, _current_indent_level):
+        if not lst:
+            yield '[]'
+            return
+        if markers is not None:
+            markerid = id(lst)
+            if markerid in markers:
+                raise ValueError("Circular reference detected")
+            markers[markerid] = lst
+        buf = '['
+        if _indent is not None:
+            _current_indent_level += 1
+            newline_indent = '\n' + (' ' * (_indent * _current_indent_level))
+            separator = _item_separator + newline_indent
+            buf += newline_indent
+        else:
+            newline_indent = None
+            separator = _item_separator
+        first = True
+        for value in lst:
+            if first:
+                first = False
+            else:
+                buf = separator
+            if isinstance(value, basestring):
+                yield buf + _encoder(value)
+            elif value is None:
+                yield buf + 'null'
+            elif value is True:
+                yield buf + 'true'
+            elif value is False:
+                yield buf + 'false'
+            elif isinstance(value, (int, long)):
+                yield buf + str(value)
+            elif isinstance(value, float):
+                yield buf + _floatstr(value)
+            else:
+                yield buf
+                if isinstance(value, (list, tuple)):
+                    chunks = _iterencode_list(value, _current_indent_level)
+                elif isinstance(value, dict):
+                    chunks = _iterencode_dict(value, _current_indent_level)
+                else:
+                    chunks = _iterencode(value, _current_indent_level)
+                for chunk in chunks:
+                    yield chunk
+        if newline_indent is not None:
+            _current_indent_level -= 1
+            yield '\n' + (' ' * (_indent * _current_indent_level))
+        yield ']'
+        if markers is not None:
+            del markers[markerid]
+
+    def _iterencode_dict(dct, _current_indent_level):
+        if not dct:
+            yield '{}'
+            return
+        if markers is not None:
+            markerid = id(dct)
+            if markerid in markers:
+                raise ValueError("Circular reference detected")
+            markers[markerid] = dct
+        yield '{'
+        if _indent is not None:
+            _current_indent_level += 1
+            newline_indent = '\n' + (' ' * (_indent * _current_indent_level))
+            item_separator = _item_separator + newline_indent
+            yield newline_indent
+        else:
+            newline_indent = None
+            item_separator = _item_separator
+        first = True
+        if _sort_keys:
+            items = dct.items()
+            items.sort(key=lambda kv: kv[0])
+        else:
+            items = dct.iteritems()
+        for key, value in items:
+            if isinstance(key, basestring):
+                pass
+            # JavaScript is weakly typed for these, so it makes sense to
+            # also allow them.  Many encoders seem to do something like this.
+            elif isinstance(key, float):
+                key = _floatstr(key)
+            elif key is True:
+                key = 'true'
+            elif key is False:
+                key = 'false'
+            elif key is None:
+                key = 'null'
+            elif isinstance(key, (int, long)):
+                key = str(key)
+            elif _skipkeys:
+                continue
+            else:
+                raise TypeError("key " + repr(key) + " is not a string")
+            if first:
+                first = False
+            else:
+                yield item_separator
+            yield _encoder(key)
+            yield _key_separator
+            if isinstance(value, basestring):
+                yield _encoder(value)
+            elif value is None:
+                yield 'null'
+            elif value is True:
+                yield 'true'
+            elif value is False:
+                yield 'false'
+            elif isinstance(value, (int, long)):
+                yield str(value)
+            elif isinstance(value, float):
+                yield _floatstr(value)
+            else:
+                if isinstance(value, (list, tuple)):
+                    chunks = _iterencode_list(value, _current_indent_level)
+                elif isinstance(value, dict):
+                    chunks = _iterencode_dict(value, _current_indent_level)
+                else:
+                    chunks = _iterencode(value, _current_indent_level)
+                for chunk in chunks:
+                    yield chunk
+        if newline_indent is not None:
+            _current_indent_level -= 1
+            yield '\n' + (' ' * (_indent * _current_indent_level))
+        yield '}'
+        if markers is not None:
+            del markers[markerid]
+
+    def _iterencode(o, _current_indent_level):
+        if isinstance(o, basestring):
+            yield _encoder(o)
+        elif o is None:
+            yield 'null'
+        elif o is True:
+            yield 'true'
+        elif o is False:
+            yield 'false'
+        elif isinstance(o, (int, long)):
+            yield str(o)
+        elif isinstance(o, float):
+            yield _floatstr(o)
+        elif isinstance(o, (list, tuple)):
+            for chunk in _iterencode_list(o, _current_indent_level):
+                yield chunk
+        elif isinstance(o, dict):
+            for chunk in _iterencode_dict(o, _current_indent_level):
+                yield chunk
+        else:
+            if markers is not None:
+                markerid = id(o)
+                if markerid in markers:
+                    raise ValueError("Circular reference detected")
+                markers[markerid] = o
+            o = _default(o)
+            for chunk in _iterencode(o, _current_indent_level):
+                yield chunk
+            if markers is not None:
+                del markers[markerid]
+
+    return _iterencode

mitogen/ansible_mitogen/compat/simplejson/scanner.py

@@ -0,0 +1,65 @@
+"""JSON token scanner
+"""
+import re
+try:
+    from simplejson._speedups import make_scanner as c_make_scanner
+except ImportError:
+    c_make_scanner = None
+
+__all__ = ['make_scanner']
+
+NUMBER_RE = re.compile(
+    r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?',
+    (re.VERBOSE | re.MULTILINE | re.DOTALL))
+
+def py_make_scanner(context):
+    parse_object = context.parse_object
+    parse_array = context.parse_array
+    parse_string = context.parse_string
+    match_number = NUMBER_RE.match
+    encoding = context.encoding
+    strict = context.strict
+    parse_float = context.parse_float
+    parse_int = context.parse_int
+    parse_constant = context.parse_constant
+    object_hook = context.object_hook
+
+    def _scan_once(string, idx):
+        try:
+            nextchar = string[idx]
+        except IndexError:
+            raise StopIteration
+
+        if nextchar == '"':
+            return parse_string(string, idx + 1, encoding, strict)
+        elif nextchar == '{':
+            return parse_object((string, idx + 1), encoding, strict, _scan_once, object_hook)
+        elif nextchar == '[':
+            return parse_array((string, idx + 1), _scan_once)
+        elif nextchar == 'n' and string[idx:idx + 4] == 'null':
+            return None, idx + 4
+        elif nextchar == 't' and string[idx:idx + 4] == 'true':
+            return True, idx + 4
+        elif nextchar == 'f' and string[idx:idx + 5] == 'false':
+            return False, idx + 5
+
+        m = match_number(string, idx)
+        if m is not None:
+            integer, frac, exp = m.groups()
+            if frac or exp:
+                res = parse_float(integer + (frac or '') + (exp or ''))
+            else:
+                res = parse_int(integer)
+            return res, m.end()
+        elif nextchar == 'N' and string[idx:idx + 3] == 'NaN':
+            return parse_constant('NaN'), idx + 3
+        elif nextchar == 'I' and string[idx:idx + 8] == 'Infinity':
+            return parse_constant('Infinity'), idx + 8
+        elif nextchar == '-' and string[idx:idx + 9] == '-Infinity':
+            return parse_constant('-Infinity'), idx + 9
+        else:
+            raise StopIteration
+
+    return _scan_once
+
+make_scanner = c_make_scanner or py_make_scanner

mitogen/ansible_mitogen/loaders.py

@@ -0,0 +1,62 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+"""
+Stable names for PluginLoader instances across Ansible versions.
+"""
+
+from __future__ import absolute_import
+
+__all__ = [
+    'action_loader',
+    'connection_loader',
+    'module_loader',
+    'module_utils_loader',
+    'shell_loader',
+    'strategy_loader',
+]
+
+try:
+    from ansible.plugins.loader import action_loader
+    from ansible.plugins.loader import connection_loader
+    from ansible.plugins.loader import module_loader
+    from ansible.plugins.loader import module_utils_loader
+    from ansible.plugins.loader import shell_loader
+    from ansible.plugins.loader import strategy_loader
+except ImportError:  # Ansible <2.4
+    from ansible.plugins import action_loader
+    from ansible.plugins import connection_loader
+    from ansible.plugins import module_loader
+    from ansible.plugins import module_utils_loader
+    from ansible.plugins import shell_loader
+    from ansible.plugins import strategy_loader
+
+
+# These are original, unwrapped implementations
+action_loader__get = action_loader.get
+connection_loader__get = connection_loader.get

mitogen/ansible_mitogen/logging.py

@@ -0,0 +1,128 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import logging
+import os
+
+import mitogen.core
+import mitogen.utils
+
+try:
+    from __main__ import display
+except ImportError:
+    from ansible.utils.display import Display
+    display = Display()
+
+
+#: The process name set via :func:`set_process_name`.
+_process_name = None
+
+#: The PID of the process that last called :func:`set_process_name`, so its
+#: value can be ignored in unknown fork children.
+_process_pid = None
+
+
+def set_process_name(name):
+    """
+    Set a name to adorn log messages with.
+    """
+    global _process_name
+    _process_name = name
+
+    global _process_pid
+    _process_pid = os.getpid()
+
+
+class Handler(logging.Handler):
+    """
+    Use Mitogen's log format, but send the result to a Display method.
+    """
+    def __init__(self, normal_method):
+        logging.Handler.__init__(self)
+        self.formatter = mitogen.utils.log_get_formatter()
+        self.normal_method = normal_method
+
+    #: Set of target loggers that produce warnings and errors that spam the
+    #: console needlessly. Their log level is forced to INFO. A better strategy
+    #: may simply be to bury all target logs in DEBUG output, but not by
+    #: overriding their log level as done here.
+    NOISY_LOGGERS = frozenset([
+        'dnf',   # issue #272; warns when a package is already installed.
+        'boto',  # issue #541; normal boto retry logic can cause ERROR logs.
+    ])
+
+    def emit(self, record):
+        mitogen_name = getattr(record, 'mitogen_name', '')
+        if mitogen_name == 'stderr':
+            record.levelno = logging.ERROR
+        if mitogen_name in self.NOISY_LOGGERS and record.levelno >= logging.WARNING:
+            record.levelno = logging.DEBUG
+
+        if _process_pid == os.getpid():
+            process_name = _process_name
+        else:
+            process_name = '?'
+
+        s = '[%-4s %d] %s' % (process_name, os.getpid(), self.format(record))
+        if record.levelno >= logging.ERROR:
+            display.error(s, wrap_text=False)
+        elif record.levelno >= logging.WARNING:
+            display.warning(s, formatted=True)
+        else:
+            self.normal_method(s)
+
+
+def setup():
+    """
+    Install handlers for Mitogen loggers to redirect them into the Ansible
+    display framework. Ansible installs its own logging framework handlers when
+    C.DEFAULT_LOG_PATH is set, therefore disable propagation for our handlers.
+    """
+    l_mitogen = logging.getLogger('mitogen')
+    l_mitogen_io = logging.getLogger('mitogen.io')
+    l_ansible_mitogen = logging.getLogger('ansible_mitogen')
+    l_operon = logging.getLogger('operon')
+
+    for logger in l_mitogen, l_mitogen_io, l_ansible_mitogen, l_operon:
+        logger.handlers = [Handler(display.vvv)]
+        logger.propagate = False
+
+    if display.verbosity > 2:
+        l_ansible_mitogen.setLevel(logging.DEBUG)
+        l_mitogen.setLevel(logging.DEBUG)
+    else:
+        # Mitogen copies the active log level into new children, allowing them
+        # to filter tiny messages before they hit the network, and therefore
+        # before they wake the IO loop. Explicitly setting INFO saves ~4%
+        # running against just the local machine.
+        l_mitogen.setLevel(logging.ERROR)
+        l_ansible_mitogen.setLevel(logging.ERROR)
+
+    if display.verbosity > 3:
+        l_mitogen_io.setLevel(logging.DEBUG)

mitogen/ansible_mitogen/mixins.py

@@ -0,0 +1,428 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import logging
+import os
+import pwd
+import random
+import traceback
+
+try:
+    from shlex import quote as shlex_quote
+except ImportError:
+    from pipes import quote as shlex_quote
+
+from ansible.module_utils._text import to_bytes
+from ansible.parsing.utils.jsonify import jsonify
+
+import ansible
+import ansible.constants
+import ansible.plugins
+import ansible.plugins.action
+
+import mitogen.core
+import mitogen.select
+import mitogen.utils
+
+import ansible_mitogen.connection
+import ansible_mitogen.planner
+import ansible_mitogen.target
+from ansible.module_utils._text import to_text
+
+try:
+    from ansible.utils.unsafe_proxy import wrap_var
+except ImportError:
+    from ansible.vars.unsafe_proxy import wrap_var
+
+
+LOG = logging.getLogger(__name__)
+
+
+class ActionModuleMixin(ansible.plugins.action.ActionBase):
+    """
+    The Mitogen-patched PluginLoader dynamically mixes this into every action
+    class that Ansible attempts to load. It exists to override all the
+    assumptions built into the base action class that should really belong in
+    some middle layer, or at least in the connection layer.
+
+    Functionality is defined here for:
+
+    * Capturing the final set of task variables and giving Connection a chance
+      to update its idea of the correct execution environment, before any
+      attempt is made to call a Connection method. While it's not expected for
+      the interpreter to change on a per-task basis, Ansible permits this, and
+      so it must be supported.
+
+    * Overriding lots of methods that try to call out to shell for mundane
+      reasons, such as copying files around, changing file permissions,
+      creating temporary directories and suchlike.
+
+    * Short-circuiting any use of Ansiballz or related code for executing a
+      module remotely using shell commands and SSH.
+
+    * Short-circuiting most of the logic in dealing with the fact that Ansible
+      always runs become: tasks across at least the SSH user account and the
+      destination user account, and handling the security permission issues
+      that crop up due to this. Mitogen always runs a task completely within
+      the target user account, so it's not a problem for us.
+    """
+    def __init__(self, task, connection, *args, **kwargs):
+        """
+        Verify the received connection is really a Mitogen connection. If not,
+        transmute this instance back into the original unadorned base class.
+
+        This allows running the Mitogen strategy in mixed-target playbooks,
+        where some targets use SSH while others use WinRM or some fancier UNIX
+        connection plug-in. That's because when the Mitogen strategy is active,
+        ActionModuleMixin is unconditionally mixed into any action module that
+        is instantiated, and there is no direct way for the monkey-patch to
+        know what kind of connection will be used upfront.
+        """
+        super(ActionModuleMixin, self).__init__(task, connection, *args, **kwargs)
+        if not isinstance(connection, ansible_mitogen.connection.Connection):
+            _, self.__class__ = type(self).__bases__
+
+    def run(self, tmp=None, task_vars=None):
+        """
+        Override run() to notify Connection of task-specific data, so it has a
+        chance to know e.g. the Python interpreter in use.
+        """
+        self._connection.on_action_run(
+            task_vars=task_vars,
+            delegate_to_hostname=self._task.delegate_to,
+            loader_basedir=self._loader.get_basedir(),
+        )
+        return super(ActionModuleMixin, self).run(tmp, task_vars)
+
+    COMMAND_RESULT = {
+        'rc': 0,
+        'stdout': '',
+        'stdout_lines': [],
+        'stderr': ''
+    }
+
+    def fake_shell(self, func, stdout=False):
+        """
+        Execute a function and decorate its return value in the style of
+        _low_level_execute_command(). This produces a return value that looks
+        like some shell command was run, when really func() was implemented
+        entirely in Python.
+
+        If the function raises :py:class:`mitogen.core.CallError`, this will be
+        translated into a failed shell command with a non-zero exit status.
+
+        :param func:
+            Function invoked as `func()`.
+        :returns:
+            See :py:attr:`COMMAND_RESULT`.
+        """
+        dct = self.COMMAND_RESULT.copy()
+        try:
+            rc = func()
+            if stdout:
+                dct['stdout'] = repr(rc)
+        except mitogen.core.CallError:
+            LOG.exception('While emulating a shell command')
+            dct['rc'] = 1
+            dct['stderr'] = traceback.format_exc()
+
+        return dct
+
+    def _remote_file_exists(self, path):
+        """
+        Determine if `path` exists by directly invoking os.path.exists() in the
+        target user account.
+        """
+        LOG.debug('_remote_file_exists(%r)', path)
+        return self._connection.get_chain().call(
+            ansible_mitogen.target.file_exists,
+            mitogen.utils.cast(path)
+        )
+
+    def _configure_module(self, module_name, module_args, task_vars=None):
+        """
+        Mitogen does not use the Ansiballz framework. This call should never
+        happen when ActionMixin is active, so crash if it does.
+        """
+        assert False, "_configure_module() should never be called."
+
+    def _is_pipelining_enabled(self, module_style, wrap_async=False):
+        """
+        Mitogen does not use SSH pipelining. This call should never happen when
+        ActionMixin is active, so crash if it does.
+        """
+        assert False, "_is_pipelining_enabled() should never be called."
+
+    def _generate_tmp_path(self):
+        return os.path.join(
+            self._connection.get_good_temp_dir(),
+            'ansible_mitogen_action_%016x' % (
+                random.getrandbits(8*8),
+            )
+        )
+
+    def _make_tmp_path(self, remote_user=None):
+        """
+        Create a temporary subdirectory as a child of the temporary directory
+        managed by the remote interpreter.
+        """
+        LOG.debug('_make_tmp_path(remote_user=%r)', remote_user)
+        path = self._generate_tmp_path()
+        LOG.debug('Temporary directory: %r', path)
+        self._connection.get_chain().call_no_reply(os.mkdir, path)
+        self._connection._shell.tmpdir = path
+        return path
+
+    def _remove_tmp_path(self, tmp_path):
+        """
+        Replace the base implementation's invocation of rm -rf, replacing it
+        with a pipelined call to :func:`ansible_mitogen.target.prune_tree`.
+        """
+        LOG.debug('_remove_tmp_path(%r)', tmp_path)
+        if tmp_path is None and ansible.__version__ > '2.6':
+            tmp_path = self._connection._shell.tmpdir  # 06f73ad578d
+        if tmp_path is not None:
+            self._connection.get_chain().call_no_reply(
+                ansible_mitogen.target.prune_tree,
+                tmp_path,
+            )
+        self._connection._shell.tmpdir = None
+
+    def _transfer_data(self, remote_path, data):
+        """
+        Used by the base _execute_module(), and in <2.4 also by the template
+        action module, and probably others.
+        """
+        if isinstance(data, dict):
+            data = jsonify(data)
+        if not isinstance(data, bytes):
+            data = to_bytes(data, errors='surrogate_or_strict')
+
+        LOG.debug('_transfer_data(%r, %s ..%d bytes)',
+                  remote_path, type(data), len(data))
+        self._connection.put_data(remote_path, data)
+        return remote_path
+
+    #: Actions listed here cause :func:`_fixup_perms2` to avoid a needless
+    #: roundtrip, as they modify file modes separately afterwards. This is due
+    #: to the method prototype having a default of `execute=True`.
+    FIXUP_PERMS_RED_HERRING = set(['copy'])
+
+    def _fixup_perms2(self, remote_paths, remote_user=None, execute=True):
+        """
+        Mitogen always executes ActionBase helper methods in the context of the
+        target user account, so it is never necessary to modify permissions
+        except to ensure the execute bit is set if requested.
+        """
+        LOG.debug('_fixup_perms2(%r, remote_user=%r, execute=%r)',
+                  remote_paths, remote_user, execute)
+        if execute and self._task.action not in self.FIXUP_PERMS_RED_HERRING:
+            return self._remote_chmod(remote_paths, mode='u+x')
+        return self.COMMAND_RESULT.copy()
+
+    def _remote_chmod(self, paths, mode, sudoable=False):
+        """
+        Issue an asynchronous set_file_mode() call for every path in `paths`,
+        then format the resulting return value list with fake_shell().
+        """
+        LOG.debug('_remote_chmod(%r, mode=%r, sudoable=%r)',
+                  paths, mode, sudoable)
+        return self.fake_shell(lambda: mitogen.select.Select.all(
+            self._connection.get_chain().call_async(
+                ansible_mitogen.target.set_file_mode, path, mode
+            )
+            for path in paths
+        ))
+
+    def _remote_chown(self, paths, user, sudoable=False):
+        """
+        Issue an asynchronous os.chown() call for every path in `paths`, then
+        format the resulting return value list with fake_shell().
+        """
+        LOG.debug('_remote_chown(%r, user=%r, sudoable=%r)',
+                  paths, user, sudoable)
+        ent = self._connection.get_chain().call(pwd.getpwnam, user)
+        return self.fake_shell(lambda: mitogen.select.Select.all(
+            self._connection.get_chain().call_async(
+                os.chown, path, ent.pw_uid, ent.pw_gid
+            )
+            for path in paths
+        ))
+
+    def _remote_expand_user(self, path, sudoable=True):
+        """
+        Replace the base implementation's attempt to emulate
+        os.path.expanduser() with an actual call to os.path.expanduser().
+
+        :param bool sudoable:
+            If :data:`True`, indicate unqualified tilde ("~" with no username)
+            should be evaluated in the context of the login account, not any
+            become_user.
+        """
+        LOG.debug('_remote_expand_user(%r, sudoable=%r)', path, sudoable)
+        if not path.startswith('~'):
+            # /home/foo -> /home/foo
+            return path
+        if sudoable or not self._play_context.become:
+            if path == '~':
+                # ~ -> /home/dmw
+                return self._connection.homedir
+            if path.startswith('~/'):
+                # ~/.ansible -> /home/dmw/.ansible
+                return os.path.join(self._connection.homedir, path[2:])
+        # ~root/.ansible -> /root/.ansible
+        return self._connection.get_chain(use_login=(not sudoable)).call(
+            os.path.expanduser,
+            mitogen.utils.cast(path),
+        )
+
+    def get_task_timeout_secs(self):
+        """
+        Return the task "async:" value, portable across 2.4-2.5.
+        """
+        try:
+            return self._task.async_val
+        except AttributeError:
+            return getattr(self._task, 'async')
+
+    def _set_temp_file_args(self, module_args, wrap_async):
+        # Ansible>2.5 module_utils reuses the action's temporary directory if
+        # one exists. Older versions error if this key is present.
+        if ansible.__version__ > '2.5':
+            if wrap_async:
+                # Sharing is not possible with async tasks, as in that case,
+                # the directory must outlive the action plug-in.
+                module_args['_ansible_tmpdir'] = None
+            else:
+                module_args['_ansible_tmpdir'] = self._connection._shell.tmpdir
+
+        # If _ansible_tmpdir is unset, Ansible>2.6 module_utils will use
+        # _ansible_remote_tmp as the location to create the module's temporary
+        # directory. Older versions error if this key is present.
+        if ansible.__version__ > '2.6':
+            module_args['_ansible_remote_tmp'] = (
+                self._connection.get_good_temp_dir()
+            )
+
+    def _execute_module(self, module_name=None, module_args=None, tmp=None,
+                        task_vars=None, persist_files=False,
+                        delete_remote_tmp=True, wrap_async=False):
+        """
+        Collect up a module's execution environment then use it to invoke
+        target.run_module() or helpers.run_module_async() in the target
+        context.
+        """
+        if module_name is None:
+            module_name = self._task.action
+        if module_args is None:
+            module_args = self._task.args
+        if task_vars is None:
+            task_vars = {}
+
+        self._update_module_args(module_name, module_args, task_vars)
+        env = {}
+        self._compute_environment_string(env)
+        self._set_temp_file_args(module_args, wrap_async)
+
+        self._connection._connect()
+        result = ansible_mitogen.planner.invoke(
+            ansible_mitogen.planner.Invocation(
+                action=self,
+                connection=self._connection,
+                module_name=mitogen.core.to_text(module_name),
+                module_args=mitogen.utils.cast(module_args),
+                task_vars=task_vars,
+                templar=self._templar,
+                env=mitogen.utils.cast(env),
+                wrap_async=wrap_async,
+                timeout_secs=self.get_task_timeout_secs(),
+            )
+        )
+
+        if tmp and ansible.__version__ < '2.5' and delete_remote_tmp:
+            # Built-in actions expected tmpdir to be cleaned up automatically
+            # on _execute_module().
+            self._remove_tmp_path(tmp)
+
+        return wrap_var(result)
+
+    def _postprocess_response(self, result):
+        """
+        Apply fixups mimicking ActionBase._execute_module(); this is copied
+        verbatim from action/__init__.py, the guts of _parse_returned_data are
+        garbage and should be removed or reimplemented once tests exist.
+
+        :param dict result:
+            Dictionary with format::
+
+                {
+                    "rc": int,
+                    "stdout": "stdout data",
+                    "stderr": "stderr data"
+                }
+        """
+        data = self._parse_returned_data(result)
+
+        # Cutpasted from the base implementation.
+        if 'stdout' in data and 'stdout_lines' not in data:
+            data['stdout_lines'] = (data['stdout'] or u'').splitlines()
+        if 'stderr' in data and 'stderr_lines' not in data:
+            data['stderr_lines'] = (data['stderr'] or u'').splitlines()
+
+        return data
+
+    def _low_level_execute_command(self, cmd, sudoable=True, in_data=None,
+                                   executable=None,
+                                   encoding_errors='surrogate_then_replace',
+                                   chdir=None):
+        """
+        Override the base implementation by simply calling
+        target.exec_command() in the target context.
+        """
+        LOG.debug('_low_level_execute_command(%r, in_data=%r, exe=%r, dir=%r)',
+                  cmd, type(in_data), executable, chdir)
+        if executable is None:  # executable defaults to False
+            executable = self._play_context.executable
+        if executable:
+            cmd = executable + ' -c ' + shlex_quote(cmd)
+
+        rc, stdout, stderr = self._connection.exec_command(
+            cmd=cmd,
+            in_data=in_data,
+            sudoable=sudoable,
+            mitogen_chdir=chdir,
+        )
+        stdout_text = to_text(stdout, errors=encoding_errors)
+
+        return {
+            'rc': rc,
+            'stdout': stdout_text,
+            'stdout_lines': stdout_text.splitlines(),
+            'stderr': stderr,
+        }

mitogen/ansible_mitogen/module_finder.py

@@ -0,0 +1,157 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import collections
+import imp
+import os
+
+import mitogen.master
+
+
+PREFIX = 'ansible.module_utils.'
+
+
+Module = collections.namedtuple('Module', 'name path kind parent')
+
+
+def get_fullname(module):
+    """
+    Reconstruct a Module's canonical path by recursing through its parents.
+    """
+    bits = [str(module.name)]
+    while module.parent:
+        bits.append(str(module.parent.name))
+        module = module.parent
+    return '.'.join(reversed(bits))
+
+
+def get_code(module):
+    """
+    Compile and return a Module's code object.
+    """
+    fp = open(module.path, 'rb')
+    try:
+        return compile(fp.read(), str(module.name), 'exec')
+    finally:
+        fp.close()
+
+
+def is_pkg(module):
+    """
+    Return :data:`True` if a Module represents a package.
+    """
+    return module.kind == imp.PKG_DIRECTORY
+
+
+def find(name, path=(), parent=None):
+    """
+    Return a Module instance describing the first matching module found on the
+    search path.
+
+    :param str name:
+        Module name.
+    :param list path:
+        List of directory names to search for the module.
+    :param Module parent:
+        Optional module parent.
+    """
+    assert isinstance(path, tuple)
+    head, _, tail = name.partition('.')
+    try:
+        tup = imp.find_module(head, list(path))
+    except ImportError:
+        return parent
+
+    fp, modpath, (suffix, mode, kind) = tup
+    if fp:
+        fp.close()
+
+    if parent and modpath == parent.path:
+        # 'from timeout import timeout', where 'timeout' is a function but also
+        # the name of the module being imported.
+        return None
+
+    if kind == imp.PKG_DIRECTORY:
+        modpath = os.path.join(modpath, '__init__.py')
+
+    module = Module(head, modpath, kind, parent)
+    # TODO: this code is entirely wrong on Python 3.x, but works well enough
+    # for Ansible. We need a new find_child() that only looks in the package
+    # directory, never falling back to the parent search path.
+    if tail and kind == imp.PKG_DIRECTORY:
+        return find_relative(module, tail, path)
+    return module
+
+
+def find_relative(parent, name, path=()):
+    if parent.kind == imp.PKG_DIRECTORY:
+        path = (os.path.dirname(parent.path),) + path
+    return find(name, path, parent=parent)
+
+
+def scan_fromlist(code):
+    for level, modname_s, fromlist in mitogen.master.scan_code_imports(code):
+        for name in fromlist:
+            yield level, '%s.%s' % (modname_s, name)
+        if not fromlist:
+            yield level, modname_s
+
+
+def scan(module_name, module_path, search_path):
+    module = Module(module_name, module_path, imp.PY_SOURCE, None)
+    stack = [module]
+    seen = set()
+
+    while stack:
+        module = stack.pop(0)
+        for level, fromname in scan_fromlist(get_code(module)):
+            if not fromname.startswith(PREFIX):
+                continue
+
+            imported = find(fromname[len(PREFIX):], search_path)
+            if imported is None or imported in seen:
+                continue
+
+            seen.add(imported)
+            stack.append(imported)
+            parent = imported.parent
+            while parent:
+                fullname = get_fullname(parent)
+                module = Module(fullname, parent.path, parent.kind, None)
+                if module not in seen:
+                    seen.add(module)
+                    stack.append(module)
+                parent = parent.parent
+
+    return sorted(
+        (PREFIX + get_fullname(module), module.path, is_pkg(module))
+        for module in seen
+    )

mitogen/ansible_mitogen/parsing.py

@@ -0,0 +1,76 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import mitogen.core
+
+
+def parse_script_interpreter(source):
+    """
+    Parse the script interpreter portion of a UNIX hashbang using the rules
+    Linux uses.
+
+    :param str source: String like "/usr/bin/env python".
+
+    :returns:
+        Tuple of `(interpreter, arg)`, where `intepreter` is the script
+        interpreter and `arg` is its sole argument if present, otherwise
+        :py:data:`None`.
+    """
+    # Find terminating newline. Assume last byte of binprm_buf if absent.
+    nl = source.find(b'\n', 0, 128)
+    if nl == -1:
+        nl = min(128, len(source))
+
+    # Split once on the first run of whitespace. If no whitespace exists,
+    # bits just contains the interpreter filename.
+    bits = source[0:nl].strip().split(None, 1)
+    if len(bits) == 1:
+        return mitogen.core.to_text(bits[0]), None
+    return mitogen.core.to_text(bits[0]), mitogen.core.to_text(bits[1])
+
+
+def parse_hashbang(source):
+    """
+    Parse a UNIX "hashbang line" using the syntax supported by Linux.
+
+    :param str source: String like "#!/usr/bin/env python".
+
+    :returns:
+        Tuple of `(interpreter, arg)`, where `intepreter` is the script
+        interpreter and `arg` is its sole argument if present, otherwise
+        :py:data:`None`.
+    """
+    # Linux requires first 2 bytes with no whitespace, pretty sure it's the
+    # same everywhere. See binfmt_script.c.
+    if not source.startswith(b'#!'):
+        return None, None
+
+    return parse_script_interpreter(source[2:])

mitogen/ansible_mitogen/planner.py

@@ -0,0 +1,576 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+"""
+Classes to detect each case from [0] and prepare arguments necessary for the
+corresponding Runner class within the target, including preloading requisite
+files/modules known missing.
+
+[0] "Ansible Module Architecture", developing_program_flow_modules.html
+"""
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import json
+import logging
+import os
+import random
+
+from ansible.executor import module_common
+import ansible.errors
+import ansible.module_utils
+import ansible.release
+import mitogen.core
+import mitogen.select
+
+import ansible_mitogen.loaders
+import ansible_mitogen.parsing
+import ansible_mitogen.target
+
+
+LOG = logging.getLogger(__name__)
+NO_METHOD_MSG = 'Mitogen: no invocation method found for: '
+NO_INTERPRETER_MSG = 'module (%s) is missing interpreter line'
+NO_MODULE_MSG = 'The module %s was not found in configured module paths.'
+
+_planner_by_path = {}
+
+
+class Invocation(object):
+    """
+    Collect up a module's execution environment then use it to invoke
+    target.run_module() or helpers.run_module_async() in the target context.
+    """
+    def __init__(self, action, connection, module_name, module_args,
+                 task_vars, templar, env, wrap_async, timeout_secs):
+        #: ActionBase instance invoking the module. Required to access some
+        #: output postprocessing methods that don't belong in ActionBase at
+        #: all.
+        self.action = action
+        #: Ansible connection to use to contact the target. Must be an
+        #: ansible_mitogen connection.
+        self.connection = connection
+        #: Name of the module ('command', 'shell', etc.) to execute.
+        self.module_name = module_name
+        #: Final module arguments.
+        self.module_args = module_args
+        #: Task variables, needed to extract ansible_*_interpreter.
+        self.task_vars = task_vars
+        #: Templar, needed to extract ansible_*_interpreter.
+        self.templar = templar
+        #: Final module environment.
+        self.env = env
+        #: Boolean, if :py:data:`True`, launch the module asynchronously.
+        self.wrap_async = wrap_async
+        #: Integer, if >0, limit the time an asynchronous job may run for.
+        self.timeout_secs = timeout_secs
+        #: Initially ``None``, but set by :func:`invoke`. The path on the
+        #: master to the module's implementation file.
+        self.module_path = None
+        #: Initially ``None``, but set by :func:`invoke`. The raw source or
+        #: binary contents of the module.
+        self._module_source = None
+
+    def get_module_source(self):
+        if self._module_source is None:
+            self._module_source = read_file(self.module_path)
+        return self._module_source
+
+    def __repr__(self):
+        return 'Invocation(module_name=%s)' % (self.module_name,)
+
+
+class Planner(object):
+    """
+    A Planner receives a module name and the contents of its implementation
+    file, indicates whether or not it understands how to run the module, and
+    exports a method to run the module.
+    """
+    def __init__(self, invocation):
+        self._inv = invocation
+
+    @classmethod
+    def detect(cls, path, source):
+        """
+        Return true if the supplied `invocation` matches the module type
+        implemented by this planner.
+        """
+        raise NotImplementedError()
+
+    def should_fork(self):
+        """
+        Asynchronous tasks must always be forked.
+        """
+        return self._inv.wrap_async
+
+    def get_push_files(self):
+        """
+        Return a list of files that should be propagated to the target context
+        using PushFileService. The default implementation pushes nothing.
+        """
+        return []
+
+    def get_module_deps(self):
+        """
+        Return a list of the Python module names imported by the module.
+        """
+        return []
+
+    def get_kwargs(self, **kwargs):
+        """
+        If :meth:`detect` returned :data:`True`, plan for the module's
+        execution, including granting access to or delivering any files to it
+        that are known to be absent, and finally return a dict::
+
+            {
+                # Name of the class from runners.py that implements the
+                # target-side execution of this module type.
+                "runner_name": "...",
+
+                # Remaining keys are passed to the constructor of the class
+                # named by `runner_name`.
+            }
+        """
+        binding = self._inv.connection.get_binding()
+
+        new = dict((mitogen.core.UnicodeType(k), kwargs[k])
+                   for k in kwargs)
+        new.setdefault('good_temp_dir',
+            self._inv.connection.get_good_temp_dir())
+        new.setdefault('cwd', self._inv.connection.get_default_cwd())
+        new.setdefault('extra_env', self._inv.connection.get_default_env())
+        new.setdefault('emulate_tty', True)
+        new.setdefault('service_context', binding.get_child_service_context())
+        return new
+
+    def __repr__(self):
+        return '%s()' % (type(self).__name__,)
+
+
+class BinaryPlanner(Planner):
+    """
+    Binary modules take their arguments and will return data to Ansible in the
+    same way as want JSON modules.
+    """
+    runner_name = 'BinaryRunner'
+
+    @classmethod
+    def detect(cls, path, source):
+        return module_common._is_binary(source)
+
+    def get_push_files(self):
+        return [mitogen.core.to_text(self._inv.module_path)]
+
+    def get_kwargs(self, **kwargs):
+        return super(BinaryPlanner, self).get_kwargs(
+            runner_name=self.runner_name,
+            module=self._inv.module_name,
+            path=self._inv.module_path,
+            json_args=json.dumps(self._inv.module_args),
+            env=self._inv.env,
+            **kwargs
+        )
+
+
+class ScriptPlanner(BinaryPlanner):
+    """
+    Common functionality for script module planners -- handle interpreter
+    detection and rewrite.
+    """
+    def _rewrite_interpreter(self, path):
+        """
+        Given the original interpreter binary extracted from the script's
+        interpreter line, look up the associated `ansible_*_interpreter`
+        variable, render it and return it.
+
+        :param str path:
+            Absolute UNIX path to original interpreter.
+
+        :returns:
+            Shell fragment prefix used to execute the script via "/bin/sh -c".
+            While `ansible_*_interpreter` documentation suggests shell isn't
+            involved here, the vanilla implementation uses it and that use is
+            exploited in common playbooks.
+        """
+        key = u'ansible_%s_interpreter' % os.path.basename(path).strip()
+        try:
+            template = self._inv.task_vars[key]
+        except KeyError:
+            return path
+
+        return mitogen.utils.cast(self._inv.templar.template(template))
+
+    def _get_interpreter(self):
+        path, arg = ansible_mitogen.parsing.parse_hashbang(
+            self._inv.get_module_source()
+        )
+        if path is None:
+            raise ansible.errors.AnsibleError(NO_INTERPRETER_MSG % (
+                self._inv.module_name,
+            ))
+
+        fragment = self._rewrite_interpreter(path)
+        if arg:
+            fragment += ' ' + arg
+
+        return fragment, path.startswith('python')
+
+    def get_kwargs(self, **kwargs):
+        interpreter_fragment, is_python = self._get_interpreter()
+        return super(ScriptPlanner, self).get_kwargs(
+            interpreter_fragment=interpreter_fragment,
+            is_python=is_python,
+            **kwargs
+        )
+
+
+class JsonArgsPlanner(ScriptPlanner):
+    """
+    Script that has its interpreter directive and the task arguments
+    substituted into its source as a JSON string.
+    """
+    runner_name = 'JsonArgsRunner'
+
+    @classmethod
+    def detect(cls, path, source):
+        return module_common.REPLACER_JSONARGS in source
+
+
+class WantJsonPlanner(ScriptPlanner):
+    """
+    If a module has the string WANT_JSON in it anywhere, Ansible treats it as a
+    non-native module that accepts a filename as its only command line
+    parameter. The filename is for a temporary file containing a JSON string
+    containing the module's parameters. The module needs to open the file, read
+    and parse the parameters, operate on the data, and print its return data as
+    a JSON encoded dictionary to stdout before exiting.
+
+    These types of modules are self-contained entities. As of Ansible 2.1,
+    Ansible only modifies them to change a shebang line if present.
+    """
+    runner_name = 'WantJsonRunner'
+
+    @classmethod
+    def detect(cls, path, source):
+        return b'WANT_JSON' in source
+
+
+class NewStylePlanner(ScriptPlanner):
+    """
+    The Ansiballz framework differs from module replacer in that it uses real
+    Python imports of things in ansible/module_utils instead of merely
+    preprocessing the module.
+    """
+    runner_name = 'NewStyleRunner'
+    marker = b'from ansible.module_utils.'
+
+    @classmethod
+    def detect(cls, path, source):
+        return cls.marker in source
+
+    def _get_interpreter(self):
+        return None, None
+
+    def get_push_files(self):
+        return super(NewStylePlanner, self).get_push_files() + [
+            mitogen.core.to_text(path)
+            for fullname, path, is_pkg in self.get_module_map()['custom']
+        ]
+
+    def get_module_deps(self):
+        return self.get_module_map()['builtin']
+
+    #: Module names appearing in this set always require forking, usually due
+    #: to some terminal leakage that cannot be worked around in any sane
+    #: manner.
+    ALWAYS_FORK_MODULES = frozenset([
+        'dnf',  # issue #280; py-dnf/hawkey need therapy
+        'firewalld',  # issue #570: ansible module_utils caches dbus conn
+    ])
+
+    def should_fork(self):
+        """
+        In addition to asynchronous tasks, new-style modules should be forked
+        if:
+
+        * the user specifies mitogen_task_isolation=fork, or
+        * the new-style module has a custom module search path, or
+        * the module is known to leak like a sieve.
+        """
+        return (
+            super(NewStylePlanner, self).should_fork() or
+            (self._inv.task_vars.get('mitogen_task_isolation') == 'fork') or
+            (self._inv.module_name in self.ALWAYS_FORK_MODULES) or
+            (len(self.get_module_map()['custom']) > 0)
+        )
+
+    def get_search_path(self):
+        return tuple(
+            path
+            for path in ansible_mitogen.loaders.module_utils_loader._get_paths(
+                subdirs=False
+            )
+        )
+
+    _module_map = None
+
+    def get_module_map(self):
+        if self._module_map is None:
+            binding = self._inv.connection.get_binding()
+            self._module_map = mitogen.service.call(
+                call_context=binding.get_service_context(),
+                service_name='ansible_mitogen.services.ModuleDepService',
+                method_name='scan',
+
+                module_name='ansible_module_%s' % (self._inv.module_name,),
+                module_path=self._inv.module_path,
+                search_path=self.get_search_path(),
+                builtin_path=module_common._MODULE_UTILS_PATH,
+                context=self._inv.connection.context,
+            )
+        return self._module_map
+
+    def get_kwargs(self):
+        return super(NewStylePlanner, self).get_kwargs(
+            module_map=self.get_module_map(),
+            py_module_name=py_modname_from_path(
+                self._inv.module_name,
+                self._inv.module_path,
+            ),
+        )
+
+
+class ReplacerPlanner(NewStylePlanner):
+    """
+    The Module Replacer framework is the original framework implementing
+    new-style modules. It is essentially a preprocessor (like the C
+    Preprocessor for those familiar with that programming language). It does
+    straight substitutions of specific substring patterns in the module file.
+    There are two types of substitutions.
+
+    * Replacements that only happen in the module file. These are public
+      replacement strings that modules can utilize to get helpful boilerplate
+      or access to arguments.
+
+      "from ansible.module_utils.MOD_LIB_NAME import *" is replaced with the
+      contents of the ansible/module_utils/MOD_LIB_NAME.py. These should only
+      be used with new-style Python modules.
+
+      "#<<INCLUDE_ANSIBLE_MODULE_COMMON>>" is equivalent to
+      "from ansible.module_utils.basic import *" and should also only apply to
+      new-style Python modules.
+
+      "# POWERSHELL_COMMON" substitutes the contents of
+      "ansible/module_utils/powershell.ps1". It should only be used with
+      new-style Powershell modules.
+    """
+    runner_name = 'ReplacerRunner'
+
+    @classmethod
+    def detect(cls, path, source):
+        return module_common.REPLACER in source
+
+
+class OldStylePlanner(ScriptPlanner):
+    runner_name = 'OldStyleRunner'
+
+    @classmethod
+    def detect(cls, path, source):
+        # Everything else.
+        return True
+
+
+_planners = [
+    BinaryPlanner,
+    # ReplacerPlanner,
+    NewStylePlanner,
+    JsonArgsPlanner,
+    WantJsonPlanner,
+    OldStylePlanner,
+]
+
+
+try:
+    _get_ansible_module_fqn = module_common._get_ansible_module_fqn
+except AttributeError:
+    _get_ansible_module_fqn = None
+
+
+def py_modname_from_path(name, path):
+    """
+    Fetch the logical name of a new-style module as it might appear in
+    :data:`sys.modules` of the target's Python interpreter.
+
+    * For Ansible <2.7, this is an unpackaged module named like
+      "ansible_module_%s".
+
+    * For Ansible <2.9, this is an unpackaged module named like
+      "ansible.modules.%s"
+
+    * Since Ansible 2.9, modules appearing within a package have the original
+      package hierarchy approximated on the target, enabling relative imports
+      to function correctly. For example, "ansible.modules.system.setup".
+    """
+    # 2.9+
+    if _get_ansible_module_fqn:
+        try:
+            return _get_ansible_module_fqn(path)
+        except ValueError:
+            pass
+
+    if ansible.__version__ < '2.7':
+        return 'ansible_module_' + name
+
+    return 'ansible.modules.' + name
+
+
+def read_file(path):
+    fd = os.open(path, os.O_RDONLY)
+    try:
+        bits = []
+        chunk = True
+        while True:
+            chunk = os.read(fd, 65536)
+            if not chunk:
+                break
+            bits.append(chunk)
+    finally:
+        os.close(fd)
+
+    return mitogen.core.b('').join(bits)
+
+
+def _propagate_deps(invocation, planner, context):
+    binding = invocation.connection.get_binding()
+    mitogen.service.call(
+        call_context=binding.get_service_context(),
+        service_name='mitogen.service.PushFileService',
+        method_name='propagate_paths_and_modules',
+
+        context=context,
+        paths=planner.get_push_files(),
+        modules=planner.get_module_deps(),
+    )
+
+
+def _invoke_async_task(invocation, planner):
+    job_id = '%016x' % random.randint(0, 2**64)
+    context = invocation.connection.spawn_isolated_child()
+    _propagate_deps(invocation, planner, context)
+
+    with mitogen.core.Receiver(context.router) as started_recv:
+        call_recv = context.call_async(
+            ansible_mitogen.target.run_module_async,
+            job_id=job_id,
+            timeout_secs=invocation.timeout_secs,
+            started_sender=started_recv.to_sender(),
+            kwargs=planner.get_kwargs(),
+        )
+
+        # Wait for run_module_async() to crash, or for AsyncRunner to indicate
+        # the job file has been written.
+        for msg in mitogen.select.Select([started_recv, call_recv]):
+            if msg.receiver is call_recv:
+                # It can only be an exception.
+                raise msg.unpickle()
+            break
+
+        return {
+            'stdout': json.dumps({
+                # modules/utilities/logic/async_wrapper.py::_run_module().
+                'changed': True,
+                'started': 1,
+                'finished': 0,
+                'ansible_job_id': job_id,
+            })
+        }
+
+
+def _invoke_isolated_task(invocation, planner):
+    context = invocation.connection.spawn_isolated_child()
+    _propagate_deps(invocation, planner, context)
+    try:
+        return context.call(
+            ansible_mitogen.target.run_module,
+            kwargs=planner.get_kwargs(),
+        )
+    finally:
+        context.shutdown()
+
+
+def _get_planner(name, path, source):
+    for klass in _planners:
+        if klass.detect(path, source):
+            LOG.debug('%r accepted %r (filename %r)', klass, name, path)
+            return klass
+        LOG.debug('%r rejected %r', klass, name)
+    raise ansible.errors.AnsibleError(NO_METHOD_MSG + repr(invocation))
+
+
+def invoke(invocation):
+    """
+    Find a Planner subclass corresnding to `invocation` and use it to invoke
+    the module.
+
+    :param Invocation invocation:
+    :returns:
+        Module return dict.
+    :raises ansible.errors.AnsibleError:
+        Unrecognized/unsupported module type.
+    """
+    path = ansible_mitogen.loaders.module_loader.find_plugin(
+        invocation.module_name,
+        '',
+    )
+    if path is None:
+        raise ansible.errors.AnsibleError(NO_MODULE_MSG % (
+            invocation.module_name,
+        ))
+
+    invocation.module_path = mitogen.core.to_text(path)
+    if invocation.module_path not in _planner_by_path:
+        _planner_by_path[invocation.module_path] = _get_planner(
+            invocation.module_name,
+            invocation.module_path,
+            invocation.get_module_source()
+        )
+
+    planner = _planner_by_path[invocation.module_path](invocation)
+    if invocation.wrap_async:
+        response = _invoke_async_task(invocation, planner)
+    elif planner.should_fork():
+        response = _invoke_isolated_task(invocation, planner)
+    else:
+        _propagate_deps(invocation, planner, invocation.connection.context)
+        response = invocation.connection.get_chain().call(
+            ansible_mitogen.target.run_module,
+            kwargs=planner.get_kwargs(),
+        )
+
+    return invocation.action._postprocess_response(response)

mitogen/ansible_mitogen/plugins/action/mitogen_fetch.py

@@ -0,0 +1,162 @@
+# (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
+#
+# This file is part of Ansible
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+import os
+
+from ansible.module_utils._text import to_bytes
+from ansible.module_utils.six import string_types
+from ansible.module_utils.parsing.convert_bool import boolean
+from ansible.plugins.action import ActionBase
+from ansible.utils.hashing import checksum, md5, secure_hash
+from ansible.utils.path import makedirs_safe
+
+
+REMOTE_CHECKSUM_ERRORS = {
+    '0': "unable to calculate the checksum of the remote file",
+    '1': "the remote file does not exist",
+    '2': "no read permission on remote file",
+    '3': "remote file is a directory, fetch cannot work on directories",
+    '4': "python isn't present on the system.  Unable to compute checksum",
+    '5': "stdlib json was not found on the remote machine. Only the raw module can work without those installed",
+}
+
+
+class ActionModule(ActionBase):
+
+    def run(self, tmp=None, task_vars=None):
+        ''' handler for fetch operations '''
+        if task_vars is None:
+            task_vars = dict()
+
+        result = super(ActionModule, self).run(tmp, task_vars)
+        try:
+            if self._play_context.check_mode:
+                result['skipped'] = True
+                result['msg'] = 'check mode not (yet) supported for this module'
+                return result
+
+            flat = boolean(self._task.args.get('flat'), strict=False)
+            fail_on_missing = boolean(self._task.args.get('fail_on_missing', True), strict=False)
+            validate_checksum = boolean(self._task.args.get('validate_checksum', True), strict=False)
+
+            # validate source and dest are strings FIXME: use basic.py and module specs
+            source = self._task.args.get('src')
+            if not isinstance(source, string_types):
+                result['msg'] = "Invalid type supplied for source option, it must be a string"
+
+            dest = self._task.args.get('dest')
+            if not isinstance(dest, string_types):
+                result['msg'] = "Invalid type supplied for dest option, it must be a string"
+
+            if result.get('msg'):
+                result['failed'] = True
+                return result
+
+            source = self._connection._shell.join_path(source)
+            source = self._remote_expand_user(source)
+
+            # calculate checksum for the remote file, don't bother if using
+            # become as slurp will be used Force remote_checksum to follow
+            # symlinks because fetch always follows symlinks
+            remote_checksum = self._remote_checksum(source, all_vars=task_vars, follow=True)
+
+            # calculate the destination name
+            if os.path.sep not in self._connection._shell.join_path('a', ''):
+                source = self._connection._shell._unquote(source)
+                source_local = source.replace('\\', '/')
+            else:
+                source_local = source
+
+            dest = os.path.expanduser(dest)
+            if flat:
+                if os.path.isdir(to_bytes(dest, errors='surrogate_or_strict')) and not dest.endswith(os.sep):
+                    result['msg'] = "dest is an existing directory, use a trailing slash if you want to fetch src into that directory"
+                    result['file'] = dest
+                    result['failed'] = True
+                    return result
+                if dest.endswith(os.sep):
+                    # if the path ends with "/", we'll use the source filename as the
+                    # destination filename
+                    base = os.path.basename(source_local)
+                    dest = os.path.join(dest, base)
+                if not dest.startswith("/"):
+                    # if dest does not start with "/", we'll assume a relative path
+                    dest = self._loader.path_dwim(dest)
+            else:
+                # files are saved in dest dir, with a subdir for each host, then the filename
+                if 'inventory_hostname' in task_vars:
+                    target_name = task_vars['inventory_hostname']
+                else:
+                    target_name = self._play_context.remote_addr
+                dest = "%s/%s/%s" % (self._loader.path_dwim(dest), target_name, source_local)
+
+            dest = dest.replace("//", "/")
+
+            if remote_checksum in REMOTE_CHECKSUM_ERRORS:
+                result['changed'] = False
+                result['file'] = source
+                result['msg'] = REMOTE_CHECKSUM_ERRORS[remote_checksum]
+                # Historically, these don't fail because you may want to transfer
+                # a log file that possibly MAY exist but keep going to fetch other
+                # log files. Today, this is better achieved by adding
+                # ignore_errors or failed_when to the task.  Control the behaviour
+                # via fail_when_missing
+                if fail_on_missing:
+                    result['failed'] = True
+                    del result['changed']
+                else:
+                    result['msg'] += ", not transferring, ignored"
+                return result
+
+            # calculate checksum for the local file
+            local_checksum = checksum(dest)
+
+            if remote_checksum != local_checksum:
+                # create the containing directories, if needed
+                makedirs_safe(os.path.dirname(dest))
+
+                # fetch the file and check for changes
+                self._connection.fetch_file(source, dest)
+                new_checksum = secure_hash(dest)
+                # For backwards compatibility. We'll return None on FIPS enabled systems
+                try:
+                    new_md5 = md5(dest)
+                except ValueError:
+                    new_md5 = None
+
+                if validate_checksum and new_checksum != remote_checksum:
+                    result.update(dict(failed=True, md5sum=new_md5,
+                                       msg="checksum mismatch", file=source, dest=dest, remote_md5sum=None,
+                                       checksum=new_checksum, remote_checksum=remote_checksum))
+                else:
+                    result.update({'changed': True, 'md5sum': new_md5, 'dest': dest,
+                                   'remote_md5sum': None, 'checksum': new_checksum,
+                                   'remote_checksum': remote_checksum})
+            else:
+                # For backwards compatibility. We'll return None on FIPS enabled systems
+                try:
+                    local_md5 = md5(dest)
+                except ValueError:
+                    local_md5 = None
+                result.update(dict(changed=False, md5sum=local_md5, file=source, dest=dest, checksum=local_checksum))
+
+        finally:
+            self._remove_tmp_path(self._connection._shell.tmpdir)
+
+        return result

mitogen/ansible_mitogen/plugins/action/mitogen_get_stack.py

@@ -0,0 +1,55 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+"""
+Fetch the connection configuration stack that would be used to connect to a
+target, without actually connecting to it.
+"""
+
+import ansible_mitogen.connection
+
+from ansible.plugins.action import ActionBase
+
+
+class ActionModule(ActionBase):
+    def run(self, tmp=None, task_vars=None):
+        if not isinstance(self._connection,
+                          ansible_mitogen.connection.Connection):
+            return {
+                'skipped': True,
+            }
+
+        _, stack = self._connection._build_stack()
+        return {
+            'changed': True,
+            'result': stack,
+            '_ansible_verbose_always': True,
+        }

mitogen/ansible_mitogen/plugins/connection/mitogen_buildah.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'buildah'

mitogen/ansible_mitogen/plugins/connection/mitogen_doas.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen.connection
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'mitogen_doas'

mitogen/ansible_mitogen/plugins/connection/mitogen_docker.py

@@ -0,0 +1,51 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'docker'
+
+    @property
+    def docker_cmd(self):
+        """
+        Ansible 2.3 synchronize module wants to know how we run Docker.
+        """
+        return 'docker'

mitogen/ansible_mitogen/plugins/connection/mitogen_jail.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'jail'

mitogen/ansible_mitogen/plugins/connection/mitogen_kubectl.py

@@ -0,0 +1,79 @@
+# coding: utf-8
+# Copyright 2018, Yannig Perré
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+from ansible.errors import AnsibleConnectionFailure
+from ansible.module_utils.six import iteritems
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+import ansible_mitogen.loaders
+
+
+_class = ansible_mitogen.loaders.connection_loader__get(
+    'kubectl',
+    class_only=True,
+)
+
+if _class:
+    kubectl = sys.modules[_class.__module__]
+    del _class
+else:
+    kubectl = None
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'kubectl'
+
+    not_supported_msg = (
+        'The "mitogen_kubectl" plug-in requires a version of Ansible '
+        'that ships with the "kubectl" connection plug-in.'
+    )
+
+    def __init__(self, *args, **kwargs):
+        if kubectl is None:
+            raise AnsibleConnectionFailure(self.not_supported_msg)
+        super(Connection, self).__init__(*args, **kwargs)
+
+    def get_extra_args(self):
+        parameters = []
+        for key, option in iteritems(kubectl.CONNECTION_OPTIONS):
+            if self.get_task_var('ansible_' + key) is not None:
+                parameters += [ option, self.get_task_var('ansible_' + key) ]
+
+        return parameters

mitogen/ansible_mitogen/plugins/connection/mitogen_local.py

@@ -0,0 +1,86 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen.connection
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+import ansible_mitogen.process
+
+
+if sys.version_info > (3,):
+    viewkeys = dict.keys
+elif sys.version_info > (2, 7):
+    viewkeys = dict.viewkeys
+else:
+    viewkeys = lambda dct: set(dct)
+
+
+def dict_diff(old, new):
+    """
+    Return a dict representing the differences between the dicts `old` and
+    `new`. Deleted keys appear as a key with the value :data:`None`, added and
+    changed keys appear as a key with the new value.
+    """
+    old_keys = viewkeys(old)
+    new_keys = viewkeys(dict(new))
+    out = {}
+    for key in new_keys - old_keys:
+        out[key] = new[key]
+    for key in old_keys - new_keys:
+        out[key] = None
+    for key in old_keys & new_keys:
+        if old[key] != new[key]:
+            out[key] = new[key]
+    return out
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'local'
+
+    def get_default_cwd(self):
+        # https://github.com/ansible/ansible/issues/14489
+        return self.loader_basedir
+
+    def get_default_env(self):
+        """
+        Vanilla Ansible local commands execute with an environment inherited
+        from WorkerProcess, we must emulate that.
+        """
+        return dict_diff(
+            old=ansible_mitogen.process.MuxProcess.cls_original_env,
+            new=os.environ,
+        )

mitogen/ansible_mitogen/plugins/connection/mitogen_lxc.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'lxc'

mitogen/ansible_mitogen/plugins/connection/mitogen_lxd.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'lxd'

mitogen/ansible_mitogen/plugins/connection/mitogen_machinectl.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen.connection
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'machinectl'

mitogen/ansible_mitogen/plugins/connection/mitogen_setns.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen.connection
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'setns'

mitogen/ansible_mitogen/plugins/connection/mitogen_ssh.py

@@ -0,0 +1,67 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+DOCUMENTATION = """
+    author: David Wilson <dw@botanicus.net>
+    connection: mitogen_ssh
+    short_description: Connect over SSH via Mitogen
+    description:
+        - This connects using an OpenSSH client controlled by the Mitogen for
+          Ansible extension. It accepts every option the vanilla ssh plugin
+          accepts.
+    version_added: "2.5"
+    options:
+"""
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+import ansible_mitogen.loaders
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'ssh'
+    vanilla_class = ansible_mitogen.loaders.connection_loader__get(
+        'ssh',
+        class_only=True,
+    )
+
+    @staticmethod
+    def _create_control_path(*args, **kwargs):
+        """Forward _create_control_path() to the implementation in ssh.py."""
+        # https://github.com/dw/mitogen/issues/342
+        return Connection.vanilla_class._create_control_path(*args, **kwargs)

mitogen/ansible_mitogen/plugins/connection/mitogen_su.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen.connection
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'mitogen_su'

mitogen/ansible_mitogen/plugins/connection/mitogen_sudo.py

@@ -0,0 +1,44 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+try:
+    import ansible_mitogen.connection
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../../..')))
+    del base_dir
+
+import ansible_mitogen.connection
+
+
+class Connection(ansible_mitogen.connection.Connection):
+    transport = 'mitogen_sudo'

mitogen/ansible_mitogen/plugins/strategy/mitogen.py

@@ -0,0 +1,61 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+#
+# This is not the real Strategy implementation module, it simply exists as a
+# proxy to the real module, which is loaded using Python's regular import
+# mechanism, to prevent Ansible's PluginLoader from making up a fake name that
+# results in ansible_mitogen plugin modules being loaded twice: once by
+# PluginLoader with a name like "ansible.plugins.strategy.mitogen", which is
+# stuffed into sys.modules even though attempting to import it will trigger an
+# ImportError, and once under its canonical name, "ansible_mitogen.strategy".
+#
+# Therefore we have a proxy module that imports it under the real name, and
+# sets up the duff PluginLoader-imported module to just contain objects from
+# the real module, so duplicate types don't exist in memory, and things like
+# debuggers and isinstance() work predictably.
+#
+
+BASE_DIR = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '../../..')
+)
+
+if BASE_DIR not in sys.path:
+    sys.path.insert(0, BASE_DIR)
+
+import ansible_mitogen.strategy
+import ansible.plugins.strategy.linear
+
+
+class StrategyModule(ansible_mitogen.strategy.StrategyMixin,
+                     ansible.plugins.strategy.linear.StrategyModule):
+    pass

mitogen/ansible_mitogen/plugins/strategy/mitogen_free.py

@@ -0,0 +1,62 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+#
+# This is not the real Strategy implementation module, it simply exists as a
+# proxy to the real module, which is loaded using Python's regular import
+# mechanism, to prevent Ansible's PluginLoader from making up a fake name that
+# results in ansible_mitogen plugin modules being loaded twice: once by
+# PluginLoader with a name like "ansible.plugins.strategy.mitogen", which is
+# stuffed into sys.modules even though attempting to import it will trigger an
+# ImportError, and once under its canonical name, "ansible_mitogen.strategy".
+#
+# Therefore we have a proxy module that imports it under the real name, and
+# sets up the duff PluginLoader-imported module to just contain objects from
+# the real module, so duplicate types don't exist in memory, and things like
+# debuggers and isinstance() work predictably.
+#
+
+BASE_DIR = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '../../..')
+)
+
+if BASE_DIR not in sys.path:
+    sys.path.insert(0, BASE_DIR)
+
+import ansible_mitogen.loaders
+import ansible_mitogen.strategy
+
+
+Base = ansible_mitogen.loaders.strategy_loader.get('free', class_only=True)
+
+class StrategyModule(ansible_mitogen.strategy.StrategyMixin, Base):
+    pass

mitogen/ansible_mitogen/plugins/strategy/mitogen_host_pinned.py

@@ -0,0 +1,67 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+#
+# This is not the real Strategy implementation module, it simply exists as a
+# proxy to the real module, which is loaded using Python's regular import
+# mechanism, to prevent Ansible's PluginLoader from making up a fake name that
+# results in ansible_mitogen plugin modules being loaded twice: once by
+# PluginLoader with a name like "ansible.plugins.strategy.mitogen", which is
+# stuffed into sys.modules even though attempting to import it will trigger an
+# ImportError, and once under its canonical name, "ansible_mitogen.strategy".
+#
+# Therefore we have a proxy module that imports it under the real name, and
+# sets up the duff PluginLoader-imported module to just contain objects from
+# the real module, so duplicate types don't exist in memory, and things like
+# debuggers and isinstance() work predictably.
+#
+
+BASE_DIR = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '../../..')
+)
+
+if BASE_DIR not in sys.path:
+    sys.path.insert(0, BASE_DIR)
+
+import ansible_mitogen.loaders
+import ansible_mitogen.strategy
+
+
+Base = ansible_mitogen.loaders.strategy_loader.get('host_pinned', class_only=True)
+
+if Base is None:
+    raise ImportError(
+        'The host_pinned strategy is only available in Ansible 2.7 or newer.'
+    )
+
+class StrategyModule(ansible_mitogen.strategy.StrategyMixin, Base):
+    pass

mitogen/ansible_mitogen/plugins/strategy/mitogen_linear.py

@@ -0,0 +1,62 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import os.path
+import sys
+
+#
+# This is not the real Strategy implementation module, it simply exists as a
+# proxy to the real module, which is loaded using Python's regular import
+# mechanism, to prevent Ansible's PluginLoader from making up a fake name that
+# results in ansible_mitogen plugin modules being loaded twice: once by
+# PluginLoader with a name like "ansible.plugins.strategy.mitogen", which is
+# stuffed into sys.modules even though attempting to import it will trigger an
+# ImportError, and once under its canonical name, "ansible_mitogen.strategy".
+#
+# Therefore we have a proxy module that imports it under the real name, and
+# sets up the duff PluginLoader-imported module to just contain objects from
+# the real module, so duplicate types don't exist in memory, and things like
+# debuggers and isinstance() work predictably.
+#
+
+BASE_DIR = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '../../..')
+)
+
+if BASE_DIR not in sys.path:
+    sys.path.insert(0, BASE_DIR)
+
+import ansible_mitogen.loaders
+import ansible_mitogen.strategy
+
+
+Base = ansible_mitogen.loaders.strategy_loader.get('linear', class_only=True)
+
+class StrategyModule(ansible_mitogen.strategy.StrategyMixin, Base):
+    pass

mitogen/ansible_mitogen/process.py

@@ -0,0 +1,745 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import atexit
+import logging
+import multiprocessing
+import os
+import resource
+import socket
+import signal
+import sys
+
+try:
+    import faulthandler
+except ImportError:
+    faulthandler = None
+
+try:
+    import setproctitle
+except ImportError:
+    setproctitle = None
+
+import mitogen
+import mitogen.core
+import mitogen.debug
+import mitogen.fork
+import mitogen.master
+import mitogen.parent
+import mitogen.service
+import mitogen.unix
+import mitogen.utils
+
+import ansible
+import ansible.constants as C
+import ansible.errors
+import ansible_mitogen.logging
+import ansible_mitogen.services
+
+from mitogen.core import b
+import ansible_mitogen.affinity
+
+
+LOG = logging.getLogger(__name__)
+
+ANSIBLE_PKG_OVERRIDE = (
+    u"__version__ = %r\n"
+    u"__author__ = %r\n"
+)
+
+MAX_MESSAGE_SIZE = 4096 * 1048576
+
+worker_model_msg = (
+    'Mitogen connection types may only be instantiated when one of the '
+    '"mitogen_*" or "operon_*" strategies are active.'
+)
+
+shutting_down_msg = (
+    'The task worker cannot connect. Ansible may be shutting down, or '
+    'the maximum open files limit may have been exceeded. If this occurs '
+    'midway through a run, please retry after increasing the open file '
+    'limit (ulimit -n). Original error: %s'
+)
+
+
+#: The worker model as configured by the currently running strategy. This is
+#: managed via :func:`get_worker_model` / :func:`set_worker_model` functions by
+#: :class:`StrategyMixin`.
+_worker_model = None
+
+
+#: A copy of the sole :class:`ClassicWorkerModel` that ever exists during a
+#: classic run, as return by :func:`get_classic_worker_model`.
+_classic_worker_model = None
+
+
+def set_worker_model(model):
+    """
+    To remove process model-wiring from
+    :class:`ansible_mitogen.connection.Connection`, it is necessary to track
+    some idea of the configured execution environment outside the connection
+    plug-in.
+
+    That is what :func:`set_worker_model` and :func:`get_worker_model` are for.
+    """
+    global _worker_model
+    assert model is None or _worker_model is None
+    _worker_model = model
+
+
+def get_worker_model():
+    """
+    Return the :class:`WorkerModel` currently configured by the running
+    strategy.
+    """
+    if _worker_model is None:
+        raise ansible.errors.AnsibleConnectionFailure(worker_model_msg)
+    return _worker_model
+
+
+def get_classic_worker_model(**kwargs):
+    """
+    Return the single :class:`ClassicWorkerModel` instance, constructing it if
+    necessary.
+    """
+    global _classic_worker_model
+    assert _classic_worker_model is None or (not kwargs), \
+        "ClassicWorkerModel kwargs supplied but model already constructed"
+
+    if _classic_worker_model is None:
+        _classic_worker_model = ClassicWorkerModel(**kwargs)
+    return _classic_worker_model
+
+
+def getenv_int(key, default=0):
+    """
+    Get an integer-valued environment variable `key`, if it exists and parses
+    as an integer, otherwise return `default`.
+    """
+    try:
+        return int(os.environ.get(key, str(default)))
+    except ValueError:
+        return default
+
+
+def save_pid(name):
+    """
+    When debugging and profiling, it is very annoying to poke through the
+    process list to discover the currently running Ansible and MuxProcess IDs,
+    especially when trying to catch an issue during early startup. So here, if
+    a magic environment variable set, stash them in hidden files in the CWD::
+
+        alias muxpid="cat .ansible-mux.pid"
+        alias anspid="cat .ansible-controller.pid"
+
+        gdb -p $(muxpid)
+        perf top -p $(anspid)
+    """
+    if os.environ.get('MITOGEN_SAVE_PIDS'):
+        with open('.ansible-%s.pid' % (name,), 'w') as fp:
+            fp.write(str(os.getpid()))
+
+
+def setup_pool(pool):
+    """
+    Configure a connection multiplexer's :class:`mitogen.service.Pool` with
+    services accessed by clients and WorkerProcesses.
+    """
+    pool.add(mitogen.service.FileService(router=pool.router))
+    pool.add(mitogen.service.PushFileService(router=pool.router))
+    pool.add(ansible_mitogen.services.ContextService(router=pool.router))
+    pool.add(ansible_mitogen.services.ModuleDepService(pool.router))
+    LOG.debug('Service pool configured: size=%d', pool.size)
+
+
+def _setup_simplejson(responder):
+    """
+    We support serving simplejson for Python 2.4 targets on Ansible 2.3, at
+    least so the package's own CI Docker scripts can run without external
+    help, however newer versions of simplejson no longer support Python
+    2.4. Therefore override any installed/loaded version with a
+    2.4-compatible version we ship in the compat/ directory.
+    """
+    responder.whitelist_prefix('simplejson')
+
+    # issue #536: must be at end of sys.path, in case existing newer
+    # version is already loaded.
+    compat_path = os.path.join(os.path.dirname(__file__), 'compat')
+    sys.path.append(compat_path)
+
+    for fullname, is_pkg, suffix in (
+        (u'simplejson', True, '__init__.py'),
+        (u'simplejson.decoder', False, 'decoder.py'),
+        (u'simplejson.encoder', False, 'encoder.py'),
+        (u'simplejson.scanner', False, 'scanner.py'),
+    ):
+        path = os.path.join(compat_path, 'simplejson', suffix)
+        fp = open(path, 'rb')
+        try:
+            source = fp.read()
+        finally:
+            fp.close()
+
+        responder.add_source_override(
+            fullname=fullname,
+            path=path,
+            source=source,
+            is_pkg=is_pkg,
+        )
+
+
+def _setup_responder(responder):
+    """
+    Configure :class:`mitogen.master.ModuleResponder` to only permit
+    certain packages, and to generate custom responses for certain modules.
+    """
+    responder.whitelist_prefix('ansible')
+    responder.whitelist_prefix('ansible_mitogen')
+    _setup_simplejson(responder)
+
+    # Ansible 2.3 is compatible with Python 2.4 targets, however
+    # ansible/__init__.py is not. Instead, executor/module_common.py writes
+    # out a 2.4-compatible namespace package for unknown reasons. So we
+    # copy it here.
+    responder.add_source_override(
+        fullname='ansible',
+        path=ansible.__file__,
+        source=(ANSIBLE_PKG_OVERRIDE % (
+            ansible.__version__,
+            ansible.__author__,
+        )).encode(),
+        is_pkg=True,
+    )
+
+
+def increase_open_file_limit():
+    """
+    #549: in order to reduce the possibility of hitting an open files limit,
+    increase :data:`resource.RLIMIT_NOFILE` from its soft limit to its hard
+    limit, if they differ.
+
+    It is common that a low soft limit is configured by default, where the hard
+    limit is much higher.
+    """
+    soft, hard = resource.getrlimit(resource.RLIMIT_NOFILE)
+    if hard == resource.RLIM_INFINITY:
+        hard_s = '(infinity)'
+        # cap in case of O(RLIMIT_NOFILE) algorithm in some subprocess.
+        hard = 524288
+    else:
+        hard_s = str(hard)
+
+    LOG.debug('inherited open file limits: soft=%d hard=%s', soft, hard_s)
+    if soft >= hard:
+        LOG.debug('max open files already set to hard limit: %d', hard)
+        return
+
+    # OS X is limited by kern.maxfilesperproc sysctl, rather than the
+    # advertised unlimited hard RLIMIT_NOFILE. Just hard-wire known defaults
+    # for that sysctl, to avoid the mess of querying it.
+    for value in (hard, 10240):
+        try:
+            resource.setrlimit(resource.RLIMIT_NOFILE, (value, hard))
+            LOG.debug('raised soft open file limit from %d to %d', soft, value)
+            break
+        except ValueError as e:
+            LOG.debug('could not raise soft open file limit from %d to %d: %s',
+                      soft, value, e)
+
+
+def common_setup(enable_affinity=True, _init_logging=True):
+    save_pid('controller')
+    ansible_mitogen.logging.set_process_name('top')
+
+    if _init_logging:
+        ansible_mitogen.logging.setup()
+
+    if enable_affinity:
+        ansible_mitogen.affinity.policy.assign_controller()
+
+    mitogen.utils.setup_gil()
+    if faulthandler is not None:
+        faulthandler.enable()
+
+    MuxProcess.profiling = getenv_int('MITOGEN_PROFILING') > 0
+    if MuxProcess.profiling:
+        mitogen.core.enable_profiling()
+
+    MuxProcess.cls_original_env = dict(os.environ)
+    increase_open_file_limit()
+
+
+def get_cpu_count(default=None):
+    """
+    Get the multiplexer CPU count from the MITOGEN_CPU_COUNT environment
+    variable, returning `default` if one isn't set, or is out of range.
+
+    :param int default:
+        Default CPU, or :data:`None` to use all available CPUs.
+    """
+    max_cpus = multiprocessing.cpu_count()
+    if default is None:
+        default = max_cpus
+
+    cpu_count = getenv_int('MITOGEN_CPU_COUNT', default=default)
+    if cpu_count < 1 or cpu_count > max_cpus:
+        cpu_count = default
+
+    return cpu_count
+
+
+class Broker(mitogen.master.Broker):
+    """
+    WorkerProcess maintains at most 2 file descriptors, therefore does not need
+    the exuberant syscall expense of EpollPoller, so override it and restore
+    the poll() poller.
+    """
+    poller_class = mitogen.core.Poller
+
+
+class Binding(object):
+    """
+    Represent a bound connection for a particular inventory hostname. When
+    operating in sharded mode, the actual MuxProcess implementing a connection
+    varies according to the target machine. Depending on the particular
+    implementation, this class represents a binding to the correct MuxProcess.
+    """
+    def get_child_service_context(self):
+        """
+        Return the :class:`mitogen.core.Context` to which children should
+        direct requests for services such as FileService, or :data:`None` for
+        the local process.
+
+        This can be different from :meth:`get_service_context` where MuxProcess
+        and WorkerProcess are combined, and it is discovered a task is
+        delegated after being assigned to its initial worker for the original
+        un-delegated hostname. In that case, connection management and
+        expensive services like file transfer must be implemented by the
+        MuxProcess connected to the target, rather than routed to the
+        MuxProcess responsible for executing the task.
+        """
+        raise NotImplementedError()
+
+    def get_service_context(self):
+        """
+        Return the :class:`mitogen.core.Context` to which this process should
+        direct ContextService requests, or :data:`None` for the local process.
+        """
+        raise NotImplementedError()
+
+    def close(self):
+        """
+        Finalize any associated resources.
+        """
+        raise NotImplementedError()
+
+
+class WorkerModel(object):
+    """
+    Interface used by StrategyMixin to manage various Mitogen services, by
+    default running in one or more connection multiplexer subprocesses spawned
+    off the top-level Ansible process.
+    """
+    def on_strategy_start(self):
+        """
+        Called prior to strategy start in the top-level process. Responsible
+        for preparing any worker/connection multiplexer state.
+        """
+        raise NotImplementedError()
+
+    def on_strategy_complete(self):
+        """
+        Called after strategy completion in the top-level process. Must place
+        Ansible back in a "compatible" state where any other strategy plug-in
+        may execute.
+        """
+        raise NotImplementedError()
+
+    def get_binding(self, inventory_name):
+        """
+        Return a :class:`Binding` to access Mitogen services for
+        `inventory_name`. Usually called from worker processes, but may also be
+        called from top-level process to handle "meta: reset_connection".
+        """
+        raise NotImplementedError()
+
+
+class ClassicBinding(Binding):
+    """
+    Only one connection may be active at a time in a classic worker, so its
+    binding just provides forwarders back to :class:`ClassicWorkerModel`.
+    """
+    def __init__(self, model):
+        self.model = model
+
+    def get_service_context(self):
+        """
+        See Binding.get_service_context().
+        """
+        return self.model.parent
+
+    def get_child_service_context(self):
+        """
+        See Binding.get_child_service_context().
+        """
+        return self.model.parent
+
+    def close(self):
+        """
+        See Binding.close().
+        """
+        self.model.on_binding_close()
+
+
+class ClassicWorkerModel(WorkerModel):
+    #: In the top-level process, this references one end of a socketpair(),
+    #: whose other end child MuxProcesses block reading from to determine when
+    #: the master process dies. When the top-level exits abnormally, or
+    #: normally but where :func:`_on_process_exit` has been called, this socket
+    #: will be closed, causing all the children to wake.
+    parent_sock = None
+
+    #: In the mux process, this is the other end of :attr:`cls_parent_sock`.
+    #: The main thread blocks on a read from it until :attr:`cls_parent_sock`
+    #: is closed.
+    child_sock = None
+
+    #: mitogen.master.Router for this worker.
+    router = None
+
+    #: mitogen.master.Broker for this worker.
+    broker = None
+
+    #: Name of multiplexer process socket we are currently connected to.
+    listener_path = None
+
+    #: mitogen.parent.Context representing the parent Context, which is the
+    #: connection multiplexer process when running in classic mode, or the
+    #: top-level process when running a new-style mode.
+    parent = None
+
+    def __init__(self, _init_logging=True):
+        """
+        Arrange for classic model multiplexers to be started. The parent choses
+        UNIX socket paths each child will use prior to fork, creates a
+        socketpair used essentially as a semaphore, then blocks waiting for the
+        child to indicate the UNIX socket is ready for use.
+
+        :param bool _init_logging:
+            For testing, if :data:`False`, don't initialize logging.
+        """
+        # #573: The process ID that installed the :mod:`atexit` handler. If
+        # some unknown Ansible plug-in forks the Ansible top-level process and
+        # later performs a graceful Python exit, it may try to wait for child
+        # PIDs it never owned, causing a crash. We want to avoid that.
+        self._pid = os.getpid()
+
+        common_setup(_init_logging=_init_logging)
+
+        self.parent_sock, self.child_sock = socket.socketpair()
+        mitogen.core.set_cloexec(self.parent_sock.fileno())
+        mitogen.core.set_cloexec(self.child_sock.fileno())
+
+        self._muxes = [
+            MuxProcess(self, index)
+            for index in range(get_cpu_count(default=1))
+        ]
+        for mux in self._muxes:
+            mux.start()
+
+        atexit.register(self._on_process_exit)
+        self.child_sock.close()
+        self.child_sock = None
+
+    def _listener_for_name(self, name):
+        """
+        Given an inventory hostname, return the UNIX listener that should
+        communicate with it. This is a simple hash of the inventory name.
+        """
+        mux = self._muxes[abs(hash(name)) % len(self._muxes)]
+        LOG.debug('will use multiplexer %d (%s) to connect to "%s"',
+                  mux.index, mux.path, name)
+        return mux.path
+
+    def _reconnect(self, path):
+        if self.router is not None:
+            # Router can just be overwritten, but the previous parent
+            # connection must explicitly be removed from the broker first.
+            self.router.disconnect(self.parent)
+            self.parent = None
+            self.router = None
+
+        try:
+            self.router, self.parent = mitogen.unix.connect(
+                path=path,
+                broker=self.broker,
+            )
+        except mitogen.unix.ConnectError as e:
+            # This is not AnsibleConnectionFailure since we want to break
+            # with_items loops.
+            raise ansible.errors.AnsibleError(shutting_down_msg % (e,))
+
+        self.router.max_message_size = MAX_MESSAGE_SIZE
+        self.listener_path = path
+
+    def _on_process_exit(self):
+        """
+        This is an :mod:`atexit` handler installed in the top-level process.
+
+        Shut the write end of `sock`, causing the receive side of the socket in
+        every :class:`MuxProcess` to return 0-byte reads, and causing their
+        main threads to wake and initiate shutdown. After shutting the socket
+        down, wait on each child to finish exiting.
+
+        This is done using :mod:`atexit` since Ansible lacks any better hook to
+        run code during exit, and unless some synchronization exists with
+        MuxProcess, debug logs may appear on the user's terminal *after* the
+        prompt has been printed.
+        """
+        if self._pid != os.getpid():
+            return
+
+        try:
+            self.parent_sock.shutdown(socket.SHUT_WR)
+        except socket.error:
+            # Already closed. This is possible when tests are running.
+            LOG.debug('_on_process_exit: ignoring duplicate call')
+            return
+
+        mitogen.core.io_op(self.parent_sock.recv, 1)
+        self.parent_sock.close()
+
+        for mux in self._muxes:
+            _, status = os.waitpid(mux.pid, 0)
+            status = mitogen.fork._convert_exit_status(status)
+            LOG.debug('multiplexer %d PID %d %s', mux.index, mux.pid,
+                      mitogen.parent.returncode_to_str(status))
+
+    def _test_reset(self):
+        """
+        Used to clean up in unit tests.
+        """
+        self.on_binding_close()
+        self._on_process_exit()
+        set_worker_model(None)
+
+        global _classic_worker_model
+        _classic_worker_model = None
+
+    def on_strategy_start(self):
+        """
+        See WorkerModel.on_strategy_start().
+        """
+
+    def on_strategy_complete(self):
+        """
+        See WorkerModel.on_strategy_complete().
+        """
+
+    def get_binding(self, inventory_name):
+        """
+        See WorkerModel.get_binding().
+        """
+        if self.broker is None:
+            self.broker = Broker()
+
+        path = self._listener_for_name(inventory_name)
+        if path != self.listener_path:
+            self._reconnect(path)
+
+        return ClassicBinding(self)
+
+    def on_binding_close(self):
+        if not self.broker:
+            return
+
+        self.broker.shutdown()
+        self.broker.join()
+        self.router = None
+        self.broker = None
+        self.parent = None
+        self.listener_path = None
+
+        # #420: Ansible executes "meta" actions in the top-level process,
+        # meaning "reset_connection" will cause :class:`mitogen.core.Latch` FDs
+        # to be cached and erroneously shared by children on subsequent
+        # WorkerProcess forks. To handle that, call on_fork() to ensure any
+        # shared state is discarded.
+        # #490: only attempt to clean up when it's known that some resources
+        # exist to cleanup, otherwise later __del__ double-call to close() due
+        # to GC at random moment may obliterate an unrelated Connection's
+        # related resources.
+        mitogen.fork.on_fork()
+
+
+class MuxProcess(object):
+    """
+    Implement a subprocess forked from the Ansible top-level, as a safe place
+    to contain the Mitogen IO multiplexer thread, keeping its use of the
+    logging package (and the logging package's heavy use of locks) far away
+    from os.fork(), which is used continuously by the multiprocessing package
+    in the top-level process.
+
+    The problem with running the multiplexer in that process is that should the
+    multiplexer thread be in the process of emitting a log entry (and holding
+    its lock) at the point of fork, in the child, the first attempt to log any
+    log entry using the same handler will deadlock the child, as in the memory
+    image the child received, the lock will always be marked held.
+
+    See https://bugs.python.org/issue6721 for a thorough description of the
+    class of problems this worker is intended to avoid.
+    """
+    #: A copy of :data:`os.environ` at the time the multiplexer process was
+    #: started. It's used by mitogen_local.py to find changes made to the
+    #: top-level environment (e.g. vars plugins -- issue #297) that must be
+    #: applied to locally executed commands and modules.
+    cls_original_env = None
+
+    def __init__(self, model, index):
+        #: :class:`ClassicWorkerModel` instance we were created by.
+        self.model = model
+        #: MuxProcess CPU index.
+        self.index = index
+        #: Individual path of this process.
+        self.path = mitogen.unix.make_socket_path()
+
+    def start(self):
+        self.pid = os.fork()
+        if self.pid:
+            # Wait for child to boot before continuing.
+            mitogen.core.io_op(self.model.parent_sock.recv, 1)
+            return
+
+        ansible_mitogen.logging.set_process_name('mux:' + str(self.index))
+        if setproctitle:
+            setproctitle.setproctitle('mitogen mux:%s (%s)' % (
+                self.index,
+                os.path.basename(self.path),
+            ))
+
+        self.model.parent_sock.close()
+        self.model.parent_sock = None
+        try:
+            try:
+                self.worker_main()
+            except Exception:
+                LOG.exception('worker_main() crashed')
+        finally:
+            sys.exit()
+
+    def worker_main(self):
+        """
+        The main function of the mux process: setup the Mitogen broker thread
+        and ansible_mitogen services, then sleep waiting for the socket
+        connected to the parent to be closed (indicating the parent has died).
+        """
+        save_pid('mux')
+
+        # #623: MuxProcess ignores SIGINT because it wants to live until every
+        # Ansible worker process has been cleaned up by
+        # TaskQueueManager.cleanup(), otherwise harmles yet scary warnings
+        # about being unable connect to MuxProess could be printed.
+        signal.signal(signal.SIGINT, signal.SIG_IGN)
+        ansible_mitogen.logging.set_process_name('mux')
+        ansible_mitogen.affinity.policy.assign_muxprocess(self.index)
+
+        self._setup_master()
+        self._setup_services()
+
+        try:
+            # Let the parent know our listening socket is ready.
+            mitogen.core.io_op(self.model.child_sock.send, b('1'))
+            # Block until the socket is closed, which happens on parent exit.
+            mitogen.core.io_op(self.model.child_sock.recv, 1)
+        finally:
+            self.broker.shutdown()
+            self.broker.join()
+
+            # Test frameworks living somewhere higher on the stack of the
+            # original parent process may try to catch sys.exit(), so do a C
+            # level exit instead.
+            os._exit(0)
+
+    def _enable_router_debug(self):
+        if 'MITOGEN_ROUTER_DEBUG' in os.environ:
+            self.router.enable_debug()
+
+    def _enable_stack_dumps(self):
+        secs = getenv_int('MITOGEN_DUMP_THREAD_STACKS', default=0)
+        if secs:
+            mitogen.debug.dump_to_logger(secs=secs)
+
+    def _setup_master(self):
+        """
+        Construct a Router, Broker, and mitogen.unix listener
+        """
+        self.broker = mitogen.master.Broker(install_watcher=False)
+        self.router = mitogen.master.Router(
+            broker=self.broker,
+            max_message_size=MAX_MESSAGE_SIZE,
+        )
+        _setup_responder(self.router.responder)
+        mitogen.core.listen(self.broker, 'shutdown', self._on_broker_shutdown)
+        mitogen.core.listen(self.broker, 'exit', self._on_broker_exit)
+        self.listener = mitogen.unix.Listener.build_stream(
+            router=self.router,
+            path=self.path,
+            backlog=C.DEFAULT_FORKS,
+        )
+        self._enable_router_debug()
+        self._enable_stack_dumps()
+
+    def _setup_services(self):
+        """
+        Construct a ContextService and a thread to service requests for it
+        arriving from worker processes.
+        """
+        self.pool = mitogen.service.Pool(
+            router=self.router,
+            size=getenv_int('MITOGEN_POOL_SIZE', default=32),
+        )
+        setup_pool(self.pool)
+
+    def _on_broker_shutdown(self):
+        """
+        Respond to broker shutdown by shutting down the pool. Do not join on it
+        yet, since that would block the broker thread which then cannot clean
+        up pending handlers and connections, which is required for the threads
+        to exit gracefully.
+        """
+        self.pool.stop(join=False)
+
+    def _on_broker_exit(self):
+        """
+        Respond to the broker thread about to exit by finally joining on the
+        pool. This is safe since pools only block in connection attempts, and
+        connection attempts fail with CancelledError when broker shutdown
+        begins.
+        """
+        self.pool.join()

mitogen/ansible_mitogen/services.py

@@ -0,0 +1,559 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+# !mitogen: minify_safe
+
+"""
+Classes in this file define Mitogen 'services' that run (initially) within the
+connection multiplexer process that is forked off the top-level controller
+process.
+
+Once a worker process connects to a multiplexer process
+(Connection._connect()), it communicates with these services to establish new
+connections, grant access to files by children, and register for notification
+when a child has completed a job.
+"""
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import logging
+import os
+import os.path
+import sys
+import threading
+
+import ansible.constants
+
+import mitogen
+import mitogen.service
+import mitogen.utils
+import ansible_mitogen.loaders
+import ansible_mitogen.module_finder
+import ansible_mitogen.target
+
+
+LOG = logging.getLogger(__name__)
+
+# Force load of plugin to ensure ConfigManager has definitions loaded. Done
+# during module import to ensure a single-threaded environment; PluginLoader
+# is not thread-safe.
+ansible_mitogen.loaders.shell_loader.get('sh')
+
+
+if sys.version_info[0] == 3:
+    def reraise(tp, value, tb):
+        if value is None:
+            value = tp()
+        if value.__traceback__ is not tb:
+            raise value.with_traceback(tb)
+        raise value
+else:
+    exec(
+        "def reraise(tp, value, tb=None):\n"
+        "    raise tp, value, tb\n"
+     )
+
+
+def _get_candidate_temp_dirs():
+    try:
+        # >=2.5
+        options = ansible.constants.config.get_plugin_options('shell', 'sh')
+        remote_tmp = options.get('remote_tmp') or ansible.constants.DEFAULT_REMOTE_TMP
+        system_tmpdirs = options.get('system_tmpdirs', ('/var/tmp', '/tmp'))
+    except AttributeError:
+        # 2.3
+        remote_tmp = ansible.constants.DEFAULT_REMOTE_TMP
+        system_tmpdirs = ('/var/tmp', '/tmp')
+
+    return mitogen.utils.cast([remote_tmp] + list(system_tmpdirs))
+
+
+def key_from_dict(**kwargs):
+    """
+    Return a unique string representation of a dict as quickly as possible.
+    Used to generated deduplication keys from a request.
+    """
+    out = []
+    stack = [kwargs]
+    while stack:
+        obj = stack.pop()
+        if isinstance(obj, dict):
+            stack.extend(sorted(obj.items()))
+        elif isinstance(obj, (list, tuple)):
+            stack.extend(obj)
+        else:
+            out.append(str(obj))
+    return ''.join(out)
+
+
+class Error(Exception):
+    pass
+
+
+class ContextService(mitogen.service.Service):
+    """
+    Used by workers to fetch the single Context instance corresponding to a
+    connection configuration, creating the matching connection if it does not
+    exist.
+
+    For connection methods and their parameters, see:
+        https://mitogen.readthedocs.io/en/latest/api.html#context-factories
+
+    This concentrates connections in the top-level process, which may become a
+    bottleneck. The bottleneck can be removed using per-CPU connection
+    processes and arranging for the worker to select one according to a hash of
+    the connection parameters (sharding).
+    """
+    max_interpreters = int(os.getenv('MITOGEN_MAX_INTERPRETERS', '20'))
+
+    def __init__(self, *args, **kwargs):
+        super(ContextService, self).__init__(*args, **kwargs)
+        self._lock = threading.Lock()
+        #: Records the :meth:`get` result dict for successful calls, returned
+        #: for identical subsequent calls. Keyed by :meth:`key_from_dict`.
+        self._response_by_key = {}
+        #: List of :class:`mitogen.core.Latch` awaiting the result for a
+        #: particular key.
+        self._latches_by_key = {}
+        #: Mapping of :class:`mitogen.core.Context` -> reference count. Each
+        #: call to :meth:`get` increases this by one. Calls to :meth:`put`
+        #: decrease it by one.
+        self._refs_by_context = {}
+        #: List of contexts in creation order by via= parameter. When
+        #: :attr:`max_interpreters` is reached, the most recently used context
+        #: is destroyed to make room for any additional context.
+        self._lru_by_via = {}
+        #: :func:`key_from_dict` result by Context.
+        self._key_by_context = {}
+        #: Mapping of Context -> parent Context
+        self._via_by_context = {}
+
+    @mitogen.service.expose(mitogen.service.AllowParents())
+    @mitogen.service.arg_spec({
+        'stack': list,
+    })
+    def reset(self, stack):
+        """
+        Return a reference, forcing close and discard of the underlying
+        connection. Used for 'meta: reset_connection' or when some other error
+        is detected.
+
+        :returns:
+            :data:`True` if a connection was found to discard, otherwise
+            :data:`False`.
+        """
+        LOG.debug('%r.reset(%r)', self, stack)
+
+        l = mitogen.core.Latch()
+        context = None
+        with self._lock:
+            for i, spec in enumerate(stack):
+                key = key_from_dict(via=context, **spec)
+                response = self._response_by_key.get(key)
+                if response is None:
+                    LOG.debug('%r: could not find connection to shut down; '
+                              'failed at hop %d', self, i)
+                    return False
+
+                context = response['context']
+
+            mitogen.core.listen(context, 'disconnect', l.put)
+            self._shutdown_unlocked(context)
+
+        # The timeout below is to turn a hang into a crash in case there is any
+        # possible race between 'disconnect' signal subscription, and the child
+        # abruptly disconnecting.
+        l.get(timeout=30.0)
+        return True
+
+    @mitogen.service.expose(mitogen.service.AllowParents())
+    @mitogen.service.arg_spec({
+        'context': mitogen.core.Context
+    })
+    def put(self, context):
+        """
+        Return a reference, making it eligable for recycling once its reference
+        count reaches zero.
+        """
+        LOG.debug('decrementing reference count for %r', context)
+        self._lock.acquire()
+        try:
+            if self._refs_by_context.get(context, 0) == 0:
+                LOG.warning('%r.put(%r): refcount was 0. shutdown_all called?',
+                            self, context)
+                return
+            self._refs_by_context[context] -= 1
+        finally:
+            self._lock.release()
+
+    def _produce_response(self, key, response):
+        """
+        Reply to every waiting request matching a configuration key with a
+        response dictionary, deleting the list of waiters when done.
+
+        :param str key:
+            Result of :meth:`key_from_dict`
+        :param dict response:
+            Response dictionary
+        :returns:
+            Number of waiters that were replied to.
+        """
+        self._lock.acquire()
+        try:
+            latches = self._latches_by_key.pop(key)
+            count = len(latches)
+            for latch in latches:
+                latch.put(response)
+        finally:
+            self._lock.release()
+        return count
+
+    def _forget_context_unlocked(self, context):
+        key = self._key_by_context.get(context)
+        if key is None:
+            LOG.debug('%r: attempt to forget unknown %r', self, context)
+            return
+
+        self._response_by_key.pop(key, None)
+        self._latches_by_key.pop(key, None)
+        self._key_by_context.pop(context, None)
+        self._refs_by_context.pop(context, None)
+        self._via_by_context.pop(context, None)
+        self._lru_by_via.pop(context, None)
+
+    def _shutdown_unlocked(self, context, lru=None, new_context=None):
+        """
+        Arrange for `context` to be shut down, and optionally add `new_context`
+        to the LRU list while holding the lock.
+        """
+        LOG.info('%r._shutdown_unlocked(): shutting down %r', self, context)
+        context.shutdown()
+        via = self._via_by_context.get(context)
+        if via:
+            lru = self._lru_by_via.get(via)
+            if lru:
+                if context in lru:
+                    lru.remove(context)
+                if new_context:
+                    lru.append(new_context)
+        self._forget_context_unlocked(context)
+
+    def _update_lru_unlocked(self, new_context, spec, via):
+        """
+        Update the LRU ("MRU"?) list associated with the connection described
+        by `kwargs`, destroying the most recently created context if the list
+        is full. Finally add `new_context` to the list.
+        """
+        self._via_by_context[new_context] = via
+
+        lru = self._lru_by_via.setdefault(via, [])
+        if len(lru) < self.max_interpreters:
+            lru.append(new_context)
+            return
+
+        for context in reversed(lru):
+            if self._refs_by_context[context] == 0:
+                break
+        else:
+            LOG.warning('via=%r reached maximum number of interpreters, '
+                        'but they are all marked as in-use.', via)
+            return
+
+        self._shutdown_unlocked(context, lru=lru, new_context=new_context)
+
+    def _update_lru(self, new_context, spec, via):
+        self._lock.acquire()
+        try:
+            self._update_lru_unlocked(new_context, spec, via)
+        finally:
+            self._lock.release()
+
+    @mitogen.service.expose(mitogen.service.AllowParents())
+    def dump(self):
+        """
+        For testing, return a list of dicts describing every currently
+        connected context.
+        """
+        return [
+            {
+                'context_name': context.name,
+                'via': getattr(self._via_by_context.get(context),
+                               'name', None),
+                'refs': self._refs_by_context.get(context),
+            }
+            for context, key in sorted(self._key_by_context.items(),
+                                       key=lambda c_k: c_k[0].context_id)
+        ]
+
+    @mitogen.service.expose(mitogen.service.AllowParents())
+    def shutdown_all(self):
+        """
+        For testing use, arrange for all connections to be shut down.
+        """
+        self._lock.acquire()
+        try:
+            for context in list(self._key_by_context):
+                self._shutdown_unlocked(context)
+        finally:
+            self._lock.release()
+
+    def _on_context_disconnect(self, context):
+        """
+        Respond to Context disconnect event by deleting any record of the no
+        longer reachable context.  This method runs in the Broker thread and
+        must not to block.
+        """
+        self._lock.acquire()
+        try:
+            LOG.info('%r: Forgetting %r due to stream disconnect', self, context)
+            self._forget_context_unlocked(context)
+        finally:
+            self._lock.release()
+
+    ALWAYS_PRELOAD = (
+        'ansible.module_utils.basic',
+        'ansible.module_utils.json_utils',
+        'ansible.release',
+        'ansible_mitogen.runner',
+        'ansible_mitogen.target',
+        'mitogen.fork',
+        'mitogen.service',
+    )
+
+    def _send_module_forwards(self, context):
+        if hasattr(self.router.responder, 'forward_modules'):
+            self.router.responder.forward_modules(context, self.ALWAYS_PRELOAD)
+
+    _candidate_temp_dirs = None
+
+    def _get_candidate_temp_dirs(self):
+        """
+        Return a list of locations to try to create the single temporary
+        directory used by the run. This simply caches the (expensive) plugin
+        load of :func:`_get_candidate_temp_dirs`.
+        """
+        if self._candidate_temp_dirs is None:
+            self._candidate_temp_dirs = _get_candidate_temp_dirs()
+        return self._candidate_temp_dirs
+
+    def _connect(self, key, spec, via=None):
+        """
+        Actual connect implementation. Arranges for the Mitogen connection to
+        be created and enqueues an asynchronous call to start the forked task
+        parent in the remote context.
+
+        :param key:
+            Deduplication key representing the connection configuration.
+        :param spec:
+            Connection specification.
+        :returns:
+            Dict like::
+
+                {
+                    'context': mitogen.core.Context or None,
+                    'via': mitogen.core.Context or None,
+                    'init_child_result': {
+                        'fork_context': mitogen.core.Context,
+                        'home_dir': str or None,
+                    },
+                    'msg': str or None
+                }
+
+            Where `context` is a reference to the newly constructed context,
+            `init_child_result` is the result of executing
+            :func:`ansible_mitogen.target.init_child` in that context, `msg` is
+            an error message and the remaining fields are :data:`None`, or
+            `msg` is :data:`None` and the remaining fields are set.
+        """
+        try:
+            method = getattr(self.router, spec['method'])
+        except AttributeError:
+            raise Error('unsupported method: %(method)s' % spec)
+
+        context = method(via=via, unidirectional=True, **spec['kwargs'])
+        if via and spec.get('enable_lru'):
+            self._update_lru(context, spec, via)
+
+        # Forget the context when its disconnect event fires.
+        mitogen.core.listen(context, 'disconnect',
+            lambda: self._on_context_disconnect(context))
+
+        self._send_module_forwards(context)
+        init_child_result = context.call(
+            ansible_mitogen.target.init_child,
+            log_level=LOG.getEffectiveLevel(),
+            candidate_temp_dirs=self._get_candidate_temp_dirs(),
+        )
+
+        if os.environ.get('MITOGEN_DUMP_THREAD_STACKS'):
+            from mitogen import debug
+            context.call(debug.dump_to_logger)
+
+        self._key_by_context[context] = key
+        self._refs_by_context[context] = 0
+        return {
+            'context': context,
+            'via': via,
+            'init_child_result': init_child_result,
+            'msg': None,
+        }
+
+    def _wait_or_start(self, spec, via=None):
+        latch = mitogen.core.Latch()
+        key = key_from_dict(via=via, **spec)
+        self._lock.acquire()
+        try:
+            response = self._response_by_key.get(key)
+            if response is not None:
+                self._refs_by_context[response['context']] += 1
+                latch.put(response)
+                return latch
+
+            latches = self._latches_by_key.setdefault(key, [])
+            first = len(latches) == 0
+            latches.append(latch)
+        finally:
+            self._lock.release()
+
+        if first:
+            # I'm the first requestee, so I will create the connection.
+            try:
+                response = self._connect(key, spec, via=via)
+                count = self._produce_response(key, response)
+                # Only record the response for non-error results.
+                self._response_by_key[key] = response
+                # Set the reference count to the number of waiters.
+                self._refs_by_context[response['context']] += count
+            except Exception:
+                self._produce_response(key, sys.exc_info())
+
+        return latch
+
+    disconnect_msg = (
+        'Channel was disconnected while connection attempt was in progress; '
+        'this may be caused by an abnormal Ansible exit, or due to an '
+        'unreliable target.'
+    )
+
+    @mitogen.service.expose(mitogen.service.AllowParents())
+    @mitogen.service.arg_spec({
+        'stack': list
+    })
+    def get(self, stack):
+        """
+        Return a Context referring to an established connection with the given
+        configuration, establishing new connections as necessary.
+
+        :param list stack:
+            Connection descriptions. Each element is a dict containing 'method'
+            and 'kwargs' keys describing the Router method and arguments.
+            Subsequent elements are proxied via the previous.
+
+        :returns dict:
+            * context: mitogen.parent.Context or None.
+            * init_child_result: Result of :func:`init_child`.
+            * msg: StreamError exception text or None.
+            * method_name: string failing method name.
+        """
+        via = None
+        for spec in stack:
+            try:
+                result = self._wait_or_start(spec, via=via).get()
+                if isinstance(result, tuple):  # exc_info()
+                    reraise(*result)
+                via = result['context']
+            except mitogen.core.ChannelError:
+                return {
+                    'context': None,
+                    'init_child_result': None,
+                    'method_name': spec['method'],
+                    'msg': self.disconnect_msg,
+                }
+            except mitogen.core.StreamError as e:
+                return {
+                    'context': None,
+                    'init_child_result': None,
+                    'method_name': spec['method'],
+                    'msg': str(e),
+                }
+
+        return result
+
+
+class ModuleDepService(mitogen.service.Service):
+    """
+    Scan a new-style module and produce a cached mapping of module_utils names
+    to their resolved filesystem paths.
+    """
+    invoker_class = mitogen.service.SerializedInvoker
+
+    def __init__(self, *args, **kwargs):
+        super(ModuleDepService, self).__init__(*args, **kwargs)
+        self._cache = {}
+
+    def _get_builtin_names(self, builtin_path, resolved):
+        return [
+            mitogen.core.to_text(fullname)
+            for fullname, path, is_pkg in resolved
+            if os.path.abspath(path).startswith(builtin_path)
+        ]
+
+    def _get_custom_tups(self, builtin_path, resolved):
+        return [
+            (mitogen.core.to_text(fullname),
+             mitogen.core.to_text(path),
+             is_pkg)
+            for fullname, path, is_pkg in resolved
+            if not os.path.abspath(path).startswith(builtin_path)
+        ]
+
+    @mitogen.service.expose(policy=mitogen.service.AllowParents())
+    @mitogen.service.arg_spec({
+        'module_name': mitogen.core.UnicodeType,
+        'module_path': mitogen.core.FsPathTypes,
+        'search_path': tuple,
+        'builtin_path': mitogen.core.FsPathTypes,
+        'context': mitogen.core.Context,
+    })
+    def scan(self, module_name, module_path, search_path, builtin_path, context):
+        key = (module_name, search_path)
+        if key not in self._cache:
+            resolved = ansible_mitogen.module_finder.scan(
+                module_name=module_name,
+                module_path=module_path,
+                search_path=tuple(search_path) + (builtin_path,),
+            )
+            builtin_path = os.path.abspath(builtin_path)
+            builtin = self._get_builtin_names(builtin_path, resolved)
+            custom = self._get_custom_tups(builtin_path, resolved)
+            self._cache[key] = {
+                'builtin': builtin,
+                'custom': custom,
+            }
+        return self._cache[key]

mitogen/ansible_mitogen/strategy.py

@@ -0,0 +1,373 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import distutils.version
+import os
+import signal
+import threading
+
+try:
+    import setproctitle
+except ImportError:
+    setproctitle = None
+
+import mitogen.core
+import ansible_mitogen.affinity
+import ansible_mitogen.loaders
+import ansible_mitogen.mixins
+import ansible_mitogen.process
+
+import ansible
+import ansible.executor.process.worker
+
+try:
+    # 2.8+ has a standardized "unset" object.
+    from ansible.utils.sentinel import Sentinel
+except ImportError:
+    Sentinel = None
+
+
+ANSIBLE_VERSION_MIN = (2, 3)
+ANSIBLE_VERSION_MAX = (2, 9)
+NEW_VERSION_MSG = (
+    "Your Ansible version (%s) is too recent. The most recent version\n"
+    "supported by Mitogen for Ansible is %s.x. Please check the Mitogen\n"
+    "release notes to see if a new version is available, otherwise\n"
+    "subscribe to the corresponding GitHub issue to be notified when\n"
+    "support becomes available.\n"
+    "\n"
+    "    https://mitogen.rtfd.io/en/latest/changelog.html\n"
+    "    https://github.com/dw/mitogen/issues/\n"
+)
+OLD_VERSION_MSG = (
+    "Your version of Ansible (%s) is too old. The oldest version supported by "
+    "Mitogen for Ansible is %s."
+)
+
+
+def _assert_supported_release():
+    """
+    Throw AnsibleError with a descriptive message in case of being loaded into
+    an unsupported Ansible release.
+    """
+    v = ansible.__version__
+    if not isinstance(v, tuple):
+        v = tuple(distutils.version.LooseVersion(v).version)
+
+    if v[:2] < ANSIBLE_VERSION_MIN:
+        raise ansible.errors.AnsibleError(
+            OLD_VERSION_MSG % (v, ANSIBLE_VERSION_MIN)
+        )
+
+    if v[:2] > ANSIBLE_VERSION_MAX:
+        raise ansible.errors.AnsibleError(
+            NEW_VERSION_MSG % (ansible.__version__, ANSIBLE_VERSION_MAX)
+        )
+
+
+def _patch_awx_callback():
+    """
+    issue #400: AWX loads a display callback that suffers from thread-safety
+    issues. Detect the presence of older AWX versions and patch the bug.
+    """
+    # AWX uses sitecustomize.py to force-load this package. If it exists, we're
+    # running under AWX.
+    try:
+        from awx_display_callback.events import EventContext
+        from awx_display_callback.events import event_context
+    except ImportError:
+        return
+
+    if hasattr(EventContext(), '_local'):
+        # Patched version.
+        return
+
+    def patch_add_local(self, **kwargs):
+        tls = vars(self._local)
+        ctx = tls.setdefault('_ctx', {})
+        ctx.update(kwargs)
+
+    EventContext._local = threading.local()
+    EventContext.add_local = patch_add_local
+
+_patch_awx_callback()
+
+
+def wrap_action_loader__get(name, *args, **kwargs):
+    """
+    While the mitogen strategy is active, trap action_loader.get() calls,
+    augmenting any fetched class with ActionModuleMixin, which replaces various
+    helper methods inherited from ActionBase with implementations that avoid
+    the use of shell fragments wherever possible.
+
+    This is used instead of static subclassing as it generalizes to third party
+    action plugins outside the Ansible tree.
+    """
+    get_kwargs = {'class_only': True}
+    if name in ('fetch',):
+        name = 'mitogen_' + name
+    if ansible.__version__ >= '2.8':
+        get_kwargs['collection_list'] = kwargs.pop('collection_list', None)
+
+    klass = ansible_mitogen.loaders.action_loader__get(name, **get_kwargs)
+    if klass:
+        bases = (ansible_mitogen.mixins.ActionModuleMixin, klass)
+        adorned_klass = type(str(name), bases, {})
+        if kwargs.get('class_only'):
+            return adorned_klass
+        return adorned_klass(*args, **kwargs)
+
+
+REDIRECTED_CONNECTION_PLUGINS = (
+    'buildah',
+    'docker',
+    'kubectl',
+    'jail',
+    'local',
+    'lxc',
+    'lxd',
+    'machinectl',
+    'setns',
+    'ssh',
+)
+
+
+def wrap_connection_loader__get(name, *args, **kwargs):
+    """
+    While a Mitogen strategy is active, rewrite connection_loader.get() calls
+    for some transports into requests for a compatible Mitogen transport.
+    """
+    if name in REDIRECTED_CONNECTION_PLUGINS:
+        name = 'mitogen_' + name
+
+    return ansible_mitogen.loaders.connection_loader__get(name, *args, **kwargs)
+
+
+def wrap_worker__run(self):
+    """
+    While a Mitogen strategy is active, trap WorkerProcess.run() calls and use
+    the opportunity to set the worker's name in the process list and log
+    output, activate profiling if requested, and bind the worker to a specific
+    CPU.
+    """
+    if setproctitle:
+        setproctitle.setproctitle('worker:%s task:%s' % (
+            self._host.name,
+            self._task.action,
+        ))
+
+    # Ignore parent's attempts to murder us when we still need to write
+    # profiling output.
+    if mitogen.core._profile_hook.__name__ != '_profile_hook':
+        signal.signal(signal.SIGTERM, signal.SIG_IGN)
+
+    ansible_mitogen.logging.set_process_name('task')
+    ansible_mitogen.affinity.policy.assign_worker()
+    return mitogen.core._profile_hook('WorkerProcess',
+        lambda: worker__run(self)
+    )
+
+
+class AnsibleWrappers(object):
+    """
+    Manage add/removal of various Ansible runtime hooks.
+    """
+    def _add_plugin_paths(self):
+        """
+        Add the Mitogen plug-in directories to the ModuleLoader path, avoiding
+        the need for manual configuration.
+        """
+        base_dir = os.path.join(os.path.dirname(__file__), 'plugins')
+        ansible_mitogen.loaders.connection_loader.add_directory(
+            os.path.join(base_dir, 'connection')
+        )
+        ansible_mitogen.loaders.action_loader.add_directory(
+            os.path.join(base_dir, 'action')
+        )
+
+    def _install_wrappers(self):
+        """
+        Install our PluginLoader monkey patches and update global variables
+        with references to the real functions.
+        """
+        ansible_mitogen.loaders.action_loader.get = wrap_action_loader__get
+        ansible_mitogen.loaders.connection_loader.get = wrap_connection_loader__get
+
+        global worker__run
+        worker__run = ansible.executor.process.worker.WorkerProcess.run
+        ansible.executor.process.worker.WorkerProcess.run = wrap_worker__run
+
+    def _remove_wrappers(self):
+        """
+        Uninstall the PluginLoader monkey patches.
+        """
+        ansible_mitogen.loaders.action_loader.get = (
+            ansible_mitogen.loaders.action_loader__get
+        )
+        ansible_mitogen.loaders.connection_loader.get = (
+            ansible_mitogen.loaders.connection_loader__get
+        )
+        ansible.executor.process.worker.WorkerProcess.run = worker__run
+
+    def install(self):
+        self._add_plugin_paths()
+        self._install_wrappers()
+
+    def remove(self):
+        self._remove_wrappers()
+
+
+class StrategyMixin(object):
+    """
+    This mix-in enhances any built-in strategy by arranging for an appropriate
+    WorkerModel instance to be constructed as necessary, or for the existing
+    one to be reused.
+
+    The WorkerModel in turn arranges for a connection multiplexer to be started
+    somewhere (by default in an external process), and for WorkerProcesses to
+    grow support for using those top-level services to communicate with remote
+    hosts.
+
+    Mitogen:
+
+        A private Broker IO multiplexer thread is created to dispatch IO
+        between the local Router and any connected streams, including streams
+        connected to Ansible WorkerProcesses, and SSH commands implementing
+        connections to remote machines.
+
+        A Router is created that implements message dispatch to any locally
+        registered handlers, and message routing for remote streams. Router is
+        the junction point through which WorkerProceses and remote SSH contexts
+        can communicate.
+
+        Router additionally adds message handlers for a variety of base
+        services, review the Standard Handles section of the How It Works guide
+        in the documentation.
+
+        A ContextService is installed as a message handler in the connection
+        mutliplexer subprocess and run on a private thread. It is responsible
+        for accepting requests to establish new SSH connections from worker
+        processes, and ensuring precisely one connection exists and is reused
+        for subsequent playbook steps. The service presently runs in a single
+        thread, so to begin with, new SSH connections are serialized.
+
+        Finally a mitogen.unix listener is created through which WorkerProcess
+        can establish a connection back into the connection multiplexer, in
+        order to avail of ContextService. A UNIX listener socket is necessary
+        as there is no more sane mechanism to arrange for IPC between the
+        Router in the connection multiplexer, and the corresponding Router in
+        the worker process.
+
+    Ansible:
+
+        PluginLoader monkey patches are installed to catch attempts to create
+        connection and action plug-ins.
+
+        For connection plug-ins, if the desired method is "local" or "ssh", it
+        is redirected to one of the "mitogen_*" connection plug-ins. That
+        plug-in implements communication via a UNIX socket connection to the
+        connection multiplexer process, and uses ContextService running there
+        to establish a persistent connection to the target.
+
+        For action plug-ins, the original class is looked up as usual, but a
+        new subclass is created dynamically in order to mix-in
+        ansible_mitogen.target.ActionModuleMixin, which overrides many of the
+        methods usually inherited from ActionBase in order to replace them with
+        pure-Python equivalents that avoid the use of shell.
+
+        In particular, _execute_module() is overridden with an implementation
+        that uses ansible_mitogen.target.run_module() executed in the target
+        Context. run_module() implements module execution by importing the
+        module as if it were a normal Python module, and capturing its output
+        in the remote process. Since the Mitogen module loader is active in the
+        remote process, all the heavy lifting of transferring the action module
+        and its dependencies are automatically handled by Mitogen.
+    """
+
+    def _queue_task(self, host, task, task_vars, play_context):
+        """
+        Many PluginLoader caches are defective as they are only populated in
+        the ephemeral WorkerProcess. Touch each plug-in path before forking to
+        ensure all workers receive a hot cache.
+        """
+        ansible_mitogen.loaders.module_loader.find_plugin(
+            name=task.action,
+            mod_type='',
+        )
+        ansible_mitogen.loaders.action_loader.get(
+            name=task.action,
+            class_only=True,
+        )
+        if play_context.connection is not Sentinel:
+            # 2.8 appears to defer computing this until inside the worker.
+            # TODO: figure out where it has moved.
+            ansible_mitogen.loaders.connection_loader.get(
+                name=play_context.connection,
+                class_only=True,
+            )
+
+        return super(StrategyMixin, self)._queue_task(
+            host=host,
+            task=task,
+            task_vars=task_vars,
+            play_context=play_context,
+        )
+
+    def _get_worker_model(self):
+        """
+        In classic mode a single :class:`WorkerModel` exists, which manages
+        references and configuration of the associated connection multiplexer
+        process.
+        """
+        return ansible_mitogen.process.get_classic_worker_model()
+
+    def run(self, iterator, play_context, result=0):
+        """
+        Wrap :meth:`run` to ensure requisite infrastructure and modifications
+        are configured for the duration of the call.
+        """
+        _assert_supported_release()
+        wrappers = AnsibleWrappers()
+        self._worker_model = self._get_worker_model()
+        ansible_mitogen.process.set_worker_model(self._worker_model)
+        try:
+            self._worker_model.on_strategy_start()
+            try:
+                wrappers.install()
+                try:
+                    run = super(StrategyMixin, self).run
+                    return mitogen.core._profile_hook('Strategy',
+                        lambda: run(iterator, play_context)
+                    )
+                finally:
+                    wrappers.remove()
+            finally:
+                self._worker_model.on_strategy_complete()
+        finally:
+            ansible_mitogen.process.set_worker_model(None)

mitogen/ansible_mitogen/target.py

@@ -0,0 +1,777 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+# !mitogen: minify_safe
+
+"""
+Helper functions intended to be executed on the target. These are entrypoints
+for file transfer, module execution and sundry bits like changing file modes.
+"""
+
+import errno
+import grp
+import operator
+import os
+import pwd
+import re
+import signal
+import stat
+import subprocess
+import sys
+import tempfile
+import traceback
+import types
+
+# Absolute imports for <2.5.
+logging = __import__('logging')
+
+import mitogen.core
+import mitogen.fork
+import mitogen.parent
+import mitogen.service
+from mitogen.core import b
+
+try:
+    import json
+except ImportError:
+    import simplejson as json
+
+try:
+    reduce
+except NameError:
+    # Python 3.x.
+    from functools import reduce
+
+try:
+    BaseException
+except NameError:
+    # Python 2.4
+    BaseException = Exception
+
+
+# Ansible since PR #41749 inserts "import __main__" into
+# ansible.module_utils.basic. Mitogen's importer will refuse such an import, so
+# we must setup a fake "__main__" before that module is ever imported. The
+# str() is to cast Unicode to bytes on Python 2.6.
+if not sys.modules.get(str('__main__')):
+    sys.modules[str('__main__')] = types.ModuleType(str('__main__'))
+
+import ansible.module_utils.json_utils
+import ansible_mitogen.runner
+
+
+LOG = logging.getLogger(__name__)
+
+MAKE_TEMP_FAILED_MSG = (
+    u"Unable to find a useable temporary directory. This likely means no\n"
+    u"system-supplied TMP directory can be written to, or all directories\n"
+    u"were mounted on 'noexec' filesystems.\n"
+    u"\n"
+    u"The following paths were tried:\n"
+    u"    %(paths)s\n"
+    u"\n"
+    u"Please check '-vvv' output for a log of individual path errors."
+)
+
+# Python 2.4/2.5 cannot support fork+threads whatsoever, it doesn't even fix up
+# interpreter state. So 2.4/2.5 interpreters start .local() contexts for
+# isolation instead. Since we don't have any crazy memory sharing problems to
+# avoid, there is no virginal fork parent either. The child is started directly
+# from the login/become process. In future this will be default everywhere,
+# fork is brainwrong from the stone age.
+FORK_SUPPORTED = sys.version_info >= (2, 6)
+
+#: Initialized to an econtext.parent.Context pointing at a pristine fork of
+#: the target Python interpreter before it executes any code or imports.
+_fork_parent = None
+
+#: Set by :func:`init_child` to the name of a writeable and executable
+#: temporary directory accessible by the active user account.
+good_temp_dir = None
+
+
+def subprocess__Popen__close_fds(self, but):
+    """
+    issue #362, #435: subprocess.Popen(close_fds=True) aka.
+    AnsibleModule.run_command() loops the entire FD space on Python<3.2.
+    CentOS>5 ships with 1,048,576 FDs by default, resulting in huge (>500ms)
+    latency starting children. Therefore replace Popen._close_fds on Linux with
+    a version that is O(fds) rather than O(_SC_OPEN_MAX).
+    """
+    try:
+        names = os.listdir(u'/proc/self/fd')
+    except OSError:
+        # May fail if acting on a container that does not have /proc mounted.
+        self._original_close_fds(but)
+        return
+
+    for name in names:
+        if not name.isdigit():
+            continue
+
+        fd = int(name, 10)
+        if fd > 2 and fd != but:
+            try:
+                os.close(fd)
+            except OSError:
+                pass
+
+
+if (
+    sys.platform.startswith(u'linux') and
+    sys.version < u'3.0' and
+    hasattr(subprocess.Popen, u'_close_fds') and
+    not mitogen.is_master
+):
+    subprocess.Popen._original_close_fds = subprocess.Popen._close_fds
+    subprocess.Popen._close_fds = subprocess__Popen__close_fds
+
+
+def get_small_file(context, path):
+    """
+    Basic in-memory caching module fetcher. This generates one roundtrip for
+    every previously unseen file, so it is only a temporary solution.
+
+    :param context:
+        Context we should direct FileService requests to. For now (and probably
+        forever) this is just the top-level Mitogen connection manager process.
+    :param path:
+        Path to fetch from FileService, must previously have been registered by
+        a privileged context using the `register` command.
+    :returns:
+        Bytestring file data.
+    """
+    pool = mitogen.service.get_or_create_pool(router=context.router)
+    service = pool.get_service(u'mitogen.service.PushFileService')
+    return service.get(path)
+
+
+def transfer_file(context, in_path, out_path, sync=False, set_owner=False):
+    """
+    Streamily download a file from the connection multiplexer process in the
+    controller.
+
+    :param mitogen.core.Context context:
+        Reference to the context hosting the FileService that will transmit the
+        file.
+    :param bytes in_path:
+        FileService registered name of the input file.
+    :param bytes out_path:
+        Name of the output path on the local disk.
+    :param bool sync:
+        If :data:`True`, ensure the file content and metadat are fully on disk
+        before renaming the temporary file over the existing file. This should
+        ensure in the case of system crash, either the entire old or new file
+        are visible post-reboot.
+    :param bool set_owner:
+        If :data:`True`, look up the metadata username and group on the local
+        system and file the file owner using :func:`os.fchmod`.
+    """
+    out_path = os.path.abspath(out_path)
+    fd, tmp_path = tempfile.mkstemp(suffix='.tmp',
+                                    prefix='.ansible_mitogen_transfer-',
+                                    dir=os.path.dirname(out_path))
+    fp = os.fdopen(fd, 'wb', mitogen.core.CHUNK_SIZE)
+    LOG.debug('transfer_file(%r) temporary file: %s', out_path, tmp_path)
+
+    try:
+        try:
+            ok, metadata = mitogen.service.FileService.get(
+                context=context,
+                path=in_path,
+                out_fp=fp,
+            )
+            if not ok:
+                raise IOError('transfer of %r was interrupted.' % (in_path,))
+
+            set_file_mode(tmp_path, metadata['mode'], fd=fp.fileno())
+            if set_owner:
+                set_file_owner(tmp_path, metadata['owner'], metadata['group'],
+                               fd=fp.fileno())
+        finally:
+            fp.close()
+
+        if sync:
+            os.fsync(fp.fileno())
+        os.rename(tmp_path, out_path)
+    except BaseException:
+        os.unlink(tmp_path)
+        raise
+
+    os.utime(out_path, (metadata['atime'], metadata['mtime']))
+
+
+def prune_tree(path):
+    """
+    Like shutil.rmtree(), but log errors rather than discard them, and do not
+    waste multiple os.stat() calls discovering whether the object can be
+    deleted, just try deleting it instead.
+    """
+    try:
+        os.unlink(path)
+        return
+    except OSError:
+        e = sys.exc_info()[1]
+        if not (os.path.isdir(path) and
+                e.args[0] in (errno.EPERM, errno.EISDIR)):
+            LOG.error('prune_tree(%r): %s', path, e)
+            return
+
+    try:
+        # Ensure write access for readonly directories. Ignore error in case
+        # path is on a weird filesystem (e.g. vfat).
+        os.chmod(path, int('0700', 8))
+    except OSError:
+        e = sys.exc_info()[1]
+        LOG.warning('prune_tree(%r): %s', path, e)
+
+    try:
+        for name in os.listdir(path):
+            if name not in ('.', '..'):
+                prune_tree(os.path.join(path, name))
+        os.rmdir(path)
+    except OSError:
+        e = sys.exc_info()[1]
+        LOG.error('prune_tree(%r): %s', path, e)
+
+
+def is_good_temp_dir(path):
+    """
+    Return :data:`True` if `path` can be used as a temporary directory, logging
+    any failures that may cause it to be unsuitable. If the directory doesn't
+    exist, we attempt to create it using :func:`os.makedirs`.
+    """
+    if not os.path.exists(path):
+        try:
+            os.makedirs(path, mode=int('0700', 8))
+        except OSError:
+            e = sys.exc_info()[1]
+            LOG.debug('temp dir %r unusable: did not exist and attempting '
+                      'to create it failed: %s', path, e)
+            return False
+
+    try:
+        tmp = tempfile.NamedTemporaryFile(
+            prefix='ansible_mitogen_is_good_temp_dir',
+            dir=path,
+        )
+    except (OSError, IOError):
+        e = sys.exc_info()[1]
+        LOG.debug('temp dir %r unusable: %s', path, e)
+        return False
+
+    try:
+        try:
+            os.chmod(tmp.name, int('0700', 8))
+        except OSError:
+            e = sys.exc_info()[1]
+            LOG.debug('temp dir %r unusable: chmod failed: %s', path, e)
+            return False
+
+        try:
+            # access(.., X_OK) is sufficient to detect noexec.
+            if not os.access(tmp.name, os.X_OK):
+                raise OSError('filesystem appears to be mounted noexec')
+        except OSError:
+            e = sys.exc_info()[1]
+            LOG.debug('temp dir %r unusable: %s', path, e)
+            return False
+    finally:
+        tmp.close()
+
+    return True
+
+
+def find_good_temp_dir(candidate_temp_dirs):
+    """
+    Given a list of candidate temp directories extracted from ``ansible.cfg``,
+    combine it with the Python-builtin list of candidate directories used by
+    :mod:`tempfile`, then iteratively try each until one is found that is both
+    writeable and executable.
+
+    :param list candidate_temp_dirs:
+        List of candidate $variable-expanded and tilde-expanded directory paths
+        that may be usable as a temporary directory.
+    """
+    paths = [os.path.expandvars(os.path.expanduser(p))
+             for p in candidate_temp_dirs]
+    paths.extend(tempfile._candidate_tempdir_list())
+
+    for path in paths:
+        if is_good_temp_dir(path):
+            LOG.debug('Selected temp directory: %r (from %r)', path, paths)
+            return path
+
+    raise IOError(MAKE_TEMP_FAILED_MSG % {
+        'paths': '\n    '.join(paths),
+    })
+
+
+@mitogen.core.takes_econtext
+def init_child(econtext, log_level, candidate_temp_dirs):
+    """
+    Called by ContextService immediately after connection; arranges for the
+    (presently) spotless Python interpreter to be forked, where the newly
+    forked interpreter becomes the parent of any newly forked future
+    interpreters.
+
+    This is necessary to prevent modules that are executed in-process from
+    polluting the global interpreter state in a way that effects explicitly
+    isolated modules.
+
+    :param int log_level:
+        Logging package level active in the master.
+    :param list[str] candidate_temp_dirs:
+        List of $variable-expanded and tilde-expanded directory names to add to
+        candidate list of temporary directories.
+
+    :returns:
+        Dict like::
+
+            {
+                'fork_context': mitogen.core.Context or None,
+                'good_temp_dir': ...
+                'home_dir': str
+            }
+
+        Where `fork_context` refers to the newly forked 'fork parent' context
+        the controller will use to start forked jobs, and `home_dir` is the
+        home directory for the active user account.
+    """
+    # Copying the master's log level causes log messages to be filtered before
+    # they reach LogForwarder, thus reducing an influx of tiny messges waking
+    # the connection multiplexer process in the master.
+    LOG.setLevel(log_level)
+    logging.getLogger('ansible_mitogen').setLevel(log_level)
+
+    # issue #536: if the json module is available, remove simplejson from the
+    # importer whitelist to avoid confusing certain Ansible modules.
+    if json.__name__ == 'json':
+        econtext.importer.whitelist.remove('simplejson')
+
+    global _fork_parent
+    if FORK_SUPPORTED:
+        mitogen.parent.upgrade_router(econtext)
+        _fork_parent = econtext.router.fork()
+
+    global good_temp_dir
+    good_temp_dir = find_good_temp_dir(candidate_temp_dirs)
+
+    return {
+        u'fork_context': _fork_parent,
+        u'home_dir': mitogen.core.to_text(os.path.expanduser('~')),
+        u'good_temp_dir': good_temp_dir,
+    }
+
+
+@mitogen.core.takes_econtext
+def spawn_isolated_child(econtext):
+    """
+    For helper functions executed in the fork parent context, arrange for
+    the context's router to be upgraded as necessary and for a new child to be
+    prepared.
+
+    The actual fork occurs from the 'virginal fork parent', which does not have
+    any Ansible modules loaded prior to fork, to avoid conflicts resulting from
+    custom module_utils paths.
+    """
+    mitogen.parent.upgrade_router(econtext)
+    if FORK_SUPPORTED:
+        context = econtext.router.fork()
+    else:
+        context = econtext.router.local()
+    LOG.debug('create_fork_child() -> %r', context)
+    return context
+
+
+def run_module(kwargs):
+    """
+    Set up the process environment in preparation for running an Ansible
+    module. This monkey-patches the Ansible libraries in various places to
+    prevent it from trying to kill the process on completion, and to prevent it
+    from reading sys.stdin.
+    """
+    runner_name = kwargs.pop('runner_name')
+    klass = getattr(ansible_mitogen.runner, runner_name)
+    impl = klass(**mitogen.core.Kwargs(kwargs))
+    return impl.run()
+
+
+def _get_async_dir():
+    return os.path.expanduser(
+        os.environ.get('ANSIBLE_ASYNC_DIR', '~/.ansible_async')
+    )
+
+
+class AsyncRunner(object):
+    def __init__(self, job_id, timeout_secs, started_sender, econtext, kwargs):
+        self.job_id = job_id
+        self.timeout_secs = timeout_secs
+        self.started_sender = started_sender
+        self.econtext = econtext
+        self.kwargs = kwargs
+        self._timed_out = False
+        self._init_path()
+
+    def _init_path(self):
+        async_dir = _get_async_dir()
+        if not os.path.exists(async_dir):
+            os.makedirs(async_dir)
+        self.path = os.path.join(async_dir, self.job_id)
+
+    def _update(self, dct):
+        """
+        Update an async job status file.
+        """
+        LOG.info('%r._update(%r, %r)', self, self.job_id, dct)
+        dct.setdefault('ansible_job_id', self.job_id)
+        dct.setdefault('data', '')
+
+        fp = open(self.path + '.tmp', 'w')
+        try:
+            fp.write(json.dumps(dct))
+        finally:
+            fp.close()
+        os.rename(self.path + '.tmp', self.path)
+
+    def _on_sigalrm(self, signum, frame):
+        """
+        Respond to SIGALRM (job timeout) by updating the job file and killing
+        the process.
+        """
+        msg = "Job reached maximum time limit of %d seconds." % (
+            self.timeout_secs,
+        )
+        self._update({
+            "failed": 1,
+            "finished": 1,
+            "msg": msg,
+        })
+        self._timed_out = True
+        self.econtext.broker.shutdown()
+
+    def _install_alarm(self):
+        signal.signal(signal.SIGALRM, self._on_sigalrm)
+        signal.alarm(self.timeout_secs)
+
+    def _run_module(self):
+        kwargs = dict(self.kwargs, **{
+            'detach': True,
+            'econtext': self.econtext,
+            'emulate_tty': False,
+        })
+        return run_module(kwargs)
+
+    def _parse_result(self, dct):
+        filtered, warnings = (
+            ansible.module_utils.json_utils.
+            _filter_non_json_lines(dct['stdout'])
+        )
+        result = json.loads(filtered)
+        result.setdefault('warnings', []).extend(warnings)
+        result['stderr'] = dct['stderr'] or result.get('stderr', '')
+        self._update(result)
+
+    def _run(self):
+        """
+        1. Immediately updates the status file to mark the job as started.
+        2. Installs a timer/signal handler to implement the time limit.
+        3. Runs as with run_module(), writing the result to the status file.
+
+        :param dict kwargs:
+            Runner keyword arguments.
+        :param str job_id:
+            String job ID.
+        :param int timeout_secs:
+            If >0, limit the task's maximum run time.
+        """
+        self._update({
+            'started': 1,
+            'finished': 0,
+            'pid': os.getpid()
+        })
+        self.started_sender.send(True)
+
+        if self.timeout_secs > 0:
+            self._install_alarm()
+
+        dct = self._run_module()
+        if not self._timed_out:
+            # After SIGALRM fires, there is a window between broker responding
+            # to shutdown() by killing the process, and work continuing on the
+            # main thread. If main thread was asleep in at least
+            # basic.py/select.select(), an EINTR will be raised. We want to
+            # discard that exception.
+            try:
+                self._parse_result(dct)
+            except Exception:
+                self._update({
+                    "failed": 1,
+                    "msg": traceback.format_exc(),
+                    "data": dct['stdout'],  # temporary notice only
+                    "stderr": dct['stderr']
+                })
+
+    def run(self):
+        try:
+            try:
+                self._run()
+            except Exception:
+                self._update({
+                    "failed": 1,
+                    "msg": traceback.format_exc(),
+                })
+        finally:
+            self.econtext.broker.shutdown()
+
+
+@mitogen.core.takes_econtext
+def run_module_async(kwargs, job_id, timeout_secs, started_sender, econtext):
+    """
+    Execute a module with its run status and result written to a file,
+    terminating on the process on completion. This function must run in a child
+    forked using :func:`create_fork_child`.
+
+    @param mitogen.core.Sender started_sender:
+        A sender that will receive :data:`True` once the job has reached a
+        point where its initial job file has been written. This is required to
+        avoid a race where an overly eager controller can check for a task
+        before it has reached that point in execution, which is possible at
+        least on Python 2.4, where forking is not available for async tasks.
+    """
+    arunner = AsyncRunner(
+        job_id,
+        timeout_secs,
+        started_sender,
+        econtext,
+        kwargs
+    )
+    arunner.run()
+
+
+def get_user_shell():
+    """
+    For commands executed directly via an SSH command-line, SSH looks up the
+    user's shell via getpwuid() and only defaults to /bin/sh if that field is
+    missing or empty.
+    """
+    try:
+        pw_shell = pwd.getpwuid(os.geteuid()).pw_shell
+    except KeyError:
+        pw_shell = None
+
+    return pw_shell or '/bin/sh'
+
+
+def exec_args(args, in_data='', chdir=None, shell=None, emulate_tty=False):
+    """
+    Run a command in a subprocess, emulating the argument handling behaviour of
+    SSH.
+
+    :param list[str]:
+        Argument vector.
+    :param bytes in_data:
+        Optional standard input for the command.
+    :param bool emulate_tty:
+        If :data:`True`, arrange for stdout and stderr to be merged into the
+        stdout pipe and for LF to be translated into CRLF, emulating the
+        behaviour of a TTY.
+    :return:
+        (return code, stdout bytes, stderr bytes)
+    """
+    LOG.debug('exec_args(%r, ..., chdir=%r)', args, chdir)
+    assert isinstance(args, list)
+
+    if emulate_tty:
+        stderr = subprocess.STDOUT
+    else:
+        stderr = subprocess.PIPE
+
+    proc = subprocess.Popen(
+        args=args,
+        stdout=subprocess.PIPE,
+        stderr=stderr,
+        stdin=subprocess.PIPE,
+        cwd=chdir,
+    )
+    stdout, stderr = proc.communicate(in_data)
+
+    if emulate_tty:
+        stdout = stdout.replace(b('\n'), b('\r\n'))
+    return proc.returncode, stdout, stderr or b('')
+
+
+def exec_command(cmd, in_data='', chdir=None, shell=None, emulate_tty=False):
+    """
+    Run a command in a subprocess, emulating the argument handling behaviour of
+    SSH.
+
+    :param bytes cmd:
+        String command line, passed to user's shell.
+    :param bytes in_data:
+        Optional standard input for the command.
+    :return:
+        (return code, stdout bytes, stderr bytes)
+    """
+    assert isinstance(cmd, mitogen.core.UnicodeType)
+    return exec_args(
+        args=[get_user_shell(), '-c', cmd],
+        in_data=in_data,
+        chdir=chdir,
+        shell=shell,
+        emulate_tty=emulate_tty,
+    )
+
+
+def read_path(path):
+    """
+    Fetch the contents of a filesystem `path` as bytes.
+    """
+    return open(path, 'rb').read()
+
+
+def set_file_owner(path, owner, group=None, fd=None):
+    if owner:
+        uid = pwd.getpwnam(owner).pw_uid
+    else:
+        uid = os.geteuid()
+
+    if group:
+        gid = grp.getgrnam(group).gr_gid
+    else:
+        gid = os.getegid()
+
+    if fd is not None and hasattr(os, 'fchown'):
+        os.fchown(fd, (uid, gid))
+    else:
+        # Python<2.6
+        os.chown(path, (uid, gid))
+
+
+def write_path(path, s, owner=None, group=None, mode=None,
+               utimes=None, sync=False):
+    """
+    Writes bytes `s` to a filesystem `path`.
+    """
+    path = os.path.abspath(path)
+    fd, tmp_path = tempfile.mkstemp(suffix='.tmp',
+                                    prefix='.ansible_mitogen_transfer-',
+                                    dir=os.path.dirname(path))
+    fp = os.fdopen(fd, 'wb', mitogen.core.CHUNK_SIZE)
+    LOG.debug('write_path(path=%r) temporary file: %s', path, tmp_path)
+
+    try:
+        try:
+            if mode:
+                set_file_mode(tmp_path, mode, fd=fp.fileno())
+            if owner or group:
+                set_file_owner(tmp_path, owner, group, fd=fp.fileno())
+            fp.write(s)
+        finally:
+            fp.close()
+
+        if sync:
+            os.fsync(fp.fileno())
+        os.rename(tmp_path, path)
+    except BaseException:
+        os.unlink(tmp_path)
+        raise
+
+    if utimes:
+        os.utime(path, utimes)
+
+
+CHMOD_CLAUSE_PAT = re.compile(r'([uoga]*)([+\-=])([ugo]|[rwx]*)')
+CHMOD_MASKS = {
+    'u': stat.S_IRWXU,
+    'g': stat.S_IRWXG,
+    'o': stat.S_IRWXO,
+    'a': (stat.S_IRWXU | stat.S_IRWXG | stat.S_IRWXO),
+}
+CHMOD_BITS = {
+    'u': {'r': stat.S_IRUSR, 'w': stat.S_IWUSR, 'x': stat.S_IXUSR},
+    'g': {'r': stat.S_IRGRP, 'w': stat.S_IWGRP, 'x': stat.S_IXGRP},
+    'o': {'r': stat.S_IROTH, 'w': stat.S_IWOTH, 'x': stat.S_IXOTH},
+    'a': {
+        'r': (stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH),
+        'w': (stat.S_IWUSR | stat.S_IWGRP | stat.S_IWOTH),
+        'x': (stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH)
+    }
+}
+
+
+def apply_mode_spec(spec, mode):
+    """
+    Given a symbolic file mode change specification in the style of chmod(1)
+    `spec`, apply changes in the specification to the numeric file mode `mode`.
+    """
+    for clause in mitogen.core.to_text(spec).split(','):
+        match = CHMOD_CLAUSE_PAT.match(clause)
+        who, op, perms = match.groups()
+        for ch in who or 'a':
+            mask = CHMOD_MASKS[ch]
+            bits = CHMOD_BITS[ch]
+            cur_perm_bits = mode & mask
+            new_perm_bits = reduce(operator.or_, (bits[p] for p in perms), 0)
+            mode &= ~mask
+            if op == '=':
+                mode |= new_perm_bits
+            elif op == '+':
+                mode |= new_perm_bits | cur_perm_bits
+            else:
+                mode |= cur_perm_bits & ~new_perm_bits
+    return mode
+
+
+def set_file_mode(path, spec, fd=None):
+    """
+    Update the permissions of a file using the same syntax as chmod(1).
+    """
+    if isinstance(spec, int):
+        new_mode = spec
+    elif not mitogen.core.PY3 and isinstance(spec, long):
+        new_mode = spec
+    elif spec.isdigit():
+        new_mode = int(spec, 8)
+    else:
+        mode = os.stat(path).st_mode
+        new_mode = apply_mode_spec(spec, mode)
+
+    if fd is not None and hasattr(os, 'fchmod'):
+        os.fchmod(fd, new_mode)
+    else:
+        os.chmod(path, new_mode)
+
+
+def file_exists(path):
+    """
+    Return :data:`True` if `path` exists. This is a wrapper function over
+    :func:`os.path.exists`, since its implementation module varies across
+    Python versions.
+    """
+    return os.path.exists(path)

mitogen/ansible_mitogen/transport_config.py

@@ -0,0 +1,699 @@
+# Copyright 2019, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+"""
+Mitogen extends Ansible's target configuration mechanism in several ways that
+require some care:
+
+* Per-task configurables in Ansible like ansible_python_interpreter are
+  connection-layer configurables in Mitogen. They must be extracted during each
+  task execution to form the complete connection-layer configuration.
+
+* Mitogen has extra configurables not supported by Ansible at all, such as
+  mitogen_ssh_debug_level. These are extracted the same way as
+  ansible_python_interpreter.
+
+* Mitogen allows connections to be delegated to other machines. Ansible has no
+  internal framework for this, and so Mitogen must figure out a delegated
+  connection configuration all on its own. It cannot reuse much of the Ansible
+  machinery for building a connection configuration, as that machinery is
+  deeply spread out and hard-wired to expect Ansible's usual mode of operation.
+
+For normal and delegate_to connections, Ansible's PlayContext is reused where
+possible to maximize compatibility, but for proxy hops, configurations are
+built up using the HostVars magic class to call VariableManager.get_vars()
+behind the scenes on our behalf. Where Ansible has multiple sources of a
+configuration item, for example, ansible_ssh_extra_args, Mitogen must (ideally
+perfectly) reproduce how Ansible arrives at its value, without using mechanisms
+that are hard-wired or change across Ansible versions.
+
+That is what this file is for. It exports two spec classes, one that takes all
+information from PlayContext, and another that takes (almost) all information
+from HostVars.
+"""
+
+import abc
+import os
+import ansible.utils.shlex
+import ansible.constants as C
+
+from ansible.module_utils.six import with_metaclass
+
+
+import mitogen.core
+
+
+def parse_python_path(s):
+    """
+    Given the string set for ansible_python_interpeter, parse it using shell
+    syntax and return an appropriate argument vector.
+    """
+    if s:
+        return ansible.utils.shlex.shlex_split(s)
+
+
+def optional_secret(value):
+    """
+    Wrap `value` in :class:`mitogen.core.Secret` if it is not :data:`None`,
+    otherwise return :data:`None`.
+    """
+    if value is not None:
+        return mitogen.core.Secret(value)
+
+
+def first_true(it, default=None):
+    """
+    Return the first truthy element from `it`.
+    """
+    for elem in it:
+        if elem:
+            return elem
+    return default
+
+
+class Spec(with_metaclass(abc.ABCMeta, object)):
+    """
+    A source for variables that comprise a connection configuration.
+    """
+
+    @abc.abstractmethod
+    def transport(self):
+        """
+        The name of the Ansible plug-in implementing the connection.
+        """
+
+    @abc.abstractmethod
+    def inventory_name(self):
+        """
+        The name of the target being connected to as it appears in Ansible's
+        inventory.
+        """
+
+    @abc.abstractmethod
+    def remote_addr(self):
+        """
+        The network address of the target, or for container and other special
+        targets, some other unique identifier.
+        """
+
+    @abc.abstractmethod
+    def remote_user(self):
+        """
+        The username of the login account on the target.
+        """
+
+    @abc.abstractmethod
+    def password(self):
+        """
+        The password of the login account on the target.
+        """
+
+    @abc.abstractmethod
+    def become(self):
+        """
+        :data:`True` if privilege escalation should be active.
+        """
+
+    @abc.abstractmethod
+    def become_method(self):
+        """
+        The name of the Ansible become method to use.
+        """
+
+    @abc.abstractmethod
+    def become_user(self):
+        """
+        The username of the target account for become.
+        """
+
+    @abc.abstractmethod
+    def become_pass(self):
+        """
+        The password of the target account for become.
+        """
+
+    @abc.abstractmethod
+    def port(self):
+        """
+        The port of the login service on the target machine.
+        """
+
+    @abc.abstractmethod
+    def python_path(self):
+        """
+        Path to the Python interpreter on the target machine.
+        """
+
+    @abc.abstractmethod
+    def private_key_file(self):
+        """
+        Path to the SSH private key file to use to login.
+        """
+
+    @abc.abstractmethod
+    def ssh_executable(self):
+        """
+        Path to the SSH executable.
+        """
+
+    @abc.abstractmethod
+    def timeout(self):
+        """
+        The generic timeout for all connections.
+        """
+
+    @abc.abstractmethod
+    def ansible_ssh_timeout(self):
+        """
+        The SSH-specific timeout for a connection.
+        """
+
+    @abc.abstractmethod
+    def ssh_args(self):
+        """
+        The list of additional arguments that should be included in an SSH
+        invocation.
+        """
+
+    @abc.abstractmethod
+    def become_exe(self):
+        """
+        The path to the executable implementing the become method on the remote
+        machine.
+        """
+
+    @abc.abstractmethod
+    def sudo_args(self):
+        """
+        The list of additional arguments that should be included in a become
+        invocation.
+        """
+        # TODO: split out into sudo_args/become_args.
+
+    @abc.abstractmethod
+    def mitogen_via(self):
+        """
+        The value of the mitogen_via= variable for this connection. Indicates
+        the connection should be established via an intermediary.
+        """
+
+    @abc.abstractmethod
+    def mitogen_kind(self):
+        """
+        The type of container to use with the "setns" transport.
+        """
+
+    @abc.abstractmethod
+    def mitogen_mask_remote_name(self):
+        """
+        Specifies whether to set a fixed "remote_name" field. The remote_name
+        is the suffix of `argv[0]` for remote interpreters. By default it
+        includes identifying information from the local process, which may be
+        undesirable in some circumstances.
+        """
+
+    @abc.abstractmethod
+    def mitogen_buildah_path(self):
+        """
+        The path to the "buildah" program for the 'buildah' transport.
+        """
+
+    @abc.abstractmethod
+    def mitogen_docker_path(self):
+        """
+        The path to the "docker" program for the 'docker' transport.
+        """
+
+    @abc.abstractmethod
+    def mitogen_kubectl_path(self):
+        """
+        The path to the "kubectl" program for the 'docker' transport.
+        """
+
+    @abc.abstractmethod
+    def mitogen_lxc_path(self):
+        """
+        The path to the "lxc" program for the 'lxd' transport.
+        """
+
+    @abc.abstractmethod
+    def mitogen_lxc_attach_path(self):
+        """
+        The path to the "lxc-attach" program for the 'lxc' transport.
+        """
+
+    @abc.abstractmethod
+    def mitogen_lxc_info_path(self):
+        """
+        The path to the "lxc-info" program for the 'lxc' transport.
+        """
+
+    @abc.abstractmethod
+    def mitogen_machinectl_path(self):
+        """
+        The path to the "machinectl" program for the 'setns' transport.
+        """
+
+    @abc.abstractmethod
+    def mitogen_ssh_keepalive_interval(self):
+        """
+        The SSH ServerAliveInterval.
+        """
+
+    @abc.abstractmethod
+    def mitogen_ssh_keepalive_count(self):
+        """
+        The SSH ServerAliveCount.
+        """
+
+    @abc.abstractmethod
+    def mitogen_ssh_debug_level(self):
+        """
+        The SSH debug level.
+        """
+
+    @abc.abstractmethod
+    def mitogen_ssh_compression(self):
+        """
+        Whether SSH compression is enabled.
+        """
+
+    @abc.abstractmethod
+    def extra_args(self):
+        """
+        Connection-specific arguments.
+        """
+
+    @abc.abstractmethod
+    def ansible_doas_exe(self):
+        """
+        Value of "ansible_doas_exe" variable.
+        """
+
+
+class PlayContextSpec(Spec):
+    """
+    PlayContextSpec takes almost all its information as-is from Ansible's
+    PlayContext. It is used for normal connections and delegate_to connections,
+    and should always be accurate.
+    """
+    def __init__(self, connection, play_context, transport, inventory_name):
+        self._connection = connection
+        self._play_context = play_context
+        self._transport = transport
+        self._inventory_name = inventory_name
+
+    def transport(self):
+        return self._transport
+
+    def inventory_name(self):
+        return self._inventory_name
+
+    def remote_addr(self):
+        return self._play_context.remote_addr
+
+    def remote_user(self):
+        return self._play_context.remote_user
+
+    def become(self):
+        return self._play_context.become
+
+    def become_method(self):
+        return self._play_context.become_method
+
+    def become_user(self):
+        return self._play_context.become_user
+
+    def become_pass(self):
+        return optional_secret(self._play_context.become_pass)
+
+    def password(self):
+        return optional_secret(self._play_context.password)
+
+    def port(self):
+        return self._play_context.port
+
+    def python_path(self):
+        s = self._connection.get_task_var('ansible_python_interpreter')
+        # #511, #536: executor/module_common.py::_get_shebang() hard-wires
+        # "/usr/bin/python" as the default interpreter path if no other
+        # interpreter is specified.
+        return parse_python_path(s or '/usr/bin/python')
+
+    def private_key_file(self):
+        return self._play_context.private_key_file
+
+    def ssh_executable(self):
+        return self._play_context.ssh_executable
+
+    def timeout(self):
+        return self._play_context.timeout
+
+    def ansible_ssh_timeout(self):
+        return (
+            self._connection.get_task_var('ansible_timeout') or
+            self._connection.get_task_var('ansible_ssh_timeout') or
+            self.timeout()
+        )
+
+    def ssh_args(self):
+        return [
+            mitogen.core.to_text(term)
+            for s in (
+                getattr(self._play_context, 'ssh_args', ''),
+                getattr(self._play_context, 'ssh_common_args', ''),
+                getattr(self._play_context, 'ssh_extra_args', '')
+            )
+            for term in ansible.utils.shlex.shlex_split(s or '')
+        ]
+
+    def become_exe(self):
+        # In Ansible 2.8, PlayContext.become_exe always has a default value due
+        # to the new options mechanism. Previously it was only set if a value
+        # ("somewhere") had been specified for the task.
+        # For consistency in the tests, here we make older Ansibles behave like
+        # newer Ansibles.
+        exe = self._play_context.become_exe
+        if exe is None and self._play_context.become_method == 'sudo':
+            exe = 'sudo'
+        return exe
+
+    def sudo_args(self):
+        return [
+            mitogen.core.to_text(term)
+            for term in ansible.utils.shlex.shlex_split(
+                first_true((
+                    self._play_context.become_flags,
+                    # Ansible <=2.7.
+                    getattr(self._play_context, 'sudo_flags', ''),
+                    # Ansible <=2.3.
+                    getattr(C, 'DEFAULT_BECOME_FLAGS', ''),
+                    getattr(C, 'DEFAULT_SUDO_FLAGS', '')
+                ), default='')
+            )
+        ]
+
+    def mitogen_via(self):
+        return self._connection.get_task_var('mitogen_via')
+
+    def mitogen_kind(self):
+        return self._connection.get_task_var('mitogen_kind')
+
+    def mitogen_mask_remote_name(self):
+        return self._connection.get_task_var('mitogen_mask_remote_name')
+
+    def mitogen_buildah_path(self):
+        return self._connection.get_task_var('mitogen_buildah_path')
+
+    def mitogen_docker_path(self):
+        return self._connection.get_task_var('mitogen_docker_path')
+
+    def mitogen_kubectl_path(self):
+        return self._connection.get_task_var('mitogen_kubectl_path')
+
+    def mitogen_lxc_path(self):
+        return self._connection.get_task_var('mitogen_lxc_path')
+
+    def mitogen_lxc_attach_path(self):
+        return self._connection.get_task_var('mitogen_lxc_attach_path')
+
+    def mitogen_lxc_info_path(self):
+        return self._connection.get_task_var('mitogen_lxc_info_path')
+
+    def mitogen_ssh_keepalive_interval(self):
+        return self._connection.get_task_var('mitogen_ssh_keepalive_interval')
+
+    def mitogen_ssh_keepalive_count(self):
+        return self._connection.get_task_var('mitogen_ssh_keepalive_count')
+
+    def mitogen_machinectl_path(self):
+        return self._connection.get_task_var('mitogen_machinectl_path')
+
+    def mitogen_ssh_debug_level(self):
+        return self._connection.get_task_var('mitogen_ssh_debug_level')
+
+    def mitogen_ssh_compression(self):
+        return self._connection.get_task_var('mitogen_ssh_compression')
+
+    def extra_args(self):
+        return self._connection.get_extra_args()
+
+    def ansible_doas_exe(self):
+        return (
+            self._connection.get_task_var('ansible_doas_exe') or
+            os.environ.get('ANSIBLE_DOAS_EXE')
+        )
+
+
+class MitogenViaSpec(Spec):
+    """
+    MitogenViaSpec takes most of its information from the HostVars of the
+    running task. HostVars is a lightweight wrapper around VariableManager, so
+    it is better to say that VariableManager.get_vars() is the ultimate source
+    of MitogenViaSpec's information.
+
+    Due to this, mitogen_via= hosts must have all their configuration
+    information represented as host and group variables. We cannot use any
+    per-task configuration, as all that data belongs to the real target host.
+
+    Ansible uses all kinds of strange historical logic for calculating
+    variables, including making their precedence configurable. MitogenViaSpec
+    must ultimately reimplement all of that logic. It is likely that if you are
+    having a configruation problem with connection delegation, the answer to
+    your problem lies in the method implementations below!
+    """
+    def __init__(self, inventory_name, host_vars, become_method, become_user,
+                 play_context):
+        """
+        :param str inventory_name:
+            The inventory name of the intermediary machine, i.e. not the target
+            machine.
+        :param dict host_vars:
+            The HostVars magic dictionary provided by Ansible in task_vars.
+        :param str become_method:
+            If the mitogen_via= spec included a become method, the method it
+            specifies.
+        :param str become_user:
+            If the mitogen_via= spec included a become user, the user it
+            specifies.
+        :param PlayContext play_context:
+            For some global values **only**, the PlayContext used to describe
+            the real target machine. Values from this object are **strictly
+            restricted** to values that are Ansible-global, e.g. the passwords
+            specified interactively.
+        """
+        self._inventory_name = inventory_name
+        self._host_vars = host_vars
+        self._become_method = become_method
+        self._become_user = become_user
+        # Dangerous! You may find a variable you want in this object, but it's
+        # almost certainly for the wrong machine!
+        self._dangerous_play_context = play_context
+
+    def transport(self):
+        return (
+            self._host_vars.get('ansible_connection') or
+            C.DEFAULT_TRANSPORT
+        )
+
+    def inventory_name(self):
+        return self._inventory_name
+
+    def remote_addr(self):
+        # play_context.py::MAGIC_VARIABLE_MAPPING
+        return (
+            self._host_vars.get('ansible_ssh_host') or
+            self._host_vars.get('ansible_host') or
+            self._inventory_name
+        )
+
+    def remote_user(self):
+        return (
+            self._host_vars.get('ansible_ssh_user') or
+            self._host_vars.get('ansible_user') or
+            C.DEFAULT_REMOTE_USER
+        )
+
+    def become(self):
+        return bool(self._become_user)
+
+    def become_method(self):
+        return (
+            self._become_method or
+            self._host_vars.get('ansible_become_method') or
+            C.DEFAULT_BECOME_METHOD
+        )
+
+    def become_user(self):
+        return self._become_user
+
+    def become_pass(self):
+        return optional_secret(
+            self._host_vars.get('ansible_become_password') or
+            self._host_vars.get('ansible_become_pass')
+        )
+
+    def password(self):
+        return optional_secret(
+            self._host_vars.get('ansible_ssh_pass') or
+            self._host_vars.get('ansible_password')
+        )
+
+    def port(self):
+        return (
+            self._host_vars.get('ansible_ssh_port') or
+            self._host_vars.get('ansible_port') or
+            C.DEFAULT_REMOTE_PORT
+        )
+
+    def python_path(self):
+        s = self._host_vars.get('ansible_python_interpreter')
+        # #511, #536: executor/module_common.py::_get_shebang() hard-wires
+        # "/usr/bin/python" as the default interpreter path if no other
+        # interpreter is specified.
+        return parse_python_path(s or '/usr/bin/python')
+
+    def private_key_file(self):
+        # TODO: must come from PlayContext too.
+        return (
+            self._host_vars.get('ansible_ssh_private_key_file') or
+            self._host_vars.get('ansible_private_key_file') or
+            C.DEFAULT_PRIVATE_KEY_FILE
+        )
+
+    def ssh_executable(self):
+        return (
+            self._host_vars.get('ansible_ssh_executable') or
+            C.ANSIBLE_SSH_EXECUTABLE
+        )
+
+    def timeout(self):
+        # TODO: must come from PlayContext too.
+        return C.DEFAULT_TIMEOUT
+
+    def ansible_ssh_timeout(self):
+        return (
+            self._host_vars.get('ansible_timeout') or
+            self._host_vars.get('ansible_ssh_timeout') or
+            self.timeout()
+        )
+
+    def ssh_args(self):
+        return [
+            mitogen.core.to_text(term)
+            for s in (
+                (
+                    self._host_vars.get('ansible_ssh_args') or
+                    getattr(C, 'ANSIBLE_SSH_ARGS', None) or
+                    os.environ.get('ANSIBLE_SSH_ARGS')
+                    # TODO: ini entry. older versions.
+                ),
+                (
+                    self._host_vars.get('ansible_ssh_common_args') or
+                    os.environ.get('ANSIBLE_SSH_COMMON_ARGS')
+                    # TODO: ini entry.
+                ),
+                (
+                    self._host_vars.get('ansible_ssh_extra_args') or
+                    os.environ.get('ANSIBLE_SSH_EXTRA_ARGS')
+                    # TODO: ini entry.
+                ),
+            )
+            for term in ansible.utils.shlex.shlex_split(s)
+            if s
+        ]
+
+    def become_exe(self):
+        return (
+            self._host_vars.get('ansible_become_exe') or
+            C.DEFAULT_BECOME_EXE
+        )
+
+    def sudo_args(self):
+        return [
+            mitogen.core.to_text(term)
+            for s in (
+                self._host_vars.get('ansible_sudo_flags') or '',
+                self._host_vars.get('ansible_become_flags') or '',
+            )
+            for term in ansible.utils.shlex.shlex_split(s)
+        ]
+
+    def mitogen_via(self):
+        return self._host_vars.get('mitogen_via')
+
+    def mitogen_kind(self):
+        return self._host_vars.get('mitogen_kind')
+
+    def mitogen_mask_remote_name(self):
+        return self._host_vars.get('mitogen_mask_remote_name')
+
+    def mitogen_buildah_path(self):
+        return self._host_vars.get('mitogen_buildah_path')
+
+    def mitogen_docker_path(self):
+        return self._host_vars.get('mitogen_docker_path')
+
+    def mitogen_kubectl_path(self):
+        return self._host_vars.get('mitogen_kubectl_path')
+
+    def mitogen_lxc_path(self):
+        return self.host_vars.get('mitogen_lxc_path')
+
+    def mitogen_lxc_attach_path(self):
+        return self._host_vars.get('mitogen_lxc_attach_path')
+
+    def mitogen_lxc_info_path(self):
+        return self._host_vars.get('mitogen_lxc_info_path')
+
+    def mitogen_ssh_keepalive_interval(self):
+        return self._host_vars.get('mitogen_ssh_keepalive_interval')
+
+    def mitogen_ssh_keepalive_count(self):
+        return self._host_vars.get('mitogen_ssh_keepalive_count')
+
+    def mitogen_machinectl_path(self):
+        return self._host_vars.get('mitogen_machinectl_path')
+
+    def mitogen_ssh_debug_level(self):
+        return self._host_vars.get('mitogen_ssh_debug_level')
+
+    def mitogen_ssh_compression(self):
+        return self._host_vars.get('mitogen_ssh_compression')
+
+    def extra_args(self):
+        return []  # TODO
+
+    def ansible_doas_exe(self):
+        return (
+            self._host_vars.get('ansible_doas_exe') or
+            os.environ.get('ANSIBLE_DOAS_EXE')
+        )