monitoring/check_vpn.sh

#!/usr/bin/env bash

check_string_ps=""
if [[ -f "/usr/sbin/openvpn" ]] ; then
	check_string_ps="/usr/sbin/openvpn"
fi

check_string_ps_plus="--daemon"


# - used, if systemd is NOT supported
init_script=""
if [[ -x "/etc/init.d/openvpn" ]] ; then
   init_script="/etc/init.d/openvpn"
fi

# - Used if systemd is supported
# -
service_name=openvpn

LOCK_DIR=`mktemp -d`


#---------------------------------------
#-----------------------------
# Base Function(s)
#-----------------------------
#---------------------------------------

clean_up() {

   # Perform program exit housekeeping
   rm -rf $LOCK_DIR
   exit $1
}

fatal(){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[31m\033[1mFatal\033[m ] $*"
   else
      echo -e "   [ Fatal ] $*"
   fi
   echo ""
   if $terminal ; then
      echo -e "             \033[1mScript terminated\033[m.."
   else
      echo -e "             Script terminated.."
   fi
   echo ""
   rm -rf $LOCK_DIR
   exit 1
}

error (){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[31m\033[1mError\033[m ] $*"
   else
      echo "   [ Error ] $*"
   fi
   echo ""
}

warn (){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[33m\033[1mWarn\033[m ]  $*"
   else
      echo "   [ Warn ]  $*"
   fi
   echo ""
}

info (){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[32m\033[1mInfo\033[m ]  $*"
   else
      echo "   [ Info ]  $*"
   fi
   echo ""
}

ok (){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[32m\033[1mOk\033[m ]    $*"
   else
      echo "   [ Ok ]    $*"
   fi
   echo ""
}

trim() {
    local var="$*"
    var="${var#"${var%%[![:space:]]*}"}"   # remove leading whitespace characters
    var="${var%"${var##*[![:space:]]}"}"   # remove trailing whitespace characters
    echo -n "$var"
}

# - The trap command allows you to execute a command when a signal 
# - is received by your script. 
# -
trap clean_up SIGHUP SIGINT SIGTERM

#---------------------------------------
#-----------------------------
# Check some prerequisites
#-----------------------------
#---------------------------------------

# - Running in a terminal?
# -
if [[ -t 1 ]] ; then
      terminal=true
      LOGGING=true
else
   terminal=false
   LOGGING=false
fi

# - Running in a terminal?
# -
if [[ -t 1 ]] ; then
      terminal=true
      LOGGING=true
else
   terminal=false
   LOGGING=false
fi

if [[ -z $check_string_ps ]]; then
   fatal "$(basename $0): OpenVPN Service seems NOT to be installed"
fi

# - Systemd supported ?
# -
systemd=$(which systemd)
systemctl=$(which systemctl)

systemd_supported=false
if [[ -n "$systemd" ]] && [[ -n "$systemctl" ]] ; then
   systemd_supported=true
else
   if [[ ! -x $init_script ]]; then
      fatal "$(basename $0): Missing Bind Init-Script!"
   fi
fi


#---------------------------------------
#-----------------------------
# Check if OpenVPN Service is running
#-----------------------------
#---------------------------------------

if $LOGGING ; then
   echo -e "\n   Check if OpenVPN Service is running.."
   echo -e "   ====================================="
fi

PID=$(ps -e f | grep -E "[[:digit:]]\ ${check_string_ps}" | grep "\ ${check_string_ps_plus}\ " | grep -v grep | awk '{print$2}')
if [[ "X${PID}" = "X" ]]; then

   error "OpenVPN Service seems to be down! Trying to restart service now.."

   if $systemd_supported ; then
      $systemctl stop $service_name > /dev/null 2> ${LOCK_DIR}/err_msg.log
      if [[ $? -ne 0 ]]; then
         error "$(cat ${LOCK_DIR}/err_msg.log)"
      fi
      sleep 10
      $systemctl start $service_name > /dev/null 2> ${LOCK_DIR}/err_msg.log
      if [[ $? -ne 0 ]]; then
         error "$(cat ${LOCK_DIR}/err_msg.log)"
      fi
   else
      $init_script stop > /dev/null 2>&1
      if [[ $? -ne 0 ]]; then
         error "Stopping OpenVPN Service failed!"
      fi
      sleep 10
      $init_script start > /dev/null 2>&1
      if [[ $? -ne 0 ]]; then
         error "Starting OpenVPN Service failed!"
      fi
   fi

   declare -i counter=0
   PID=$(ps -e f | grep -E "[[:digit:]]\ ${check_string_ps}" | grep "\ ${check_string_ps_plus}\ " | grep -v grep | awk '{print$2}')
   while [[ "X${PID}" = "X" ]]; do
      sleep 1
      PID=$(ps -e f | grep -E "[[:digit:]]\ ${check_string_ps}" | grep "\ ${check_string_ps_plus}\ " | grep -v grep | awk '{print$2}')
      if [[ $counter -gt 10 ]]; then
         break
      else
         ((counter++))
      fi
   done

   if [[ "X${PID}" = "X" ]] ; then
      error "Restarting OpenVPN Service failed!"
   else
      ok "OpenVPN Service is up and running."
   fi

else
   if $LOGGING ; then
      ok "OpenVPN Service is up and running."
   fi
fi
   
clean_up