#!/bin/bash

###########################################################
###########################################################
###########################################################
###########################################################
###### Author - Vaibhav Sharma (vaebhav)
###### Date Created -
###########################################################
###########################################################
###########################################################

##########
#### The Wrapper ensures only 1 instance of the Script is executed , Skips Scheduled runs if an instance is already in execution.
#### Maintains a PIDFILE for each execution schedule , and triggers an email alert first @ 5 skips and finally an 10 skips and kiling any subsequent child processes spawned
#### Intermediate Skips can be customized by changing the value for RUNTHRES
#### Maintains a INFOLOG file for its execution
##########


###Script which you want to schedule.
### Ex - /home/vaebhav/Test.py

SCRIPT="<Script Path>"
PIDFILE=~/work/$0.pid
SKIPCOUNT=~/work/$0.runcount

RED="RED"
CRITICAL="CRITICAL"
ERRLOG=~/work/$0.err
INFOLOG=~/work/$0.info



mail_alert(){

echo "Sending Mail Alert [$2] for $0 Shell RunCount Threshold - [$$] [$(date +"%T %D")] " >> $INFOLOG

subj=" $(hostname) [$1] Execution Threshold Skipped for $0 Process"

if [[ "$3" == "FALSE" ]]
then
	eMsg="$0 Process has skipped Threshold count of $2 . PID for long running Process can be found at - $PIDFILE"
elif [[ "$3" == "TRUE" ]]
then
	eMsg="$0 Process has skipped Threshold count of $2 . PID for long running Process can be found at - $PIDFILE. Resetting Runcount to - 0. Killing All subsequent child processes as well."
fi
eTo=" Curate the email list for Notifications"

        #echo $eMsg | mail -s "$subj" $eTo
	mail -s "$subj"  $eTo <<- EMB

	$eMsg

        -----------------------------------------------------------------
        Processed at host - $(hostname) -  $(date +"%m-%d-%Y %T %Z")
        ------------------------------------------------------------------
EMB

}

remove_pid(){

	echo "Removing PID File of $0 Shell due to $1 - [$$] [$(date +"%T %D")] " >> $INFOLOG

        if [ -f $PIDFILE ]
        then
                rm $PIDFILE

        fi

	if [ -f $SKIPCOUNT ]
        then
                RUNTHRES=0
                echo $RUNTHRES > $SKIPCOUNT
        fi

}

control_c() {

    echo "Removing PID File of $0 Shell due to Cntrl - C SIGNAL Trap - [$$] [$(date +"%T %D")] " >> $INFOLOG
    remove_pid
    exit
}

shutdown() {
  # Get our process group id
  PGID=$(ps -o pgid= $$ | grep -o [0-9]*)

  # Kill it in a new new process group
  setsid kill -- -$PGID
  exit 0
}

#trap "shutdown" SIGINT SIGTERM

kill_child(){

WAV_ARRAY=($(ps -ef | grep "$0" | awk '{print $2}'));
echo "CHILD PROCESS ARRAY - ${WAV_ARRAY[@]} ----- " >> $INFOLOG
for cid in "${WAV_ARRAY[@]}"
do
	killCmd=$(kill -9 $cid)
	if [ $? -ne 0 ]
	then
		echo "Killing the child process $cid did not succeded" >> $INFOLOG
	else
		echo "Killed Child Process - [$cid] " >> $INFOLOG
	fi

done
remove_pid "[CRITICAL] LONG RUNNING CHILD PROCESSES"
ParentKill=$(kill -9 $PID)
}

trap control_c SIGINT


echo "--------------------- Starting $0  -----------------------" >> $INFOLOG

if [ -f $PIDFILE ]
then
  PID=$(cat $PIDFILE)
  ps -p $PID > /dev/null 2>&1
  if [ $? -eq 0 ]
  then
    echo "$0 Shell Already Running Skipping the Immediate Schedule - [$$] [$(date +"%T %D")] " >> $INFOLOG
    if [ -f $SKIPCOUNT ]
    then
	COUNT=1
	RUNTHRES=$(cat $SKIPCOUNT)
	RUNTHRES=$(($RUNTHRES+$COUNT))
	if [[ $RUNTHRES == 5 ]]
	then
		mail_alert $RED $RUNTHRES "FALSE"
	elif [[ $RUNTHRES == 10 ]]
	then
		mail_alert $CRITICAL $RUNTHRES "TRUE"
		kill_child
		echo "Killing Child process of $0_Shell.sh i.e Win_API_Int_Test.py " >> $INFOLOG
		RUNTHRES=0
		echo $RUNTHRES > $SKIPCOUNT
	else
                echo $RUNTHRES > $SKIPCOUNT
	fi
	echo "Current $0 Shell RunCount - [$RUNTHRES] [$(date +"%T %D")] " >> $INFOLOG
    else
	RUNTHRES=0
	echo $RUNTHRES > $SKIPCOUNT
    fi
    exit 1
  else
    ## Process not found assume not running
    echo $$ > $PIDFILE
    if [ $? -ne 0 ]
    then
      echo "Could not create PID file - [$$] [$(date +"%T %D")] " >> $ERRLOG
      exit 1
    fi
  fi
else
  echo $$ > $PIDFILE
  if [ $? -ne 0 ]
  then
    echo "Could not create PID file - [$$] [$(date +"%T %D")] " >> $ERRLOG
    exit 1
  fi
fi


if [ -f $SCRIPT ]
then
	cmd=$(python $SCRIPT)
	if [ $? -eq 0 ]
	then
		remove_pid "SUCCESS"
		echo "$SCRIPT was succesfully executed, Exiting Shell script [$(date +"%T %D")] " >> $INFOLOG
		exit 0
	elif [ $? -eq 1 ]
	then
		remove_pid "EXCEPTION"
		echo "$SCRIPT was unsuccesfully, Exiting Shell script [$(date +"%T %D")] " >> $INFOLOG
		exit 1
	fi
else
	echo "$SCRIPT was not found, Exiting Shell script [$(date +"%T %D")]" >> $INFOLOG
	echo "$SCRIPT was not found, Exiting Shell script [$(date +"%T %D")] " >> $ERRLOG
	exit 1
fi