#!/bin/bash
#
# Small script to check services and to alert if a certain service
# exceeds a certain CPU percentage. Be warned about my poor programming
# skills. I do not assume any responsobility if this script doesn't 
# work properly, creates false warnings or takes over the world!
# 
# cc-by-3.0 Michael Kesler
# http://michaelkesler.net

# This defines if you want to trigger a critical alert if the checked 
# processes is not running at all!
# 0 = NO NOTIFICATION; 1 = WARNING; 2 = CRITICAL

STATE_NOPROCESS=2


# Set States
STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2


# Set help
print_help () {
	echo ""
	echo "Usage: check_ps_cpu -w <warning> -c <critical> -p <process>"
	echo ""
	echo "This plugin checks ps for a specific running process and"
	echo "compares the CPU usage against a set threshold."
	echo ""
	echo "<process> can be a full or part of a process name that you"
	echo "want to monitor. If you do not specify a process name, the"
	echo "check will fail. If the provided process name does not seem"
	echo "to be running, the check will exit with status code 2."
	echo ""
	exit 0
}

# Read input
case "$1" in

	--help)
		print_help
		exit $STATE_OK
		;;
	-h)
		print_help
		exit $STATE_OK
		;;
esac

WARNING=$2
CRITICAL=$4
PROCESS=$6


# Lets get to work

if [ $WARNING -lt $CRITICAL ] && [ $6 ]; 
then
        CHECK_PROCESS="$(/bin/ps -eo pcpu,comm,user,pid,time | sort -rnk1 | grep $PROCESS)"

	if [ -n "$CHECK_PROCESS" ];
	then


# Output the check results on the command line

#		echo "%CPU COMMAND USER PID TIME"
#		echo $CHECK_PROCESS
#		echo ""
	

# This is rather ugly, please do not read... ;)

	 	declare -a CHECK_PROCESS_ARRAY
		CHECK_PROCESS_ARRAY=($CHECK_PROCESS)
		CHECK_PROCESS_CPU=${CHECK_PROCESS_ARRAY[0]}
		CHECK_PROCESS_CPU_SHORT=${CHECK_PROCESS_CPU%.*}


# Okay, it's getting less ugly again, you can resume reading my code...
# Comparing the check results against the set thresholds

		if [ $CHECK_PROCESS_CPU_SHORT -gt $CRITICAL ];
		then
			echo $CHECK_PROCESS_CPU_SHORT
			echo $CHECK_PROCESS_CPU
			echo "${CHECK_PROCESS_ARRAY[1]} is above critical threshold of $CRITICAL%: Current CPU usage ${CHECK_PROCESS_ARRAY[0]}%"
			exit $STATE_CRITICAL
		elif [ $CHECK_PROCESS_CPU_SHORT -gt $WARNING ]; 
		then
			echo "${CHECK_PROCESS_ARRAY[1]} is above warning threshold of $CRITICAL%: Current CPU usage ${CHECK_PROCESS_ARRAY[0]}%"
			exit $STATE_WARNING
		else
			echo "No problems found: CPU usage of ${CHECK_PROCESS_ARRAY[1]} is at ${CHECK_PROCESS_ARRAY[0]}%"
			exit $STATE_OK
		fi


# In case the checked service is not running, do the following

	else
	echo "Process $PROCESS does not seem to be running!"
	exit $STATE_NOPROCESS	
	fi
			
else


# In case we received a wrong syntax, do the following

        echo "Error: Please check your syntax!"
	echo "Use 'check_ps_cpu --help' for help!"
        exit $STATE_OK
fi