#!/bin/bash
##############################################################################
# Bash script written by Vahid Hedayati April 2013
##############################################################################
# This program 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.
#
# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
##############################################################################
# This script takes:
# <host> <community> <load_limit(optional)>
# Once given a hostname and community string with or without specific load limit
# with no load limit, using snmp it will look at amount of cpu's and calculate load average / cpu count - 
# cpu count hacked to be more than 2 than actually on host to alert when it looks really serious

# This script requires SNMP to be configured and installed on both local / remote servers 
# -- UPDATES - debian - ubuntu systems run:
# sudo apt-get install snmp-mibs-downloader

snmpwalk="/usr/bin/snmpwalk"
snmpget="/usr/bin/snmpget"

# Set to 0 if no load limit set then it will get cpu count and increment this
get_cpu=0;


function usage() { 
	echo "$0 -H localhost -l 1 -p public"
	echo "$0 -H localhost -p public"
	echo "-----------------------------------"
	echo "-H is hostname set to localhost"
	echo "-l is load limit set to 1 or not set at all"
	echo "-p is snmp passsword"
	echo "-----------------------------------"
	echo "You can leave the load blank , this then defines the load according to CPU's"
	echo "so a 4 cpu server will have a load set to 6 if it goes above 4 then alerts are sent"
}



function return_cpu() { 
	# Below had been working on work machines 
	#cpu_count=$($snmpwalk -v2c -c $pass -Oq $server hrProcessorLoad|wc -l)

	# This is a generic view that should hopefully work on all Linux Machines
	cpu_count=$($snmpwalk -v2c -c $pass -Oq $server HOST-RESOURCES-MIB::hrProcessorLoad|wc -l)

	if [ "$cpu_count" == "" ]; then
		cpu_count=1;
	fi

	actual_cpus=$cpu_count

	# VH: To stop default cpu count from alerting we will add an extra cpu to ensure load is sufficient for an alert
	((cpu_count++))
	((cpu_count++))
}


function calculate_load() { 
	return_cpu;
	good_res="";
	bad_res="";
	graphtest="|";
       
	if [ "$limit" == "" ]; then 
 		limit=$cpu_count;
	fi
	loads="1 2 3"
	bad=0;
	loadrun="";
	cpu_info="Actual_cpus:$actual_cpus - Alert_Limit:$limit";
	for ids in $loads
	do
		if [[ $ids == 1 ]]; then
			loadrun="1_minute";
		elif [[ $ids == 2 ]]; then
                	loadrun="5_minutes";
		elif [[ $ids == 3 ]]; then
                	loadrun="15_minutes";
		fi
		run=$($snmpget -v2c -c $pass $server  .1.3.6.1.4.1.2021.10.1.3.$ids)
		if [[ $run =~ "STRING" ]]; then 
			actual_load=$(echo $run|awk  -F"STRING: " '{ print $2; }'|tr -d '"')
			current_load=$(echo $run|awk  -v limit=$limit -v cpus=$cpu_count -F"STRING: " '{ if  ( ($2 > 0)) { smb=($2 / cpus); print smb;} else { print $2; } }'|tr -d '"')
			calc=$(echo $limit|awk -v cload=$current_load '{$3 = cload / $1; printf "%f", $3}')
                	if [[ $calc < 1 ]]; then
				good_res=$good_res" ("$loadrun"_avg:"$current_load", "$loadrun"_actual="$actual_load" ) - " 
				graphtest=$graphtest" $loadrun"_avg"="$current_load"m;;;0  "$loadrun"_actual="$actual_load"m;;;0 "
                	else
				bad_res=$bad_res" ("$loadrun"_avg:"$current_load", "$loadrun"_actual="$actual_load" ) - " 
				graphtest=$graphtest" $loadrun"_avg"="$current_load"m;;;0 "$loadrun"_actual="$actual_load"m;;;0 "
                        	((bad++))
                	fi
		else 
			echo -n "$loadrun does not exist "; 
			((bad++))
		fi 
	done

	if [[ $bad > 0 ]]; then
		echo  "CRITICAL: $cpu_info $bad_res $graphtest"
		exit 2;
	else
		echo  "OK: $cpu_info $good_res" $graphtest;
		exit 0;
	fi

}

while test -n "$1"; do
    case "$1" in
        --help|-h)
           usage
            exit 0
            ;;
        --host|-H)
		server=$2;
		shift
            ;;
        --limit|-l)
		limit=$2;
		if [ "$limit" == "-p" ]; then
		 	limit="";
			pass=$3;
                	calculate_load;
                	exit
		fi
		shift
            ;;

        --snmpass|-p)
		pass=$2;
		calculate_load;
		exit
            ;;
  	*)

		echo "Unknown argument: $1"
	 	echo "-h for help";
		exit 1
            ;;
    esac
	shift
done


if [ $# -eq 0 ]; then
	echo "-h for help";
    	exit 1;
fi