#!/bin/bash
# Usage: "Linux - CPU usage monitor.sh 75 95"
# 
# Description:
#   This script is used from inside of Tactical RMM instances to check the CPU usage. 
#   This script should be deployed as a check script.
#
# Options:
#   Arg1 - Warning limit
#   Arg2 - Error limit
#
# Author: D. de Kooker (info@dcomputers.nl)
# Sources: https://www.activexperts.com/support/network-monitor/online/linux/
# Changelog :
#   27-06-2022 - Initial script from source, tweaked for my environment

#region Parameters, functions and global variables
nWarnCpuUsage=$1
nMaxCpuUsage=$2
#endregion

# Validate number of arguments
if [ $# -ne 2 ] ; then
  echo "UNCERTAIN: Invalid number of arguments - Usage: cpu nWarnCpuUsage nMaxCpuUsage"
  exit 1
fi

# Validate numeric parameter nWarnCpuUsage
regExpNumber='^[0-9]+$'
if ! [[ $1 =~ $regExpNumber ]] ; then
  echo "UNCERTAIN: Invalid argument: nWarnCpuUsage (number expected)"
  exit 1
fi

# Validate numeric parameter nMaxCpuUsage
regExpNumber='^[0-9]+$'
if ! [[ $1 =~ $regExpNumber ]] ; then
  echo "UNCERTAIN: Invalid argument: nMaxCpuUsage (number expected)"
  exit 1
fi

# Check the CPU usage
nCpuLoadPercentage=`ps -A -o pcpu | tail -n+2 | paste -sd+ | bc`
nCpuLoadPercentage=$( echo "$nCpuLoadPercentage / 1" | bc )

if [ $nCpuLoadPercentage -le $nWarnCpuUsage ] ; then
  echo "SUCCESS: CPU usage is [$nCpuLoadPercentage%]"
  echo ""
  echo "Warning limit=[$1%], Error limit=[$2%]"
  exit 0
fi
if [ $nCpuLoadPercentage -gt $nWarnCpuUsage -a $nCpuLoadPercentage -le $nMaxCpuUsage ] ; then
  echo "WARNING: CPU usage is [$nCpuLoadPercentage%]"
  echo ""
  echo "Warning limit=[$1%], Error limit=[$2%]"
  exit 2
fi
if [ $nCpuLoadPercentage -gt $nMaxCpuUsage ] ; then
  echo "ERROR: CPU usage is [$nCpuLoadPercentage%]"
  echo ""
  echo "Warning limit=[$1%], Error limit=[$2%]"
  exit 1
fi