WebApplication heartbeat script intended to poll remote web application whether it responds correctly (HTTP 200 OK) or not - thus resulting in Linux GNOME alert being generated. Useful when dealing with unstable webservers or appications behind VPN connection.

webapplication-heartbeat.sh

#!/bin/bash

#
# Simple script intended to poll remote web application to check whether it is available
# and returns 200 OK. If it is not, then Linux GNOME-related alert will be generated.
#
# Mariusz B., 2016
#

REMOTE_HOST="http://<webapplication>"
TIMEOUT=5

USER_AGENT='Mozilla/5.0 (X11; Linux x86_64; rv:43.0) Gecko/20100101 Firefox/43.0'

RESTORE=$(echo -en '\033[0m')
RED=$(echo -en '\033[00;31m')
GREEN=$(echo -en '\033[00;32m')
LIGHTGRAY=$(echo -en '\033[00;37m')

red() { 
    echo $RED$1$RESTORE 
}
green() { 
    echo $GREEN$1$RESTORE 
}
lightgray() {
 echo $LIGHTGRAY$1$RESTORE 
}

alert() {
  notify-send "$1"
  aplay /usr/share/sounds/speech-dispatcher/test.wav 2> /dev/null
}


echo "Polling $REMOTE_HOST ..."

CNT=0
while true
do
  date
  RESP=`curl -sD- -A '$USER_AGENT' --connect-timeout 5 "$REMOTE_HOST" -o /dev/null `
  if echo "$RESP" | grep -q "200" ; then
    green "Responding"
    if [ $CNT -gt 0 ]; then
      CNT=0
    fi
  else 
    red "Not responding"
    CNT=$((CNT+1))
    if [ $CNT -gt 1 ]; then
      alert "Remote host $REMOTE_HOST is not responding"
      echo "$RESP"
    fi
  fi
  sleep $TIMEOUT
done