Summary: This script will check to see if a web server is functioning properly by checking the output of a specific location. If this output is wrong, or unavailable, a message will be emailed. Additionally, if the server returns output which the script was not expecting, it has the ability to run a custom restore command and hopefully get the server functioning again.

Requirements:

• mail
• curl

Code:

#!/bin/bash
##Set Default Options
CHECKFOR="" ##This is the what the script expects to find in the result.
TIMEOUT="10" ##Max amount of time to wait for a connection.
MAXTIME="30" ##Max time to spend trying to load page.

##Do not edit anything below this comment!

function Restore {
	echo
	echo -n "Attempting Recovery..."
	${RESTORECMD} > /dev/null 2>&1
	
	if [ $? == 0 ]
	then
		echo -n -e "33[1;32mOK!"
		echo -e "33[0m"
		echo -e "Recovery successful.nnNothing is needed for ${CHECKURL}nn" | mail -s "ServerCheck" "${EMAIL}"
	else
		echo -n -e "33[1;31mFailed!"
		echo -e "33[0m"
		echo -e "Recovery failed.nnManual fix may be needed for ${CHECKURL}.nn" | mail -s "ServerCheck" "${EMAIL}"
	fi
}

USAGE="Usage: ${0} -s  -e  -f [CHECKFOR] -d [POST_DATA] -r [RESTORECMD]"

echo "ServerCheck"
echo "Scripted by Blake Johnson"
echo "http://www.blakeanthonyjohnson.com/"
echo

while getopts ':s:f:r:e:d:h' OPTION; do
	case ${OPTION} in
		s) CHECKURL="${OPTARG}";;
		f) CHECKFOR="${OPTARG}";;
		r) RESTORECMD="${OPTARG}";;
		e) EMAIL="${OPTARG}";;
		d) POSTDATA="${OPTARG}";;
		h) echo ${USAGE};;
		?) echo "Unknown option "-${OPTARG}"." >&2
			echo ${USAGE};;
		:) echo "Option "-${OPTARG}" needs an argument." >&2
  			echo ${USAGE}
  			exit 1;;
  		*) echo ${USAGE}
  			exit 1;;
  	esac
done

if [ -z "$CHECKURL" ]
then
	echo "One or more parameters are missing."
	echo "${USAGE}"
	exit 1
fi

if [ -z "$EMAIL" ]
then
	echo "One or more parameters are missing."
	echo "${USAGE}"
	exit 1
fi

echo "Checking URL:  "${CHECKURL}""
echo "Email: "${EMAIL}""
echo "Checking for: "${CHECKFOR}""
echo

echo -n "Checking if server is working properly... "

CURLCOMMAND="curl -s ${CHECKURL} --connect-timeout ${TIMEOUT} --max-time ${MAXTIME}"

if [ $POSTDATA ]
then
	CURLCOMMAND="${CURLCOMMAND} -d ${POSTDATA}"
fi

CURLOUTPUT=`${CURLCOMMAND}`

if [ $? == 0 ]
then
	if [[ "$CURLOUTPUT" =~ "$CHECKFOR" ]]
	then
		echo -n -e "33[1;32mOK!"
		echo -e "33[0m"
	else
		echo -n -e "33[1;31mFailed!"
		echo -e "33[0m"
		echo "String not found."
		
		if [ "$RESTORECMD" ]
		then
			Restore	
		else
			echo -e "Wrong output recieved.nnPlease check ${CHECKURL}.nn" | mail -s "ServerCheck" "${EMAIL}"
		fi
	fi
else
	echo -n -e "33[1;31mFailed!"
	echo -e "33[0m"
	echo "Some other error occurred."
	
	if [ "$RESTORECMD" ]
	then
		Restore
	else
		echo -e "Server may be down.nnPlease check ${CHECKURL}.nn" | mail -s "ServerCheck" "${EMAIL}"
	fi
fi

echo
echo "This script will self-destruct in 6 seconds."
sleep 6
exit 0

Note: Mac OS X users may have to change the line endings to the Unix equivalent.

Changes:
v0.6: Adds the ability to run a custom restore command.
v0.5: Adds the ability to add post data to a page request.
v0.3: Restructured how the parameters are read in.
v0.2: Allowed parameters to be set at the command line.
v0.1: Initial release.