Monitor a custom Java HTTP server from a bash shell?

Question

How could I monitor a service port from a bash shell?

I want to monitor a Java service (once per minute on port 9090) and then call "/etc/init.d/myservice -restart" if the service isn't responding with a simple HTML message.

How would you do something like this?

My idea was to use something similar to this:

wget -O - --no-check-certificate --progress=dot https://localhost:9090 

Or

curl --insecure https://localhost:9090 

Answer 1

Use monit, it's more secure than writing a shell script for that.

If you are really want to write a script, use curl to get the content, grep it and restart the service in case of fail.

Answer 2

Thanks "coredump" . You gave me the hint I needed to solve the issue. I'll use a combination of CURL and also the answer on this page .

Here is what I came up with, which seems to work for me. If you can improve this answer, I might award the points to you.

#!/bin/bash rm -f listening.htm curl -s --connect-timeout 10 --insecure $1 > listening.htm RETVAL=$? echo "Curl return value : $RETVAL" if [ $RETVAL -eq 2 ]; then echo "Missing URL parameter. Add URL and try again." fi if [ $RETVAL -eq 6 ]; then echo "Unable to resolve host. Check URL and try again." fi if [ $RETVAL -eq 0 ]; then echo "Is the site listening...?" elif [ $RETVAL -eq 7 ]; then echo "Server timeout." elif [ $RETVAL -eq 22 ];then echo "HTTP error above 400" else rm listening.htm exit 1 fi if grep -Fq "The site is listening..." listening.htm then echo "Health is ok." else echo "Service didn't respond. Stopping." /home/ec2-user/SITE/stopService.sh sleep 6 echo "Starting service." /home/ec2-user/SITE/startService.sh sleep 10 echo "Restarted at `date`" >> monitor.log rm listening.htm fi exit 1