So here’s something that I have found that waits for tomcat to come up but rather than polling or a static time based wait, it uses FIFO pipeline to wait.
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function isTomcatUp { # Use FIFO pipeline to check catalina.out for server startup notification rather than # ping with an HTTP request. This was recommended by ForgeRock (Zoltan). FIFO=/tmp/notifytomcatfifo mkfifo "${FIFO}" || exit 1 { # run tail in the background so that the shell can # kill tail when notified that grep has exited tail -f $CATALINA_HOME/logs/catalina.out & # remember tail's PID TAILPID=$! # wait for notification that grep has exited read foo <${FIFO} # grep has exited, time to go kill "${TAILPID}" } | { grep -m 1 "INFO: Server startup" # notify the first pipeline stage that grep is done echo >${FIFO} } # clean up rm "${FIFO}" } |
Drop this into a tomcat-util.sh file, make it executable and then source the file:
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chmod u+x tomcat-util.sh source tomcat-util.sh |
You’ll now have isTomcatUp available as a bash command.
Hi, thanks for this script. Works like a charm. I just have a query (a use case if you will).
What if grep does not find “INFO: Server startup” in ‘ catalina.out’, then in such a situation will the ‘tail’ end?
If it does end then how will the calling function know of the failure?
Hope I make sense.