I have a script that tries to make a DB connection using another program and the timeout(2.5min) of the program is to long. I want to add this functionality to the script.
I don't know if it's identical but I did fix a similar issue a few years ago. However I'm a programmer, not a Unix-like sysadmin so take the following with a grain of salt because my Bash-fu may not be that strong...
Basically I did fork, fork and fork : )
Out of memory After founding back my old code (which I amazingly still use daily) because my memory wasn't good enough, in Bash it worked a bit like this:
commandThatMayHang.sh 2 > /dev/null 2>&1 & # notice that last '&', we're forking
MAYBE_HUNG_PID=$!
sleepAndMaybeKill.sh $MAYBE_HUNG_PID 2 > /dev/null 2>&1 & # we're forking again
SLEEP_AND_MAYBE_KILL_PID=$!
wait $MAYBE_HUNG_PID > /dev/null 2>&1
if [ $? -eq 0 ]
# commandThatMayHand.sh did not hang, fine, no need to monitor it anymore
kill -9 $SLEEP_AND_MAYBE_KILL 2> /dev/null 2>&1
fi
where sleepAndMaybeKill.sh sleeps the amount of time you want and then kills commandThatMayHand.sh.
So basically the two scenario are:
your command exits fine (before your 5 seconds timeout or whatever) and so the wait stop as soon as your command exits fine (and kills the "killer" because it's not needed anymore
the command locks up, the killer ends up killing the command
In any case you're guaranteed to either succeed as soon as the command is done or to fail after the timeout.