Stop execution of python script when parent Bash shell script is killed

Question

I'm working on a Bash shell script that runs several Python scripts like so:

cd ${SCRIPT_PATH}
python -u ${SCRIPT_NAME} ${SCRIPT_ARGS} >> $JOBLOG 2>&1

At one point, I killed the shell script (using kill PID), but the Python script continued running, even after the script terminated. I thought these would die as soon as the main script died. What am I misunderstanding about Bash scripting, and what can I do to get the functionality I'm looking for? Thanks in advance!

tzot · Accepted Answer · 2010-04-16 19:29:07Z

3

You need to install a signal handler to take care of your child processes:

trap "echo killing childs; pkill -P $$"  EXIT

edited Apr 16, 2010 at 19:29

tzot

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answered Apr 16, 2010 at 19:17

Jürgen Hötzel

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4 Comments

jrdioko Over a year ago

It looks like that will do it, although I think you need to trap more than just EXIT.

jrdioko Over a year ago

And an exit at the end of the trap commands, so the script itself will die too.

jrdioko Over a year ago

And this won't even work... since the trap arguments won't be executed until after the current line terminates, and it's the current line that I want to terminate.

Jürgen Hötzel Over a year ago

No, signal handlers are called async. An no need to call exit at the and of the trap commands, because a exit handler is called ON TERMINATION of the shell.

Douglas Leeder · Accepted Answer · 2010-04-16 18:56:16Z

1

Children should be sent SIGHUP when the parent process dies - however:

a) The child process can ignore SIGHUP, or handle it a non-fatal manner.

b) The Child could disassociate itself from the parent process by fork() and becoming a process group leader.

You could just exec the python code, so that the shell is replaced with the python.

answered Apr 16, 2010 at 18:56

Douglas Leeder

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1 Comment

jrdioko Over a year ago

I see, thanks! I think (a) is the problem in my case (probably a bare "except" clause).

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