How to stop python from propagating signals to subprocesses?

Question

I\'m using python to manage some simulations. I build the parameters and run the program using:

pipe = open(\'/dev/null\', \'w\')
pid = subprocess.Popen(shle         


        

Answer 1

I resolved this problem by creating a helper app that I call instead of creating the child directly. This helper changes its parent group and then spawn the real child process.

import os
import sys

from time import sleep
from subprocess import Popen

POLL_INTERVAL=2

# dettach from parent group (no more inherited signals!)
os.setpgrp()

app = Popen(sys.argv[1:])
while app.poll() is None:
    sleep(POLL_INTERVAL)

exit(app.returncode)

I call this helper in the parent, passing the real child and its parameters as arguments:

Popen(["helper", "child", "arg1", ...])

I have to do this because my child app is not under my control, if it were I could have added the setpgrp there and bypassed the helper altogether.