How not to kill a subprocess opened by another python file?

Question

I would like from a script in python to run a program I developed in python as well. However I would like to terminate my script but not the program I opened by it.

I’m opening my program for a subprocess like this:

self.davros_p = subprocess.Popen(
        [python_path, "-m", "meu_programa", "start"],
        stdout=open(os.devnull, 'w'),
        stderr=open(os.devnull, 'w')
    )

Both run perfectly, however much I kill my script, I end up killing my program along. I would have some way of making sure that my program wasn’t finalized together?

Answer 1

Apparently this is a problem in Windows. When a Signal is given to kill the script, that Signal is passed to the subprocess, which is the meu_program. One way to solve this is to include "creationflags=subprocess.CREATE_NEW_PROCESS_GROUP" the list of Popen parameters.

self.proc = subprocess.Popen(
    [python_path, "-m", "meu_programa", "start"],
    stdout=open(os.devnull, 'w'),
    stderr=open(os.devnull, 'w'),
    creationflags=subprocess.CREATE_NEW_PROCESS_GROUP,

)

Windows passes Signal to all processes of the same group, so including creationflags you create a new group for the subprocess of the meu_program and it will not be killed when you want to kill only the script.