CODEWITHSUNDEEP
pythonsubprocessdetach
pepoluan
pepoluan

Reputation: 6808

Launch modules as subprocesses in the background, and detach

In bash, I can do the following:

for f in subdir/*.sh; do
    nohup "$f" "$@" &> /dev/null &
done

in other words, it runs all *.sh scripts in subdir in the background, and detached so that if the main script ends, the background scripts won't be terminated.

Now, let's say I have the following Python project:

proj/
    __init__.py
    main.py
    subdir/
        __init__.py
        mod_a.py
        mod_b.py
        mod_c.py

How do I do something similar to the bash script? But with parameters passed as Python objects?

E.g.: I have two strings a and b, a list l, and a dictionary d

Upvotes: 1

Views: 934

Answers (3)

proski
proski

Reputation: 3949

It's probably a duplicate of Run a program from python, and have it continue to run after the script is killed and no, ignoring SIGHUP doesn't help, but preexec_fn=os.setpgrp does.

Upvotes: 0

jfs
jfs

Reputation: 414795

To emulate nohup in Python, you could make child processes to ignore SIGHUP signal:

import signal

def ignore_sighup():
    signal.signal(signal.SIGHUP, signal.SIG_IGN)

i.e., to emulate the bash script:

#!/bin/bash
for f in subdir/*.sh; do
    nohup "$f" "$@" &> /dev/null &
done

using subprocess module in Python:

#!/usr/bin/env python3
import sys
from glob import glob
from subprocess import Popen, DEVNULL, STDOUT

for path in glob('subdir/*.sh'):
    Popen([path] + sys.argv[1:], 
          stdout=DEVNULL, stderr=STDOUT, preexec_fn=ignore_sighup)

To create proper daemons, you could use python-daemon package.

Upvotes: 1

Nebril
Nebril

Reputation: 3273

I don't know about any mechanism for it in python, but you may try to use nohup. You may try to run 

nohup python your_script.py arguments

Using os.system or subprocess.call.

Upvotes: 0

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