Python subprocess: callback when cmd exits

Question

I\'m currently launching a programme using subprocess.Popen(cmd, shell=TRUE)

I\'m fairly new to Python, but it \'feels\' like there ought to be some api

Answer 1

I modified Daniel G's answer to simply pass the subprocess.Popen args and kwargs as themselves instead of as a separate tuple/list, since I wanted to use keyword arguments with subprocess.Popen.

In my case I had a method postExec() that I wanted to run after subprocess.Popen('exe', cwd=WORKING_DIR)

With the code below, it simply becomes popenAndCall(postExec, 'exe', cwd=WORKING_DIR)

import threading
import subprocess

def popenAndCall(onExit, *popenArgs, **popenKWArgs):
    """
    Runs a subprocess.Popen, and then calls the function onExit when the
    subprocess completes.

    Use it exactly the way you'd normally use subprocess.Popen, except include a
    callable to execute as the first argument. onExit is a callable object, and
    *popenArgs and **popenKWArgs are simply passed up to subprocess.Popen.
    """
    def runInThread(onExit, popenArgs, popenKWArgs):
        proc = subprocess.Popen(*popenArgs, **popenKWArgs)
        proc.wait()
        onExit()
        return

    thread = threading.Thread(target=runInThread,
                              args=(onExit, popenArgs, popenKWArgs))
    thread.start()

    return thread # returns immediately after the thread starts