subprocess.wait() not waiting for Popen process to finish (when using threads)?

Question

I am experiencing some problems when using subprocess.Popen() to spawn several instances of the same application from my python script using threads to have the

Answer 1

Make sure all applications your are calling have valid system return codes when they finish

Answer 2

I was having issues as well, but was inspired by yours.

Mine looks like this, and works beautifully:

    startupinfo = subprocess.STARTUPINFO()
    startupinfo.dwFlags = subprocess.STARTF_USESHOWWINDOW
    startupinfo.wShowWindow = subprocess.SW_HIDE
    proc = subprocess.Popen(command, startupinfo=startupinfo)
    proc.communicate()
    proc.wait()

Notice that this one hides the window as well.

Answer 3

Sadly when running your subprocess using shell=True, wait() will only wait for the sh subprocess to finish and not for the command cmd.

I will suggest if it possible to don't use the shell=True, if not possible you can create a process group like in this answer and use os.waitpid to wait for the process group not just the shell process.

Hope this was helpful :)

Answer 4

You could also use check_call() instead of Popen. check_call() waits for the command to finish, even when shell=True and then returns the exit code of the job.