Add a new option (and parameter) --kill-children

[benjastudio]

This option forces simpleflow to kill child processes in simpleflow.execute, on exit.

Note: I wasn't be able to use atexit correctly (at least with Pypy).

Related issue: #291

[ybastide]

Minor: you can use

action='store_true'

instead of the 3 lines

[ybastide]

try ... except NoSuchProcess: pass around the loops?
Or do you think the caller should know this?

[jbbarth]

I don't think the caller should now, +1 for catching

[benjastudio]

I think it's okay since children list come from https://pythonhosted.org/psutil/#psutil.Process.children call.
BTW: I just saw that and I think I'll use wait_procs instead of sleep it: https://pythonhosted.org/psutil/#psutil.wait_procs

[ybastide]

Er, your test catches it 🙂
EDIT: and if a child was terminated (as it should), kill won't find it

[ybastide]

Anyway you're right, wait_proc is the way to go

[benjastudio]

I think that even if they die by themselves it's ok since the references are kept (they are zombies).

In [1]: import subprocess, psutil, os, time

In [2]: sleeper = subprocess.Popen(['sleep', '5']) ; children = psutil.Process(os.getpid()).children(recursive=True)

In [3]: time.sleep(6)

In [4]: children
Out[4]: [<psutil.Process(pid=15234, name='sleep') at 140707464425808>]

In [5]: [c.status() for c in children]
Out[5]: ['zombie']

In [6]: [c.terminate() for c in children]
Out[6]: [None]

In [7]: [c.status() for c in children]
Out[7]: ['zombie']

In [8]: [c.kill() for c in children]
Out[8]: [None]

In [9]: [c.status() for c in children]
Out[9]: ['zombie']

[benjastudio]

But I can add it, may be there is a case where this won't work?

[jbbarth]

Yet another reason to use psutil! No no, don't bother adding a useless try/except, I think @ybastide and I are too cautious but looks like psutil is smart there 👍 Thanks a lot for testing it!

[ybastide]

well, here's psutil:

        def _send_signal(self, sig):
            assert not self.pid < 0, self.pid
            if self.pid == 0:
                # see "man 2 kill"
                raise ValueError(
                    "preventing sending signal to process with PID 0 as it "
                    "would affect every process in the process group of the "
                    "calling process (os.getpid()) instead of PID 0")
            try:
                os.kill(self.pid, sig)
            except OSError as err:
                if err.errno == errno.ESRCH:
                    if OPENBSD and pid_exists(self.pid):
                        # We do this because os.kill() lies in case of
                        # zombie processes.
                        raise ZombieProcess(self.pid, self._name, self._ppid)
                    else:
                        self._gone = True
                        raise NoSuchProcess(self.pid, self._name)
                if err.errno in (errno.EPERM, errno.EACCES):
                    raise AccessDenied(self.pid, self._name)
                raise

[jbbarth]

Always look the code 👌

[ybastide]

👍

[jbbarth]

@ybastide or @benjastudio : I let one of you merge and try the new release script so we confirm it works for you? if you want to do it @benjastudio you'd need credentials on the pypi package, signup there and give me or @ybastide your nickname so we add you.