bye, bye, bye, popen bye...

#!/usr/bin/env python

import time
import subprocess
import multiprocessing

class A(multiprocessing.Process):

    def __init__(self):
        multiprocessing.Process.__init__(self)
        proc = subprocess.Popen(args  = '/bin/false')
        print proc, proc.pid
        time.sleep(0.01)
        ec = proc.poll()
        print 'EXIT CODE: %s' % ec


class B(multiprocessing.Process):

    def __init__(self):
        multiprocessing.Process.__init__(self)

    def run(self):

        proc = subprocess.Popen(args  = '/bin/false')
        print proc, proc.pid
        time.sleep(0.01)

        self._watch_queue = multiprocessing.Queue()
        self._watch_queue.put(proc)
        self._watcher     = multiprocessing.Process(target=self._watch)
        self._watcher.start ()

    def _watch(self):
        proc = self._watch_queue.get()
        print proc, proc.pid
        ec = proc.poll()
        print 'exit code: %s' % ec

class C(multiprocessing.Process):

    def __init__(self):
        multiprocessing.Process.__init__(self)
        self.proc = None

    def run(self):
        self.proc = subprocess.Popen(args  = '/bin/false')
        print self.proc, self.proc.pid
        time.sleep(0.01)

        self._watcher = multiprocessing.Process(target=self._watch)
        self._watcher.start ()

    def _watch(self):
        print self.proc, self.proc.pid
        ec = self.proc.poll()
        print 'exit code: %s' % ec


class D(multiprocessing.Process):

    def __init__(self):
        multiprocessing.Process.__init__(self)

    def run(self):
        proc = subprocess.Popen(args  = '/bin/false')
        print proc, proc.pid
        time.sleep(0.01)

        def watch(proc):
            print proc, proc.pid
            ec = proc.poll()
            print 'exit code: %s' % ec

        self._watcher = multiprocessing.Process(target=watch, args=[proc])
        self._watcher.start ()


a = A()
a.start()
a.join()
print
b = B()
b.start()
b.join()
print
c = C()
c.start()
c.join()
print
d = D()
d.start()
d.join()
print