multiprocess/subprocess pipe

#!/usr/bin/python

import multiprocessing
import os
import subprocess
import sys
import tempfile
import threading
import time

t_fd, t_fn = tempfile.mkstemp()
os.write(t_fd, b'''\
#!/bin/sh

for i in `seq 1 40`; do
    echo $i
    sleep 1
done
''')
os.close(t_fd)


class OutputHandler(multiprocessing.Process):

    def __init__(self):
        super(OutputHandler, self).__init__()
        self._pipe_r, self._pipe_w = os.pipe()
        self.stdout = self.stderr = self._pipe_w
        self.start()

    def run(self):
        os.close(self._pipe_w)
        d = os.read(self._pipe_r, 1)
        while d:
            sys.stderr.write(d.decode())
            d = os.read(self._pipe_r, 1)

    def close(self):
        os.close(self._pipe_w)


class Runner(multiprocessing.Process):

    def __init__(self):
        super(Runner, self).__init__()

    def run(self):
        self.o = OutputHandler()
        p = subprocess.Popen(['/bin/sh', t_fn],
                             stdin=open(os.devnull),
                             stdout=self.o.stdout,
                             stderr=self.o.stderr)
        p.wait()
        self.o.close()
        print('Finished')
        os.unlink(t_fn)


def main():
    Runner().start()

if __name__ == '__main__':
    main()