Implementing a timeout in python with multiprocessing

timed_run.py

import time
import multiprocessing as mp
from Queue import Empty


def timed_run(func, args=(), kwargs={}, timeout=10, default=None):
    def run_func(q):
        result = func(*args, **kwargs)
        q.put(result)

    queue = mp.Queue()
    p = mp.Process(target=run_func, args=(queue,))
    p.start()

    print 'calling %s for %r seconds' % (func, timeout)

    started_at = time.time()
    p.join(timeout)
    ended_at = time.time()
    diff = round(ended_at - started_at)
    print '%s exited after %r seconds' % (func, diff)

    if p.is_alive():
        print 'terminating process %s' % p
        p.terminate()

    try:
        return queue.get(False)
    except Empty:
        return default


def loop_forever():
    while True:
        time.sleep(1)
        print 'still sleeping (forever)'

def loop_for(seconds):
    i = 0
    while i < seconds:
        time.sleep(1)
        print 'still sleeping (for %d seconds)' % seconds
        i += 1
    return i


if __name__ == '__main__':
    result = timed_run(loop_forever, timeout=5, default=-1)
    print 'Result:', result
    print

    result = timed_run(loop_for, args=(10,), timeout=5, default=-1)
    print 'Result:', result
    print

    result = timed_run(loop_for, args=(3,), timeout=5, default=-1)
    print 'Result:', result
    print

    result = timed_run(loop_for, args=(20,), timeout=5, default=-1)
    print 'Result:', result

Output:

calling <function loop_forever at 0x101f959b0> for 5 seconds
still sleeping (forever)
still sleeping (forever)
still sleeping (forever)
still sleeping (forever)
<function loop_forever at 0x101f959b0> exited after 5.0 seconds
terminating process <Process(Process-1, started)>
Result: -1

calling <function loop_for at 0x101f95a28> for 5 seconds
still sleeping (for 10 seconds)
still sleeping (for 10 seconds)
still sleeping (for 10 seconds)
still sleeping (for 10 seconds)
<function loop_for at 0x101f95a28> exited after 5.0 seconds
terminating process <Process(Process-2, started)>
Result: -1

calling <function loop_for at 0x101f95a28> for 5 seconds
still sleeping (for 3 seconds)
still sleeping (for 3 seconds)
still sleeping (for 3 seconds)
<function loop_for at 0x101f95a28> exited after 3.0 seconds
Result: 3

calling <function loop_for at 0x101f95a28> for 5 seconds
still sleeping (for 20 seconds)
still sleeping (for 20 seconds)
still sleeping (for 20 seconds)
still sleeping (for 20 seconds)
<function loop_for at 0x101f95a28> exited after 5.0 seconds
terminating process <Process(Process-4, started)>
Result: -1