kill a function after a certain time in windows

Question

I\'ve read a lot of posts about using threads, subprocesses, etc.. A lot of it seems over complicated for what I\'m trying to do...

All I want to do is stop executin

Answer 1

Can't you just return from the loop?

start = time.time()
endt = start + 30
while True:
    now = time.time()
    if now > endt:
        return
    else:
        print end - start

Answer 2

Use the building blocks in the multiprocessing module:

import multiprocessing
import Queue

TIMEOUT = 5

def big_loop(bob):
    import time
    time.sleep(4)
    return bob*2

def wrapper(queue, bob):
    result = big_loop(bob)
    queue.put(result)
    queue.close()

def run_loop_with_timeout():
    bob = 21 # Whatever sensible value you need
    queue = multiprocessing.Queue(1) # Maximum size is 1
    proc = multiprocessing.Process(target=wrapper, args=(queue, bob))
    proc.start()

    # Wait for TIMEOUT seconds
    try:
        result = queue.get(True, TIMEOUT)
    except Queue.Empty:
        # Deal with lack of data somehow
        result = None
    finally:
        proc.terminate()

    # Process data here, not in try block above, otherwise your process keeps running
    print result

if __name__ == "__main__":
    run_loop_with_timeout()

You could also accomplish this with a Pipe/Connection pair, but I'm not familiar with their API. Change the sleep time or TIMEOUT to check the behaviour for either case.

Answer 3

import os,signal,time
cpid = os.fork()
if cpid == 0:
  while True:
     # do stuff
else:
  time.sleep(10)
  os.kill(cpid, signal.SIGKILL)

You can also check in the loop of a thread for an event, which is more portable and flexible as it allows other reactions than brute killing. However, this approach fails if # do stuff can take time (or even wait forever on some event).

Answer 4

There is no straightforward way to kill a function after a certain amount of time without running the function in a separate process. A better approach would probably be to rewrite the function so that it returns after a specified time:

import time

def big_loop(bob, timeout):
    x = bob
    start = time.time()
    end = start + timeout
    while time.time() < end:
        print time.time() - start
        # Do more stuff here as needed