Stop code after time period

Question

I would like to call foo(n) but stop it if it runs for more than 10 seconds. What's a good way to do this?

I can see that I could in theory modify foo itself to periodically check how long it has been running for but I would prefer not to do that.

Answer 1

Here you go:

import multiprocessing
import time

# Your foo function
def foo(n):
    for i in range(10000 * n):
        print "Tick"
        time.sleep(1)

if __name__ == '__main__':
    # Start foo as a process
    p = multiprocessing.Process(target=foo, name="Foo", args=(10,))
    p.start()

    # Wait 10 seconds for foo
    time.sleep(10)

    # Terminate foo
    p.terminate()

    # Cleanup
    p.join()

This will wait 10 seconds for foo and then kill it.

Update

Terminate the process only if it is running.

# If thread is active
if p.is_alive():
    print "foo is running... let's kill it..."

    # Terminate foo
    p.terminate()

Update 2 : Recommended

Use join with timeout. If foo finishes before timeout, then main can continue.

# Wait a maximum of 10 seconds for foo
# Usage: join([timeout in seconds])
p.join(10)

# If thread is active
if p.is_alive():
    print "foo is running... let's kill it..."

    # Terminate foo
    p.terminate()
    p.join()