Eventlet timeout not exiting

Question

Why does eventlet allow it to finish the 6 seconds, when it should exit the indentation after 5 seconds?

>>> with eventlet.Timeout(5):
        time.sleep(6)
        x = 1
>>> x
1

Answer 1

Eventlet provides cooperative multithreading. Which means you need to yield control to give hub or coroutines (in this case, hub implements timeouts) chance to run. To yield control:

• either use green versions of IO and sleep
• or execute eventlet.monkey_patch(), now you can use regular time, socket, etc modules, replaced by "green" versions, cooperating with Eventlet.

Any CPU tight code without green calls, for example [_ for _ in xrange(1000000000)] is impossible to interrupt at all. If you find yourself in similar situation, place eventlet.sleep(0) somewhere in loop, that would enter Eventlet hub and allow timeouts to work.