How to implement timeout in python truly?

Question

How to truly implement timeout in python? http://eventlet.net/doc/modules/timeout.html

Code looks like:

#!/usr/bin/python
import eventlet
import time
import sys
import random

while True:
        try:
         with eventlet.timeout.Timeout(1, False):
                print 'limited by timeout execution'
                while True:
                        print '\r' + str(random.random()),
                        sys.stdout.flush()
                        eventlet.sleep(0)
                print ' Never printed Secret! '
        except Exception as e:
                print ' Exception: ', e
        finally:
                print ''
                print ' Timeout reached '
                print ''

Time out will never reached. Where am I wrong?

P.s. I replaced:

 time.sleep(0.1)

with:

 eventlet.sleep(0)

Add False for exception, now it works well:

with eventlet.timeout.Timeout(1):

change to:

with eventlet.timeout.Timeout(1, False):

But it works only with eventlet.sleep(0.1)

E.g this code wrong:

#!/usr/bin/python
import eventlet
import time
start_time = time.time()
data = 0
with eventlet.timeout.Timeout(1, False):
        while True:
                data +=1
print 'Catch data ', data, ' in ', time.time() - start_time

I simply add sleep 0 seconds:

eventlet.sleep(0)

And it works like a charm.

Solved

Answer 1

eventlet's Timeout isn't as magical as you'd hoped. It can only detect timeouts in "greenthreaded" code -- code that uses eventlet's system of cooperative multihtreading. As noted in the Timeout docs, "you cannot time out CPU-only operations with this class". time.sleep pauses with Python's internal threading system, not eventlet's greenthreads.

Instead, use eventlet.sleep which works correctly with greenthreads.