threading_event.py

#!/usr/bin/env python

# this is from The Python
# Standard Library by example
# ISBN13: 9780321767349

import logging
import threading
import time

logging.basicConfig(level=logging.DEBUG,
                    format='(%(threadName)-10s) %(message)s',
                    )


def wait_for_event(e):
    """Wait for the event to be set before doing anything"""
    logging.debug('wait_for_event starting')
    event_is_set = e.wait()
    logging.debug('event set: %s', event_is_set)


def wait_for_event_timeout(e, t):
    """Wait t seconds then timeout"""
    while not e.isSet():
        logging.debug('wait_for_event_timeout starting')
        event_is_set = e.wait(t)
        logging.debug('event set: %s', event_is_set)
        if event_is_set:
            logging.debug('processing event')
        else:
            logging.debug('doing other work')

e = threading.Event()
t1 = threading.Thread(name='block',
                      target=wait_for_event,
                      args=(e,))
t1.start()

t2 = threading.Thread(name='nonblock',
                      target=wait_for_event_timeout,
                      args=(e, 2))

t2.start()

logging.debug('Waiting before calling Event.set()')
time.sleep(3)
e.set()
logging.debug('Event is set')