Example for waking a poller in another thread by using a PUSH/PULL waker socket pair

wake.py

"""
Example for waking a poller in another thread by using a PUSH/PULL waker socket pair
"""
import threading
import time
import zmq

ctx = zmq.Context()

# setup the wake machinery
waker_pull = ctx.socket(zmq.PULL)
waker_push = ctx.socket(zmq.PUSH)
waker_pull.bind('inproc://wake')
waker_push.connect('inproc://wake')

def wake():
    waker_push.send(b'Wake up, sleepyhead!')

def halt():
    waker_push.send(b'die')

def worker(waker):
    """the worker thread"""
    rep = ctx.socket(zmq.REP)
    rep.bind('tcp://127.0.0.1:5555')
    
    poller = zmq.Poller()
    poller.register(waker, zmq.POLLIN)
    poller.register(rep, zmq.POLLIN)
    while True:
        events = dict(poller.poll())
        if rep in events:
            msg = rep.recv_multipart()
            print "REP received %s" % msg
            rep.send_multipart(msg)
        if waker in events:
            print "I'm up!"
            msg = waker.recv_multipart()
            if msg == [b'die']:
                print "halting..."
                return

worker_thread = threading.Thread(target=worker, args=(waker_pull,))
worker_thread.start()

# this is our application socket:
req = ctx.socket(zmq.REQ)
req.connect('tcp://127.0.0.1:5555')


time.sleep(1)
print "REQ sending 'hi'"
req.send(b'hi')
print "REQ received %s" % req.recv_multipart()
time.sleep(1)
print "waking poller"
wake()
time.sleep(1)
print "REQ sending 'hi again'"
req.send_multipart([b'hi', b'again'])
print "REQ received %s" % req.recv_multipart()
time.sleep(1)
print "asking poller to halt"
halt()
while worker_thread.is_alive():
    print '.',
    time.sleep(0.1)