Databases
StackOverflow2013
Postsdbo
POZMQ Poller not working within Class Instance
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POZMQ Poller not working within Class Instance
    primarykey
    data
    text
    <p>Hi I am having some issues wrapping some ZMQ pull clients in Python classes. These classes are instanced and called in a Subprocess via the multiprocessing module. When the clients are functions all works but when they are classes the poller.poll() hangs.</p> <p>The code bellow has both versions: One works, the other doesn't. Why?</p> <pre><code>import zmq import time import sys import random from multiprocessing import Process def server_push(port="5556"): context = zmq.Context() socket = context.socket(zmq.PUSH) socket.bind("tcp://*:%s" % port) print "Running server on port: ", port # serves only 5 request and dies for reqnum in range(10): if reqnum &lt; 6: socket.send("Continue") else: socket.send("Exit") break time.sleep (1) def server_pub(port="5558"): context = zmq.Context() socket = context.socket(zmq.PUB) socket.bind("tcp://*:%s" % port) publisher_id = random.randrange(0,9999) print "Running server on port: ", port # serves only 5 request and dies for reqnum in range(10): # Wait for next request from client topic = random.randrange(8,10) messagedata = "server#%s" % publisher_id print "%s %s" % (topic, messagedata) socket.send("%d %s" % (topic, messagedata)) time.sleep(1) class Client: def __init__(self,port_push, port_sub): context = zmq.Context() self.socket_pull = context.socket(zmq.PULL) self.socket_pull.connect ("tcp://localhost:%s" % port_push) print "Connected to server with port %s" % port_push self.socket_sub = context.socket(zmq.SUB) self.socket_sub.connect ("tcp://localhost:%s" % port_sub) self.socket_sub.setsockopt(zmq.SUBSCRIBE, "9") print "Connected to publisher with port %s" % port_sub # Initialize poll set def __call__(self): poller = zmq.Poller() poller.register(self.socket_pull, zmq.POLLIN) poller.register(self.socket_sub, zmq.POLLIN) # Work on requests from both server and publisher should_continue = True print "listening" while should_continue: print "hello" socks = dict(poller.poll()) print poller if self.socket_pull in socks and socks[self.socket_pull] == zmq.POLLIN: message = self.socket_pull.recv() print "Recieved control command: %s" % message if message == "Exit": print "Recieved exit command, client will stop recieving messages" should_continue = False if self.socket_sub in socks and socks[self.socket_sub] == zmq.POLLIN: string = self.socket_sub.recv() topic, messagedata = string.split() print "Processing ... ", topic, messagedata def client(port_push, port_sub): context = zmq.Context() socket_pull = context.socket(zmq.PULL) socket_pull.connect ("tcp://localhost:%s" % port_push) print "Connected to server with port %s" % port_push socket_sub = context.socket(zmq.SUB) socket_sub.connect ("tcp://localhost:%s" % port_sub) socket_sub.setsockopt(zmq.SUBSCRIBE, "9") print "Connected to publisher with port %s" % port_sub # Initialize poll set poller = zmq.Poller() poller.register(socket_pull, zmq.POLLIN) poller.register(socket_sub, zmq.POLLIN) # Work on requests from both server and publisher should_continue = True while should_continue: socks = dict(poller.poll()) if socket_pull in socks and socks[socket_pull] == zmq.POLLIN: message = socket_pull.recv() print "Recieved control command: %s" % message if message == "Exit": print "Recieved exit command, client will stop recieving messages" should_continue = False if socket_sub in socks and socks[socket_sub] == zmq.POLLIN: string = socket_sub.recv() topic, messagedata = string.split() print "Processing ... ", topic, messagedata if __name__ == "__main__": # Now we can run a few servers server_push_port = "5556" server_pub_port = "5558" Process(target=server_push, args=(server_push_port,)).start() Process(target=server_pub, args=(server_pub_port,)).start() #~ Process(target=client,args=(server_push_port,server_pub_port)).start() Process(target=Client(server_push_port,server_pub_port)).start() </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USfccoelho
    1. USfccoelho
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POZMQ Poller not working within Class Instance
      1. USfccoelho
      1. VTFavorite
    2. VO
      singulars
      1. POZMQ Poller not working within Class Instance
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POZMQ Poller not working within Class Instance
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIn limited work with the subprocess module I've noticed that it can be difficult to diagnose exceptions -- are you sure you have diagnosed it correctly and you aren't raising an exception somewhere else? One thing I've done in the past is explicitly break out the subprocesses into processes I can monitor in their own console window.
      singulars
      1. POZMQ Poller not working within Class Instance
      1. USAaron Watters
    2. COThis is just a test code, there is nothing hidden. Whatever is supposedly breaking, is taking place within pyzmq. I am hoping for a workaround regarding this, so that don't have to wait for a fix in pyzmq. I Agree that it is hard to debug when using multiprocess, but the convenience it provides outweighs this issue.
      singulars
      1. POZMQ Poller not working within Class Instance
      1. USfccoelho
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload