ZeroMQ PUB / SUB - why don't multiple subscribers work?

Question

I use ZeroMQ to facilitate the publishing / subscribing environment I need. I am running the publishing server on machine A using Python (using EventLoop), and now I have one subscriber working in C ++ on computer B, and a second subscriber working in Python (using EventLoop) on computer C.

If machine B subscribes to machine A before machine C, then B receives signed messages, but C does not. Also, if I look at the established connections on machine A, there is only a connection for machine B, but not for C. If machine C subscribes to A before doing B, then it is the other way around.

Here is my publisher code:

import zmq from zmq.eventloop import ioloop, zmqstream ioloop.install() context = zmq.Context(1) socket = context.socket(zmq.PUB) publisher = zmqstream.ZMQStream(socket) socket.bind("tcp://*:1337") def publish(): publisher.send_multipart(("heartbeat", "OHAI")) ioloop.PeriodicCallback(publish, 5000).start() ioloop.IOLoop.instance().start() 

Here is my Python subscriber code:

 import zmq from zmq.eventloop import ioloop, zmqstream ioloop.install() context = zmq.Context(1) socket = context.socket(zmq.SUB) subscriber = zmqstream.ZMQStream(socket) socket.setsockopt(zmq.SUBSCRIBE, "heartbeat") socket.connect("tcp://pub.local:1337") def subscription(message): print "Message Received: %s" % (message[1]) subscriber.on_recv(subscription) ioloop.IOLoop.instance().start() 

Why does my publisher not accept multiple incoming subscriber sockets? It is probably worth noting that several subscribers work fine when running on machine A, but I do not think that this is a problem with the firewall, because I tested the connections of subscribers from B and C to A with the firewall disabled.

Answer 1

Thanks to everyone for the helpful comments in the original post. This behavior turned out to be due to the inconsistency of the version of ZeroMQ used ... supervision on my part.