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POZeroMQ PUB/SUB - why won't multiple subscribers work?
 

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  1. POZeroMQ PUB/SUB - why won't multiple subscribers work?
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    <p>I'm using ZeroMQ to facilitate a publish/subscribe environment I'm needing. I'm running a publish server on machine A using Python (using EventLoop), and right now I have one subscriber running in C++ on machine B and a second subscriber running in Python (using EventLoop) on machine C.</p> <p>If machine B subscribes to machine A before machine C does, then B gets subscribed messages and C does not. Furthermore, if I look at the established connections on machine A, there only exists a connection for machine B but not for C. If machine C subscribes to A before B does, then it's the other way around.</p> <p>Here's my publisher code:</p> <pre><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() </code></pre> <p>Here's my Python subscriber code:</p> <pre><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() </code></pre> <p>Why isn't my publisher accepting multiple incoming subscriber sockets? It's probably worth noting that multiple subscribers works fine when running them on machine A, but I don't think it's a firewall issue because I tested subscriber connections from B and C to A with the firewall disabled.</p>
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    1. COany chance you could publish either (or both) of your subscriber codes?
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      1. USg19fanatic
    2. CO@g19fanatic - sure, I've edited my original question to include the code for my Python subscriber. I don't have access to the C++ subscriber right now, but I've confirmed that I get the same result if the Python subscriber is running on both machines B and C (meaning, the fact that one of the subscribers is written in C++ doesn't seem to be relevant so I probably shouldn't have complicated the question by making that distinction).
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      1. USBryan
    3. COVery strange. Can you test the code with publisher on B and then on C, with subscribers on other nodes? Looks like there is a network issue.
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