CoffeeScript ZMQ Pub不发送消息

Question

The same pub-sub code works on local machine (Linux zephyr 3.13.0-27-generic #50-Ubuntu SMP Thu May 15 18:08:16 UTC 2014 i686 i686 i686 GNU/Linux).

However, on EC2 machine (Linux <host> 3.2.0-60-virtual #91-Ubuntu SMP Wed Feb 19 04:13:28 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux) it fails. The security group is set to allow all for 19019 port and also, for all TCP ports starting from 0. I tried adding prints in the NodeJS ZMQ module and was able to get the data that I am sending when I added it in flush function. What else could be the problem?

I tried listening to pub traffic using tcpflow on port 19019 but it didn't work. How can I listen to this traffic?

sudo tcpflow -i eth0 port 19019 and sudo tcpflow -i lo port 19019

Both didn't work. Is there any tool through which I can debug this?

Pub.coffee

zmq = require 'zmq'
dpush_socket = zmq.socket 'pub'
dpush_socket.bind 'tcp://127.0.0.1:19019', (err) ->
  if not err?
    console.log "Bind successful"

dpush_socket.send 'pid' + ' req ' + req.query.pid

Sub.coffee

zmq = require "zmq"

endPoint = "tcp://0.0.0.0:19019"

sub = zmq.socket "sub"
sub.identity = 'worker' + process.pid;
sub.connect endPoint
console.log "worker connected!"

sub.subscribe('')

sub.on "message", (msg) ->
  console.log(sub.identity + 'got ' + msg.toString())

Answer 1

Transport Class shall rather meet each other on the same IP:PORT#

Sub .coffee

zmq = require "zmq"
#                                    # rather set URL, where PUB .bind() listens
endPoint = "tcp://127.0.0.1:19019"   # endPoint = "tcp://0.0.0.0:19019"

Answer 2

Part of the answer is probably what user3666197 pointed out: you need to bind and connect on the same IP. I'm not sure what you intend with the 0.0.0.0 address, and it shouldn't work even on your local machine unless you found some undocumented corner of your network stack that supports this behavior.

The other thing is that you either want to include your send call in your callback, or probably want to use bindSync to ensure that the socket is bound before you attempt to send anything. What may be happening is that the socket is discarding your sent message because the socket hasn't completed binding by the time you get to the call. This could well be different between different machines.

Answer 3

The problem is I use a nodejs cluster module and in each of the work a zmq pub socket is created which binds on same port which messes up the issue. On my local machine its a single worker spawning.