Not Receiving Messages in ZeroMQ Output Plugin

Elastic Stack Logstash
#1

I have a simple client subscribing to messages on port 2120:

zmq = require('zmq');


port = 2120;
sock = zmq.socket('sub');
sock.connect("tcp://127.0.0.1:" + port);

sock.on('message', function (topic, msg) {
  console.log('received message');
});

sock.subscribe('foo');
console.log("zeromq listening to port" + port)

Logstash is outputting to the zeromq plugin like this:

output {
    zeromq {
      topology => "pushpull"
      topic => "foo"
    }
}

When I execute run logstash ./bin/logstash -f site.conf and subscribe with my node.js client node index, I never receive a message. Why is that?

#2

Are messages being pushed through the LS pipeline? Are you sure of that?

#3