Get TCP address information in ZeroMQ

sockets zeromq service-discovery jzmq
AlexLiesenfeld picture AlexLiesenfeld · Jan 30, 2013 · Viewed 8.3k times · Source

I want to connect clients to a server using ZeroMQ (java bindings, jzmq), but I need the TCP information badly, for example the TCP/IP address of a client request! The problem is, for being able to announce a service in the network I need to grab the TCP address of a request to be able to redirect clients to that service. The broker is a central "service registry" in that case. However, having ZeroMQ services on both sides, I do not see an option to retrieve that information.

What I do now, is to establish a dummy connection using a standard socket to the broker, after the connection is established I grab the IP address used for this connection and close the connection again. The IP address which has been retrieved is now being used for binding on it using a ZeroMQ socket on a random port.

I think this solution is the ugliest solution ever possible, so: What is a better solution to this problem?

Greetings.

Answer

Pieter Hintjens picture Pieter Hintjens · Jan 30, 2013

0MQ doesn't provide the address of peers, for a number of reasons. It's also not that useful since what you really want is the endpoint to receive connections on, not the address the connection was made on.

What I usually do, and it's elegant enough, is pass bind a service to an ephemeral port, get a full connection endpoint ("tcp://ipaddress:port") and send that string in some way, either broadcast to peers, to a central registry, etc. along with my service name. Then, peers who want to connect back can take the service name, look up to find my endpoint, and connect back to me.

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