RPC not working: What I am doing wrong? Is there an example of its implementation?

Greetings,

Will you help me?

I apologize to bother but I am having troubles implementing RPC correctly.

Perhaps someone can point out what I am doing wrong in the code since I couldn’t find in the documentation a full example on how to implemented.

// Publish RPC from this client to server
var extension = {
 id: UUID.random(),
}

var body = {...};

rabbit.publish('rpc.extension.request', {
    routingKey: 'extend.rpc',
    correlationId: extension.id,
    replyTo: "rpc.extension.response",
    contentType: "application/json",
    body: body,
    expiresAfter: 60000 // TTL in ms, in this example 60 seconds - can be removed after consumer working, just here to prevent junk accumulating on servers.
  }).then(
    () => { // a list of the messages of that succeeded
      log.info(`Success publishing extension for rpc ${extension.id}`);
    },
    (failed) => { // a list of failed messages and the errors `{ err, message }`
      log.info(`Error publishing extension for rpc ${extension.id} ->  ${failed.err}: ${failed.message}`);
    });

-----------------------
// Consuming RPC result sent by server to this client.

module.exports.setup = function () {
	...

	const handleRPC = rabbit.handle({queue: 'rpc.extension.response'}, handleExtendRPCResponse);
	handleRPC.catch(onHandleError);
};

function handleExtendRPCResponse(msg) {
	logger.info(`RPC Received message : ${msg}`)

	try {
		messageHandler.processMessage(msg, function (err) {
			if (err) {
				logger.error(`ERROR in RPC Process message: "${err.error}"`);
				msg.reject();
			} else {
				logger.info("Process RPC message passed");
				msg.ack();
			}
		})
	} catch(e){
		logger.error(`ERROR while Processing RPC message: "${e.message}"`);
		msg.reject();
	}
}

function onHandleError (err, msg) {
    // not able to hit this with a test...not sure how to.
    logger.error('Error:', JSON.stringify(err), 'Message:', JSON.stringify(msg));
    // Temporary, but if we can't handle it we don't want it requeued.
    msg.reject();
}

Thanks for your time and the creation of this package.

[acarlstein]

I figured out the issue. In the topology, when creating the exchange, I needed to add ‘subscribe:true’ property since the queue was already created but used as publish instead of request.

Thanks anyways for the feedback. I appreciate it.

[zlintz]

That makes sense why this problem seemed so familiar. I helped @fifthfloorsoftware with this back then