javascript - NodeJS Event Emitter Blocking Issue -

i have node application handling zeromq events coming application utilizing node-zmq bindings found here: https://github.com/justintulloss/zeromq.node

the issue running 1 of operations event takes long time process , appears blocking other event being processed during time. although application not clustered, doing afford few more threads , doesn't solve issue. wondering if there way of allowing these async calls not block other incoming requests while process, , how might go implementing them.

here highly condensed/contrived code example of doing currently:

var zmq = require('zmq'); var zmqresponder = zmq.socket('rep'); var client = require('node-rest-client').client; var client = new client();  zmqresponder.on('message', function (msg, data) {   var parsed = json.parse(msg);   logging.info('zmq request received: ' + parsed.event);   switch (parsed.event) {     case 'create':         //typically short running process, not issue     case 'update':         //long running process issue         serverrequest().then(function(response){             zmqresponder.send(json.stringify(response));         });      }  });  function serverrequest(){     var deferred = q.defer();       client.get(function (data, response) {       if (response.statuscode !== 200) {         deferred.reject(data.data);       } else {         deferred.resolve(data.data);       }   });     return deferred.promise; } 

edit** here's gist of code: https://gist.github.com/battlecow/cd0c2233e9f197ec0049

i think, through comment thread, i've identified issue. req/rep has strict synchronous message order guarantee... must receive-send-receive-send-etc. req must start send , rep must start receive. so, you're processing 1 message @ time because socket types you've chosen enforce that.

if using different, non-event-driven language, you'd error telling you'd done wrong when tried send or receive twice in row, node lets , queues subsequent messages until it's turn in message order.

you want change req/rep dealer/router , it'll work way expect. you'll have change logic router socket send appropriately, else should work same.

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rough example code, using relevant portions of posted gist:

var zmqresponder = zmq.socket('router');  zmqresponder.on('message', function (msg, data) {     var peer_id = msg[0];     var parsed = json.parse(msg[1]);     switch (parsed.event) {         case 'create':             // build parsedresponse, then...             zmqresponder.send([peer_id, json.stringify(parsedresponse)]);             break;     } });  zmqresponder.bind('tcp://*:5668', function (err) {     if (err) {         logging.error(err);     } else {         logging.info("zmq awaiting orders on port 5668");     } }); 

... need grab peer_id (or whatever want call it, in zmq nomenclature it's socket id of socket you're sending from, think of "address" of sorts) first frame of message receive, , use send first frame of message send back.

by way, noticed in gist both connect()-ing , bind()-ing on same socket (zmq.js lines 52 & 143, respectively). don't that. inferring other clues, want bind() on side of process.