#AMQP-RPC

RPC library based on AMQP protocol. Tested with RabbitMQ on the highload project.

###Install RabitMQ

apt-get install rabbitmq-server

###Install library

npm install amqp-rpc

##round-robin

Example: Call remote function. Run multiple servers.js for round-robin shared.

###server.js example

var rpc = require('amqp-rpc').factory({
                                 exchange: "uuu-test", exchange_options: {exclusive: false, autoDelete: true},
                                 conn_options: {url: "amqp://guest:guest@rabbitmq:5672", heartbeat: 10}
                             });


rpc.on('inc', function(param, cb){
    var prevVal = param;
    var nextVal = param+2;
    cb(++param, prevVal, nextVal);
});

rpc.on('say.*', function(param, cb, inf){

    var arr = inf.cmd.split('.');

    var name = (param && param.name) ? param.name : 'world';

    cb(arr[1] + ' ' + name + '!');

});

rpc.on('withoutCB', function(param, cb, inf) {

  if(cb){
    cb('please run function without cb parameter')
  }
  else{
    console.log('this is function withoutCB');
  }

});

###client.js example

var rpc = require('amqp-rpc').factory({
                                 exchange: "uuu-test", exchange_options: {exclusive: false, autoDelete: true},
                                 conn_options: {url: "amqp://guest:guest@rabbitmq:5672", heartbeat: 10}
                             });

rpc.call('inc', 5, function() {
    console.log('results of inc:', arguments);  //output: [6,4,7]
});

rpc.call('say.Hello', { name: 'John' }, function(msg) {
    console.log('results of say.Hello:', msg);  //output: Hello John!
});

rpc.call('withoutCB', {}, function(msg) {
    console.log('withoutCB results:', msg);  //output: please run function without cb parameter
});

rpc.call('withoutCB', {}); //output message on server side console

##broadcast

Example: Core receiving data from all workers. Run multiple worker.js for broadcast witness. The core.js must be launched after all worker.js instances.

###example/broadcast/worker.js

var os = require('os');
var worker_name = os.hostname() + ':' + process.pid;
var counter = 0;

var rpc = require('../../index').factory({
    url: "amqp://guest:guest@localhost:5672"
});

rpc.onBroadcast('getWorkerStat', function(params, cb)    {
    if(params && params.type == 'fullStat') {
        cb(null, {
            pid: process.pid,
            hostname: os.hostname(),
            uptime: process.uptime(),
            counter: counter++
        });
    }
    else {
        cb(null, { counter: counter++ })
    }
});

###example/broadcast/core.js

var rpc = require('../../index').factory({
    url: "amqp://guest:guest@localhost:5672"
});

var all_stats = {};

//rpc.callBroadcast() is rpc.call() + waiting multiple responses
//If remote handler without response data, you can use rpc.call() for initiate broadcast calls.

rpc.callBroadcast(
    'getWorkerStat',
    { type: 'fullStat'},                    //request parameters
    {                                       //call options
        ttl: 1000,                          //wait response time  (1 seconds), after run onComplete
        onResponse: function(err, stat)  {  //callback on each worker response
            all_stats[ stat.hostname+':'+ stat.pid ] = stat;

        },
        onComplete: function()  {   //callback on ttl expired
            console.log('----------------------- WORKER STATISTICS ----------------------------------------');
            for(var worker in all_stats) {
                s = all_stats[worker];
                console.log(worker, '\tuptime=', s.uptime.toFixed(2) + ' seconds', '\tcounter=', s.counter);
            }
        }
    });

Results for three workers:

----------------------- WORKER STATISTICS ----------------------------------------
host1:2612 	uptime= 2470.39 seconds 	counter= 2
host2:1615 	uptime= 3723.53 seconds 	counter= 8
host2:2822 	uptime= 2279.16 seconds 	counter= 3

Eugene Demchenko aka Goldy skype demchenkoe email demchenkoev@gmail.com

Changelog

0.2.4:

* bugfix memory leak

0.2.3:

* support for other exchanges than rpc_exchange

0.2.2:

* print channels fn