ESB-node-driver

ESB nodejs driver - under heavy development

Installation

You need to install zeromq 4 and google protobuf. And then:

npm install esb-node-driver

You will need a redis server, place his ip into /etc/hosts as domain esb-redis.

Usage

var ESB = require('esb-node-driver');

var esb = new ESB({
	//your hostname, needed for back connection from ESB proxy
	publisherHost: 'h0x91b.toyga.local',
	//some free port for listen on it
	publisherPort: 7786,
	
	//Hostname with redis, redis used for proxy registry, place it in /etc/hosts
	redisHost: 'esb-redis',
	redisPort: 6379
});

esb.on('error', function(err){
	console.log('ESB error', err);
});

esb.on('ready', function(){
	console.log('ESB ready for use');
	
	//register some method that will be accessed from any client ESB
	esb.register('/math/plus', 1, function(data, cb){
		console.log('/math/plus cb #1 is invoked with data: ', data);
		cb(null, data.a + data.b);
	});
	
	//you can register any number of responders for same identifier
	esb.register('/math/plus', 1, function(data, cb){
		console.log('/math/plus cb #2 is invoked with data: ', data);
		cb(null, data.a + data.b);
	});
	
	//pubsub :)
	esb.subscribe('/hello', 1, function(data){
		console.log('get message on channel /hello', data);
	});
	
	setInterval(function(){
		
		//lets invoke method above every second
		esb.invoke('/math/plus', {a: 2, b: 3}, function(err, resp, errStr){
			if(err){
				console.log('error while invoking a /math/plus', err, errStr);
				return;
			}
			console.assert(resp == 5);
			console.log('2+3=%s', resp);
		});
		
		//publish something
		esb.publish('/hello', {foo:'bar', rand: Math.random()});
		
	}, 1000);
});

API

• ESB.register(<identifier>, <version>, <callback>[ ,options])

  Currently is no options here

• ESB.invoke(<identifier>, <data>, <callback>[ ,options])

  Options may contain:

  • version - by default version is 1
  • timeout - in ms, by default 15000

• ESB.publish(<identifier>, <data>[ ,options])

  Options may contain:

  • version - by default version is 1

• ESB.subscribe(<identifier>, <version>, <callback>)

• ESB.regQueue(<channelName>, <persistentQueueName>)

  This will make a persistent queue <persistentQueueName> from any publish

• ESB.unregQueue(<channelName>, <persistentQueueName>)

  This will destroy persistent queue

• ESB.peek(<channelName>, <persistentQueueName>, <timeoutMs>, <callback>)

  Peek & lock entry from persistent queue for <timeoutMs> or until done callback fired

  • callback -> function(msg, done, msgId)

    msg - message done - done callback, fire it for dequeue msgId - autoincrement id used internally in ESB

Issues

If you get error similar to this

module.js:356
  Module._extensions[extension](this, filename);
                               ^
Error: libzmq.so.3: cannot open shared object file: No such file or directory
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Object.<anonymous> (/root/node_modules/ESB-proxy-server/main.js:7:10)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)

You need to add export LD_LIBRARY_PATH="/usr/local/lib:$LD_LIBRARY_PATH" to your ~/.bashrc

Building zmq and protobuf from source

#ZMQ
cd /tmp/
wget http://download.zeromq.org/zeromq-4.0.3.tar.gz
tar -xzvf zeromq-4.0.3.tar.gz
cd zeromq-*
./configure && make && sudo make install
#protobuf
cd /tmp/
wget https://protobuf.googlecode.com/files/protobuf-2.5.0.tar.gz
tar -xzvf protobuf-2.5.0.tar.gz
cd protobuf-2.5.0/
./configure && make && sudo make install