service-discovery v1.1.0

node-discovery

Simple UDP multicast node discovery

Emits events with name of catched service description

Custom event '*' catches all messages (except own or force)

Example

var Description = require('../lib/service').Description;
var Listener = require('../lib/service').Listener;

//Create listener of announced notifications
var listener = new Listener();

//Generate unique client name
var serviceName = 'service-' + Math.random();

//Create new service
var service = new Description(serviceName);

//Add some meta info
service.attr('author', 'reddec');

//Add listeners for all messages
listener.on('*', function(serviceName, ip, data) {
  console.log("Service", serviceName, "found from", ip, ":", data);
});

API

Constants

• MULTICAST_PORT = 22000
• MULTICAST_IP = '239.155.155.150'
• MULTICAST_INTERVAL = 2000

class Description

Contains description of service and announce it periodically

constructor

Description(name, port = MULTICAST_PORT, ip = MULTICAST_IP, interval = INTERVAL)

Create new instance of service description and starts announcing

• name {string} Name of service
• port {number} Multicast port
• ip {string} Multicast IP
• interval {number} Sending interval in ms

attr

attr:(name, data)

Add attribute of description. Same name will be replaced

• name {string} Name of attribute
• data {object} Serializeable description
• return itself

close

close:()

Close sockets and remove all listeners and timers

• return itself

notify

notify:()

Send self description to multicast group

• return itself

class Listener extends EventEmitter

Simple service discovery over UDP multicast. Emits events with name of catched service description. Custom event '*' catches all messages

constructor

Listener(done, port = MULTICAST_PORT, ip = MULTICAST_IP, interval = INTERVAL)

Create new instance of service finder

• done {function(Listener)} Ready callback
• port {number} Multicast port
• ip {string} Multicast IP

on_message

on_message:(msg, rinfo)

Listener function for incoming UDP messages

close

close:()

Close sockets and remove all listeners and timers

• return itself