This implementation is inspired in Akka actor implementation.
This model encourage the writing of application consisting in actors that collaborates using message passing.
In this module, method invocation is like a message passing operation, that not returns value. The application
that uses actor model doesn't need continuation callbacks: each agent receives messages as method invocation,
and produces new messages calling other agent methods.
Via npm on Node:
npm install simpleactors
Reference in your program:
var simpleactors = require('simpleactors');
Create a system application:
var system = simpleactors.create('webcrawler');
Create an object of class Downloader, wrap it as an actor, and returns an actor reference:
var ref = system.actorOf(Downloader, 'downloader');
Alternatively, you can use an already create object as first parameter:
var downloader = new Downloader();
var ref = system.actorOf(downloader, 'downloader');
The second parameter is optional. A name is automatically assigned if the second parameter is missing.
Sends a message to an actor reference:
ref.tell(msg);
An object wrapped as an actor has:
- context: Actor context, with information about the actor environment.
- self: This actor reference.
It should implement the function:
- receive(msg): Process an incoming message
Example:
function Logger() {
this.receive = function (msg) {
console.log(msg);
}
}
var system = simpleactors.create('mysys');
var ref = system.actorOf(Logger);
ref.tell('Hello, world');
How to create an actor in our actor object:
this.context.actorOf(MyActor, name);
How to get an actor reference in our actor object:
var ref = this.context.actorFor(path);
Examples:
var refchild = this.context.actorFor('mychild'); // child of current actor
var refactor = this.context.actorFor('/myroot/myactor'); // actor in current system
How to get an actor reference in a system:
var ref = system.actorFor(path);
Example:
var ref = system.actorFor('/myroot/myactor'); // actor in current system
ref.tell('Hello');
An actor system can run in many nodes (running process).
var node = simpleactors.createNode(port [, host]);
Example creating a node, a system, and two actors:
var node = simpleactors.createNode(3000);
var system = node.create('mysys');
var actor1 = system.actorOf(MyActor, 'actor1');
var actor2 = actor1.context.actorOf(MyActor, 'actor2');
// actor1.self.path === 'sactors://mysys@localhost:3000/actor1'
// actor2.self.path === 'sactors://mysys@localhost:3000/actor1/actor2'
A node can refer to another running node. In node A:
var node = simpleactors.createNode(3000);
var system = node.create('mysys');
var actor1 = system.actorOf(MyActor, 'actor1');
node.start();
In node B:
var node = simpleactors.createNode(3001);
var remotenode = node.createRemoteNode(3000);
var remotesystem = remotenode.create('mysys');
var remoteref = remotesystem.actorFor('/actor1');
remotenode.start(function () {
// after connection, you can tell messages to remote actors
remoteref.tell('hello');
});
git clone git://github.com/ajlopez/SimpleActors.git
cd SimpleActors
npm install
npm test
Web Crawler sample shows
how you can create an application that don't depend on calling a method and receiving a response: each agent
does its works, receiving calls and sending calls to other agents.
Distributed Web Crawler sample has a
server that launch the web crawling process, and many clients can be launched that collaborates with the download and
harvest of new links to process. It uses a custom router.
Last modified 02 October 2024