Humus inspired actor framework for Node.js
Stability: 0 - Deprecated -- For an improved way of expressing actors in Node.js see Tiny Actor Run-Time
Follow instructions at http://nodejs.org/
curl http://npmjs.org/install.sh | sh
npm install anode
The intent behind anode is to provide a way to write "pure" actors in JavaScript. Over the years, the idea of what actors are has evolved quite a bit. In the context of what anode is trying to provide, "pure" actors are actors as defined by Carl Hewitt and elaborated by Gul Agha. Dale Schumacher (the author of pure actor language Humus on which anode is inspired) provides an excellent introduction to this perspective on actors on his blog here.
Actor processing starts on receipt of a message. In response to a message, an actor can do three things:
- send a finite number of new messages (
@send) - create a finite number of new actors (
@create) - designate a new behavior to process subsequent messages (
@become)
A quick note about CoffeeScript... Because of how anode actors are implemented, the code relies heavily on the this keyword. There is nothing preventing you from writing anode actors in JavaScript, however, the CoffeeScript syntax just happens to perfectly fit what each actor behavior is trying to express, so I highly recommend taking look at anode through the CoffeeScript lens.
Taking a pointer from Node.js, here is an example webserver in anode included in examples/helloworld.example.coffee
anode = require 'anode'
cnf = new anode.Configuration()
httpServer = cnf.actor anode.http.server_beh()
helloworld = cnf.actor anode.behavior( 'httpServer'
'#start' : ->
@send( @, '#listen', 8080, '127.0.0.1' ).to @httpServer
'$httpServer, #listen' : ->
@send( 'Server running at http://127.0.0.1:8080/' ).to cnf.console.log
'$httpServer, #request, request, response' : ->
@send( null, '#end', 'Hello Actor World\n' ).to @response
)( httpServer ) # helloworld
cnf.send( '#start' ).to helloworldTo run the server, go into the examples directory and execute it with coffee:
% coffee helloworld.example.coffee
Server running at http://127.0.0.1:8080/
*note: not all of the Node.js 'http' functionality has been wrapped yet.
A more involved echo server using sockets directly can be found in examples/echoserver.example.coffee
anode = require 'anode'
# set debug mode to see the messages
cnf = new anode.Configuration debug : true
# we are naming our actors here to make debug output friendlier
netServer = cnf.actor 'netServer', anode.net.server_beh()
echoServer = cnf.actor 'echoServer', anode.beh( 'netServer'
'#start' : ->
@send( @, '#listen', 8124 ).to @netServer
# response from netServer acknowledging that it is listening and ready
'$netServer, #listen' : ->
@send( 'server bound' ).to cnf.console.log
# message from netServer when it receives a new connection
'$netServer, #connection, socket' : ->
@send( 'server connected' ).to cnf.console.log
# request ack after #write completes by including self (@)
@send( @, '#write', 'hello\r\n' ).to @socket
'socket, #end' : ->
@send( 'server disconnected' ).to cnf.console.log
# once socket gives us its socket object
'socket, #socket, socketObj' : ->
# pipe the socket to itself to echo
# don't care about confirmation so send null as customer
@send( null, '#pipe', @socketObj ).to @socket
# write ack
'socket, #write, _' : ->
# request the actual socket object so we can pipe to it
@send( @, '#socket' ).to @socket
)( netServer ) # echoServer
cnf.send( '#start' ).to echoServerTo run the server, go into the examples directory and execute it with coffee:
% coffee echoserver.example.coffee
FROM [configuration] TO [echoServer::10] SEND [ '#start' ]
FROM [echoServer::10] TO [netServer::9] SEND [ '[echoServer::10]', '#listen', '8124' ]
FROM [netServer::9] TO [echoServer::10] SEND [ '[netServer::9]', '#listen' ]
FROM [echoServer::10] TO [console.log::1] SEND [ 'server bound' ]
server bound
You can connect to it using telnet:
% telnet localhost 8124
I've begun a tutorial to demonstrate some of the elementary concepts of coding actors in anode. It is documented in code in examples/tutorial/one.coffee.
Take a look at the examples in the examples folder. As of this writing, there
are three non-trivial examples of setting up an actor configuration:
erlangMailbox.coffeeis an implementation of Erlang-style mailbox modeled on Dale's blog post, runcoffee erlangMailbox.example.coffeelambda1.coffeeis an implementation of lambda calculus modeled on Dale's blog post, runcoffee lambda1.example.coffee(you should see42)lambda2.coffeeis a follow-on implementation of lambda calculus modeled on the second blog post in that series, runcoffee lambda2.example.coffee(you should seetrueandfalse)
Other examples show simpler functionality:
console.warn.example.coffeedemonstrates actor wrappers around node.js console, runcoffee console.warn.example.coffeevaluematch.example.coffeeshows how$syntax matches pattern by evaluating the variable, runcoffee valuematch.example.coffeesimple.example.coffeeshows a simple counter system, runcoffee simple.example.coffeeoptional.example.coffeeshows use of optional parameters in a message, runcoffee optional.example.coffeeassert.example.coffeeshows the use of assertions as well as demonstrating theanodemessage "stack trace" in case an unexpected error occurs, runcoffee assert.example.coffee
(The MIT License)
Copyright (c) 2011 Tristan Slominski
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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