Carbon

Middleware based proxy for table or cluster based routing.

Features

• Node http server export balancing with file watching and no-downtime restarts
• ProxyTable routing and balancing
• Websocket / socket.io compatibible
• CLI helper for ProxyFile based routing
• Support for custom middleware

Middleware

Carbon support many types of middlware. The bundled middlware is specifically for different types of balancing techniques. You can find other middleware projects by following the links below.

Bundled Middleware

• Balancer: Given a module.export node compatible webserver, start n processes and balance traffic. (Psuedo-clustering)
• ProxyTable: Route requests for host to port, or balance between many ports

Qualiancy Middleware

• Logging (qualiancy/carbon-logger): Multi-transport logging middleware suitable for debugging or production use.
• Stats (qualiancy/carbon-stats): Create a stats store and measure count of hits/misses and response time.

Installation

$ npm install carbon

Usage

To get the basics, you can also check out the examples folder.

Basic

Carbon allow you to build your own routing logic. In this really basic example, all traffic to port 8080 will be routed to port 8081.

var proxy = require('carbon').listen(8080);

proxy.use(function (req, res, next) {
  next(8081);
});

// for websockets
proxy.ws.use(function (req, res, next) {
  next(8081);
});

Proxy Table

The Carbon ProxyTable middleware makes it easy to route any traffic for a specific host to a different host, port, or set of host/ports.

var proxy = require('carbon').listen(8080);

// Single port proxy table
proxy.use(carbon.proxyTable([
  { hostname: 'localhost:8080'
  , port: 8081 }
]));

// Balanced proxyTable
proxy.use(carbon.proxyTable([
  { hostname: 'proxytable.com'
  , dest: [ 'localhost:9091', 9191, 'ec2-10-10-10-10:9090' ] }
]));

The proxyTable middleware takes an array of object definitions. If an array of port or dest is provided, requests will be round-robin balanced for each.

Balancer

Carbon Balancer middleware will take any node compatible http server (http, connect, express, ect..) and spawn up several node processes and balance traffic between them. Instead of using node's clusting component, carbon will find open ports available on the system and instruct the webserver to listen on that port.

To use, ensure the the server is the primary module.export for a given file, and pass that file to the balancer middleware.

var carbon = require('carbon')
  , proxy = carbon.listen(8080);

var balancer = carbon.balancer(
    path.join(__dirname, 'app.js')
  , { host: 'localhost' // required
    , watch: true       // optional (defaults to true)
    , maxWorkers: 4     // optional (defaults to hardware cpu count)
});

// for http requests
proxy.use(balancer.middleware);

// for websocket requests
proxy.ws(balancer.middleware);

In this example, any traffic that goes to localhost:8080 will be balanced between several instances of app.js. Balancer defaults to the number of CPU cores available on the current machine, but can be adjusted with options. Balancer also, by default, will watch app.js for changes and restart a new set of workers with no downtime. You can turn this off with the option watch: false.

Debugging

Carbon has integrated the fantastic debug module to allow for descriptive debugging. When starting any file that requires carbon, include the DEBUG environment variable to get robust CLI output:

DEBUG=carbon:* node proxy.js

Tests

Tests are written in the BDD styles for the Mocha test runner using the should assertion interface from Chai. Running tests is simple:

make test

Contributing

Interested in contributing? Fork to get started. Contact @logicalparadox if you are interested in being regular contributor.

Contibutors

• Jake Luer (@logicalparadox)

Inspiration

Carbon was inspired by these modules:

• node-http-proxy: proxy http & websocket requests
• distribute: proxy api
• up: psuedo-clustering

License

(The MIT License)

Copyright (c) 2012 Jake Luer [email protected]

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.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.