surrogate

About

Description

Surrogate is a dynamic TCP proxy implemented in nodejs. Surrogate proxies traffic to an upstream in a round-robin fashion.

Author

• Norman Joyner - [email protected]

Getting Started

Installation

npm install tcp-surrogate

Usage

To get started, simply require tcp-surrogate in your program, and instantiate a new Surrogate object. Once instantiated, you are free to spawn new surrogates.

var Surrogate = require("tcp-surrogate");
var surrogate = new Surrogate();

If you want to configure your surrogate, pass in an object with the values you would like to configure during instantiation.

var Surrogate = require("tcp-surrogate");
var surrogate = new Surrogate({
    port: 12345
});

The possible configuration values are as follows:

• port - Integer (optional) - Port the surrogate should run on. Defaults to a random port between 1024 and 2048.
• retries - Integer (optional) - Number of times to attempt to create the surrogate. Defaults to 3.
• upstreams - Array (optional) - List of upstreams in "host:port" format. Defaults to [].
• self_update - Function (optional) - Function which will run on interval and populate upstreams. Defaults to undefined.
• self_update_interval - Integer (optional) - Interval (in milliseconds) on which to run the self_update function. Defaults to 60000.

To modify upstreams after the surrogate has been spawned, you can use the edit_upstreams function.

var Surrogate = require("tcp-surrogate");
var surrogate = new Surrogate({
    port: 12345,
    upstreams: ["myupstream:myport"]
});

surrogate.on("listening", function(){
    surrogate.edit_upstreams(["myusptream:myport", "mysecondupstream:mysecondport"]);
});

Alternatively you can rely on the self_update function to keep upstreams in sync. This function runs on an interval set by self_update_interval, or can be triggered manually by calling force_population.

var Surrogate = require("tcp-surrogate");
var surrogate = new Surrogate({
    port: 12345,
    self_update: function(){
        return [Math.random()]
    },
    self_update_interval: 10000
});

surrogate.on("listening", function(){
    surrogate.force_population();
});

To deactivate a surrogate in use, you can use the deactivate function.

var Surrogate = require("tcp-surrogate");
var surrogate = new Surrogate({
    port: 12345,
    upstreams: ["myupstream:myport"]
});

surrogate.on("listening", function(){
    surrogate.deactivate();
});

surrogate.on("close", function(){
    console.log("deactivated!");
});

Events

Surrogate emits two events, listening and close. listening is emitted when the surrogate can start accepting connections. close is emitted when the surrogate is deactivated, and can no longer accept connections.

var Surrogate = require("tcp-surrogate");
var surrogate = new Surrogate();

surrogate.on("listening", function(){
    console.log("accepting connections ...");
});

surrogate.on("close", function(){
    console.log("... no longer accepting connections");
});