Gatling

A simple node.js script that turns a simple single-process server into a multi-process cluster'd server with automatic restarting.

Plays nice with Express and similar libraries.

Installation

npm install --save gatlin

Recommended Setup

Instead of calling node server.js call npx gatling server.js. It will start one manager process + one worker process for each logical CPU core.

package.json

Add a scripts.start entry like so:

{
  //...
  "scripts": {
    "start": "gatling app.js"
  }
}

Legacy Setup

This was the only option in v1, and is preserved for backwards-compatibility.

Instead of starting the server, simply export the handler function and then call gatlin with the path to your server.js or app.js.

(The reason this was needed is that Gatlin ran each request inside a domain in v1. It prevented errors in one request from interfering with any other requests, but the API has since been deprecated.)

Express

Just change

app.listen(port)

to

module.exports = app;

HTTP

Your app should export the function that gets passed to http.createServer and not create the server itself.

For example, say your app.js looks like this:

var http = require('http');
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(1337);

Change it to this:

module.exports = function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
});

Usage

To start your server, run npm start. Or, to call gatling directly, run ./node_modules/bin/gatling app.js

API

The following command line options are accepted

-q, --quiet: silences all non-error output --processes 2: Set the number of worker processes. Defaults to one per CPU core. -p 1234, --port 1234: defaults to the PORT or VCAP_APP_PORT (bluemix) environment properties, or 8080 if not set. (Only applies when gatling starts the server rathern than your app.)

Changelog

v2.0.0

• Removed Domain support
• Removed newrellic support
• Added support for regular app.js / server.js files that start call listen() themselves
• Bumped minimum Node.js version to 6.0.0