node-gearman

node-gearman is an extremely simple Gearman client/worker module for Node.JS. You can register workers and you can submit jobs, that's all about it.

Installation

Install through npm

npm install node-gearman

Usage

Connect to a Gearman server

Set up connection data and create a new Gearman object

var Gearman = require("node-gearman");

var gearman = new Gearman(hostname, port);

Where hostname defaults to "localhost" and port to 4730

This doesn't actually create the connection yet. Connection is created when needed but you can force it with gearman.connect()

var gearman = Gearman(hostname, port);
gearman.connect();

Connection events

The following events can be listened for a Gearman object:

• connected - when the connection has been successfully established to the server
• idle - when a there's no jobs available for workers
• close - connection closed
• error - an error occured. Connection is automatically closed.

Submit a Job

Jobs can be submitted with gearman.submitJob(name, payload) where name is the name of the function and payload is a string or a Buffer. The returned object (Event Emitter) can be used to detect job status and has the following events:

• error - if the job failed, has parameter error
• data - contains a chunk of data as a Buffer
• end - when the job has been completed, has no parameters

Example:

var gearman = Gearman(hostname, port);
var job = gearman.submitJob("reverse", "test string");

job.on("data", function(data){
    console.log(data.toString("utf-8")); // gnirts tset
});

job.on("end", function(){
    console.log("Job completed!");
});

job.on("error", function(error){
    console.log(error.message);
});

Setup a Worker

Workers can be set up with gearman.registerWorker(name, callback) where name is the name of the function and callback is the function to be run when a job is received.

Worker function callback gets two parameters - payload (received data as a Buffer) and worker which is a helper object to communicate with the server. worker object has following methods:

• write(data) - for sending data chunks to the client
• end([data]) for completing the job
• error() to indicate that the job failed

Example:

var gearman = Gearman(hostname, port);

gearman.registerWorker("reverse", function(payload, worker){
    if(!payload){
        return worker.error();
    }
    var reversed = payload.toString("utf-8").split("").reverse().join("");
    worker.end(reversed);
});

License

MIT