gearman-node

gearman-node is an implementation of the Gearman protocol in CoffeeScript. It exposes a conventional Node library for creating Gearman workers and clients, and listening for events related to both. It aims to be a very a lightweight wrapper around the protocol itself.

Installation

npm install gearman-node

Workers

Workers are created with the name and function that they perform:

vargearman=require('gearman-node');varworker=newgearman.Worker('reverse',function(payload,worker){varreversed;if(payload==null){returnworker.error('No payload');}reversed=payload.toString("utf-8").split('').reverse().join('');returnworker.complete(reversed);});

The worker function itself is passed an object that contains the following convenience methods:

• warning(warning): sends a 'WORK_WARNING' packet
• status(num,den): sends a 'WORK_STATUS' packet
• data(data): sends a 'WORK_DATA' packet
• error([warning]): sends an optional 'WORK_WARNING' before 'WORK_FAIL'
• complete([data]): sends an optional 'WORK_DATA' before 'WORK_COMPLETE'
• done([warning]): calls error if warning passed, otherwise complete

The exact meaning of these is best documented on the Gearman website itself: http://gearman.org/protocol/.

Workers optionally take a hash of options. These options control the Gearman server connection settings as well as debug output and retry behavior:

vargearman=require('gearman-node');vardefault_options,worker;default_options={host: 'localhost',port: 4730,debug: false,max_retries: 0};worker=newgearman.Worker('unstable',function(payload,worker){if(Math.random()<0.5){returnworker.error();}returnworker.done();},default_options);

Clients

Clients are used to submit work to Gearman. By default they connect to Gearman at localhost:4730:

vargearman=require('gearman-node');varclient,default_options;default_options={host: 'localhost',port: 4730,debug: false};client=newgearman.Client(default_options);

The submitJob method of the client takes in the name of the worker and the workload you'd like to send. It returns an EventEmitter that relays Gearman server notifications:

client.submitJob('reverse','kitteh').on('created',function(handle){ ... });// JOB_CREATED.on('data',function(handle,data){ ... });// WORK_DATA.on('warning',function(handle,warning){ ... });// WORK_WARNING.on('status',function(handle,num,den){ ... });// WORK_STATUS.on('complete',function(handle,data){ ... });// WORK_COMPLETE.on('fail',function(handle){ ... });// WORK_FAIL

License

MIT