Celery client for Node.js

Celery is an asynchronous task/job queue based on distributed message passing. celery-shoot allows to queue tasks from Node.js. If you are new to Celery check out http://celeryproject.org/

Differences with node-celery

1. This library is now based on amqp-coffee, instead of node-amqp.

2. EventEmitter based code has been removed; only pure callbacks are available.

3. Support for the Redis Backend has been removed.

   • I will accept pull-requests if you would like to re-add support.

4. Primary Queue / Exchange declaration has been removed. This means if you start up celery-shoot on a fresh RabbitMQ vhost, you'll get an error.

   To get around this, just start a celery worker on that vhost first.

   • Why? If you declared your Queues/Exchanges from node, you need to mirror the celery settings exactly. If you don't, you need to stop both node & celery, delete the queues, restart both services (with the correct settings, or with the celery worker first). This was a big trap, that often came up deploying to production so we're better off without it!

Usage

Simple example, included as examples/hello-world.js:

varcelery=require('celery-shoot'),client=celery.connectWithUri('amqp://guest:guest@localhost:5672//',function(err){assert(err==null);vartask=client.createTask('tasks.echo');task.invoke(["Hello Wolrd"],function(err,result){console.log(err,result);})});

ETA

The ETA (estimated time of arrival) lets you set a specific date and time that is the earliest time at which your task will be executed:

varcelery=require('celery-shoot'),client=celery.connectWithUri('amqp://guest:guest@localhost:5672//',function(err){assert(err==null);vartask=client.createTask('tasks.send_email',{eta: 60*60*1000// execute in an hour from invocation},{ignoreResult: true// ignore results});task.invoke([],{to: 'to@example.com',title: 'sample email'})});

Expiration

The expires argument defines an optional expiry time, a specific date and time using Date:

varcelery=require('celery-shoot'),client=celery.connectWithUri('amqp://guest:guest@localhost:5672//',function(err){assert(err==null);vartask=client.createTask('tasks.sleep',{eta: 60*60*1000// expire in an hour});task.invoke([2*60*60],function(err,res){console.log(err,res);})});

Routing

The simplest way to route tasks to different queues is using options.routes:

varcelery=require('celery-shoot'),client=celery.connectWithUri('amqp://guest:guest@localhost:5672//',{routes: {'tasks.send_mail': {'queue': 'mail'}}},function(err){assert(err==null);vartask=client.createTask('tasks.send_email');task.invoke([],{to: 'to@example.com',title: 'sample email'});vartask2=client.createTask('tasks.calculate_rating');task2.invoke([],{item: 1345});});

You can also configure custom routers, similar to http://celery.readthedocs.org/en/latest/userguide/routing.html#routers

varmyRouter=function(task,args,kwargs){if(task==='myapp.tasks.compress_video'){return{'exchange': 'video','routingKey': 'video.compress'}}returnnull;}Client({routes: [myRouter]});