Scarlett

Scarlett is a simple background system for Ruby.

Features/Problems

• Uses Rubinius Actors API (and a port for MRI) for jobs processing.
• Uses RabbitMQ as backend for jobs queue.
• Uses a reliable queue maintaining jobs saved in a backup queue when the workers crash.
• Use a simple API for jobs, Jobs are Marshallable objects that respond to #run method

Installation

Add this line to your application's Gemfile:

gem 'scarlett'

And then execute:

$ bundle

Or install it yourself as:

$ gem install scarlett

Usage

Queue

You must set a queue in your application to save jobs:

JobQueue = Scarlett::Queue.new(:jobs)

Jobs

The jobs should be Ruby objects that respond to run method (without arguments, the arguments should be set in other method, ex. initialize), there is a simple example:

class ComputationJob
  def initialize(seconds)
    @seconds = seconds
  end

  def run
    sleep @seconds
  end
end

Then you can insert jobs in the queue:

job = ComputationJob.new(10)
JobQueue.push(job)

Consumers

One or multiple workers should be started to consume jobs, this can be done for example in a rake task:

# jobs.rake
namespace :jobs do
  desc "Run worker for jobs"
  task :work => :environment do
    consumer = Scarlett::Consumer.new(:jobs)
    consumer.start
  end
end

Acknowledges

This libraby is done thanks to the work of:

• MenTaLguY and his awesome work in Rubinius Actors API
• mperham and his posts about Rubinius Actors and his work in GirlFriday
• All Rubinius team and contributors

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request