DJ Remixes

A boat load of incredibly useful ‘plugins’ for Delayed::Job! DJ is a wonderful project and is incredibly useful, however it can be even more useful with just a few extras added in.

The Extras

• A proper ‘Worker’ class: DJ::Worker that accepts attributes.
• Callbacks
• Airbrake (Hoptoad) support, if using Airbrake.
• Priority settings
• Automatic re-enqueueing
• Better scheduling
• Unique jobs.
• more …

These are a few of the extras for DJ that are included here.

Installation

In your Gemfile add the following:

  gem "delayed_job", "2.1.4"
  gem "dj_remixes"

Then install the gems:

  $ bundle install

Create a migration to add the required dj_remixes fields to the delayed_job table:

  class AddDjRemixesColumns < ActiveRecord::Migration
    def self.up
      add_column :delayed_jobs, :worker_class_name,   :string
      add_column :delayed_jobs, :started_at,          :datetime
      add_column :delayed_jobs, :finished_at,         :datetime
    end

    def self.down
      remove_column :delayed_jobs, :worker_class_name
      remove_column :delayed_jobs, :started_at
      remove_column :delayed_jobs, :finished_at
    end
  end

Using

Basic Worker

  class FooWorker < DJ::Worker
  
    def perform
      # do work
    end
  
  end
  
  FooWorker.enqueue

Unique Worker

Tell DJ to only allow one of this worker at a given time.

  # We only want to charge the card once!
  class PurchaseWorker < DJ::Worker
    is_unique
  
    def perform
      # charge the credit card...
    end
  end

If the worker has an id attribute that then will be used in conjunction with the class name of the worker to form the unique key.

Priority

Tell DJ to run this worker with a higher priority than others.

  class FooWorker < DJ::Worker
    priority :high
  
    def perform
      # do work
    end
  
  end
  
  FooWorker.enqueue

Re-Enqueueing

Tell DJ to re-enqueue this worker after it has successfully completely. NOTE: This will actually create a new DJ object in the database, not reuse the same one.

  # Run every 30 days and charge a credit card.
  class SubscriptionWorker < DJ::Worker
    re_enqueue

    def run_at
      30.days.from_now
    end

    def perform
      # charge the credit card...
    end
  end

Attributes

The DJ::Worker class can accept attributes, similar to the way an ActiveRecord model can.

  class FooWorker < DJ::Worker
    priority :high
  
    def perform
      # do work
      puts self.id # => 1
      puts self.person # => 'Mark Bates'
    end
  
  end
  
  worker = FooWorker.new(:id => 1, :person => 'Mark Bates')
  worker.enqueue!

Contributors

• Mark Bates
• Stuart Garner
• Brent Kirby
• Luke Pearce
• Lars Pindrake