Active Job -- Make work happen later

Active Job is a framework for declaring jobs and making them run on a variety of queueing backends. These jobs can be everything from regularly scheduled clean-ups, to billing charges, to mailings. Anything that can be chopped up into small units of work and run in parallel, really.

It also serves as the backend for Action Mailer's #deliver_later functionality that makes it easy to turn any mailing into a job for running later. That's one of the most common jobs in a modern web application: sending emails outside of the request-response cycle, so the user doesn't have to wait on it.

The main point is to ensure that all Rails apps will have a job infrastructure in place, even if it's in the form of an "immediate runner". We can then have framework features and other gems build on top of that, without having to worry about API differences between Delayed Job and Resque. Picking your queuing backend becomes more of an operational concern, then. And you'll be able to switch between them without having to rewrite your jobs.

Usage

To learn how to use your preferred queueing backend see its adapter documentation at ActiveJob::QueueAdapters.

Declare a job like so:

class MyJob < ActiveJob::Base
  queue_as :my_jobs

  def perform(record)
    record.do_work
  end
end

Enqueue a job like so:

MyJob.perform_later record  # Enqueue a job to be performed as soon as the queueing system is free.

MyJob.set(wait_until: Date.tomorrow.noon).perform_later(record)  # Enqueue a job to be performed tomorrow at noon.

MyJob.set(wait: 1.week).perform_later(record) # Enqueue a job to be performed 1 week from now.

That's it!

GlobalID support

Active Job supports GlobalID serialization for parameters. This makes it possible to pass live Active Record objects to your job instead of class/id pairs, which you then have to manually deserialize. Before, jobs would look like this:

class TrashableCleanupJob
  def perform(trashable_class, trashable_id, depth)
    trashable = trashable_class.constantize.find(trashable_id)
    trashable.cleanup(depth)
  end
end

Now you can simply do:

class TrashableCleanupJob
  def perform(trashable, depth)
    trashable.cleanup(depth)
  end
end

This works with any class that mixes in GlobalID::Identification, which by default has been mixed into Active Record classes.

Supported queueing systems

Active Job has built-in adapters for multiple queueing backends (Sidekiq, Resque, Delayed Job and others). To get an up-to-date list of the adapters see the API Documentation for ActiveJob::QueueAdapters.