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async_observer is great, but is dated and doesn't really support running jobs outside of the async_send idiom. Quebert is an attempt to mix how jobs are run in other popular worker queue frameworks, like resque and dj, with async_observer so that you can have it both ways.

Why Quebert (or how is it different from DJ and Resque)?

Because it has really low latency. Other Ruby queuing frameworks, like DJ or Resque, have to poll their queue servers periodicly. You could think of it as a "pull" queue. Quebert is a "push" queue. It maintains a persistent connection with beanstalkd and when is enqueud, its instantly pushed to the workers and executed.

Who uses it?

Quebert is a serious project. Its used in a production environment at Poll Everywhere to handle everything from SMS message processing to account downgrades.


  • Multiple back-ends (InProcess, Sync, and Beanstalk)
  • Rails/ActiveRecord integration similar to async_observer
  • Pluggable exception handling (for Hoptoad integration)
  • Run workers with pid, log, and config files. These do not daemonize (do it yourself punk!)
  • Provide custom hooks to be called before, after & around jobs are run

Some features that are currently missing that I will soon add include:

  • Rails plugin support (The AR integrations have to be done manually today)
  • Auto-detecting serializers. Enhanced ClassRegistry to more efficiently look up serializers for objects.

How to use

There are two ways to enqueue jobs with Quebert: through the Job itself, provided you set a default back-end for the job, or put it on the backend.


Quebert includes a Job class so you can implement how you want certain types of Jobs performed.

Quebert.backend = Quebert::Backend::InProcess.new

class WackyMathWizard < Quebert::Job
  def perform(*nums)
    nums.inject(0){|sum, n| sum = sum + n}

You can either drop a job in a queue:

Quebert.backend.put WackyMathWizard.new(1, 2, 3)

Or drop it in right from the job:

WackyMathWizard.new(4, 5, 6).enqueue

Then perform the jobs!

Quebert.backend.reserve.perform # => 6
Quebert.backend.reserve.perform # => 15

Rails integration


  backend: beanstalk
  host: localhost:11300
  queue: myapp-development
  backend: sync
# etc.


Quebert.config.logger = Rails.logger

Before/After/Around Hooks

Quebert has support for providing custom hooks to be called before, after & around your jobs are being run. A common example is making sure that any active ActiveRecord database connections are put back on the connection pool after a job is done:

Quebert.config.after_job do

Quebert.config.before_job do |job|
  # all hooks take an optional job argument
  # in case you want to do something with that job

Quebert.config.around_job do |job|
  # this hook gets called twice
  # once before & once after a job is performed

Async Sender

Take any ol' class and include the Quebert::AsyncSender.

Quebert.backend = Quebert::Backend::InProcess.new

class Greeter
  include Quebert::AsyncSender::Class

  def initialize(name)
    @name = name

  def sleep_and_greet(time_of_day)
    sleep 10000 # Sleeping, get it?
    "Oh! Hi #{name}! Good #{time_of_day}."

  def self.budweiser_greeting(name)
    "waaazup #{name}!"

walmart_greeter = Greeter.new("Brad")

Remember the send method in ruby?

walmart_greeter.send(:sleep_and_greet, "morning")
# ... time passes, you wait as greeter snores obnoxiously ...
# => "Oh! Hi Brad! Good morning."

What if the method takes a long time to run and you want to queue it? async.send it!

# ... do some shopping and come back later when the dude wakes up

Quebert figures out how to serialize the class, throw it on a worker queue, re-instantiate it on the other side, and finish up the work.

Quebert.backend.reserve.perform # => "Oh! Hi Brad! Good morning."
# ... Sorry dude! I'm shopping already

Does it work on Class methods? Yeah, that was easier than making instance methods work:

Quebert.backend.reserve.perform # => "waazup Coraline!"
  • Only basic data types are included for serialization. Serializers may be customized to include support for different types.


  • Beanstalk: Enqueue jobs in a beanstalkd service. The workers run in a separate process. Typically used in production environments.
  • Sync: Perform jobs immediately upon enqueuing. Typically used in testing environments.
  • InProcess: Enqueue jobs in an in-memory array. A worker will need to reserve a job to perform.

Using multiple queues

To start a worker pointed at a non-default queue (e.g., a Quebert "tube"), start the process with -q:

bundle exec quebert -q other-tube

Then specify the queue name in your job:

class FooJob < Quebert::Job
  def queue

  def perform(args)
    # ...

Beanstalk: Changing a job's TTR

class FooJob < Quebert::Job
  def ttr

  def perform(args)
    # ...