Adds an option on handle_asynchronously or delay that specifies which attributes to check for uniqueness on. A new job will not be created if one already exists for that method and object.


Add this line to your application's Gemfile:

gem 'delayed_job_loner'

And then execute:

$ bundle

Or install it yourself as:

$ gem install delayed_job_loner


The jobs table requires a migration to add the loner_hash string field.

$ script/rails generate delayed_job_loner
$ rake db:migrate


Pass the option :loner or :unique_on to any method that you would provide :priority or :run_at. :unique_on should be an array of attributes that you want to check the uniqueness of the job against.

  • :loner just specifies that the job should be unique and will only check against the method name and object id
  • :unique_on allows you to specify the fields that it will check uniqueness against

Here is an example:

class Foo < ActiveRecord::Base

  def do_all_the_things
    # All the things!
  handle_asynchronously :do_all_the_things, :unique_on => [:name, :other]

  def do_some_of_the_things
    # Some of the things!


This allows you to do things like this:

foo = Foo.first
  # Creates a new job
  # Doesn't create a new job because we already created one

foo.delay(:priority => 10).do_some_of_the_things
  # Creates a new job
foo.delay(:priority => 10, :loner => true).do_some_of_the_things
  # Doesn't create a new job
foo.delay(:priority => 10).do_some_of_the_things
  # Creates a new job because we didn't specify :unique_on


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