ExJob is a zero-dependency, ultra-fast (1), background job processing library.

All you need is ExJob, no Redis, no internal or external dependencies. Running ExJob is as simple as adding it to your dependencies and start writing your first job.

ExJob's interface is very similar to other job processing libraries such as Toniq or Exq.

You'll need to defined a job handler:

defmodule App.WelcomeEmail do
  use ExJob.Job

  def perform(user) do
    App.Mailer.send_welcome_email(user)
  end
end

And then enqueue your job:

user = UserRepo.first
#=> %App.User{name: "Jon", email: "jon@example.com"}
ExJob.enqueue(App.WelcomeEmail, [user])
#=> :ok

Note that because ExJob is implemented in pure elixir, you can pass any elixir term to the enqueue function (such as an Ecto struct) as it will not be serialized.

By default, ExJob will run each of your jobs concurrently in a different process. But sometimes you'll want your jobs to be processed synchronously.

ExJob allows you to define a group_by function inside your job module. Jobs for which group_by returns the same value will run synchronously in the order they were enqueued.

Let's say you wanted to send multiple text messages to your users, but you want to preserve order:

defmodule App.Jobs.SendTextMessage do
  use ExJob.Job

  def group_by(%User{id: id}, _message_type), do: id

  def perform(user, message_type) do
    text = App.Messages.for(message_type)
    number = user.phone_number
    Twilio.send(to: number, text: text)
  end
end

You can now enqueue as many messages as you want, and they will be processed in the same order as you enqueued them:

user = UserRepo.first
ExJob.enqueue(App.Jobs.SendTextMessage, [user, :welcome])
ExJob.enqueue(App.Jobs.SendTextMessage, [user, :first_use_voucher])
ExJob.enqueue(App.Jobs.SendTextMessage, [user, :more_spam])

Add :ex_job to your mix.exs dependencies.

def deps do
  [
    {:ex_job, "~> 0.2.0"}
  ]
end

ExJob runs as an OTP app, so you will need to add it to your applications as well:

def application do
  [extra_applications: [:ex_job]]
end

Documentation is mainly unwritten yet, but it can be found here: Documentation