Rak

TODO: Add description

Installation

If available in Hex, the package can be installed by adding rak to your list of dependencies in mix.exs:

def deps do
  [
    {:rak, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/rak.

Mnesia Setup

config :mnesia,
  dir: 'mnesia/#{Mix.env()}/#{node()}'

Run the following mix task to create the Mnesia schema and required databases:

$ mix rak.setup

Usage

defmodule MyApp.Worker do
  use Rak.Worker

  def perform(arg) do
    # do something
  end
end

Enqueue a job to be processed by the worker:

iex> Rak.enqueue(MyApp.Worker, :hello)
%Rak.Job{...}

Concurrency

defmodule MyApp.Worker do
  use Rak.Worker, concurrency: 5

  def perform(data) do
    MyApp.Service.perform(data)
  end
end

Max Retries

defmodule MyApp.Worker do
  use Rak.Worker, max_retries: 3

  def perform do
    raise "failed"
  end
end

Failing job retries 3 times:

iex> job = Rak.enqueue(MyApp.Worker)
iex> ... delay determined by retry strategy
iex> job in Rak.jobs(:failed)
true

Callbacks

defmodule MyApp.Worker do
  use Rak.Worker

  def perform do
    # do something
  end

  def on_completed(%Rak.Job{} = job) do
    # do something when job is completed
    :ok
  end

  def on_failed(%Rak.Job{} = job, reason, stacktrace) do
    # do something when job failed
    :ok
  end
end

Global Events

defmodule MyApp.EventHandler do
  use GenServer

  def start_link(opts \\ []) do
    GenServer.start_link(__MODULE__, opts)
  end

  def init(state) do
    :ok = Rak.subscribe()
    {:ok, state}
  end

  def handle_info({:completed, %Rak.Job{} = job}, state) do
    IO.inspect(job, label: "received `completed` event")
    {:noreply, state}
  end

  def handle_info({:failed, %Rak.Job{} = job}, state) do
    IO.inspect(job, label: "received `failed` event")
    {:noreply, state}
  end
end

Listen for events:

iex> {:ok, pid} = MyApp.EventHandler.start_link()

iex> Rak.enqueue(MyApp.Worker, :ok)
%Rak.Job{...}
... job processed
received `completed` event: %Rak.Job{...}

iex> Rak.enqueue(MyApp.Worker, :error)
%Rak.Job{...}
... job processed
received `failed` event: %Rak.Job{...}

l1h3r / rak

Rak