Shout View Source

A small library that provides Elixir modules with subscribe/publish functionality.

  • Separate core business logic from external concerns
  • Publish events synchronously or asynchronously

# Usage

Create your router, usually one per app but can be many. You'll define all the subscriptions in there. It's simply a GenServer that will keep track of subscriptions and allow you to add or remove more. (Don't forget to add it to your supervision tree)

### Router

  defmodule MyApp.Events do
    use Shout.Router

    subscribe(MyApp.Users.Create, :user_created, to: &MyApp.Emails.welcome_email/1)

    # Runs it asynchronously (uses Kernel.spawn/1)
    subscribe(MyApp.Users.Updated, :user_updated, to: &MyApp.Service.custom_task/1, asnyc: true)
  end

A subscription can be added at runtime too:

  MyApp.Events.subscribe(MyApp.SomeTask, :success, &MyApp.Notify.send_email/1)

Shout will make sure there are no duplicate subscriptions.

### Publishing By default when publishing an event using broadcast the subscriptions will be executed synchronously.

  defmodule MyApp.Users.Create do
    use MyApp.Events.Publisher

    def create(params) do
      user = User.create(params)
      broadcast(:user_created, user) # Will trigger: MyApp.Emails.welcome_email/1
    end
  end

Installation

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

def deps do
  [
    {:shout, "~> 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/shout.