# Shout
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
```elixir
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:
```elixir
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.
```elixir
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](https://hex.pm/docs/publish), the package can be installed
by adding `shout` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:shout, "~> 0.1.0"}
]
end
```
Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
be found at <https://hexdocs.pm/shout>.