Amarula.Storage.Adapter (amarula v0.5.0)

Ergonomic base for writing an Amarula.Storage adapter.

defmodule MyApp.RedisStore do
  use Amarula.Storage.Adapter

  @impl true
  def new(opts), do: %{conn: connect(opts[:url])}

  @impl true
  def get(%{conn: c}, namespace, key), do: ...

  @impl true
  def put(%{conn: c}, namespace, key, value), do: ...

  @impl true
  def delete(%{conn: c}, namespace, key), do: ...
end

Then point a connection at it:

Amarula.new(%{profile: :p, storage: {MyApp.RedisStore, url: "redis://..."}})
|> Amarula.connect()

use Amarula.Storage.Adapter declares @behaviour Amarula.Storage and gives you a default new/1 that simply returns the opts as a map — override it when your adapter needs to build real per-connection state (a pool, a dir, a table). get/3, put/4 and delete/3 have no sensible default, so you must implement them; the compiler will tell you if you forget one.

The value new/1 returns is the opaque per-connection state threaded back to every other callback — this is what lets one adapter module serve many independent connections (different accounts) without a global.