Follows agents' events into your app.

Each event comes with the cursor just past it. Save the cursor with your work, and the listener picks up from it after a restart.

defmodule MyApp.Runs do
  use Wardrik.Listener, wardrik: MyApp.AgentRuntime, types: ["wardrik.run.completed"]

  @impl true
  def handle(%Wardrik.Event{} = event, listener) do
    MyApp.Repo.transaction(fn ->
      MyApp.Repo.insert!(MyApp.Run.from(event), on_conflict: :nothing)
      MyApp.Cursors.put!("runs", listener.cursor)
    end)

    :ok
  end

  @impl true
  def cursor(_listener), do: MyApp.Cursors.get("runs")
end

Start it after Wardrik in your supervision tree, or have Wardrik start it:

Wardrik.start_link(name: MyApp.AgentRuntime, listeners: [MyApp.Runs])

Options

Give options to use, or as it starts. Your own options are kept alongside them.

• :wardrik - required. The module to follow, as MyApp.AgentRuntime.
• :resources - patterns of the agents to follow. Every agent unless set.
• :types - event types to follow. Every type unless set.
• :after - the cursor to start after, if you don't define cursor/1.

Without a cursor, it starts with events written after it starts.

Delivery

Each event is delivered at least once. Save the cursor in the same transaction as your work, and drop repeats by the event's id. If handle/2 raises or returns anything but :ok, the listener restarts and calls cursor/1 again.