This addition makes StateMachine fully compatible with Ecto.

State setter and getter are abstracted in order to provide a way to update a state in the middle of transition for a various types of models. With Ecto, we call change() |> Repo.update. We also wrap every event in transaction, which is rolled back if transition fails to finish. This unlocks a lot of beautiful effects. For example, you can enqueue some tasks into db-powered queue in callbacks, and if transition failes, those tasks will naturally disappear.

Usage

To use Ecto, simply pass repo param to defmachine, you can optionally pass a name of the Ecto.Type implementation, that will be generated automatically under state machine namespace:

defmodule EctoMachine do
  use StateMachine

  defmachine field: :state, repo: TestApp.Repo, ecto_type: CustomMod do
    state :resting
    state :working

    # ...
  end
end

In your schema you can refer to state type as EctoMachine.CustomMod, with ecto_type omitted it would generate EctoMachine.StateType. This custom type is needed to transparently use atoms as states.