Given an app_name, returns a unique list of repos that all schema implementations point to. app_name is the same one would pass for your app: key under your project definition in ones mix.exs. e.g.

defmodule MyProject.Mixfile do
  def project do
    [
      app: my_project
      <...snip...>
    ]
  end
  <...snip...>
end

with a repo

defmodule MyProject.Repo.MyRepo do
  use Ecto.Repo, otp_app: :my_project

  <...snip...>
end

and an implementation

defmodule MyProject.Schema.MySchema do
  <...snip...>

  defimpl DAL.Repo.Discoverable do
    def repo(_), do: MyProject.Repo.MyRepo
  end
end

can be used as:

iex> DAL.Repo.repos(:my_project)
[MyProject.Repo.MyRepo]

This is particularly useful for tests where one may call

setup_all do
  :ok = DAL.Sandbox.checkout_all_as_shared(DAL.Repo.repos(:my_project))
edn