MaxoAdapt

MaxoAdapt generates adapter facades from ordinary Elixir callbacks. The generated functions retain callback documentation and specs, validate implementations, and can use either direct delegates or runtime lookup.

MaxoAdapt is derived from Ian Luites' adapter library, with additional fixes and runtime modes.

Why use it?

• Fast: :compile and :get_compiled dispatch through direct delegates.
• Small: the package has no runtime dependencies beyond Logger.
• Safe: required callback name/arity pairs are validated before mutable configuration.
• Explicit: the behaviour and generated facade live in one module.
• Flexible: choose immutable compile-time configuration, global runtime configuration, or process-isolated test configuration.

Installation

def deps do
  [
    {:maxo_adapt, "~> 0.1"}
  ]
end

MaxoAdapt requires Elixir 1.14 or later.

Quick start

defmodule SessionRepo do
  use MaxoAdapt

  behaviour do
    @doc "Look up a session by token."
    @callback get(token :: binary()) :: {:ok, term() | nil} | {:error, atom()}
  end

  @spec get!(binary()) :: term() | nil
  def get!(token) do
    case get(token) do
      {:ok, result} -> result
      {:error, reason} -> raise "SessionRepo: #{reason}"
    end
  end
end

defmodule SessionRepo.PostgreSQL do
  @behaviour SessionRepo

  @impl SessionRepo
  def get(token), do: {:ok, {token, :postgresql}}
end

:ok = SessionRepo.configure(SessionRepo.PostgreSQL)
{:ok, {"token", :postgresql}} = SessionRepo.get("token")

Modes

Mode	Lookup	Runtime switching	Typical use
:compile (default)	regenerated direct delegates	yes	fast production dispatch
:get_compiled	Application.compile_env/3 + direct delegates	no	immutable compile-time choice
:get_env	Application.get_env/3 per call	yes	simple global runtime switching
:get_dict	process dictionary + live ancestors	yes	async test isolation

Call YourAdapter.__maxo_adapt__/0 to inspect the effective implementation.

Guides

• Introduction and modes
• Configuration
• Debugging
• Compatibility and quality checks

Published API documentation is available at https://hexdocs.pm/maxo_adapt.

Support

License

MaxoAdapt is available under the MIT License.