opencensus_absinthe

defmodule Opencensus.Absinthe.Plug do
  @moduledoc """
  Modify your `Absinthe.Plug` pipeline for `Opencensus.Absinthe`:

  ## Installation

  Specify `traced_pipeline/2` as your `pipeline` in your `t:Absinthe.Plug.opts/0`, e.g. via
  `Phoenix.Router.forward/4`:

  ```elixir
  forward "/graphql", Absinthe.Plug,
    schema: MyApp.Schema,
    pipeline: {Opencensus.Absinthe.Plug, :traced_pipeline}
  ```

  **WARNING:** `traced_pipeline/2` will be present _only_ if `Absinthe.Plug` is loaded.
  Don't forget your `absinthe_plug` dependency in `mix.exs`!
  """

  if Code.ensure_loaded?(Absinthe.Plug) do
    @doc """
    Return the default pipeline with tracing phases.

    See also:

    * `Absinthe.Pipeline.for_document/2`.
    * `Absinthe.Plug.default_pipeline/1`.
    """
    def traced_pipeline(config, pipeline_opts \\ []) do
      config
      |> Absinthe.Plug.default_pipeline(pipeline_opts)
      |> Opencensus.Absinthe.add_phases()
    end
  end
end