OpenApiSpex.Plug.RenderSpec.init/1 is undefined

Trying to use open_api_spex in my phoenix project.

When I try compiling the project with mix a warning pops us
OpenApiTest.OpenApiSpex.Plug.RenderSpec.init/1 is undefined

I have my router defined as below:

defmodule OpenApiTestWeb.Router do
  use OpenApiTestWeb, :router

  pipeline :browser do
    plug :accepts, ["html"]
    plug :fetch_session
    plug :fetch_flash
    plug :protect_from_forgery
    plug :put_secure_browser_headers
  end

  pipeline :api do
    plug :accepts, ["json"]
    plug OpenApiSpex.Plug.PutApiSpec, module: OpenApiTestWeb.ApiSpec
  end

  scope "/", OpenApiTestWeb do
    pipe_through :browser

    get "/", PageController, :index
    get "/payments", PaymentController, :create_payment
    get "/openapi", OpenApiSpex.Plug.RenderSpec, []
  end

  if Mix.env() in [:dev, :test] do
    import Phoenix.LiveDashboard.Router

    scope "/" do
      pipe_through :browser
      live_dashboard "/dashboard", metrics: OpenApiTestWeb.Telemetry
    end
  end
end

OpenApiSpex.Plug.RenderSpec module is present in the deps as below.

defmodule OpenApiSpex.Plug.RenderSpec do


      defmodule MyAppWeb.Router do
        use Phoenix.Router
        alias MyAppWeb.UserController

        pipeline :api do
          plug :accepts, ["json"]
          plug OpenApiSpex.Plug.PutApiSpec, module: MyAppWeb.ApiSpec
        end

        scope "/api" do
          pipe_through :api
          resources "/users", UserController, only: [:create, :index, :show]
          get "/openapi", OpenApiSpex.Plug.RenderSpec, []
        end
      end


  alias OpenApiSpex.Plug.PutApiSpec
  @behaviour Plug
  @json_encoder Enum.find([Jason, Poison], &Code.ensure_loaded?/1)

  @impl Plug
  def init(opts), do: opts

  @impl Plug
  def call(conn, _opts) do
    {spec, _} = PutApiSpec.get_spec_and_operation_lookup(conn)

    conn
    |> Plug.Conn.put_resp_content_type("application/json")
    |> Plug.Conn.send_resp(200, @json_encoder.encode!(spec))
  end
end

Could someone kindly help?

1 Like

Assuming the error message above is what Mix is printing, notice that it is prepending OpenApiTest to the module name. That’s not supposed to happen unless you are defining an alias somewhere of OpenApiSpex to OpenApiTest.OpenApiSpex or similar. Check your router and web.ex file.

If the above is not the correct warning, can you please print the full warning, including file+line info?

Thanks JV for the prompt support.

Below is the complete warning.

warning: OpenApiTestWeb.OpenApiSpex.Plug.RenderSpec.init/1 is undefined (module OpenApiTestWeb.OpenApiSpex.Plug.RenderSpec is not available or is yet to be defined)
  lib/open_api_test_web/router.ex:22: OpenApiTestWeb.Router.__checks__/0

Below is my troubleshooting:

When I have

get "/openapi", OpenApiSpex.Plug.RenderSpec, [] inside the /api block like below

scope "/api", OpenApiTestWeb do
    pipe_through :api
    get "/openapi", OpenApiSpex.Plug.RenderSpec, []  
  end

It pops us the warning, appends the OpenApiTestWeb to .OpenApiSpex.Plug.RenderSpec the and eventually fails to render the specs since the render could not take place.

When I moved get "/openapi", OpenApiSpex.Plug.RenderSpec, [] out of the “/api” scope block, the warning disappears and the call to the OpenApiSpex.Plug.RenderSpec is succesful.

Am I missing something? Curious to dig it down. Thank you.
:slight_smile:

Oh, I see. The issue is the scope. The scope ..., OpenApiTestWeb will nest everything inside under OpenApiTestWeb. Do this instead:

  scope "/api" do
    pipe_through :api
    get "/openapi", OpenApiSpex.Plug.RenderSpec, []  

    scope OpenApiTestWeb do
      ....
    end
  end
3 Likes