Route helper for getting Absinthe URL

I’m using Phoenix 1.6 (so I don’t have access to some of the new routing helpers) and I’m wondering if there’s a way to get the URL for the GraphQL endpoint?

So far, the closest I can get is to get the base URL:

iex> alias MyAppWeb.Router.Helpers, as: Routes
iex> alias MyAppWeb.Endpoint
iex> Routes.url(Endpoint)

I was inspecting the generated helpers and I don’t see any _path or _url functions for my Absinthe GraphQL endpoint. Is this disclosed anywhere?

And a further kink… if I want to access this in a mix task, what stuff needs to be (re)started? I’m getting

** (RuntimeError) could not find ets table for endpoint MyAppWeb.Endpoint. Make sure your endpoint is started and note you cannot access endpoint functions at compile-time.

Thanks in advance!