Using Ash Query context in load

Ash Forum Ash Questions / Help
, , ,
1

I have resources with a ManualRead to fetch from an external API. For all of my calls I need to pass a client that has a bearer token. I’m currently setting it on the context of the original query. I my first resource has a has_many relationship to another resource. When I try to use Ash.Query.load the second manual read doesn’t get the context, either on the query context or on the context argument.

defmodule A do
  use Ash.Resource, domain: Domain

  actions do
    read :read do
      primary? true
      manual {Actions.FetchResource, key: "/resource_a"}
    end
  end

  attributes do
    uuid_primary_key :id
  end

  relationships do
    has_many :b, B
  end
end

defmodule B do
  use Ash.Resource, domain: Domain

  actions do
    read :read do
      primary? true
      manual {Actions.FetchResource, key: "/resource_b"}
    end
  end

  attributes do
    uuid_primary_key :id
  end

  relationships do
    belongs_to :a, A
  end
end

defmodule Actions.FetchResource do
  use Ash.Resource.ManualRead
  
  @impl true
  def read(query, _, opts, context) do
   IO.inspect(query.context)
   IO.inspect(context)
  
    resource_url = Keyword.get(opts, :resource_url)

    client = Map.fetch!(query.context, :client)
    results = Req.request!(client, method: :get, url: resource_url).body["results']
     Ash.Query.apply_to(query, xform(results)
  end
end

But during usage, I can make the original query and get results, but loading the relationship fails.

A
|> Ash.Query.for_read(:read, %{}, context: %{client: client})
|> Ash.Query.limit(1)
|> Ash.read!()

This fails however, with a ** (KeyError) key :client not found in: either of the contexts for the second part of the query.

A
|> Ash.Query.for_read(:read, %{}, context: %{client: client})
|> Ash.Query.limit(1)
|> Ash.Query.load(:b)
|> Ash.read!()

How can I pass the context from the first query into the second query?

2

You can use the shared key to pass data down.

3 Likes