How to use metrics across relations?

[EyMaddis]

Hi 👋

In the demo I only see very basic metrics examples like summing a number of elements.

From the demo app:

  @impl Backpex.LiveResource
  def metrics do
    [
      total_likes: %{
        module: Backpex.Metrics.Value,
        label: "Total likes",
        class: "w-1/3",
        select: dynamic([p], sum(p.likes)),
        format: fn value ->
          Integer.to_string(value) <> " likes"
        end
      }
    ]
  end

I am struggling with what information is available using dynamic(), based on the source code I have a guess of if only adding associations that return one element (so belongs_to) into the query which gets the dynamic part appended to.

However, this does allow for more advanced metrics on the user dashboard, like "number of likes per user" (or something like that) where "likes" would be a has_many relation in the user schema.

My personal end goal is, that I have a resource "events" which has RSVPs that I want to filter based on coming/not coming and the average count and similar information. Maybe my lack of Ecto experience is showing here 🙃

I do not see metrics on the roadmap, where they just forgotten in the documentation, are they planned for improvement, or what is the goal with them?

Thanks 😊