From a submodule, expose only certain options as flake outputs

[DrRuhe]

I declared a bunch of options for perSystem.deployments.<name>. These options get built into packages under perSystem.deployments.<name>.public. How do I expose this public option as a flake output without exposing the adjacent options?

I took a look at how mkTransposedPerSystemModule does it for the packages attribute. I fail to understand how the flake output actually gets populated, given that it defaults to {} but seems to not be initialized from any config.perSystem.XY

[roberth]

I think you'd have to write the logic yourself, in order to expose only the .public value.
Maybe something like this?

flake.deployments =
  mapAttrs
    (system: v: mapAttrs (name: deployment: deployment.public) v.deployments)
    config.allSystems

Are you sure you want to have deployments for each of the systems? I would expect a flake attribute like deployments to pick a specific system type for me, similar to what we have with nixosConfigurations.

[roberth]

That is unless you want to use have a deployment script that can be launched from any of the systems, but affects a single deployment that is defined outside perSystem, in which case it does make sense.

Or maybe it's something else? What did you have in mind for deployments?

[DrRuhe]

I'm afraid I dont follow. With "pick a sytem type for me" do you mean a single output that does not contain several system attributes but rather the system gets chosen during evaluation?

By "deployment" I mean a collection of "services" where each service basically consists of a derivation to be run and some metadata like which arguments to pass etc.

Then I have several "renderers" which render the service definition into a format the "managers" can run. E.g. the "manager" honcho is running the output of the "procfile" renderer.

The output from the renderers and managers is placed under .public which should be exposed.

[roberth]

I think I need better words for talking about system.
Anyway, considering that these are configurations for local tools it makes sense to instantiate for each system, so ignore my question.

Was my suggestion with flake.deployments useful?

[DrRuhe]

Yeah, that worked. Thanks :)