Consider generating OCI-native packages

[bobh66]

What problem are you facing?

Crossplane packages are docker-compliant but they require some logic in crossplane xpkg push to implement the layer annotations that Crossplane relies upon to efficiently cache and reconcile the packages.

This makes package management (pull, push, etc) dependent on the crossplane CLI, and it would be useful to decouple that relationship so that full-functional Crossplane packages can be pushed/pulled/etc by other tools such as crane.

How could Crossplane help solve your problem?

Provide an option to crossplane xpkg build that generates a fully OCI-compliant package with the layer annotations specified in the manifest.json so that no custom logic is required to push the packages to a registry and annotate the layers based on the Labels stored in the Config section.

This is probably a lot harder than it sounds, but I wanted to at least get the idea out for discussion.

[negz]

@bobh66 I'm not following what the output of the crossplane xpkg build variant you're proposing is. Would it be an on-disk OCI Image Layout ala https://pkg.go.dev/github.com/google/go-containerregistry@v0.19.1/pkg/v1/layout?