With https://github.com/nlewo/nix2container, I'm trying to make a more standalone tool. Basically, a Go binary takes a reference graph and produces a JSON file describing a container image. This JSON file is then ingested by a Skopeo fork (it adds a new `transport`) to produce images (to file, registries,...).

Currently, it supports the dockerTools layering algorithm and is designed to work with Guix [1] as well;)

[1] https://github.com/nlewo/nix2container/blob/065e5b108650ee4c...