[REQ] support for ubuntu chiseled

[sozercan]

What kind of request is this?

New feature

What is your request or suggestion?

Ubuntu chiseled has a full status file (unlike individual ones like distroless), but may not have apt package manager

related canonical/chisel#148

Are you willing to submit PRs to contribute to this feature request?

• Yes, I am willing to implement it.

[sozercan]

hold until new manifest is supported canonical/chisel#148 (comment)

https://github.com/canonical/chisel/releases/tag/v1.0.0 is out now

[sozercan]

This is an interesting one. https://discourse.ubuntu.com/t/chisel-manifest-is-supported-in-newly-released-v1-0-0/48944 has the most information about this new format.

Chiseled images need base-files_chisel slice to generate the manifest (example usage). Manifest is generated into /var/lib/chisel/manifest.wall file, which is zstd compressed. Uncompressed it's a "jsonwall" file that contains information for various metadata like packages, paths, slices, etc. (example manifest)

For copa, we are probably most interested in the package kinds. Copa should be able to parse each of the package kinds for names and versions. However, I am not sure how would copa should handle the sha256 data since this will be changing.