Support foreign/restricted layers

[dekkagaijin]

This is mostly an issue when naively attempting to pull layers.

Docker V2 Schema2 media type: application/vnd.docker.image.rootfs.foreign.diff.tar.gzip

OCI NonDistributable: https://github.com/opencontainers/image-spec/blob/master/specs-go/v1/mediatype.go

Tagging @jonjohnsonjr for others that I missed

[dekkagaijin]

I'll be doing this for the python lib, and will do the work for ggcr, as well, if it isn't picked up beforehand.

[genevieve]

Hey @jonjohnsonjr! Are you looking for someone to make a PR for this functionality? Are you interested in this library supporting this functionality?

[dekkagaijin]

@genevieve all the love this lib gets is a good thing, most likely.

I only updated the Python lib to support remote -> remote registry pushes before leaving the team, and don't know if it's been updated internally or externally to support local pulls or pushes.

[jonjohnsonjr]

@genevieve yeah we're definitely interested in supporting this, I just haven't found the time to add it.

At one point I started working on it but got distracted: master...jonjohnsonjr:foreign

I'm not sure how far behind that branch is -- rebasing might be harder than starting from scratch :)

[genevieve]

@dekkagaijin @jonjohnsonjr Thank you both for your quick responses! I'm going to try working on it now and I'll get back to you if I find myself in over my head!