Support pulling/pushing VMs to OCI-compatible registries

[edigaryev]

This still needs some things to be done before this gets merged:

• check Registry implementation against OCI distribution specification → done in Support pulling/pushing VMs to OCI-compatible registries #32 (comment)
• garbage collection when deleting cached OCI VMs (w.r.t. symbolic links) → moved to Implement garbage collection when deleting cached OCI VMs (w.r.t. symbolic links) #37
• better RemoteName parser → moved to Improve RemoteName parser #35
• more tests
  • Registry functional/integration tests → Registry functional/integration tests #34
  • WWWAuthenticate unit tests → added in 80645ff

Resolves #6.

[fkorotkov]

Another note. I think we should deprioritize tests in favor of a sooner release and follow up with more tests in a separate PR.

Also will be great to add some logging to the push/pull process since it can take quite a while and will be great to update users about progress.

[fkorotkov]

Seems there is an issue with the reference parsing as well:

tart push monterey-vanilla ghcr.io/cirruslabs/macos-monterey-vanilla:12.3.1
error: unexpected input
 --> input:1:45
1 | …-monterey-vanilla:12.3.1
  |                      ^ expected end of input

[edigaryev]

• check Registry implementation against OCI distribution specification

Seems OK, made a couple of improvements (e.g. 0144913).

Also re-checked against https://docs.docker.com/registry/spec/auth/token/, the only thing that's missing is that we don't specify a client_id in the token request, but that parameter doesn't seem to be critical.

[edigaryev]

Seems there is an issue with the reference parsing as well:

Fixed in 20fffbb, further improvements in #35.

[edigaryev]

Another note. I think we should deprioritize tests in favor of a sooner release and follow up with more tests in a separate PR.

Deprioritized to #34.

Also will be great to add some logging to the push/pull process since it can take quite a while and will be great to update users about progress.

Implemented in 27bb3c5.

[fkorotkov]

I think you can remove this method completely and remove the for loop where it's called.

[edigaryev]

I think you can remove this method completely and remove the for loop where it's called.

Oh, good catch.

Fixed in 821a99b.