feat: implement local puller and pusher

[thesayyn]

Take two on #1433

Most of the crane cli surface will be able to work with images on oci-layout.

[imjasonh]

Can you fix the build errors so we can see if any other tests are affected?

Error: pkg/v1/local/puller.go:63:21: undefined: errors.ErrUnsupported

[thesayyn]

Can you fix the build errors so we can see if any other tests are affected?

Error: pkg/v1/local/puller.go:63:21: undefined: errors.ErrUnsupported

Done

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 43.12796% with 240 lines in your changes are missing coverage. Please review.

Project coverage is 70.43%. Comparing base (a0658aa) to head (9a1cd79).
Report is 3 commits behind head on main.

Files	Patch %	Lines
pkg/v1/layout/sink.go	42.10%	91 Missing and 19 partials ⚠️
pkg/crane/image.go	40.57%	30 Missing and 11 partials ⚠️
pkg/v1/layout/source.go	40.62%	30 Missing and 8 partials ⚠️
pkg/v1/remote/puller.go	0.00%	15 Missing ⚠️
pkg/crane/options.go	42.85%	8 Missing ⚠️
internal/cmd/edit.go	36.36%	5 Missing and 2 partials ⚠️
pkg/v1/layout/layer.go	36.36%	7 Missing ⚠️
pkg/v1/remote/artifact.go	0.00%	6 Missing ⚠️
pkg/crane/get.go	62.50%	3 Missing ⚠️
pkg/v1/layout/write.go	72.72%	2 Missing and 1 partial ⚠️
... and 1 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1871      +/-   ##
==========================================
- Coverage   71.65%   70.43%   -1.22%     
==========================================
  Files         123      128       +5     
  Lines        9928    10320     +392     
==========================================
+ Hits         7114     7269     +155     
- Misses       2115     2310     +195     
- Partials      699      741      +42     

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[jonjohnsonjr]

I think we want to define a new interface in v1 that both remote.Puller and layout.Source would implement.

In my mind I'd want:

package v1

type Source interface{
 // minimal subset of methods needed to read things
}

type Sink interface{
 // minimal subset of methods needed to write things

}

[aw185176]

That would remove the dependency between layout + remote and avoid the need to convert remote.Puller into a struct below. Spitballing the set of methods:

type Source interface {
  Layer(...)
  Head(...)
  Get(...)
  Artifact(...)
}

type Sink interface {
  Push(...)
  Upload(...) // Maybe not?
}

The verbs are a bit clunky for non-remote implementors, but I don't see a clean way around that.

[thesayyn]

Hmm, i can't put source and sink into v1 root folder as it creates cycle between v1 -> partial.Artifact -> v1

Would putting this into its own directory be acceptable?

package github.com/google/go-containerregistry/cmd/crane
        imports github.com/google/go-containerregistry/cmd/crane/cmd
        imports github.com/google/go-containerregistry/internal/cmd
        imports github.com/google/go-containerregistry/internal/verify
        imports github.com/google/go-containerregistry/pkg/v1
        imports github.com/google/go-containerregistry/pkg/v1/partial
        imports github.com/google/go-containerregistry/pkg/v1: import cycle not allowed

[thesayyn]

okay i have created the sinksource (name TBD) directory.

[thesayyn]

This is now ready for another look

[aw185176]

@jonjohnsonjr what do you think about v1.Artifact to get around the import cycle?

[thesayyn]

that one also sounds fair, though now v1.Artifact would depend on bunch of partial interfaces.

[thesayyn]

ping @jonjohnsonjr @imjasonh

[thesayyn]

anything i could do to push this over the edge @jonjohnsonjr? I'd really like to land this, as i have some people who's been waiting for it for a long time.