ggcr: registry on localhost is defaulted to docker.io - image not known when accessing image (original) (raw)

Hi!

thanks for the great work done here.

Describe the bug

When i.e leveraging podman images are tagged with localhost as default registry [1]. Docker used docker.io.
When calculating an images size [2] based on the locally tagged name, resolution will fail[3] because of defaulting back to docker.io. since localhost is not honnored as a relevant registry name.

I barely remember it, but i think containerd is defaulting to localhost as well (?)

As far as I can see, https://github.com/google/go-containerregistry/blob/main/pkg/name/repository.go#L81 could be the relevant line of code.

With docker the same behaviour works well, since docker uses internally docker.io as a registry name.

To Reproduce

• Use Podman
• Build docker image [1]
• Run Test [2]

Expected behavior

I would expect that a valid hostname, like localhost, is accepted as a registry

Additional context

Add any other context about the problem here.

• Version of the module: github.com/google/go-containerregistry v0.20.2
• Registry used (e.g., GCR, ECR, Quay)

❯ podman --version
podman version 5.3.2

[1]

❯ cat Dockerfile FROM scratch ❯ docker build . -t testimage:mytag STEP 1/1: FROM scratch COMMIT testimage:mytag --> 379ecbdbbcdc Successfully tagged localhost/testimage:mytag 379ecbdbbcdcb68e330f76f5928b8aaf37f1a5f13f63d1684a572fa4c7655965

[2]

func Test(t *testing.T) { refName := "localhost/testimage:mytag" reference, err := name.ParseReference(refName) assert.NoError(t, err) image, err := daemon.Image(reference) assert.NoError(t, err) _, err = image.Size() assert.NoError(t, err) }

[3]

=== RUN   Test
    ...test.go:176: 
            Error Trace:	...test.go:176
            Error:      	Received unexpected error:
                        	Error response from daemon: docker.io/library/testimage:mytag: image not known
            Test:       	Test
--- FAIL: Test (0.01s)

FAIL