docker.io/rabbitmq:3-management-alpine container image list cannot be imported into quay.io

[mh21]

Copying the docker.io/rabbitmq:3-management-alpine container image list to quay.io via skopeo copy --all worked up to Jul 31, 2023, when it started to fail with application/vnd.oci.image.index.v1+json(uploading manifest 3-management-alpine to [quay.io/cki/mirror_rabbitmq](http://quay.io/cki/mirror_rabbitmq): manifest invalid), application/vnd.docker.distribution.manifest.list.v2+json(uploading manifest 3-management-alpine to [quay.io/cki/mirror_rabbitmq](http://quay.io/cki/mirror_rabbitmq): manifest invalid).

Starting this date, the image list manifest changed to application/vnd.oci.image.index.v1+json. Discussing this with the quay.io folks, they were pointing at one of the referenced manifests having the mediaType of application/vnd.docker.distribution.manifest.v2+json as the most likely reason.

With this, it was possible to workaround this via the --format oci parameter of skopeo which converts the manifest above to application/vnd.oci.image.manifest.v1+json which makes the copy to go through.

Reproduction steps

1. get a quay.io account
2. skopeo login quay.io
3. on e.g. a recent Fedora container, run
4. skopeo copy --all docker://docker.io/rabbitmq:3-management-alpine docker://quay.io/foo/bar:baz

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This had been previously (incorrectly) filed as an issue at rabbitmq/rabbitmq-server#9133:

@mh21 please start a discussion here, don't just blindly assume this is a bug

Is this behavior intended, i.e. is this not a bug but a feature of some sort 🤗?

[yosifkit]

Ah, looking over the manifest (https://explore.ggcr.dev/?image=rabbitmq%3A3-management-alpine@sha256:dc50fb7c766c9c9c11f8cd1cd05ce2c3960b2c0d7bffe9cce3b3d7e581543fe6), it looks like the arm32v7 image is still an older classic docker build artifact. It has been failing to build since moving to a new pipeline and #657 wasn't quite enough to fix it. I'll work on that today.

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On a side note, it is valid according to the OCI image index spec to have an item in manifests: with an "unknown" value:

v1.1.0-rc4:
An encountered mediaType that is unknown to the implementation MUST NOT generate an error.

v1.0.2:
An encountered mediaType that is unknown SHOULD be safely ignored.

[lukebakken]

Whew, am I glad you understand what's going on 😅

[mh21]

On a side note, it is valid according to the OCI image index spec to have an item in manifests: with an "unknown" value:

Thank you! I forwarded this to the quay.io folks.

[mh21]

Verified that this is now fixed:

$ skopeo inspect --raw docker://quay.io/cki/mirror_rabbitmq:3-management-alpine|jq|grep mediaType
  "mediaType": "application/vnd.oci.image.index.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "mediaType": "application/vnd.oci.image.manifest.v1+json",