Manifest not found for buildah produced images

[pidario]

Bug description

After creating an image using buildah instead of docker, I pushed it to my private registry (v2). Everything works perfectly (I can push and pull from it), but the UI says it cannot find the manifest, so no metadata is available.

I don't know if it is an issue with buildah, but since they claim to be OCI compliant I think that maybe docker-registry-ui should be compliant to.

How to Reproduce

create container:
buildah --name test_container from alpine:edge

finalize image:
buildah commit test_container <REGISTRY_HOST>/test_image:latest

push image:
buildah push <REGISTRY_HOST>/test_image:latest

Screenshots

System information

• OS: Ubuntu 18.04
• OS/Arch: linux/amd64
• Docker registry UI:
  • Version: 1.4.0
  • Interface: static
  • Server: docker
  • Docker version: 19.03

[Joxit]

Hi, sorry for the delay.

So, if I'm understanding what you did, you have a private docker registry server and you are using buildah container client ?

The UI was built especially for docker registries, that means using docker/distribution is mandatory (or something implanting the full API). Since the UI is using the Docker Registry HTTP API V2, you can use any client as long as it can push the image through the Docker Registry HTTP API V2. If something goes wrong, this should be on your client and not the UI.

The buildah-push command says :

docker://docker-reference An image in a registry implementing the "Docker Registry HTTP API V2".

If that's true, the interface should work fine without any changes.

[pidario]

Thanks for the reply. Yes, you got it right. I built the image using buildah and I pushed it to my registry which is the official docker registry image.
Everything works as expected, except the fact that I can't see any additional data such as size or image history.

I guess the manifest that buildah produce has some (minor?) differences between the one produced by docker build. buildah is still in early development stage, so it might be their problem.

When I ask for the manifest by doing this request

GET
https://<REGISTRY_HOST>/v2/test_image/manifests/latest

I get the following response:

{
	"errors": [{
		"code": "MANIFEST_UNKNOWN",
		"message": "OCI manifest found, but accept header does not support OCI manifests"
	}]
}

On the other hand, when I perform the same request for a different image, the registry answers with a json file containing the manifest.

After a quick search I bumped in this merge request: https://gitlab.com/gitlab-org/gitlab-foss/merge_requests/31127 which seems to fix a similar problem:

Docker Distribution v2.7.0 shipped with OCI support, but our container registry client was not updated to handle the manifest format in the HTTP Accept header. As a result, API calls to retrieve a manifest would return with an error, "OCI manifest found, but accept header does not support OCI manifests". This would result in blank fields in the container registry page and prevent tags from being deleted.

And they suggest to

add application/vnd.oci.image.manifest.v1+json to the Accept header.

This issue is also pretty interesting:
containers/buildah#575

[pidario]

It actually is that simple:

where you do this:
oReq.setRequestHeader('Accept', 'application/vnd.docker.distribution.manifest.v2+json');

you just need to do this instead:
oReq.setRequestHeader('Accept', 'application/vnd.docker.distribution.manifest.v2+json, application/vnd.oci.image.manifest.v1+json');.

Just tested locally and it works like a charm.

[Joxit]

Hi,

Sorry for the late reply, I cannot give long term guarantees on this feature but I added the header as you said and I checked that it still worked for images made by docker.

I'm glad it works for you 😄.

[Joxit]

Oh, and I added you in the contributors list : https://joxit.dev/docker-registry-ui/CONTRIBUTORS 😉

[pidario]

Thanks! Glad to be there 😎