Description
Currently crfs supports GCR and uses GCR-specific API, so we can't use it with docker private registry(especially with local and unsecure(http) one).
Isn't it great to support private registry to make it easy to try crfs?
And also, isn't it good start point to support other OCI(docker) compliant registries, as we can focus on API-related issues and separate the auth-related issues aside?
like:
$ ls /crfs/layers/127.0.0.1:5000/
my
$ ls /crfs/layers/127.0.0.1:5000/my
ubuntu
$ ls /crfs/layers/127.0.0.1:5000/my/ubuntu
18.04 sha256-2bca06c5f3ca2402e6fd5ab82fad0c3d8d6ee18e2def29bcadaae5360d0d43d9
$ ls /crfs/layers/127.0.0.1:5000/my/ubuntu/18.04/
0 sha256-0c0ed20421e1c2fbadc7fb185d4e37348de9b39a390c09957f2b9a6b68bd4785
1 sha256-24e2698eca10208eab4c4dad0dfad485a30c8307902404ffec2da284ae848fb8
2 sha256-2b01b35b83e6609c41f1aac861cd65914934fa503f645ca17c9ebff45907b9c5
3 sha256-646be464f13960b2cd0bf3a741a42f1bf658bee676ffbc49183222bdfb79e249
bottom top
config
$ ls /crfs/layers/127.0.0.1:5000/my/ubuntu/18.04/bottom
bin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var
And I have an idea of patch implementation on my branch, so if possible I'm willing to contribute.
Notice on image path format:
Currently crfs supports only <owner>/<image>-styled image path format, and this patch also intend to follow the restriction. Supporting any format of image path may be future work.
Overview of the ideas is following:
Use OCI-compliant API
Currently, crfs uses GCR specific API for following purposes:
- Listing owners on a host
- Listing images stored in a owner
- Listing maps from tag digests to names labeled on an image
Use OCI(docker)-compliant API instead of GCR specific one for private registry, say:
- Listing owners on a host:
GETon/v2/_catalog(Filter the response to allow only<owner>/<image>-styled image path format, and then parse it.) - Listing images stored in a owner:
GETon/v2/_catalog(Filter the response to allow only<owner>/<image>-styled image path format, and then parse it.) - Listing maps from tag digests to names labeled on an image:
GETon/v2/<owner>/<image>/tags/listfor getting the list of tag names, andHEADon/v2/<owner>/<image>/manifests/<tag name>withAccept: application/vnd.docker.distribution.manifest.v2+jsonheader for getting digests of a V2 manifest(written inDocker-Content-Digestresponse header).
Use appropriate schema based on the host name
As used in the current code base of crfs, it is better to select appropriate API schema based on github.com/google/go-containerregistry/pkg/name.
Say, when we request API of localhost's docker private registry, it is good to use http (not https).