If the daemon is configured to use a mirror for the default (Docker Hub)
registry, the endpoint did not fall back to querying the upstream if the mirror
did not contain the given reference.
If the daemon is configured to use a mirror for the default (Docker Hub)
registry, did not fall back to querying the upstream if the mirror did not
contain the given reference.
For pull-through registry-mirrors, this was not a problem, as in that case the
registry would forward the request, but for other mirrors, no fallback would
happen. This was inconsistent with how "pulling" images handled this situation;
when pulling images, both the mirror and upstream would be tried.
This problem was caused by the logic used in GetRepository, which had an
optimization to only return the first registry it was successfully able to
configure (and connect to), with the assumption that the mirror either contained
all images used, or to be configured as a pull-through mirror.
This patch:
- Introduces a GetRepositories method, which returns all candidates (both
mirror(s) and upstream).
- Updates the endpoint to try all
Before this patch:
# the daemon is configured to use a mirror for Docker Hub
cat /etc/docker/daemon.json
{ "registry-mirrors": ["http://localhost:5000"]}
# start the mirror (empty registry, not configured as pull-through mirror)
docker run -d --name registry -p 127.0.0.1:5000:5000 registry:2
# querying the endpoint fails, because the image-manifest is not found in the mirror:
curl -s --unix-socket /var/run/docker.sock http://localhost/v1.43/distribution/docker.io/library/hello-world:latest/json
{
"message": "manifest unknown: manifest unknown"
}
With this patch applied:
# the daemon is configured to use a mirror for Docker Hub
cat /etc/docker/daemon.json
{ "registry-mirrors": ["http://localhost:5000"]}
# start the mirror (empty registry, not configured as pull-through mirror)
docker run -d --name registry -p 127.0.0.1:5000:5000 registry:2
# querying the endpoint succeeds (manifest is fetched from the upstream Docker Hub registry):
curl -s --unix-socket /var/run/docker.sock http://localhost/v1.43/distribution/docker.io/library/hello-world:latest/json | jq .
{
"Descriptor": {
"mediaType": "application/vnd.oci.image.index.v1+json",
"digest": "sha256:1b9844d846ce3a6a6af7013e999a373112c3c0450aca49e155ae444526a2c45e",
"size": 3849
},
"Platforms": [
{
"architecture": "amd64",
"os": "linux"
}
]
}
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
8aacbb3ba9