registry/registry.go
Stephen J Day 27b03f2136 Move layer interface definitions to distribution package
After consideration, it has been decided that the interfaces defined in the
storage package provide a good base for interacting with various registry
instances. Whether interacting with a remote API or a local, on-disk registry,
these types have proved flexible. By moving them here, they can become the
central components of interacting with distribution components.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2015-02-12 14:26:46 -08:00

84 lines
3 KiB
Go

package distribution
import (
"github.com/docker/distribution/digest"
"github.com/docker/distribution/manifest"
"golang.org/x/net/context"
)
// TODO(stevvooe): These types need to be moved out of the storage package.
// Registry represents a collection of repositories, addressable by name.
type Registry interface {
// Repository should return a reference to the named repository. The
// registry may or may not have the repository but should always return a
// reference.
Repository(ctx context.Context, name string) Repository
}
// Repository is a named collection of manifests and layers.
type Repository interface {
// Name returns the name of the repository.
Name() string
// Manifests returns a reference to this repository's manifest service.
Manifests() ManifestService
// Layers returns a reference to this repository's layers service.
Layers() LayerService
}
// ManifestService provides operations on image manifests.
type ManifestService interface {
// Tags lists the tags under the named repository.
Tags() ([]string, error)
// Exists returns true if the manifest exists.
Exists(tag string) (bool, error)
// Get retrieves the named manifest, if it exists.
Get(tag string) (*manifest.SignedManifest, error)
// Put creates or updates the named manifest.
// Put(tag string, manifest *manifest.SignedManifest) (digest.Digest, error)
Put(tag string, manifest *manifest.SignedManifest) error
// Delete removes the named manifest, if it exists.
Delete(tag string) error
// TODO(stevvooe): There are several changes that need to be done to this
// interface:
//
// 1. Get(tag string) should be GetByTag(tag string)
// 2. Put(tag string, manifest *manifest.SignedManifest) should be
// Put(manifest *manifest.SignedManifest). The method can read the
// tag on manifest to automatically tag it in the repository.
// 3. Need a GetByDigest(dgst digest.Digest) method.
// 4. Allow explicit tagging with Tag(digest digest.Digest, tag string)
// 5. Support reading tags with a re-entrant reader to avoid large
// allocations in the registry.
// 6. Long-term: Provide All() method that lets one scroll through all of
// the manifest entries.
// 7. Long-term: break out concept of signing from manifests. This is
// really a part of the distribution sprint.
// 8. Long-term: Manifest should be an interface. This code shouldn't
// really be concerned with the storage format.
}
// LayerService provides operations on layer files in a backend storage.
type LayerService interface {
// Exists returns true if the layer exists.
Exists(digest digest.Digest) (bool, error)
// Fetch the layer identifed by TarSum.
Fetch(digest digest.Digest) (Layer, error)
// Upload begins a layer upload to repository identified by name,
// returning a handle.
Upload() (LayerUpload, error)
// Resume continues an in progress layer upload, returning a handle to the
// upload. The caller should seek to the latest desired upload location
// before proceeding.
Resume(uuid string) (LayerUpload, error)
}