distribution/registry.go
Josh Hawn a877811c0b Update notification event Target fields
Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)
2015-03-05 18:01:50 -08:00

159 lines
5.3 KiB
Go

package distribution
import (
"io"
"time"
"github.com/docker/distribution/digest"
"github.com/docker/distribution/manifest"
"golang.org/x/net/context"
)
// 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, error)
}
// 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
// Signatures returns a reference to this repository's signatures service.
Signatures() SignatureService
}
// 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)
}
// Layer provides a readable and seekable layer object. Typically,
// implementations are *not* goroutine safe.
type Layer interface {
// http.ServeContent requires an efficient implementation of
// ReadSeeker.Seek(0, os.SEEK_END).
io.ReadSeeker
io.Closer
// Digest returns the unique digest of the blob.
Digest() digest.Digest
// Length returns the length in bytes of the blob.
Length() int64
// CreatedAt returns the time this layer was created.
CreatedAt() time.Time
}
// LayerUpload provides a handle for working with in-progress uploads.
// Instances can be obtained from the LayerService.Upload and
// LayerService.Resume.
type LayerUpload interface {
io.WriteSeeker
io.ReaderFrom
io.Closer
// UUID returns the identifier for this upload.
UUID() string
// StartedAt returns the time this layer upload was started.
StartedAt() time.Time
// Finish marks the upload as completed, returning a valid handle to the
// uploaded layer. The digest is validated against the contents of the
// uploaded layer.
Finish(digest digest.Digest) (Layer, error)
// Cancel the layer upload process.
Cancel() error
}
// SignatureService provides operations on signatures.
type SignatureService interface {
// Get retrieves all of the signature blobs for the specified digest.
Get(dgst digest.Digest) ([][]byte, error)
// Put stores the signature for the provided digest.
Put(dgst digest.Digest, signatures ...[]byte) error
}
// Descriptor describes targeted content. Used in conjunction with a blob
// store, a descriptor can be used to fetch, store and target any kind of
// blob. The struct also describes the wire protocol format. Fields should
// only be added but never changed.
type Descriptor struct {
// MediaType describe the type of the content. All text based formats are
// encoded as utf-8.
MediaType string `json:"mediaType,omitempty"`
// Length in bytes of content.
Length int64 `json:"length,omitempty"`
// Digest uniquely identifies the content. A byte stream can be verified
// against against this digest.
Digest digest.Digest `json:"digest,omitempty"`
// NOTE: Before adding a field here, please ensure that all
// other options have been exhausted. Much of the type relationships
// depend on the simplicity of this type.
}