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 { // Exists returns true if the manifest exists. Exists(dgst digest.Digest) (bool, error) // Get retrieves the identified by the digest, if it exists. Get(dgst digest.Digest) (*manifest.SignedManifest, error) // Delete removes the manifest, if it exists. Delete(dgst digest.Digest) error // Put creates or updates the manifest. Put(manifest *manifest.SignedManifest) error // TODO(stevvooe): The methods after this message should be moved to a // discrete TagService, per active proposals. // Tags lists the tags under the named repository. Tags() ([]string, error) // ExistsByTag returns true if the manifest exists. ExistsByTag(tag string) (bool, error) // GetByTag retrieves the named manifest, if it exists. GetByTag(tag string) (*manifest.SignedManifest, error) // TODO(stevvooe): There are several changes that need to be done to this // interface: // // 1. Allow explicit tagging with Tag(digest digest.Digest, tag string) // 2. Support reading tags with a re-entrant reader to avoid large // allocations in the registry. // 3. Long-term: Provide All() method that lets one scroll through all of // the manifest entries. // 4. Long-term: break out concept of signing from manifests. This is // really a part of the distribution sprint. // 5. 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. }