package distribution import ( "fmt" "io" "time" "github.com/docker/distribution/digest" "github.com/docker/distribution/manifest" ) // 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, which is the tarsum for // layers. Digest() digest.Digest // 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 } var ( // ErrLayerExists returned when layer already exists ErrLayerExists = fmt.Errorf("layer exists") // ErrLayerTarSumVersionUnsupported when tarsum is unsupported version. ErrLayerTarSumVersionUnsupported = fmt.Errorf("unsupported tarsum version") // ErrLayerUploadUnknown returned when upload is not found. ErrLayerUploadUnknown = fmt.Errorf("layer upload unknown") // ErrLayerClosed returned when an operation is attempted on a closed // Layer or LayerUpload. ErrLayerClosed = fmt.Errorf("layer closed") ) // ErrUnknownLayer returned when layer cannot be found. type ErrUnknownLayer struct { FSLayer manifest.FSLayer } func (err ErrUnknownLayer) Error() string { return fmt.Sprintf("unknown layer %v", err.FSLayer.BlobSum) } // ErrLayerInvalidDigest returned when tarsum check fails. type ErrLayerInvalidDigest struct { Digest digest.Digest Reason error } func (err ErrLayerInvalidDigest) Error() string { return fmt.Sprintf("invalid digest for referenced layer: %v, %v", err.Digest, err.Reason) }