distribution/storage/layer.go
Stephen J Day a4f42b8eea Relax requirement for size argument during blob upload
During client implementation, it was found that requiring the size argument
made client implementation more complex. The original benefit of the size
argument was to provide an additional check alongside of tarsum to validate
incoming data. For the purposes of the registry, it has been determined that
tarsum should be enough to validate incoming content.

At this time, the size check is optional but we may consider removing it
completely.
2014-12-12 19:08:50 -08:00

101 lines
2.9 KiB
Go

package storage
import (
"fmt"
"io"
"time"
"github.com/docker/docker-registry/digest"
)
// 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
// Name returns the repository under which this layer is linked.
Name() string // TODO(stevvooe): struggling with nomenclature: should this be "repo" or "name"?
// 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. Until we implement
// Stat call on storagedriver, this just returns the zero time.
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.WriteCloser
// UUID returns the identifier for this upload.
UUID() string
// Name of the repository under which the layer will be linked.
Name() string
// Offset returns the position of the last byte written to this layer.
Offset() int64
// TODO(stevvooe): Consider completely removing the size check from this
// interface. The digest check may be adequate and we are making it
// optional in the HTTP API.
// Finish marks the upload as completed, returning a valid handle to the
// uploaded layer. The final size and digest are validated against the
// contents of the uploaded layer. If the size is negative, only the
// digest will be checked.
Finish(size int64, 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 FSLayer
}
func (err ErrUnknownLayer) Error() string {
return fmt.Sprintf("unknown layer %v", err.FSLayer.BlobSum)
}
// ErrLayerInvalidDigest returned when tarsum check fails.
type ErrLayerInvalidDigest struct {
FSLayer FSLayer
}
func (err ErrLayerInvalidDigest) Error() string {
return fmt.Sprintf("invalid digest for referenced layer: %v", err.FSLayer.BlobSum)
}
// ErrLayerInvalidSize returned when length check fails.
type ErrLayerInvalidSize struct {
Size int64
}
func (err ErrLayerInvalidSize) Error() string {
return fmt.Sprintf("invalid layer size: %d", err.Size)
}