package storage import ( "fmt" "io" "path" "time" "github.com/Sirupsen/logrus" "github.com/docker/distribution" ctxu "github.com/docker/distribution/context" "github.com/docker/distribution/digest" storagedriver "github.com/docker/distribution/registry/storage/driver" ) // layerUploadController is used to control the various aspects of resumable // layer upload. It implements the LayerUpload interface. type layerUploadController struct { layerStore *layerStore uuid string startedAt time.Time // implementes io.WriteSeeker, io.ReaderFrom and io.Closer to satisy // LayerUpload Interface bufferedFileWriter } var _ distribution.LayerUpload = &layerUploadController{} // UUID returns the identifier for this upload. func (luc *layerUploadController) UUID() string { return luc.uuid } func (luc *layerUploadController) StartedAt() time.Time { return luc.startedAt } // Finish marks the upload as completed, returning a valid handle to the // uploaded layer. The final size and checksum are validated against the // contents of the uploaded layer. The checksum should be provided in the // format :. func (luc *layerUploadController) Finish(digest digest.Digest) (distribution.Layer, error) { ctxu.GetLogger(luc.layerStore.repository.ctx).Debug("(*layerUploadController).Finish") err := luc.bufferedFileWriter.Close() if err != nil { return nil, err } canonical, err := luc.validateLayer(digest) if err != nil { return nil, err } if err := luc.moveLayer(canonical); err != nil { // TODO(stevvooe): Cleanup? return nil, err } // Link the layer blob into the repository. if err := luc.linkLayer(canonical, digest); err != nil { return nil, err } if err := luc.removeResources(); err != nil { return nil, err } return luc.layerStore.Fetch(canonical) } // Cancel the layer upload process. func (luc *layerUploadController) Cancel() error { ctxu.GetLogger(luc.layerStore.repository.ctx).Debug("(*layerUploadController).Cancel") if err := luc.removeResources(); err != nil { return err } luc.Close() return nil } // validateLayer checks the layer data against the digest, returning an error // if it does not match. The canonical digest is returned. func (luc *layerUploadController) validateLayer(dgst digest.Digest) (digest.Digest, error) { digestVerifier := digest.NewDigestVerifier(dgst) // TODO(stevvooe): Store resumable hash calculations in upload directory // in driver. Something like a file at path /resumablehash/ // with the hash state up to that point would be perfect. The hasher would // then only have to fetch the difference. // Read the file from the backend driver and validate it. fr, err := newFileReader(luc.bufferedFileWriter.driver, luc.path) if err != nil { return "", err } tr := io.TeeReader(fr, digestVerifier) // TODO(stevvooe): This is one of the places we need a Digester write // sink. Instead, its read driven. This might be okay. // Calculate an updated digest with the latest version. canonical, err := digest.FromReader(tr) if err != nil { return "", err } if !digestVerifier.Verified() { return "", distribution.ErrLayerInvalidDigest{ Digest: dgst, Reason: fmt.Errorf("content does not match digest"), } } return canonical, nil } // moveLayer moves the data into its final, hash-qualified destination, // identified by dgst. The layer should be validated before commencing the // move. func (luc *layerUploadController) moveLayer(dgst digest.Digest) error { blobPath, err := luc.layerStore.repository.registry.pm.path(blobDataPathSpec{ digest: dgst, }) if err != nil { return err } // Check for existence if _, err := luc.driver.Stat(blobPath); err != nil { switch err := err.(type) { case storagedriver.PathNotFoundError: break // ensure that it doesn't exist. default: return err } } else { // If the path exists, we can assume that the content has already // been uploaded, since the blob storage is content-addressable. // While it may be corrupted, detection of such corruption belongs // elsewhere. return nil } // If no data was received, we may not actually have a file on disk. Check // the size here and write a zero-length file to blobPath if this is the // case. For the most part, this should only ever happen with zero-length // tars. if _, err := luc.driver.Stat(luc.path); err != nil { switch err := err.(type) { case storagedriver.PathNotFoundError: // HACK(stevvooe): This is slightly dangerous: if we verify above, // get a hash, then the underlying file is deleted, we risk moving // a zero-length blob into a nonzero-length blob location. To // prevent this horrid thing, we employ the hack of only allowing // to this happen for the zero tarsum. if dgst == digest.DigestSha256EmptyTar { return luc.driver.PutContent(blobPath, []byte{}) } // We let this fail during the move below. logrus. WithField("upload.uuid", luc.UUID()). WithField("digest", dgst).Warnf("attempted to move zero-length content with non-zero digest") default: return err // unrelated error } } return luc.driver.Move(luc.path, blobPath) } // linkLayer links a valid, written layer blob into the registry under the // named repository for the upload controller. func (luc *layerUploadController) linkLayer(canonical digest.Digest, aliases ...digest.Digest) error { dgsts := append([]digest.Digest{canonical}, aliases...) // Don't make duplicate links. seenDigests := make(map[digest.Digest]struct{}, len(dgsts)) for _, dgst := range dgsts { if _, seen := seenDigests[dgst]; seen { continue } seenDigests[dgst] = struct{}{} layerLinkPath, err := luc.layerStore.repository.registry.pm.path(layerLinkPathSpec{ name: luc.layerStore.repository.Name(), digest: dgst, }) if err != nil { return err } if err := luc.layerStore.repository.registry.driver.PutContent(layerLinkPath, []byte(canonical)); err != nil { return err } } return nil } // removeResources should clean up all resources associated with the upload // instance. An error will be returned if the clean up cannot proceed. If the // resources are already not present, no error will be returned. func (luc *layerUploadController) removeResources() error { dataPath, err := luc.layerStore.repository.registry.pm.path(uploadDataPathSpec{ name: luc.layerStore.repository.Name(), uuid: luc.uuid, }) if err != nil { return err } // Resolve and delete the containing directory, which should include any // upload related files. dirPath := path.Dir(dataPath) if err := luc.driver.Delete(dirPath); err != nil { switch err := err.(type) { case storagedriver.PathNotFoundError: break // already gone! default: // This should be uncommon enough such that returning an error // should be okay. At this point, the upload should be mostly // complete, but perhaps the backend became unaccessible. logrus.Errorf("unable to delete layer upload resources %q: %v", dirPath, err) return err } } return nil }