package storage import ( "github.com/docker/distribution/digest" "github.com/docker/distribution/manifest" "github.com/docker/distribution/storagedriver" ) type layerStore struct { driver storagedriver.StorageDriver pathMapper *pathMapper uploadStore layerUploadStore } func (ls *layerStore) Exists(name string, digest digest.Digest) (bool, error) { // Because this implementation just follows blob links, an existence check // is pretty cheap by starting and closing a fetch. _, err := ls.Fetch(name, digest) if err != nil { switch err.(type) { case ErrUnknownLayer: return false, nil } return false, err } return true, nil } func (ls *layerStore) Fetch(name string, digest digest.Digest) (Layer, error) { blobPath, err := ls.resolveBlobPath(name, digest) if err != nil { switch err := err.(type) { case storagedriver.PathNotFoundError, *storagedriver.PathNotFoundError: return nil, ErrUnknownLayer{manifest.FSLayer{BlobSum: digest}} default: return nil, err } } fr, err := newFileReader(ls.driver, blobPath) if err != nil { switch err := err.(type) { case storagedriver.PathNotFoundError, *storagedriver.PathNotFoundError: return nil, ErrUnknownLayer{manifest.FSLayer{BlobSum: digest}} default: return nil, err } } return &layerReader{ fileReader: *fr, name: name, digest: digest, }, nil } // Upload begins a layer upload, returning a handle. If the layer upload // is already in progress or the layer has already been uploaded, this // will return an error. func (ls *layerStore) Upload(name string) (LayerUpload, error) { // NOTE(stevvooe): Consider the issues with allowing concurrent upload of // the same two layers. Should it be disallowed? For now, we allow both // parties to proceed and the the first one uploads the layer. lus, err := ls.uploadStore.New(name) if err != nil { return nil, err } return ls.newLayerUpload(lus), nil } // Resume continues an in progress layer upload, returning the current // state of the upload. func (ls *layerStore) Resume(lus LayerUploadState) (LayerUpload, error) { _, err := ls.uploadStore.GetState(lus.UUID) if err != nil { return nil, err } return ls.newLayerUpload(lus), nil } // newLayerUpload allocates a new upload controller with the given state. func (ls *layerStore) newLayerUpload(lus LayerUploadState) LayerUpload { return &layerUploadController{ LayerUploadState: lus, layerStore: ls, uploadStore: ls.uploadStore, } } // resolveBlobId looks up the blob location in the repositories from a // layer/blob link file, returning blob path or an error on failure. func (ls *layerStore) resolveBlobPath(name string, dgst digest.Digest) (string, error) { pathSpec := layerLinkPathSpec{name: name, digest: dgst} layerLinkPath, err := ls.pathMapper.path(pathSpec) if err != nil { return "", err } layerLinkContent, err := ls.driver.GetContent(layerLinkPath) if err != nil { return "", err } // NOTE(stevvooe): The content of the layer link should match the digest. // This layer of indirection is for name-based content protection. linked, err := digest.ParseDigest(string(layerLinkContent)) if err != nil { return "", err } bp := blobPathSpec{digest: linked} return ls.pathMapper.path(bp) }