package layout import ( "io" "io/ioutil" "os" "github.com/containers/image/types" "github.com/opencontainers/go-digest" imgspecv1 "github.com/opencontainers/image-spec/specs-go/v1" ) type ociImageSource struct { ref ociReference descriptor imgspecv1.Descriptor } // newImageSource returns an ImageSource for reading from an existing directory. func newImageSource(ref ociReference) (types.ImageSource, error) { descriptor, err := ref.getManifestDescriptor() if err != nil { return nil, err } return &ociImageSource{ref: ref, descriptor: descriptor}, nil } // Reference returns the reference used to set up this source. func (s *ociImageSource) Reference() types.ImageReference { return s.ref } // Close removes resources associated with an initialized ImageSource, if any. func (s *ociImageSource) Close() error { return nil } // GetManifest returns the image's manifest along with its MIME type (which may be empty when it can't be determined but the manifest is available). // It may use a remote (= slow) service. func (s *ociImageSource) GetManifest() ([]byte, string, error) { manifestPath, err := s.ref.blobPath(digest.Digest(s.descriptor.Digest)) if err != nil { return nil, "", err } m, err := ioutil.ReadFile(manifestPath) if err != nil { return nil, "", err } return m, s.descriptor.MediaType, nil } func (s *ociImageSource) GetTargetManifest(digest digest.Digest) ([]byte, string, error) { manifestPath, err := s.ref.blobPath(digest) if err != nil { return nil, "", err } m, err := ioutil.ReadFile(manifestPath) if err != nil { return nil, "", err } // XXX: GetTargetManifest means that we don't have the context of what // mediaType the manifest has. In OCI this means that we don't know // what reference it came from, so we just *assume* that its // MediaTypeImageManifest. return m, imgspecv1.MediaTypeImageManifest, nil } // GetBlob returns a stream for the specified blob, and the blob's size. func (s *ociImageSource) GetBlob(info types.BlobInfo) (io.ReadCloser, int64, error) { path, err := s.ref.blobPath(info.Digest) if err != nil { return nil, 0, err } r, err := os.Open(path) if err != nil { return nil, 0, err } fi, err := r.Stat() if err != nil { return nil, 0, err } return r, fi.Size(), nil } func (s *ociImageSource) GetSignatures() ([][]byte, error) { return [][]byte{}, nil }