Method FetchByDigest

core/remotes/docker/fetcher.go:362–440

(ctx context.Context, dgst digest.Digest, opts ...remotes.FetchByDigestOpts)

}

func (r dockerFetcher) FetchByDigest(ctx context.Context, dgst digest.Digest, opts ...remotes.FetchByDigestOpts) (io.ReadCloser, ocispec.Descriptor, error) {
	var desc ocispec.Descriptor
	ctx = log.WithLogger(ctx, log.G(ctx).WithField("digest", dgst))
	var config remotes.FetchByDigestConfig
	for _, o := range opts {
		if err := o(ctx, &config); err != nil {
			return nil, desc, err
		}
	}

	hosts := r.filterHosts(HostCapabilityPull)
	if len(hosts) == 0 {
		return nil, desc, fmt.Errorf("no pull hosts: %w", errdefs.ErrNotFound)
	}

	ctx, err := ContextWithRepositoryScope(ctx, r.refspec, false)
	if err != nil {
		return nil, desc, err
	}

	var (
		getReq   *request
		sz       int64
		firstErr error
	)

	for i, host := range r.hosts {
		getReq, sz, err = r.createGetReq(ctx, host, i == len(r.hosts)-1, config.Mediatype, "blobs", dgst.String())
		if err == nil {
			break
		}
		// Store the error for referencing later
		if firstErr == nil {
			firstErr = err
		}
	}

	if getReq == nil {
		// Fall back to the "manifests" endpoint
		for i, host := range r.hosts {
			getReq, sz, err = r.createGetReq(ctx, host, i == len(r.hosts)-1, config.Mediatype, "manifests", dgst.String())
			if err == nil {
				break
			}
			// Store the error for referencing later
			if firstErr == nil {
				firstErr = err
			}
		}
	}

	if getReq == nil {
		if errdefs.IsNotFound(firstErr) {
			firstErr = fmt.Errorf("could not fetch content %v from remote: %w", dgst, errdefs.ErrNotFound)
		}
		if firstErr == nil {
			firstErr = fmt.Errorf("could not fetch content %v from remote: (unknown)", dgst)
		}