Function AppendDistributionSourceLabel

core/remotes/docker/handler.go:34–77

AppendDistributionSourceLabel updates the label of blob with distribution source.

(manager content.Manager, ref string)

// AppendDistributionSourceLabel updates the label of blob with distribution source.
func AppendDistributionSourceLabel(manager content.Manager, ref string) (images.HandlerFunc, error) {
	refspec, err := reference.Parse(ref)
	if err != nil {
		return nil, err
	}

	u, err := url.Parse("dummy://" + refspec.Locator)
	if err != nil {
		return nil, err
	}

	source, repo := u.Hostname(), strings.TrimPrefix(u.Path, "/")
	return func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
		info, err := manager.Info(ctx, desc.Digest)
		if err != nil {
			return nil, err
		}

		key := distributionSourceLabelKey(source)

		originLabel := ""
		if info.Labels != nil {
			originLabel = info.Labels[key]
		}
		value := appendDistributionSourceLabel(originLabel, repo)

		// The repo name has been limited under 256 and the distribution
		// label might hit the limitation of label size, when blob data
		// is used as the very, very common layer.
		if err := labels.Validate(key, value); err != nil {
			log.G(ctx).Warnf("skip to append distribution label: %s", err)
			return nil, nil
		}

		info = content.Info{
			Digest: desc.Digest,
			Labels: map[string]string{
				key: value,
			},
		}
		_, err = manager.Update(ctx, info, fmt.Sprintf("labels.%s", key))
		return nil, err
	}, nil
}

func appendDistributionSourceLabel(originLabel, repo string) string {
	repos := []string{}