Function lookasideStorageURL

docker/registries_d.go:296–303

lookasideStorageURL returns an URL usable for accessing signature index in base with known manifestDigest. base is not nil from the caller NOTE: Keep this in sync with docs/signature-protocols.md!

(base lookasideStorageBase, manifestDigest digest.Digest, index int)

// base is not nil from the caller
// NOTE: Keep this in sync with docs/signature-protocols.md!
func lookasideStorageURL(base lookasideStorageBase, manifestDigest digest.Digest, index int) (*url.URL, error) {
	if err := manifestDigest.Validate(); err != nil { // digest.Digest.Encoded() panics on failure, and could possibly result in a path with ../, so validate explicitly.
		return nil, err
	}
	sigURL := *base
	sigURL.Path = fmt.Sprintf("%s@%s=%s/signature-%d", sigURL.Path, manifestDigest.Algorithm(), manifestDigest.Encoded(), index+1)
	return &sigURL, nil
}