// NewReference returns a Docker reference for a named reference. The reference must satisfy !reference.IsNameOnly().
func NewReference(ref reference.Named) (types.ImageReference, error) {
if reference.IsNameOnly(ref) {
return nil, errors.Errorf("Docker reference %s has neither a tag nor a digest", ref.String())
}
// A github.com/distribution/reference value can have a tag and a digest at the same time!
// docker/reference does not handle that, so fail.
// (Even if it were supported, the semantics of policy namespaces are unclear - should we drop
// the tag or the digest first?)
_, isTagged := ref.(reference.NamedTagged)
_, isDigested := ref.(reference.Canonical)
if isTagged && isDigested {
return nil, errors.Errorf("Docker references with both a tag and digest are currently not supported")
}
return dockerReference{
ref: ref,
}, nil
}
// DockerReferenceIdentity returns a string representation of the reference, suitable for policy lookup,
// as a backend for ImageReference.PolicyConfigurationIdentity.
// The reference must satisfy !reference.IsNameOnly().
func DockerReferenceIdentity(ref reference.Named) (string, error) {
res := ref.FullName()
tagged, isTagged := ref.(reference.NamedTagged)
digested, isDigested := ref.(reference.Canonical)
switch {
case isTagged && isDigested: // This should not happen, docker/reference.ParseNamed drops the tag.
return "", errors.Errorf("Unexpected Docker reference %s with both a name and a digest", ref.String())
case !isTagged && !isDigested: // This should not happen, the caller is expected to ensure !reference.IsNameOnly()
return "", errors.Errorf("Internal inconsistency: Docker reference %s with neither a tag nor a digest", ref.String())
case isTagged:
res = res + ":" + tagged.Tag()
case isDigested:
res = res + "@" + digested.Digest().String()
default: // Coverage: The above was supposed to be exhaustive.
return "", errors.New("Internal inconsistency, unexpected default branch")
}
return res, nil
}