Function splitDockerDomain

docker/reference/normalize.go:90–104

splitDockerDomain splits a repository name to domain and remotename string. If no valid domain is found, the default domain is used. Repository name needs to be already validated before.

(name string)

// If no valid domain is found, the default domain is used. Repository name
// needs to be already validated before.
func splitDockerDomain(name string) (domain, remainder string) {
	i := strings.IndexRune(name, '/')
	if i == -1 || (!strings.ContainsAny(name[:i], ".:") && name[:i] != "localhost") {
		domain, remainder = defaultDomain, name
	} else {
		domain, remainder = name[:i], name[i+1:]
	}
	if domain == legacyDefaultDomain {
		domain = defaultDomain
	}
	if domain == defaultDomain && !strings.ContainsRune(remainder, '/') {
		remainder = officialRepoName + "/" + remainder
	}
	return
}

// familiarizeName returns a shortened version of the name familiar
// to the Docker UI. Familiar names have the default domain