kubernetes/pkg/apis/core/validation/names.go

// ValidateSignerName checks that signerName is syntactically valid.
//
// ensure signerName is of the form domain.com/something and up to 571 characters.
// This length and format is specified to accommodate signerNames like:
// <fqdn>/<resource-namespace>.<resource-name>.
// The max length of a FQDN is 253 characters (DNS1123Subdomain max length)
// The max length of a namespace name is 63 characters (DNS1123Label max length)
// The max length of a resource name is 253 characters (DNS1123Subdomain max length)
// We then add an additional 2 characters to account for the one '.' and one '/'.
func ValidateSignerName(fldPath *field.Path, signerName string) field.ErrorList { … }

// ValidateClusterTrustBundleName checks that a ClusterTrustBundle name conforms
// to the rules documented on the type.
func ValidateClusterTrustBundleName(signerName string) func(name string, prefix bool) []string { … }

func extractSignerNameFromClusterTrustBundleName(name string) (string, bool) { … }