Add util to validate namespaced names

pkg/api/validation/validation.go

@@ -385,19 +385,7 @@ func ValidatePodSpec(spec *api.PodSpec) errs.ValidationErrorList {
 func validateLabels(labels map[string]string, field string) errs.ValidationErrorList {
 	allErrs := errs.ValidationErrorList{}
 	for k := range labels {
-		var n, ns string
-		parts := strings.Split(k, "/")
-		switch len(parts) {
-		case 1:
-			n = parts[0]
-		case 2:
-			ns = parts[0]
-			n = parts[1]
-		default:
-			allErrs = append(allErrs, errs.NewFieldInvalid(field, k, ""))
-			continue
-		}
-		if (ns != "" && !util.IsDNSSubdomain(ns)) || !util.IsDNSLabel(n) {
+		if !util.IsQualifiedName(k) {
 			allErrs = append(allErrs, errs.NewFieldInvalid(field, k, ""))
 		}
 	}

pkg/util/validation.go

@@ -18,6 +18,7 @@ package util
 
 import (
 	"regexp"
+	"strings"
 )
 
 // IsDNSLabel tests for a string that conforms to the definition of a label in
@@ -82,3 +83,23 @@ func IsCIdentifier(value string) bool {
 func IsValidPortNum(port int) bool {
 	return 0 < port && port < 65536
 }
+
+// IsQualifiedName tests whether a string fits the "optionally-namespaced
+// name" pattern: [ DNS_SUBDOMAIN "/" ] DNS_LABEL
+func IsQualifiedName(value string) bool {
+	var n, ns string
+	parts := strings.Split(value, "/")
+	switch len(parts) {
+	case 1:
+		n = parts[0]
+	case 2:
+		ns = parts[0]
+		n = parts[1]
+	default:
+		return false
+	}
+	if (ns != "" && !IsDNSSubdomain(ns)) || !IsDNSLabel(n) {
+		return false
+	}
+	return true
+}

pkg/util/validation_test.go

@@ -153,3 +153,39 @@ func TestIsValidPortNum(t *testing.T) {
 		}
 	}
 }
+
+func TestIsQualifiedName(t *testing.T) {
+	successCases := []string{
+		"simple",
+		"now-with-dashes",
+		"1-starts-with-num",
+		"1234",
+		"simple/simple",
+		"now-with-dashes/simple",
+		"now-with-dashes/now-with-dashes",
+		"now.with.dots/simple",
+		"now-with.dashes-and.dots/simple",
+		"1-num.2-num/3-num",
+		"1234/5678",
+		"1.2.3.4/5678",
+	}
+	for i := range successCases {
+		if !IsQualifiedName(successCases[i]) {
+			t.Errorf("case[%d] expected success", i)
+		}
+	}
+
+	errorCases := []string{
+		"NoUppercase123",
+		"nospecialchars%^=@",
+		"cantendwithadash-",
+		"-cantstartwithadash",
+		"only/one/slash",
+		strings.Repeat("a", 254),
+	}
+	for i := range errorCases {
+		if IsQualifiedName(errorCases[i]) {
+			t.Errorf("case[%d] expected failure", i)
+		}
+	}
+}