Make IsHTTPHeaderName return error strings

pkg/api/validation/validation.go

@@ -1314,8 +1314,8 @@ func validateHTTPGetAction(http *api.HTTPGetAction, fldPath *field.Path) field.E
 		allErrors = append(allErrors, field.NotSupported(fldPath.Child("scheme"), http.Scheme, supportedHTTPSchemes.List()))
 	}
 	for _, header := range http.HTTPHeaders {
-		if !validation.IsHTTPHeaderName(header.Name) {
-			allErrors = append(allErrors, field.Invalid(fldPath.Child("httpHeaders"), header.Name, fmt.Sprintf("name must match %s", validation.HTTPHeaderNameFmt)))
+		for _, msg := range validation.IsHTTPHeaderName(header.Name) {
+			allErrors = append(allErrors, field.Invalid(fldPath.Child("httpHeaders"), header.Name, msg))
 		}
 	}
 	return allErrors

pkg/util/validation/validation.go

@@ -234,14 +234,17 @@ func IsValidPercent(percent string) []string {
 	return nil
 }
 
-const HTTPHeaderNameFmt string = "[-A-Za-z0-9]+"
+const httpHeaderNameFmt string = "[-A-Za-z0-9]+"
 
-var httpHeaderNameRegexp = regexp.MustCompile("^" + HTTPHeaderNameFmt + "$")
+var httpHeaderNameRegexp = regexp.MustCompile("^" + httpHeaderNameFmt + "$")
 
 // IsHTTPHeaderName checks that a string conforms to the Go HTTP library's
 // definition of a valid header field name (a stricter subset than RFC7230).
-func IsHTTPHeaderName(value string) bool {
-	return httpHeaderNameRegexp.MatchString(value)
+func IsHTTPHeaderName(value string) []string {
+	if !httpHeaderNameRegexp.MatchString(value) {
+		return []string{RegexError(httpHeaderNameFmt, "X-Header-Name")}
+	}
+	return nil
 }
 
 // MaxLenError returns a string explanation of a "string too long" validation

pkg/util/validation/validation_test.go

@@ -321,8 +321,8 @@ func TestIsHTTPHeaderName(t *testing.T) {
 		"A", "AB", "AbC", "A1", "-A", "A-", "A-B", "A-1", "A--1--2--B", "--123-ABC",
 	}
 	for _, val := range goodValues {
-		if !IsHTTPHeaderName(val) {
-			t.Errorf("expected true for '%s'", val)
+		if msgs := IsHTTPHeaderName(val); len(msgs) != 0 {
+			t.Errorf("expected true for '%s': %v", val, msgs)
 		}
 	}
 
@@ -333,7 +333,7 @@ func TestIsHTTPHeaderName(t *testing.T) {
 		"?", "@", "{",
 	}
 	for _, val := range badValues {
-		if IsHTTPHeaderName(val) {
+		if msgs := IsHTTPHeaderName(val); len(msgs) == 0 {
 			t.Errorf("expected false for '%s'", val)
 		}
 	}