optimize rewrite regex (#801)

pkg/ingress/kube/annotations/annotations.go

@@ -83,7 +83,7 @@ func (i *Ingress) NeedRegexMatch(path string) bool {
 	if i.Rewrite == nil {
 		return false
 	}
-	if strings.ContainsAny(path, `\.+*?()|[]{}^$`) {
+	if i.Rewrite.RewriteTarget != "" && strings.ContainsAny(path, `\.+*?()|[]{}^$`) {
 		return true
 	}
 	if strings.ContainsAny(i.Rewrite.RewriteTarget, `$\`) {

pkg/ingress/kube/annotations/annotations_test.go

@@ -67,6 +67,15 @@ func TestNeedRegexMatch(t *testing.T) {
 			inputPath: "/.*",
 			expect:    true,
 		},
+		{
+			input: &Ingress{
+				Rewrite: &RewriteConfig{
+					UseRegex: false,
+				},
+			},
+			inputPath: "/.",
+			expect:    false,
+		},
 		{
 			input: &Ingress{
 				Rewrite: &RewriteConfig{