Add quote function in template

Co-authored-by: Charle Demers <charle.demers@gmail.com>

internal/ingress/controller/template/template.go

@@ -160,6 +160,7 @@ var (
 		"toUpper":                    strings.ToUpper,
 		"toLower":                    strings.ToLower,
 		"formatIP":                   formatIP,
+		"quote":                      quote,
 		"buildNextUpstream":          buildNextUpstream,
 		"getIngressInformation":      getIngressInformation,
 		"serverConfig": func(all config.TemplateConfig, server *ingress.Server) interface{} {
@@ -208,6 +209,21 @@ func formatIP(input string) string {
 	return fmt.Sprintf("[%s]", input)
 }
 
+func quote(input interface{}) string {
+	var inputStr string
+	switch input := input.(type) {
+	case string:
+		inputStr = input
+		break
+	case fmt.Stringer:
+		inputStr = input.String()
+		break
+	default:
+		inputStr = fmt.Sprintf("%v", input)
+	}
+	return fmt.Sprintf("%q", inputStr)
+}
+
 func shouldConfigureLuaRestyWAF(disableLuaRestyWAF bool, mode string) bool {
 	if !disableLuaRestyWAF && len(mode) > 0 {
 		return true

internal/ingress/controller/template/template_test.go

@@ -231,6 +231,21 @@ func TestFormatIP(t *testing.T) {
 	}
 }
 
+func TestQuote(t *testing.T) {
+	cases := map[interface{}]string{
+		"foo":      `"foo"`,
+		"\"foo\"":  `"\"foo\""`,
+		"foo\nbar": `"foo\nbar"`,
+		10:         `"10"`,
+	}
+	for input, output := range cases {
+		actual := quote(input)
+		if actual != output {
+			t.Errorf("quote('%s'): expected '%v' but returned '%v'", input, output, actual)
+		}
+	}
+}
+
 func TestBuildLocation(t *testing.T) {
 	invalidType := &ingress.Ingress{}
 	expected := "/"