support comma in string pars value

docs/guide/ingress/annotations.md

@@ -965,6 +965,15 @@ Custom attributes to LoadBalancers and TargetGroups can be controlled with follo
             ```
             alb.ingress.kubernetes.io/listener-attributes.HTTP-80: routing.http.response.server.enabled=true
             ```
+        - Add Access-Control-Allow-Headers header value (with comma)
+            ```
+            alb.ingress.kubernetes.io/listener-attributes.HTTPS-443: "routing.http.response.access_control_allow_headers.header_value=exampleValue\\,anotherExampleValue"
+            ```
+            or
+            ```
+            alb.ingress.kubernetes.io/listener-attributes.HTTPS-443: routing.http.response.access_control_allow_headers.header_value=exampleValue\,anotherExampleValue
+            ```      
+            both result Access-Control-Allow-Headers header value: exampleValue,anotherExampleValue
 
 
 ## Resource Tags

pkg/annotations/parser.go

@@ -3,9 +3,10 @@ package annotations
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/pkg/errors"
 	"strconv"
 	"strings"
+
+	"github.com/pkg/errors"
 )
 
 type ParseOptions struct {
@@ -151,15 +152,15 @@ func (p *suffixAnnotationParser) ParseStringMapAnnotation(annotation string, val
 	if !exists {
 		return false, nil
 	}
-	rawKVPairs := splitCommaSeparatedString(raw)
+	rawKVPairs := splitKeyValuePairs(raw)
 	keyValues := make(map[string]string)
 	for _, kvPair := range rawKVPairs {
 		parts := strings.SplitN(kvPair, "=", 2)
 		if len(parts) != 2 {
 			return false, errors.Errorf("failed to parse stringMap annotation, %v: %v", matchedKey, raw)
 		}
-		key := parts[0]
-		value := parts[1]
+		key := strings.TrimSpace(parts[0])
+		value := strings.TrimSpace(parts[1])
 		if len(key) == 0 {
 			return false, errors.Errorf("failed to parse stringMap annotation, %v: %v", matchedKey, raw)
 		}
@@ -212,3 +213,41 @@ func splitCommaSeparatedString(commaSeparatedString string) []string {
 	}
 	return result
 }
+
+// splitKeyValuePairs this function supports escaped comma
+func splitKeyValuePairs(s string) []string {
+	var result []string
+	var currentString strings.Builder
+
+	for i := 0; i < len(s); i++ {
+		if s[i] == '\\' && i+1 < len(s) {
+			// Escape sequence - add the escaped character literally
+			currentString.WriteByte(s[i+1])
+			i++ // skip the escaped character
+		} else if s[i] == ',' {
+			// Check if next part contains '=' (a new key-value pair)
+			remaining := strings.TrimSpace(s[i+1:])
+			containsEqual := strings.Index(remaining, "=")
+			if containsEqual != -1 {
+				result = append(result, strings.TrimSpace(currentString.String()))
+				currentString.Reset()
+			} else if len(remaining) > 0 {
+				// There's content after comma but no '=' - this is malformed
+				// Add current content and the malformed part as separate items
+				result = append(result, strings.TrimSpace(currentString.String()))
+				result = append(result, remaining)
+				return result
+			} else {
+				// Empty after comma, add comma to current
+				currentString.WriteByte(s[i])
+			}
+		} else {
+			currentString.WriteByte(s[i])
+		}
+	}
+
+	if currentString.Len() > 0 {
+		result = append(result, strings.TrimSpace(currentString.String()))
+	}
+	return result
+}

pkg/annotations/parser_test.go

@@ -2,8 +2,9 @@ package annotations
 
 import (
 	"errors"
-	"github.com/stretchr/testify/assert"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func Test_annotationParser_ParseStringAnnotation(t *testing.T) {
@@ -278,6 +279,22 @@ func Test_serviceAnnotationParser_ParseStringMapAnnotation(t *testing.T) {
 				"key4/empty-value": "",
 			},
 		},
+		{
+			name:   "multiple values",
+			prefix: "p.co",
+			suffix: "sfx",
+			annotations: map[string]string{
+				"first-value": "1",
+				"p.co/sfx":    "key1=value1\\,valueOne, key2= value2, key3/with-slash=value3\\,valueThree, key4/empty-value=",
+			},
+			wantExist: true,
+			wantValue: map[string]string{
+				"key1":             "value1,valueOne",
+				"key2":             "value2",
+				"key3/with-slash":  "value3,valueThree",
+				"key4/empty-value": "",
+			},
+		},
 		{
 			name:   "values containing equals sign",
 			prefix: "prefix",