feat: add default-true FillIDs feature gate

CHANGELOG.md

@@ -79,8 +79,10 @@ Adding a new version? You'll need three changes:
   [#3883](https://github.com/Kong/kubernetes-ingress-controller/pull/3883)
 - `Service`, `Route` and `Consumer` Kong entities now get assigned deterministic
   IDs based on their unique properties (name, username, etc.) instead of random
-  UUIDs.
+  UUIDs. It is possible to opt out of this behavior by setting `FillIDs` feature
+  gate to `false`.
   [#3933](https://github.com/Kong/kubernetes-ingress-controller/pull/3933)
+  [#4075](https://github.com/Kong/kubernetes-ingress-controller/pull/4075)
 - Added translator to translate ingresses under `networking.k8s.io/v1` to
   expression based Kong routes. The translator is enabled when feature gate
   `ExpressionRoutes` is turned on and the managed Kong gateway runs in router

FEATURE_GATES.md

@@ -62,6 +62,7 @@ Features that reach GA and over time become stable will be removed from this tab
 | GatewayAlpha     | `false` | Alpha | 2.6.0   | TBD   |
 | ExpressionRoutes | `false` | Alpha | 2.10.0  | TBD   |
 | CombinedServices | `false` | Alpha | 2.10.0  | TBD   |
+| FillIDs          | `true`  | Beta  | 2.10.0  | 3.0.0 |
 
 **NOTE**: The `Gateway` feature gate refers to [Gateway
  API](https://github.com/kubernetes-sigs/gateway-api) APIs which are in

internal/dataplane/parser/parser.go

@@ -70,6 +70,10 @@ type FeatureFlags struct {
 	// CombinedServices enables parser to create a single Kong Service when a Kubernetes Service is referenced
 	// by multiple Ingresses. This is effective only when EnableCombinedServiceRoutes is enabled.
 	CombinedServices bool
+
+	// FillIDs enables the parser to fill in the IDs fields of Kong entities - Services, Routes, and Consumers - based
+	// on their names. It ensures that IDs remain stable across restarts of the controller.
+	FillIDs bool
 }
 
 func NewFeatureFlags(
@@ -93,6 +97,7 @@ func NewFeatureFlags(
 		RegexPathPrefix:                   kongVersion.MajorMinorOnly().GTE(versions.ExplicitRegexPathVersionCutoff),
 		ExpressionRoutes:                  expressionRoutesEnabled,
 		CombinedServices:                  combinedRoutesEnabled && featureGates.Enabled(featuregates.CombinedServicesFeature),
+		FillIDs:                           featureGates.Enabled(featuregates.FillIDsFeature),
 	}
 }
 
@@ -233,8 +238,10 @@ func (p *Parser) BuildKongConfig() KongConfigBuildingResult {
 		result.Licenses = append(result.Licenses, p.licenseGetter.GetLicense())
 	}
 
-	// generate IDs for Kong entities
-	result.FillIDs(p.logger)
+	if p.featureFlags.FillIDs {
+		// generate IDs for Kong entities
+		result.FillIDs(p.logger)
+	}
 
 	return KongConfigBuildingResult{
 		KongState:                   &result,

internal/dataplane/parser/parser_test.go

@@ -5321,6 +5321,15 @@ func TestNewFeatureFlags(t *testing.T) {
 				CombinedServices:      false,
 			},
 		},
+		{
+			name: "fill ids enabled",
+			featureGates: map[string]bool{
+				featuregates.FillIDsFeature: true,
+			},
+			expectedFeatureFlags: FeatureFlags{
+				FillIDs: true,
+			},
+		},
 	}
 
 	for _, tc := range testCases {
@@ -5341,7 +5350,9 @@ func TestNewFeatureFlags(t *testing.T) {
 }
 
 func mustNewParser(t *testing.T, storer store.Storer) *Parser {
-	p, err := NewParser(logrus.New(), storer, FeatureFlags{})
+	p, err := NewParser(logrus.New(), storer, FeatureFlags{
+		FillIDs: featuregates.GetFeatureGatesDefaults()[featuregates.FillIDsFeature],
+	})
 	require.NoError(t, err)
 	return p
 }

internal/manager/featuregates/feature_gates.go

@@ -37,6 +37,10 @@ const (
 	// a Kubernetes Service is referenced by multiple netv1.Ingresses. It's effective only when CombinedRoutesFeature is enabled.
 	CombinedServicesFeature = "CombinedServices"
 
+	// FillIDsFeature is the name of the feature-gate that makes KIC fill in the ID fields of Kong entities (Services,
+	// Routes, and Consumers). It ensures that IDs remain stable across restarts of the controller.
+	FillIDsFeature = "FillIDs"
+
 	// DocsURL provides a link to the documentation for feature gates in the KIC repository.
 	DocsURL = "https://github.com/Kong/kubernetes-ingress-controller/blob/main/FEATURE_GATES.md"
 )
@@ -78,5 +82,6 @@ func GetFeatureGatesDefaults() map[string]bool {
 		CombinedRoutesFeature:   true,
 		ExpressionRoutesFeature: false,
 		CombinedServicesFeature: false,
+		FillIDsFeature:          true,
 	}
 }