fix(translator): Early status push for headless Service

internal/gatewayapi/route.go

@@ -1401,6 +1401,11 @@ func validateDestinationSettings(destinationSettings *ir.DestinationSetting, end
 				status.RouteReasonUnsupportedAddressType)
 		}
 	case resource.KindService, resource.KindServiceImport:
+		if endpointRoutingDisabled && isHeadlessService(destinationSettings) {
+			return status.NewRouteStatusError(
+				fmt.Errorf("service %s is a headless Service, please set routingType=Endpoint", destinationSettings.Name),
+				status.RouteReasonUnsupportedSetting)
+		}
 		if !endpointRoutingDisabled && destinationSettings.AddressType != nil && *destinationSettings.AddressType == ir.MIXED {
 			return status.NewRouteStatusError(
 				fmt.Errorf("mixed endpointslice address type for the same backendRef is not supported"),
@@ -1411,6 +1416,17 @@ func validateDestinationSettings(destinationSettings *ir.DestinationSetting, end
 	return nil
 }
 
+// isHeadlessService reports true when any DestinationEndpoint corresponds to
+// a headless Kubernetes Service (ClusterIP="None").
+func isHeadlessService(ds *ir.DestinationSetting) bool {
+	for _, ep := range ds.Endpoints {
+		if ep.Host == "None" {
+			return true
+		}
+	}
+	return false
+}
+
 func (t *Translator) processServiceImportDestinationSetting(
 	name string,
 	backendRef gwapiv1.BackendObjectReference,

internal/gatewayapi/route_test.go

@@ -14,7 +14,10 @@ import (
 	discoveryv1 "k8s.io/api/discovery/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/utils/ptr"
+	gwapiv1 "sigs.k8s.io/gateway-api/apis/v1"
 
+	"github.com/envoyproxy/gateway/internal/gatewayapi/resource"
+	"github.com/envoyproxy/gateway/internal/gatewayapi/status"
 	"github.com/envoyproxy/gateway/internal/ir"
 )
 
@@ -226,3 +229,98 @@ func TestGetIREndpointsFromEndpointSlices(t *testing.T) {
 		})
 	}
 }
+
+func TestValidateDestinationSettings(t *testing.T) {
+	svcKind := gwapiv1.Kind(resource.KindService)
+
+	tests := []struct {
+		name                    string
+		ds                      *ir.DestinationSetting
+		endpointRoutingDisabled bool
+		kind                    *gwapiv1.Kind
+		wantErr                 bool
+		wantReason              gwapiv1.RouteConditionReason
+	}{
+		{
+			name: "headless service rejected when endpointRoutingDisabled=true",
+			ds: &ir.DestinationSetting{
+				Name:      "headless",
+				Endpoints: []*ir.DestinationEndpoint{{Host: "None"}},
+			},
+			endpointRoutingDisabled: true,
+			kind:                    &svcKind,
+			wantErr:                 true,
+			wantReason:              status.RouteReasonUnsupportedSetting,
+		},
+		{
+			name: "normal service allowed with ClusterIP routing",
+			ds: &ir.DestinationSetting{
+				Name:      "normal",
+				Endpoints: []*ir.DestinationEndpoint{{Host: "10.0.0.1"}},
+			},
+			endpointRoutingDisabled: true,
+			kind:                    &svcKind,
+			wantErr:                 false,
+		},
+		{
+			name: "mixed address type rejected when EndpointSlice routing",
+			ds: &ir.DestinationSetting{
+				Name:        "mixed",
+				Endpoints:   []*ir.DestinationEndpoint{{Host: "10.0.0.1"}},
+				AddressType: ptr.To(ir.MIXED),
+			},
+			endpointRoutingDisabled: false,
+			kind:                    &svcKind,
+			wantErr:                 true,
+			wantReason:              status.RouteReasonUnsupportedAddressType,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateDestinationSettings(tt.ds, tt.endpointRoutingDisabled, tt.kind)
+			if tt.wantErr {
+				require.Error(t, err)
+				require.Equal(t, tt.wantReason, err.Reason())
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
+
+func TestIsHeadlessService(t *testing.T) {
+	tests := []struct {
+		name      string
+		endpoints []*ir.DestinationEndpoint
+		want      bool
+	}{
+		{
+			name: "headless Service",
+			endpoints: []*ir.DestinationEndpoint{
+				{Host: "None"},
+			},
+			want: true,
+		},
+		{
+			name: "non headless Service with valid ClusterIP",
+			endpoints: []*ir.DestinationEndpoint{
+				{Host: "10.0.0.1"},
+			},
+			want: false,
+		},
+		{
+			name:      "empty slice",
+			endpoints: nil,
+			want:      false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ds := &ir.DestinationSetting{Endpoints: tt.endpoints}
+			got := isHeadlessService(ds)
+			require.Equal(t, tt.want, got)
+		})
+	}
+}

internal/gatewayapi/testdata/httproute-with-headless-service-endpoint-routing.in.yaml

@@ -0,0 +1,47 @@
+gateways:
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    namespace: envoy-gateway
+    name: gateway-1
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - name: http
+      protocol: HTTP
+      port: 80
+      allowedRoutes:
+        namespaces:
+          from: All
+httpRoutes:
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: HTTPRoute
+  metadata:
+    namespace: default
+    name: httproute-headless
+  spec:
+    parentRefs:
+    - name: gateway-1
+      namespace: envoy-gateway
+    rules:
+    - backendRefs:
+      - name: headless-service
+        port: 80
+services:
+- apiVersion: v1
+  kind: Service
+  metadata:
+    namespace: default
+    name: headless-service
+  spec:
+    clusterIP: None
+    ports:
+    - port: 80
+envoyProxyForGatewayClass:
+  apiVersion: gateway.envoyproxy.io/v1alpha1
+  kind: EnvoyProxy
+  metadata:
+    name: default
+    namespace: default
+  spec:
+    routingType: Endpoint

internal/gatewayapi/testdata/httproute-with-headless-service-endpoint-routing.out.yaml

@@ -0,0 +1,135 @@
+gateways:
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    creationTimestamp: null
+    name: gateway-1
+    namespace: envoy-gateway
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - allowedRoutes:
+        namespaces:
+          from: All
+      name: http
+      port: 80
+      protocol: HTTP
+  status:
+    listeners:
+    - attachedRoutes: 1
+      conditions:
+      - lastTransitionTime: null
+        message: Sending translated listener configuration to the data plane
+        reason: Programmed
+        status: "True"
+        type: Programmed
+      - lastTransitionTime: null
+        message: Listener has been successfully translated
+        reason: Accepted
+        status: "True"
+        type: Accepted
+      - lastTransitionTime: null
+        message: Listener references have been resolved
+        reason: ResolvedRefs
+        status: "True"
+        type: ResolvedRefs
+      name: http
+      supportedKinds:
+      - group: gateway.networking.k8s.io
+        kind: HTTPRoute
+      - group: gateway.networking.k8s.io
+        kind: GRPCRoute
+httpRoutes:
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: HTTPRoute
+  metadata:
+    creationTimestamp: null
+    name: httproute-headless
+    namespace: default
+  spec:
+    parentRefs:
+    - name: gateway-1
+      namespace: envoy-gateway
+    rules:
+    - backendRefs:
+      - name: headless-service
+        port: 80
+  status:
+    parents:
+    - conditions:
+      - lastTransitionTime: null
+        message: Route is accepted
+        reason: Accepted
+        status: "True"
+        type: Accepted
+      - lastTransitionTime: null
+        message: Resolved all the Object references for the Route
+        reason: ResolvedRefs
+        status: "True"
+        type: ResolvedRefs
+      controllerName: gateway.envoyproxy.io/gatewayclass-controller
+      parentRef:
+        name: gateway-1
+        namespace: envoy-gateway
+infraIR:
+  envoy-gateway/gateway-1:
+    proxy:
+      config:
+        apiVersion: gateway.envoyproxy.io/v1alpha1
+        kind: EnvoyProxy
+        metadata:
+          creationTimestamp: null
+          name: default
+          namespace: default
+        spec:
+          logging: {}
+          routingType: Endpoint
+        status: {}
+      listeners:
+      - address: null
+        name: envoy-gateway/gateway-1/http
+        ports:
+        - containerPort: 10080
+          name: http-80
+          protocol: HTTP
+          servicePort: 80
+      metadata:
+        labels:
+          gateway.envoyproxy.io/owning-gateway-name: gateway-1
+          gateway.envoyproxy.io/owning-gateway-namespace: envoy-gateway
+      name: envoy-gateway/gateway-1
+xdsIR:
+  envoy-gateway/gateway-1:
+    accessLog:
+      json:
+      - path: /dev/stdout
+    http:
+    - address: 0.0.0.0
+      hostnames:
+      - '*'
+      isHTTP2: false
+      metadata:
+        kind: Gateway
+        name: gateway-1
+        namespace: envoy-gateway
+        sectionName: http
+      name: envoy-gateway/gateway-1/http
+      path:
+        escapedSlashesAction: UnescapeAndRedirect
+        mergeSlashes: true
+      port: 10080
+      routes:
+      - directResponse:
+          statusCode: 500
+        hostname: '*'
+        isHTTP2: false
+        metadata:
+          kind: HTTPRoute
+          name: httproute-headless
+          namespace: default
+        name: httproute/default/httproute-headless/rule/0/match/-1/*
+    readyListener:
+      address: 0.0.0.0
+      ipFamily: IPv4
+      path: /ready
+      port: 19003

internal/gatewayapi/testdata/httproute-with-headless-service-service-routing.in.yaml

@@ -0,0 +1,47 @@
+gateways:
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    namespace: envoy-gateway
+    name: gateway-1
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - name: http
+      protocol: HTTP
+      port: 80
+      allowedRoutes:
+        namespaces:
+          from: All
+httpRoutes:
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: HTTPRoute
+  metadata:
+    namespace: default
+    name: httproute-headless
+  spec:
+    parentRefs:
+    - name: gateway-1
+      namespace: envoy-gateway
+    rules:
+    - backendRefs:
+      - name: headless-service
+        port: 80
+services:
+- apiVersion: v1
+  kind: Service
+  metadata:
+    namespace: default
+    name: headless-service
+  spec:
+    clusterIP: None
+    ports:
+    - port: 80
+envoyProxyForGatewayClass:
+  apiVersion: gateway.envoyproxy.io/v1alpha1
+  kind: EnvoyProxy
+  metadata:
+    name: default
+    namespace: default
+  spec:
+    routingType: Service