feat(source/node): fqdn support combineFQDNAnnotation (#5526)

Signed-off-by: ivan katliarchuk <ivan.katliarchuk@gmail.com>

docs/advanced/fqdn-templating.md

@@ -54,7 +54,7 @@ The template uses the following data from the source object (e.g., a `Service` o
 | `istio-gateway`        | Queries Istio Gateway resources for endpoints.                  |       ✅        |      ✅       |
 | `istio-virtualservice` | Queries Istio VirtualService resources for endpoints.           |       ✅        |      ✅       |
 | `kong-tcpingress`      | Queries Kong TCPIngress resources for endpoints.                |       ❌        |      ❌       |
-| `node`                 | Queries Kubernetes Node resources for endpoints.                |       ✅        |      ❌       |
+| `node`                 | Queries Kubernetes Node resources for endpoints.                |       ✅        |      ✅       |
 | `openshift-route`      | Queries OpenShift Route resources for endpoints.                |       ✅        |      ✅       |
 | `pod`                  | Queries Kubernetes Pod resources for endpoints.                 |       ✅        |      ✅       |
 | `service`              | Queries Kubernetes Service resources for endpoints.             |       ✅        |      ✅       |

source/node.go

@@ -38,9 +38,11 @@ import (
 const warningMsg = "The default behavior of exposing internal IPv6 addresses will change in the next minor version. Use --no-expose-internal-ipv6 flag to opt-in to the new behavior."
 
 type nodeSource struct {
-	client               kubernetes.Interface
+	client                kubernetes.Interface
-	annotationFilter     string
+	annotationFilter      string
-	fqdnTemplate         *template.Template
+	fqdnTemplate          *template.Template
+	combineFQDNAnnotation bool
+
 	nodeInformer         coreinformers.NodeInformer
 	labelSelector        labels.Selector
 	excludeUnschedulable bool
@@ -48,7 +50,14 @@ type nodeSource struct {
 }
 
 // NewNodeSource creates a new nodeSource with the given config.
-func NewNodeSource(ctx context.Context, kubeClient kubernetes.Interface, annotationFilter, fqdnTemplate string, labelSelector labels.Selector, exposeInternalIPv6, excludeUnschedulable bool) (Source, error) {
+func NewNodeSource(
+	ctx context.Context,
+	kubeClient kubernetes.Interface,
+	annotationFilter, fqdnTemplate string,
+	labelSelector labels.Selector,
+	exposeInternalIPv6,
+	excludeUnschedulable bool,
+	combineFQDNAnnotation bool) (Source, error) {
 	tmpl, err := fqdn.ParseTemplate(fqdnTemplate)
 	if err != nil {
 		return nil, err
@@ -76,18 +85,19 @@ func NewNodeSource(ctx context.Context, kubeClient kubernetes.Interface, annotat
 	}
 
 	return &nodeSource{
-		client:               kubeClient,
+		client:                kubeClient,
-		annotationFilter:     annotationFilter,
+		annotationFilter:      annotationFilter,
-		fqdnTemplate:         tmpl,
+		fqdnTemplate:          tmpl,
-		nodeInformer:         nodeInformer,
+		combineFQDNAnnotation: combineFQDNAnnotation,
-		labelSelector:        labelSelector,
+		nodeInformer:          nodeInformer,
-		excludeUnschedulable: excludeUnschedulable,
+		labelSelector:         labelSelector,
-		exposeInternalIPv6:   exposeInternalIPv6,
+		excludeUnschedulable:  excludeUnschedulable,
+		exposeInternalIPv6:    exposeInternalIPv6,
 	}, nil
 }
 
 // Endpoints returns endpoint objects for each service that should be processed.
-func (ns *nodeSource) Endpoints(ctx context.Context) ([]*endpoint.Endpoint, error) {
+func (ns *nodeSource) Endpoints(_ context.Context) ([]*endpoint.Endpoint, error) {
 	nodes, err := ns.nodeInformer.Lister().List(ns.labelSelector)
 	if err != nil {
 		return nil, err
@@ -127,21 +137,9 @@ func (ns *nodeSource) Endpoints(ctx context.Context) ([]*endpoint.Endpoint, erro
 			}
 		}
 
-		dnsNames := make(map[string]bool)
+		dnsNames, err := ns.collectDNSNames(node)
-
+		if err != nil {
-		if ns.fqdnTemplate != nil {
+			return nil, err
-			hostnames, err := fqdn.ExecTemplate(ns.fqdnTemplate, node)
-			if err != nil {
-				return nil, err
-			}
-
-			for _, name := range hostnames {
-				dnsNames[name] = true
-				log.Debugf("applied template for %s, converting to %s", node.Name, name)
-			}
-		} else {
-			dnsNames[node.Name] = true
-			log.Debugf("not applying template for %s", node.Name)
 		}
 
 		for dns := range dnsNames {
@@ -233,3 +231,36 @@ func (ns *nodeSource) filterByAnnotations(nodes []*v1.Node) ([]*v1.Node, error)
 
 	return filteredList, nil
 }
+
+// collectDNSNames returns a set of DNS names associated with the given Kubernetes Node.
+// If an FQDN template is configured, it renders the template using the Node object
+// to generate one or more DNS names.
+// If combineFQDNAnnotation is enabled, the Node's name is also included alongside
+// the templated names. If no FQDN template is provided, the result will include only
+// the Node's name.
+//
+// Returns an error if template rendering fails.
+func (ns *nodeSource) collectDNSNames(node *v1.Node) (map[string]bool, error) {
+	dnsNames := make(map[string]bool)
+	// If no FQDN template is configured, fallback to the node name
+	if ns.fqdnTemplate == nil {
+		dnsNames[node.Name] = true
+		return dnsNames, nil
+	}
+
+	names, err := fqdn.ExecTemplate(ns.fqdnTemplate, node)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, name := range names {
+		dnsNames[name] = true
+		log.Debugf("applied template for %s, converting to %s", node.Name, name)
+	}
+
+	if ns.combineFQDNAnnotation {
+		dnsNames[node.Name] = true
+	}
+
+	return dnsNames, nil
+}

source/node_fqdn_test.go

@@ -64,6 +64,7 @@ func TestNodeSourceNewNodeSourceWithFqdn(t *testing.T) {
 				labels.Everything(),
 				true,
 				true,
+				false,
 			)
 			if tt.expectError {
 				assert.Error(t, err)
@@ -80,6 +81,7 @@ func TestNodeSourceFqdnTemplatingExamples(t *testing.T) {
 		nodes        []*v1.Node
 		fqdnTemplate string
 		expected     []*endpoint.Endpoint
+		combineFQDN  bool
 	}{
 		{
 			title: "templating expansion with multiple domains",
@@ -293,6 +295,32 @@ func TestNodeSourceFqdnTemplatingExamples(t *testing.T) {
 				{DNSName: "node-name-2.domain.tld", RecordType: endpoint.RecordTypeA, Targets: endpoint.Targets{"243.186.136.178"}},
 			},
 		},
+		{
+			title:       "templating with shared all domain and fqdn combination annotation",
+			combineFQDN: true,
+			nodes: []*v1.Node{
+				{
+					ObjectMeta: metav1.ObjectMeta{Name: "node-name-1"},
+					Status: v1.NodeStatus{
+						Addresses: []v1.NodeAddress{{Type: v1.NodeExternalIP, Address: "243.186.136.160"}},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{Name: "node-name-2"},
+					Status: v1.NodeStatus{
+						Addresses: []v1.NodeAddress{{Type: v1.NodeExternalIP, Address: "243.186.136.178"}},
+					},
+				},
+			},
+			fqdnTemplate: "{{ .Name }}.domain.tld,all.example.com",
+			expected: []*endpoint.Endpoint{
+				{DNSName: "all.example.com", RecordType: endpoint.RecordTypeA, Targets: endpoint.Targets{"243.186.136.160", "243.186.136.178"}},
+				{DNSName: "node-name-1.domain.tld", RecordType: endpoint.RecordTypeA, Targets: endpoint.Targets{"243.186.136.160"}},
+				{DNSName: "node-name-2.domain.tld", RecordType: endpoint.RecordTypeA, Targets: endpoint.Targets{"243.186.136.178"}},
+				{DNSName: "node-name-1", RecordType: endpoint.RecordTypeA, Targets: endpoint.Targets{"243.186.136.160"}},
+				{DNSName: "node-name-2", RecordType: endpoint.RecordTypeA, Targets: endpoint.Targets{"243.186.136.178"}},
+			},
+		},
 	} {
 		t.Run(tt.title, func(t *testing.T) {
 			kubeClient := fake.NewClientset()
@@ -310,6 +338,7 @@ func TestNodeSourceFqdnTemplatingExamples(t *testing.T) {
 				labels.Everything(),
 				true,
 				true,
+				tt.combineFQDN,
 			)
 			require.NoError(t, err)
 

source/node_test.go

@@ -95,6 +95,7 @@ func testNodeSourceNewNodeSource(t *testing.T) {
 				labels.Everything(),
 				true,
 				true,
+				false,
 			)
 
 			if ti.expectError {
@@ -440,6 +441,7 @@ func testNodeSourceEndpoints(t *testing.T) {
 				labelSelector,
 				tc.exposeInternalIPv6,
 				tc.excludeUnschedulable,
+				false,
 			)
 			require.NoError(t, err)
 
@@ -557,6 +559,7 @@ func testNodeEndpointsWithIPv6(t *testing.T) {
 			labelSelector,
 			tc.exposeInternalIPv6,
 			tc.excludeUnschedulable,
+			false,
 		)
 		require.NoError(t, err)
 
@@ -604,6 +607,7 @@ func TestResourceLabelIsSetForEachNodeEndpoint(t *testing.T) {
 		labels.Everything(),
 		false,
 		true,
+		false,
 	)
 	require.NoError(t, err)
 

source/store.go

@@ -267,7 +267,7 @@ func BuildWithConfig(ctx context.Context, source string, p ClientGenerator, cfg
 		if err != nil {
 			return nil, err
 		}
-		return NewNodeSource(ctx, client, cfg.AnnotationFilter, cfg.FQDNTemplate, cfg.LabelFilter, cfg.ExposeInternalIPv6, cfg.ExcludeUnschedulable)
+		return NewNodeSource(ctx, client, cfg.AnnotationFilter, cfg.FQDNTemplate, cfg.LabelFilter, cfg.ExposeInternalIPv6, cfg.ExcludeUnschedulable, cfg.CombineFQDNAndAnnotation)
 	case "service":
 		client, err := p.KubeClient()
 		if err != nil {