Check if Service has Endpoints for dangling service template

pkg/lintcontext/mocks/endpoints.go

@@ -0,0 +1,17 @@
+package mocks
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	coreV1 "k8s.io/api/core/v1"
+	metaV1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+// AddMockEndpoints adds a mock Endpoint to LintContext
+func (l *MockLintContext) AddMockEndpoints(t *testing.T, name string) {
+	require.NotEmpty(t, name)
+	l.objects[name] = &coreV1.Endpoints{
+		ObjectMeta: metaV1.ObjectMeta{Name: name},
+	}
+}

pkg/templates/danglingservice/template.go

@@ -40,6 +40,20 @@
 				}
 				selector := service.Spec.Selector
 				if len(selector) == 0 {
+					// Check if Service is linked to Endpoints
+					for _, obj := range lintCtx.Objects() {
+						endpoints, ok := obj.K8sObject.(*v1.Endpoints)
+						if !ok {
+							continue
+						}
+						if endpoints.Namespace != object.K8sObject.GetNamespace() {
+							continue
+						}
+						if endpoints.Name == object.GetK8sObjectName().Name {
+							// Found!
+							return nil
+						}
+					}
 					return []diagnostic.Diagnostic{{
 						Message: "service has no selector specified",
 					}}

pkg/templates/danglingservice/template_test.go

@@ -15,6 +15,7 @@ import (
 )
 
 const (
+	endpoint1   = "endpoint1"
 	pod1        = "pod1"
 	pod2        = "pod2"
 	serviceNone = "service-matches-none"
@@ -52,6 +53,10 @@ func (s *DanglingServiceTestSuite) AddService(name string, podLabels map[string]
 	})
 }
 
+func (s *DanglingServiceTestSuite) AddEndpoints(name string) {
+	s.ctx.AddMockEndpoints(s.T(), name)
+}
+
 func (s *DanglingServiceTestSuite) AddDeploymentWithLabels(name string, labels map[string]string) {
 	s.ctx.AddMockDeployment(s.T(), name)
 	s.ctx.ModifyDeployment(s.T(), name, func(deployment *appsV1.Deployment) {
@@ -93,6 +98,36 @@ func (s *DanglingServiceTestSuite) TestNoDanglingServices() {
 	})
 }
 
+func (s *DanglingServiceTestSuite) TestNoDanglingServiceWithEndpoints() {
+	s.AddService(endpoint1, nil)
+	s.AddEndpoints(endpoint1)
+
+	s.Validate(s.ctx, []templates.TestCase{
+		{
+			Param: params.Params{},
+			Diagnostics: map[string][]diagnostic.Diagnostic{
+				endpoint1: {},
+			},
+			ExpectInstantiationError: false,
+		},
+	})
+}
+
+func (s *DanglingServiceTestSuite) TestDanglingServiceWithNoMatchingEndpoints() {
+	s.AddService(service1, nil)
+	s.AddEndpoints(endpoint1)
+
+	s.Validate(s.ctx, []templates.TestCase{
+		{
+			Param: params.Params{},
+			Diagnostics: map[string][]diagnostic.Diagnostic{
+				service1: {{Message: "service has no selector specified"}},
+			},
+			ExpectInstantiationError: false,
+		},
+	})
+}
+
 func (s *DanglingServiceTestSuite) TestOneServiceIsDangling() {
 	s.AddDeploymentWithLabels(pod2, labelselector2)
 	s.AddService(service1, labelselector1)

tests/checks/dangling-service.yml

@@ -60,4 +60,25 @@ spec:
     - name: 8080-tcp
       port: 8080
   selector:
-    app.kubernetes.io/name: app
+    app.kubernetes.io/name: app
+---
+kind: Endpoints
+apiVersion: v1
+metadata:
+  name: service-mt1
+subsets:
+  - addresses:
+      - ip: 10.1.2.3
+    ports:
+      - name: https
+        port: 443
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: service-mt1
+spec:
+  ports:
+    - name: https
+      port: 443
+      targetPort: 443