fix(bug): ignore headless svc to prevent error messages (#763)

# Description

* update service controller to ignore headless svc and re-trigger
reconcile when encountering one
* create test to validate UpdateRetinaSvc still throws an error if a
retina svc has no IPv4 (this is to make sure existing validation post
retinaSvc creation is not broken)

## Related Issue

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Additionally, make sure that the issue is assigned to you before
submitting this pull request.

fix #547 

## Checklist

- [x] I have read the [contributing
documentation](https://retina.sh/docs/contributing).
- [x] I signed and signed-off the commits (`git commit -S -s ...`). See
[this
documentation](https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification)
on signing commits.
- [x] I have correctly attributed the author(s) of the code.
- [x] I have tested the changes locally.
- [x] I have followed the project's style guidelines.
- [x] I have updated the documentation, if necessary.
- [x] I have added tests, if applicable.

## Screenshots (if applicable) or Testing Completed

Please add any relevant screenshots or GIFs to showcase the changes
made.

## Additional Notes

Add any additional notes or context about the pull request here.

---

Please refer to the [CONTRIBUTING.md](../CONTRIBUTING.md) file for more
information on how to contribute to this project.

Signed-off-by: Simone Rodigari <srodigari@microsoft.com>

pkg/controllers/daemon/service/controller.go

@@ -14,6 +14,7 @@ import (
 	errors "k8s.io/apimachinery/pkg/api/errors"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/predicate"
 
 	retinaCommon "github.com/microsoft/retina/pkg/common"
 	"github.com/microsoft/retina/pkg/controllers/cache"
@@ -76,7 +77,6 @@ func (r *ServiceReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ct
 	}
 	ips := retinaCommon.IPAddresses{}
 	ips.IPv4 = net.ParseIP(service.Spec.ClusterIP)
-	net.ParseIP(service.Spec.ClusterIP)
 	var lbIP net.IP
 	if service.Status.LoadBalancer.Ingress != nil && len(service.Status.LoadBalancer.Ingress) > 0 {
 		lbIP = net.ParseIP(service.Status.LoadBalancer.Ingress[0].IP)
@@ -93,7 +93,16 @@ func (r *ServiceReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ct
 // SetupWithManager sets up the controller with the Manager.
 func (r *ServiceReconciler) SetupWithManager(mgr ctrl.Manager) error {
 	r.l.Info("Setting up Service controller")
+	// Define a predicate to filter out Services with ClusterIP == "None"
+	pred := predicate.NewPredicateFuncs(func(object client.Object) bool {
+		service, ok := object.(*corev1.Service)
+		if !ok {
+			return false
+		}
+		return service.Spec.ClusterIP != "None"
+	})
 	return ctrl.NewControllerManagedBy(mgr).
 		For(&corev1.Service{}).
+		WithEventFilter(pred).
 		Complete(r)
 }

pkg/controllers/daemon/service/controller_test.go

@@ -0,0 +1,133 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	corev1 "k8s.io/api/core/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/event"
+	"sigs.k8s.io/controller-runtime/pkg/predicate"
+)
+
+func TestServiceFilter(t *testing.T) {
+	pred := predicate.NewPredicateFuncs(func(object client.Object) bool {
+		service, ok := object.(*corev1.Service)
+		if !ok {
+			return false
+		}
+		return service.Spec.ClusterIP != "None"
+	})
+
+	tests := []struct {
+		name   string
+		event  interface{}
+		expect bool
+	}{
+		{
+			name: "CreateEvent with ClusterIP None",
+			event: event.CreateEvent{
+				Object: &corev1.Service{
+					Spec: corev1.ServiceSpec{
+						ClusterIP: "None",
+					},
+				},
+			},
+			expect: false,
+		},
+		{
+			name: "CreateEvent with ClusterIP not None",
+			event: event.CreateEvent{
+				Object: &corev1.Service{
+					Spec: corev1.ServiceSpec{
+						ClusterIP: "10.0.0.1",
+					},
+				},
+			},
+			expect: true,
+		},
+		{
+			name: "UpdateEvent with ClusterIP None",
+			event: event.UpdateEvent{
+				ObjectNew: &corev1.Service{
+					Spec: corev1.ServiceSpec{
+						ClusterIP: "None",
+					},
+				},
+			},
+			expect: false,
+		},
+		{
+			name: "UpdateEvent with ClusterIP not None",
+			event: event.UpdateEvent{
+				ObjectNew: &corev1.Service{
+					Spec: corev1.ServiceSpec{
+						ClusterIP: "10.0.0.1",
+					},
+				},
+			},
+			expect: true,
+		},
+		{
+			name: "DeleteEvent with ClusterIP None",
+			event: event.DeleteEvent{
+				Object: &corev1.Service{
+					Spec: corev1.ServiceSpec{
+						ClusterIP: "None",
+					},
+				},
+			},
+			expect: false,
+		},
+		{
+			name: "DeleteEvent with ClusterIP not None",
+			event: event.DeleteEvent{
+				Object: &corev1.Service{
+					Spec: corev1.ServiceSpec{
+						ClusterIP: "10.0.0.1",
+					},
+				},
+			},
+			expect: true,
+		},
+		{
+			name: "GenericEvent with ClusterIP None",
+			event: event.GenericEvent{
+				Object: &corev1.Service{
+					Spec: corev1.ServiceSpec{
+						ClusterIP: "None",
+					},
+				},
+			},
+			expect: false,
+		},
+		{
+			name: "GenericEvent with ClusterIP not None",
+			event: event.GenericEvent{
+				Object: &corev1.Service{
+					Spec: corev1.ServiceSpec{
+						ClusterIP: "10.0.0.1",
+					},
+				},
+			},
+			expect: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var result bool
+			switch e := tt.event.(type) {
+			case event.CreateEvent:
+				result = pred.Create(e)
+			case event.UpdateEvent:
+				result = pred.Update(e)
+			case event.DeleteEvent:
+				result = pred.Delete(e)
+			case event.GenericEvent:
+				result = pred.Generic(e)
+			}
+			assert.Equal(t, tt.expect, result)
+		})
+	}
+}