slice mirroring controller mirror annotations

Add support to the endpoint slice mirroring controller to mirror
annotations, in addition to labels, but don´t mirror endpoint
triggertime annotation.

Also, fix a bug in the endpointslice mirroring controller, that
wasn't updating the mirrored slice with the new labels, in case
that only the endpoint labels were modified.

pkg/controller/endpointslicemirroring/utils.go

@@ -69,6 +69,7 @@ func newEndpointSlice(endpoints *corev1.Endpoints, ports []discovery.EndpointPor
 	epSlice := &discovery.EndpointSlice{
 		ObjectMeta: metav1.ObjectMeta{
 			Labels:          map[string]string{},
+			Annotations:     map[string]string{},
 			OwnerReferences: []metav1.OwnerReference{*ownerRef},
 			Namespace:       endpoints.Namespace,
 		},
@@ -77,13 +78,23 @@ func newEndpointSlice(endpoints *corev1.Endpoints, ports []discovery.EndpointPor
 		Endpoints:   []discovery.Endpoint{},
 	}
 
+	// clone all labels
 	for label, val := range endpoints.Labels {
 		epSlice.Labels[label] = val
 	}
 
+	// overwrite specific labels
 	epSlice.Labels[discovery.LabelServiceName] = endpoints.Name
 	epSlice.Labels[discovery.LabelManagedBy] = controllerName
 
+	// clone all annotations but EndpointsLastChangeTriggerTime
+	for annotation, val := range endpoints.Annotations {
+		if annotation == corev1.EndpointsLastChangeTriggerTime {
+			continue
+		}
+		epSlice.Annotations[annotation] = val
+	}
+
 	if sliceName == "" {
 		epSlice.GenerateName = getEndpointSlicePrefix(endpoints.Name)
 	} else {
@@ -228,3 +239,22 @@ func hasLeaderElection(annotations map[string]string) bool {
 	_, ok := annotations[resourcelock.LeaderElectionRecordAnnotationKey]
 	return ok
 }
+
+// cloneAndRemoveKeys is a copy of CloneAndRemoveLabels
+// it is used here for annotations and labels
+func cloneAndRemoveKeys(a map[string]string, keys ...string) map[string]string {
+	if len(keys) == 0 {
+		// Don't need to remove a key.
+		return a
+	}
+	// Clone.
+	newMap := map[string]string{}
+	for k, v := range a {
+		newMap[k] = v
+	}
+	// remove keys
+	for _, key := range keys {
+		delete(newMap, key)
+	}
+	return newMap
+}