fix(*) fix builtin gateway when adding to insights (#2980)

* fix(*) fix builtin gateway when adding to insights

As according to our validators
(https://github.com/kumahq/kuma/blob/c89ac43e1d46a16ad37f8898dbd932cda4b034dd/pkg/core/resources/apis/mesh/dataplane_validator.go#L34-L63)
both gateways (delegated and builtin) cannot contain inbounds
I added builtin gateway to skip trying to add its inbounds to the
dataplane list of insight resources.

I also refactored this parts of code to use protobuf's builtin
associate `Get[...]` functions which handles nils better (i.e.
in `dpOverview.Spec.GetDataplane().GetNetworking()` if
`dpOverview.Spec.Dataplane` will be `nil` it won't crash.

Also removed nested if statement and used `continue` to skip
to the next loop iteration instead of using `else` branch.

Signed-off-by: Bart Smykla <bartek@smykla.com>

pkg/insights/resyncer.go

@@ -213,15 +213,14 @@ func (r *resyncer) createOrUpdateServiceInsight(mesh string) error {
 
 	for _, dpOverview := range dpOverviews.Items {
 		status, _ := dpOverview.GetStatus()
+		networking := dpOverview.Spec.GetDataplane().GetNetworking()
 
-		// Builtin gateways have inbounds
-		if dpOverview.Spec.Dataplane.IsDelegatedGateway() {
-			svcName := dpOverview.Spec.Dataplane.Networking.GetGateway().GetTags()[mesh_proto.ServiceTag]
-			addDpToInsight(insight, svcName, status)
-		} else {
-			for _, inbound := range dpOverview.Spec.Dataplane.Networking.Inbound {
-				addDpToInsight(insight, inbound.GetService(), status)
-			}
+		if svc := networking.GetGateway().GetTags()[mesh_proto.ServiceTag]; svc != "" {
+			addDpToInsight(insight, svc, status)
+		}
+
+		for _, inbound := range networking.GetInbound() {
+			addDpToInsight(insight, inbound.GetService(), status)
 		}
 	}
 
@@ -338,14 +337,14 @@ func (r *resyncer) createOrUpdateMeshInsight(mesh string) error {
 		updateTotal(envoyVersion, insight.DpVersions.Envoy)
 		updateMTLS(dpInsight.GetMTLS(), status, insight.MTLS)
 
-		// Builtin gateways have inbounds
-		if dpOverview.Spec.Dataplane.IsDelegatedGateway() {
-			svcName := dpOverview.Spec.Dataplane.Networking.GetGateway().GetTags()[mesh_proto.ServiceTag]
-			internalServices[svcName] = struct{}{}
-		} else {
-			for _, inbound := range dpOverview.Spec.Dataplane.Networking.Inbound {
-				internalServices[inbound.GetService()] = struct{}{}
-			}
+		networking := dpOverview.Spec.GetDataplane().GetNetworking()
+
+		if svc := networking.GetGateway().GetTags()[mesh_proto.ServiceTag]; svc != "" {
+			internalServices[svc] = struct{}{}
+		}
+
+		for _, inbound := range networking.GetInbound() {
+			internalServices[inbound.GetService()] = struct{}{}
 		}
 	}