fix: Generate only a single CDS config update per render round

So far muliple config updates have been sent in each rendering round, one per gateway-class. This
confuses clients watching for all configs. This change makes sure that we send only single CDS
config update that contains all active configs.

internal/renderer/render_context.go

@@ -24,22 +24,21 @@ type RenderContext struct {
 }
 
 func NewRenderContext(e *event.EventRender, r *Renderer, gc *gwapiv1.GatewayClass) *RenderContext {
+	logger := r.log
+	if gc != nil {
+		logger = r.log.WithValues("gateway-class", gc.GetName())
+	}
 	return &RenderContext{
 		origin: e,
 		update: event.NewEventUpdate(r.gen),
 		gc:     gc,
 		gws:    store.NewGatewayStore(),
-		log:    r.log.WithValues("gateway-class", gc.GetName()),
+		log:    logger,
 	}
 }
 
 // Merge merges the update queues of two rendering contexts.
 func (r *RenderContext) Merge(mergeable *RenderContext) {
-	if store.GetObjectKey(r.gc) != store.GetObjectKey(mergeable.gc) ||
-		store.GetObjectKey(r.gwConf) != store.GetObjectKey(mergeable.gwConf) {
-		panic("MergeUpdateQueue: trying to merge incompatible render contexts")
-	}
-
 	// MUST BE KEPT IN SYNC WITH EventUpdate
 
 	// merge upsert queues

internal/renderer/render_pipeline.go

@@ -99,9 +99,10 @@ func (r *Renderer) renderGatewayClass(e *event.EventRender) {
 func (r *Renderer) renderManagedGateways(e *event.EventRender) {
 	r.log.Info("commencing dataplane render", "mode", "managed")
 
+	pipelineCtx := NewRenderContext(e, r, nil)
+
 	r.log.V(1).Info("obtaining gateway-class objects")
 	gcs := r.getGatewayClasses()
-
 	if len(gcs) == 0 {
 		r.log.Info("no gateway-class objects found", "event", e.String())
 		return
@@ -165,8 +166,10 @@ func (r *Renderer) renderManagedGateways(e *event.EventRender) {
 
 		setGatewayClassStatusAccepted(gc, nil)
 
-		r.operatorCh <- gcCtx.update.DeepCopy()
+		pipelineCtx.Merge(gcCtx)
 	}
+
+	r.operatorCh <- pipelineCtx.update.DeepCopy()
 }
 
 // renderForGateways renders a configuration for a set of Gateways (c.gws)