Make event handler type aware

Signed-off-by: Danil Grigorev <[email protected]>

Author: Danil-Grigorev

pkg/builder/controller.go

@@ -135,7 +135,7 @@ type WatchesInput struct {
 // This is the equivalent of calling
 // WatchesRawSource(source.Kind(cache, object), eventHandler, opts...).
 func (blder *Builder) Watches(object client.Object, eventHandler handler.EventHandler, opts ...WatchesOption) *Builder {
-	src := source.Kind(blder.mgr.GetCache(), object)
+	src := source.ObjectKind(blder.mgr.GetCache(), object)
 	return blder.WatchesRawSource(src, eventHandler, opts...)
 }
 
@@ -176,6 +176,9 @@ func (blder *Builder) WatchesMetadata(object client.Object, eventHandler handler
 //
 // STOP! Consider using For(...), Owns(...), Watches(...), WatchesMetadata(...) instead.
 // This method is only exposed for more advanced use cases, most users should use one of the higher level functions.
+//
+// Example:
+// WatchesRawSource(source.Kind(cache, &corev1.Pod{}), eventHandler, opts...) // ensure that source propagates only valid Pod objects.
 func (blder *Builder) WatchesRawSource(src source.Source, eventHandler handler.EventHandler, opts ...WatchesOption) *Builder {
 	input := WatchesInput{src: src, eventHandler: eventHandler}
 	for _, opt := range opts {
@@ -272,7 +275,7 @@ func (blder *Builder) doWatch() error {
 		if err != nil {
 			return err
 		}
-		src := source.Kind(blder.mgr.GetCache(), obj)
+		src := source.ObjectKind(blder.mgr.GetCache(), obj)
 		hdler := &handler.EnqueueRequestForObject{}
 		allPredicates := append([]predicate.Predicate(nil), blder.globalPredicates...)
 		allPredicates = append(allPredicates, blder.forInput.predicates...)
@@ -290,7 +293,7 @@ func (blder *Builder) doWatch() error {
 		if err != nil {
 			return err
 		}
-		src := source.Kind(blder.mgr.GetCache(), obj)
+		src := source.ObjectKind(blder.mgr.GetCache(), obj)
 		opts := []handler.OwnerOption{}
 		if !own.matchEveryOwner {
 			opts = append(opts, handler.OnlyControllerOwner())
@@ -313,7 +316,7 @@ func (blder *Builder) doWatch() error {
 	}
 	for _, w := range blder.watchesInput {
 		// If the source of this watch is of type Kind, project it.
-		if srcKind, ok := w.src.(*internalsource.Kind); ok {
+		if srcKind, ok := w.src.(*internalsource.Kind[client.Object]); ok {
 			typeForSrc, err := blder.project(srcKind.Type, w.objectProjection)
 			if err != nil {
 				return err

pkg/internal/source/event_handler.go

@@ -33,8 +33,8 @@ import (
 var log = logf.RuntimeLog.WithName("source").WithName("EventHandler")
 
 // NewEventHandler creates a new EventHandler.
-func NewEventHandler(ctx context.Context, queue workqueue.RateLimitingInterface, handler handler.EventHandler, predicates []predicate.Predicate) *EventHandler {
-	return &EventHandler{
+func NewEventHandler[T client.Object](ctx context.Context, queue workqueue.RateLimitingInterface, handler handler.EventHandler, predicates []predicate.Predicate) *EventHandler[T] {
+	return &EventHandler[T]{
 		ctx:        ctx,
 		handler:    handler,
 		queue:      queue,
@@ -43,7 +43,7 @@ func NewEventHandler(ctx context.Context, queue workqueue.RateLimitingInterface,
 }
 
 // EventHandler adapts a handler.EventHandler interface to a cache.ResourceEventHandler interface.
-type EventHandler struct {
+type EventHandler[T client.Object] struct {
 	// ctx stores the context that created the event handler
 	// that is used to propagate cancellation signals to each handler function.
 	ctx context.Context
@@ -55,7 +55,7 @@ type EventHandler struct {
 
 // HandlerFuncs converts EventHandler to a ResourceEventHandlerFuncs
 // TODO: switch to ResourceEventHandlerDetailedFuncs with client-go 1.27
-func (e *EventHandler) HandlerFuncs() cache.ResourceEventHandlerFuncs {
+func (e *EventHandler[T]) HandlerFuncs() cache.ResourceEventHandlerFuncs {
 	return cache.ResourceEventHandlerFuncs{
 		AddFunc:    e.OnAdd,
 		UpdateFunc: e.OnUpdate,
@@ -64,11 +64,11 @@ func (e *EventHandler) HandlerFuncs() cache.ResourceEventHandlerFuncs {
 }
 
 // OnAdd creates CreateEvent and calls Create on EventHandler.
-func (e *EventHandler) OnAdd(obj interface{}) {
+func (e *EventHandler[T]) OnAdd(obj interface{}) {
 	c := event.CreateEvent{}
 
 	// Pull Object out of the object
-	if o, ok := obj.(client.Object); ok {
+	if o, ok := obj.(T); ok {
 		c.Object = o
 	} else {
 		log.Error(nil, "OnAdd missing Object",
@@ -89,10 +89,10 @@ func (e *EventHandler) OnAdd(obj interface{}) {
 }
 
 // OnUpdate creates UpdateEvent and calls Update on EventHandler.
-func (e *EventHandler) OnUpdate(oldObj, newObj interface{}) {
+func (e *EventHandler[T]) OnUpdate(oldObj, newObj interface{}) {
 	u := event.UpdateEvent{}
 
-	if o, ok := oldObj.(client.Object); ok {
+	if o, ok := oldObj.(T); ok {
 		u.ObjectOld = o
 	} else {
 		log.Error(nil, "OnUpdate missing ObjectOld",
@@ -101,7 +101,7 @@ func (e *EventHandler) OnUpdate(oldObj, newObj interface{}) {
 	}
 
 	// Pull Object out of the object
-	if o, ok := newObj.(client.Object); ok {
+	if o, ok := newObj.(T); ok {
 		u.ObjectNew = o
 	} else {
 		log.Error(nil, "OnUpdate missing ObjectNew",
@@ -122,7 +122,7 @@ func (e *EventHandler) OnUpdate(oldObj, newObj interface{}) {
 }
 
 // OnDelete creates DeleteEvent and calls Delete on EventHandler.
-func (e *EventHandler) OnDelete(obj interface{}) {
+func (e *EventHandler[T]) OnDelete(obj interface{}) {
 	d := event.DeleteEvent{}
 
 	// Deal with tombstone events by pulling the object out.  Tombstone events wrap the object in a
@@ -131,7 +131,7 @@ func (e *EventHandler) OnDelete(obj interface{}) {
 	// This should never happen if we aren't missing events, which we have concluded that we are not
 	// and made decisions off of this belief.  Maybe this shouldn't be here?
 	var ok bool
-	if _, ok = obj.(client.Object); !ok {
+	if _, ok = obj.(T); !ok {
 		// If the object doesn't have Metadata, assume it is a tombstone object of type DeletedFinalStateUnknown
 		tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
 		if !ok {
@@ -149,7 +149,7 @@ func (e *EventHandler) OnDelete(obj interface{}) {
 	}
 
 	// Pull Object out of the object
-	if o, ok := obj.(client.Object); ok {
+	if o, ok := obj.(T); ok {
 		d.Object = o
 	} else {
 		log.Error(nil, "OnDelete missing Object",