[release-0.20] 🌱 Handlers: Default to LowPriorityWhenUnchanged without a wrapper

pkg/builder/controller.go

@@ -163,7 +163,7 @@ func (blder *TypedBuilder[request]) Watches(
 ) *TypedBuilder[request] {
 	input := WatchesInput[request]{
 		obj:     object,
-		handler: handler.WithLowPriorityWhenUnchanged(eventHandler),
+		handler: eventHandler,
 	}
 	for _, opt := range opts {
 		opt.ApplyToWatches(&input)
@@ -317,7 +317,7 @@ func (blder *TypedBuilder[request]) doWatch() error {
 		}
 
 		var hdler handler.TypedEventHandler[client.Object, request]
-		reflect.ValueOf(&hdler).Elem().Set(reflect.ValueOf(handler.WithLowPriorityWhenUnchanged(&handler.EnqueueRequestForObject{})))
+		reflect.ValueOf(&hdler).Elem().Set(reflect.ValueOf(&handler.EnqueueRequestForObject{}))
 		allPredicates := append([]predicate.Predicate(nil), blder.globalPredicates...)
 		allPredicates = append(allPredicates, blder.forInput.predicates...)
 		src := source.TypedKind(blder.mgr.GetCache(), obj, hdler, allPredicates...)
@@ -341,11 +341,11 @@ func (blder *TypedBuilder[request]) doWatch() error {
 		}
 
 		var hdler handler.TypedEventHandler[client.Object, request]
-		reflect.ValueOf(&hdler).Elem().Set(reflect.ValueOf(handler.WithLowPriorityWhenUnchanged(handler.EnqueueRequestForOwner(
+		reflect.ValueOf(&hdler).Elem().Set(reflect.ValueOf(handler.EnqueueRequestForOwner(
 			blder.mgr.GetScheme(), blder.mgr.GetRESTMapper(),
 			blder.forInput.object,
 			opts...,
-		))))
+		)))
 		allPredicates := append([]predicate.Predicate(nil), blder.globalPredicates...)
 		allPredicates = append(allPredicates, own.predicates...)
 		src := source.TypedKind(blder.mgr.GetCache(), obj, hdler, allPredicates...)

pkg/handler/enqueue.go

@@ -52,25 +52,32 @@ func (e *TypedEnqueueRequestForObject[T]) Create(ctx context.Context, evt event.
 		enqueueLog.Error(nil, "CreateEvent received with no metadata", "event", evt)
 		return
 	}
-	q.Add(reconcile.Request{NamespacedName: types.NamespacedName{
+
+	item := reconcile.Request{NamespacedName: types.NamespacedName{
 		Name:      evt.Object.GetName(),
 		Namespace: evt.Object.GetNamespace(),
-	}})
+	}}
+
+	addToQueueCreate(q, evt, item)
 }
 
 // Update implements EventHandler.
 func (e *TypedEnqueueRequestForObject[T]) Update(ctx context.Context, evt event.TypedUpdateEvent[T], q workqueue.TypedRateLimitingInterface[reconcile.Request]) {
 	switch {
 	case !isNil(evt.ObjectNew):
-		q.Add(reconcile.Request{NamespacedName: types.NamespacedName{
+		item := reconcile.Request{NamespacedName: types.NamespacedName{
 			Name:      evt.ObjectNew.GetName(),
 			Namespace: evt.ObjectNew.GetNamespace(),
-		}})
+		}}
+
+		addToQueueUpdate(q, evt, item)
 	case !isNil(evt.ObjectOld):
-		q.Add(reconcile.Request{NamespacedName: types.NamespacedName{
+		item := reconcile.Request{NamespacedName: types.NamespacedName{
 			Name:      evt.ObjectOld.GetName(),
 			Namespace: evt.ObjectOld.GetNamespace(),
-		}})
+		}}
+
+		addToQueueUpdate(q, evt, item)
 	default:
 		enqueueLog.Error(nil, "UpdateEvent received with no metadata", "event", evt)
 	}

pkg/handler/enqueue_mapped.go

@@ -21,6 +21,7 @@ import (
 
 	"k8s.io/client-go/util/workqueue"
 	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/controller/priorityqueue"
 	"sigs.k8s.io/controller-runtime/pkg/event"
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
 )
@@ -63,15 +64,17 @@ func EnqueueRequestsFromMapFunc(fn MapFunc) EventHandler {
 // TypedEnqueueRequestsFromMapFunc is experimental and subject to future change.
 func TypedEnqueueRequestsFromMapFunc[object any, request comparable](fn TypedMapFunc[object, request]) TypedEventHandler[object, request] {
 	return &enqueueRequestsFromMapFunc[object, request]{
-		toRequests: fn,
+		toRequests:                   fn,
+		objectImplementsClientObject: implementsClientObject[object](),
 	}
 }
 
 var _ EventHandler = &enqueueRequestsFromMapFunc[client.Object, reconcile.Request]{}
 
 type enqueueRequestsFromMapFunc[object any, request comparable] struct {
 	// Mapper transforms the argument into a slice of keys to be reconciled
-	toRequests TypedMapFunc[object, request]
+	toRequests                   TypedMapFunc[object, request]
+	objectImplementsClientObject bool
 }
 
 // Create implements EventHandler.
@@ -81,7 +84,15 @@ func (e *enqueueRequestsFromMapFunc[object, request]) Create(
 	q workqueue.TypedRateLimitingInterface[request],
 ) {
 	reqs := map[request]empty{}
-	e.mapAndEnqueue(ctx, q, evt.Object, reqs)
+
+	var lowPriority bool
+	if e.objectImplementsClientObject && isPriorityQueue(q) && !isNil(evt.Object) {
+		clientObjectEvent := event.CreateEvent{Object: any(evt.Object).(client.Object)}
+		if isObjectUnchanged(clientObjectEvent) {
+			lowPriority = true
+		}
+	}
+	e.mapAndEnqueue(ctx, q, evt.Object, reqs, lowPriority)
 }
 
 // Update implements EventHandler.
@@ -90,9 +101,13 @@ func (e *enqueueRequestsFromMapFunc[object, request]) Update(
 	evt event.TypedUpdateEvent[object],
 	q workqueue.TypedRateLimitingInterface[request],
 ) {
+	var lowPriority bool
+	if e.objectImplementsClientObject && isPriorityQueue(q) && !isNil(evt.ObjectOld) && !isNil(evt.ObjectNew) {
+		lowPriority = any(evt.ObjectOld).(client.Object).GetResourceVersion() == any(evt.ObjectNew).(client.Object).GetResourceVersion()
+	}
 	reqs := map[request]empty{}
-	e.mapAndEnqueue(ctx, q, evt.ObjectOld, reqs)
-	e.mapAndEnqueue(ctx, q, evt.ObjectNew, reqs)
+	e.mapAndEnqueue(ctx, q, evt.ObjectOld, reqs, lowPriority)
+	e.mapAndEnqueue(ctx, q, evt.ObjectNew, reqs, lowPriority)
 }
 
 // Delete implements EventHandler.
@@ -102,7 +117,7 @@ func (e *enqueueRequestsFromMapFunc[object, request]) Delete(
 	q workqueue.TypedRateLimitingInterface[request],
 ) {
 	reqs := map[request]empty{}
-	e.mapAndEnqueue(ctx, q, evt.Object, reqs)
+	e.mapAndEnqueue(ctx, q, evt.Object, reqs, false)
 }
 
 // Generic implements EventHandler.
@@ -112,14 +127,26 @@ func (e *enqueueRequestsFromMapFunc[object, request]) Generic(
 	q workqueue.TypedRateLimitingInterface[request],
 ) {
 	reqs := map[request]empty{}
-	e.mapAndEnqueue(ctx, q, evt.Object, reqs)
+	e.mapAndEnqueue(ctx, q, evt.Object, reqs, false)
 }
 
-func (e *enqueueRequestsFromMapFunc[object, request]) mapAndEnqueue(ctx context.Context, q workqueue.TypedRateLimitingInterface[request], o object, reqs map[request]empty) {
+func (e *enqueueRequestsFromMapFunc[object, request]) mapAndEnqueue(
+	ctx context.Context,
+	q workqueue.TypedRateLimitingInterface[request],
+	o object,
+	reqs map[request]empty,
+	lowPriority bool,
+) {
 	for _, req := range e.toRequests(ctx, o) {
 		_, ok := reqs[req]
 		if !ok {
-			q.Add(req)
+			if lowPriority {
+				q.(priorityqueue.PriorityQueue[request]).AddWithOpts(priorityqueue.AddOpts{
+					Priority: LowPriority,
+				}, req)
+			} else {
+				q.Add(req)
+			}
 			reqs[req] = empty{}
 		}
 	}

pkg/handler/enqueue_owner.go

@@ -72,7 +72,7 @@ func TypedEnqueueRequestForOwner[object client.Object](scheme *runtime.Scheme, m
 	for _, opt := range opts {
 		opt(e)
 	}
-	return e
+	return WithLowPriorityWhenUnchanged(e)
 }
 
 // OnlyControllerOwner if provided will only look at the first OwnerReference with Controller: true.

pkg/handler/eventhandler.go

@@ -18,6 +18,7 @@ package handler
 
 import (
 	"context"
+	"reflect"
 	"time"
 
 	"k8s.io/client-go/util/workqueue"
@@ -108,10 +109,46 @@ type TypedFuncs[object any, request comparable] struct {
 	GenericFunc func(context.Context, event.TypedGenericEvent[object], workqueue.TypedRateLimitingInterface[request])
 }
 
+var typeForClientObject = reflect.TypeFor[client.Object]()
+
+func implementsClientObject[object any]() bool {
+	return reflect.TypeFor[object]().Implements(typeForClientObject)
+}
+
+func isPriorityQueue[request comparable](q workqueue.TypedRateLimitingInterface[request]) bool {
+	_, ok := q.(priorityqueue.PriorityQueue[request])
+	return ok
+}
+
 // Create implements EventHandler.
 func (h TypedFuncs[object, request]) Create(ctx context.Context, e event.TypedCreateEvent[object], q workqueue.TypedRateLimitingInterface[request]) {
 	if h.CreateFunc != nil {
-		h.CreateFunc(ctx, e, q)
+		if !implementsClientObject[object]() || !isPriorityQueue(q) || isNil(e.Object) {
+			h.CreateFunc(ctx, e, q)
+			return
+		}
+		wq := workqueueWithCustomAddFunc[request]{
+			TypedRateLimitingInterface: q,
+			// We already know that we have a priority queue, that event.Object implements
+			// client.Object and that its not nil
+			addFunc: func(item request, q workqueue.TypedRateLimitingInterface[request]) {
+				// We construct a new event typed to client.Object because isObjectUnchanged
+				// is a generic and hence has to know at compile time the type of the event
+				// it gets. We only figure that out at runtime though, but we know for sure
+				// that it implements client.Object at this point so we can hardcode the event
+				// type to that.
+				evt := event.CreateEvent{Object: any(e.Object).(client.Object)}
+				var priority int
+				if isObjectUnchanged(evt) {
+					priority = LowPriority
+				}
+				q.(priorityqueue.PriorityQueue[request]).AddWithOpts(
+					priorityqueue.AddOpts{Priority: priority},
+					item,
+				)
+			},
+		}
+		h.CreateFunc(ctx, e, wq)
 	}
 }
 
@@ -125,7 +162,27 @@ func (h TypedFuncs[object, request]) Delete(ctx context.Context, e event.TypedDe
 // Update implements EventHandler.
 func (h TypedFuncs[object, request]) Update(ctx context.Context, e event.TypedUpdateEvent[object], q workqueue.TypedRateLimitingInterface[request]) {
 	if h.UpdateFunc != nil {
-		h.UpdateFunc(ctx, e, q)
+		if !implementsClientObject[object]() || !isPriorityQueue(q) || isNil(e.ObjectOld) || isNil(e.ObjectNew) {
+			h.UpdateFunc(ctx, e, q)
+			return
+		}
+
+		wq := workqueueWithCustomAddFunc[request]{
+			TypedRateLimitingInterface: q,
+			// We already know that we have a priority queue, that event.ObjectOld and ObjectNew implement
+			// client.Object and that they are  not nil
+			addFunc: func(item request, q workqueue.TypedRateLimitingInterface[request]) {
+				var priority int
+				if any(e.ObjectOld).(client.Object).GetResourceVersion() == any(e.ObjectNew).(client.Object).GetResourceVersion() {
+					priority = LowPriority
+				}
+				q.(priorityqueue.PriorityQueue[request]).AddWithOpts(
+					priorityqueue.AddOpts{Priority: priority},
+					item,
+				)
+			},
+		}
+		h.UpdateFunc(ctx, e, wq)
 	}
 }
 
@@ -142,43 +199,10 @@ const LowPriority = -100
 // WithLowPriorityWhenUnchanged reduces the priority of events stemming from the initial listwatch or from a resync if
 // and only if a priorityqueue.PriorityQueue is used. If not, it does nothing.
 func WithLowPriorityWhenUnchanged[object client.Object, request comparable](u TypedEventHandler[object, request]) TypedEventHandler[object, request] {
+	// TypedFuncs already implements this so just wrap
 	return TypedFuncs[object, request]{
-		CreateFunc: func(ctx context.Context, tce event.TypedCreateEvent[object], trli workqueue.TypedRateLimitingInterface[request]) {
-			// Due to how the handlers are factored, we have to wrap the workqueue to be able
-			// to inject custom behavior.
-			u.Create(ctx, tce, workqueueWithCustomAddFunc[request]{
-				TypedRateLimitingInterface: trli,
-				addFunc: func(item request, q workqueue.TypedRateLimitingInterface[request]) {
-					priorityQueue, isPriorityQueue := q.(priorityqueue.PriorityQueue[request])
-					if !isPriorityQueue {
-						q.Add(item)
-						return
-					}
-					var priority int
-					if isObjectUnchanged(tce) {
-						priority = LowPriority
-					}
-					priorityQueue.AddWithOpts(priorityqueue.AddOpts{Priority: priority}, item)
-				},
-			})
-		},
-		UpdateFunc: func(ctx context.Context, tue event.TypedUpdateEvent[object], trli workqueue.TypedRateLimitingInterface[request]) {
-			u.Update(ctx, tue, workqueueWithCustomAddFunc[request]{
-				TypedRateLimitingInterface: trli,
-				addFunc: func(item request, q workqueue.TypedRateLimitingInterface[request]) {
-					priorityQueue, isPriorityQueue := q.(priorityqueue.PriorityQueue[request])
-					if !isPriorityQueue {
-						q.Add(item)
-						return
-					}
-					var priority int
-					if tue.ObjectOld.GetResourceVersion() == tue.ObjectNew.GetResourceVersion() {
-						priority = LowPriority
-					}
-					priorityQueue.AddWithOpts(priorityqueue.AddOpts{Priority: priority}, item)
-				},
-			})
-		},
+		CreateFunc:  u.Create,
+		UpdateFunc:  u.Update,
 		DeleteFunc:  u.Delete,
 		GenericFunc: u.Generic,
 	}
@@ -199,3 +223,35 @@ func (w workqueueWithCustomAddFunc[request]) Add(item request) {
 func isObjectUnchanged[object client.Object](e event.TypedCreateEvent[object]) bool {
 	return e.Object.GetCreationTimestamp().Time.Before(time.Now().Add(-time.Minute))
 }
+
+// addToQueueCreate adds the reconcile.Request to the priorityqueue in the handler
+// for Create requests if and only if the workqueue being used is of type priorityqueue.PriorityQueue[reconcile.Request]
+func addToQueueCreate[T client.Object, request comparable](q workqueue.TypedRateLimitingInterface[request], evt event.TypedCreateEvent[T], item request) {
+	priorityQueue, isPriorityQueue := q.(priorityqueue.PriorityQueue[request])
+	if !isPriorityQueue {
+		q.Add(item)
+		return
+	}
+
+	var priority int
+	if isObjectUnchanged(evt) {
+		priority = LowPriority
+	}
+	priorityQueue.AddWithOpts(priorityqueue.AddOpts{Priority: priority}, item)
+}
+
+// addToQueueUpdate adds the reconcile.Request to the priorityqueue in the handler
+// for Update requests if and only if the workqueue being used is of type priorityqueue.PriorityQueue[reconcile.Request]
+func addToQueueUpdate[T client.Object, request comparable](q workqueue.TypedRateLimitingInterface[request], evt event.TypedUpdateEvent[T], item request) {
+	priorityQueue, isPriorityQueue := q.(priorityqueue.PriorityQueue[request])
+	if !isPriorityQueue {
+		q.Add(item)
+		return
+	}
+
+	var priority int
+	if evt.ObjectOld.GetResourceVersion() == evt.ObjectNew.GetResourceVersion() {
+		priority = LowPriority
+	}
+	priorityQueue.AddWithOpts(priorityqueue.AddOpts{Priority: priority}, item)
+}