Drop ineffective ForEach.RateLimit

`ForEach` uses `RequeueAfter`, which bypasses the queue's rate limiter.
We are not interested in actually rate limiting the reconciler. We just want to ensure that we are not rate limited.
Hence, use an unlimited rate limiter.

webhosting-operator/pkg/experiment/generator/reconciler.go

@@ -33,6 +33,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/handler"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
+	"sigs.k8s.io/controller-runtime/pkg/ratelimiter"
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
 )
 
@@ -79,7 +80,6 @@ type ForEach[T client.Object] struct {
 	Name      string
 	Do        func(ctx context.Context, c client.Client, obj T) error
 	Every     time.Duration
-	RateLimit rate.Limit
 	Stop      time.Time
 
 	gvk schema.GroupVersionKind
@@ -91,11 +91,6 @@ func (r *ForEach[T]) AddToManager(mgr manager.Manager) error {
 		r.Client = mgr.GetClient()
 	}
 
-	rateLimiter := workqueue.DefaultControllerRateLimiter()
-	if r.RateLimit > 0 {
-		rateLimiter = &workqueue.BucketRateLimiter{Limiter: rate.NewLimiter(r.RateLimit, int(r.RateLimit))}
-	}
-
 	var t T
 	r.obj = reflect.New(reflect.TypeOf(t).Elem()).Interface().(T)
 
@@ -109,7 +104,7 @@ func (r *ForEach[T]) AddToManager(mgr manager.Manager) error {
 		Named(r.Name).
 		WithOptions(controller.Options{
 			MaxConcurrentReconciles: reconcileWorkers,
-			RateLimiter:             rateLimiter,
+			RateLimiter:             unlimitedRateLimiter(),
 		}).
 		Watches(
 			r.obj,
@@ -140,3 +135,9 @@ func (r *ForEach[T]) Reconcile(ctx context.Context, request reconcile.Request) (
 
 	return reconcile.Result{RequeueAfter: r.Every}, r.Do(ctx, r.Client, obj)
 }
+
+// unlimitedRateLimiter returns a RateLimiter that doesn't apply any rate limits to the workqueue.
+func unlimitedRateLimiter() ratelimiter.RateLimiter {
+	// if no limiter is given, MaxOfRateLimiter returns 0 for When and NumRequeues => unlimited
+	return &workqueue.MaxOfRateLimiter{}
+}

webhosting-operator/pkg/experiment/scenario/basic/basic.go

@@ -54,7 +54,7 @@ func (s *scenario) LongDescription() string {
 	return `The ` + ScenarioName + ` scenario combines several operations typical for a lively operator environment:
 - website creation: 8000 over 10m
 - website deletion: 600 over 10m
-- website reconciliation: max 100/s
+- website reconciliation: max 130/s
 - theme reconciliation: 1/m -> triggers reconciliation of all referencing websites
 `
 }
@@ -99,18 +99,18 @@ func (s *scenario) Run(ctx context.Context) error {
 		return fmt.Errorf("error adding website-deleter: %w", err)
 	}
 
-	// trigger individual reconciliations for website twice per minute, 100 per second at max
+	// trigger individual reconciliations for website once per minute
+	// => peaks at about 130 reconciliations per second
 	if err := (&generator.ForEach[*webhostingv1alpha1.Website]{
-		Name:      "website-mutator",
-		Do:        generator.ReconcileWebsite,
-		Every:     time.Minute,
-		RateLimit: rate.Limit(100),
+		Name:  "website-mutator",
+		Do:    generator.ReconcileWebsite,
+		Every: time.Minute,
 	}).AddToManager(s.Manager); err != nil {
 		return fmt.Errorf("error adding website-mutator: %w", err)
 	}
 
 	// update one theme every minute which causes all referencing websites to be reconciled
-	// => peeks at about 2.6 reconciliations per second on average
+	// => peaks at about 2.6 reconciliations per second on average
 	// (note: these reconciliation triggers occur in bursts of up to ~156)
 	if err := (&generator.Every{
 		Name: "theme-mutator",

webhosting-operator/pkg/experiment/scenario/reconcile/reconcile.go

@@ -21,8 +21,6 @@ import (
 	"fmt"
 	"time"
 
-	"golang.org/x/time/rate"
-
 	webhostingv1alpha1 "github.com/timebertt/kubernetes-controller-sharding/webhosting-operator/pkg/apis/webhosting/v1alpha1"
 	"github.com/timebertt/kubernetes-controller-sharding/webhosting-operator/pkg/experiment"
 	"github.com/timebertt/kubernetes-controller-sharding/webhosting-operator/pkg/experiment/generator"
@@ -76,10 +74,9 @@ func (s *scenario) Prepare(ctx context.Context) error {
 func (s *scenario) Run(ctx context.Context) error {
 	// trigger individual reconciliations for website every 10s
 	if err := (&generator.ForEach[*webhostingv1alpha1.Website]{
-		Name:      "website-reconcile-trigger",
-		Do:        generator.ReconcileWebsite,
-		Every:     10 * time.Second,
-		RateLimit: rate.Limit(1000),
+		Name:  "website-reconcile-trigger",
+		Do:    generator.ReconcileWebsite,
+		Every: 10 * time.Second,
 	}).AddToManager(s.Manager); err != nil {
 		return fmt.Errorf("error adding website-reconcile-trigger: %w", err)
 	}