Prefactor: Every supports rate < 1/s

Author: timebertt

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

@@ -54,18 +54,33 @@ func (r *Every) AddToManager(mgr manager.Manager) error {
 		r.Client = mgr.GetClient()
 	}
 
+	initialDelay := time.Duration(0)
 	workers := defaultReconcileWorkers
 	if r.Workers > 0 {
 		workers = r.Workers
 	}
 
+	var rateLimiter workqueue.TypedRateLimiter[reconcile.Request] = &workqueue.TypedBucketRateLimiter[reconcile.Request]{
+		Limiter: rate.NewLimiter(r.Rate, int(r.Rate)),
+	}
+	if r.Rate < 1 {
+		// Special case for controllers running less frequent than every second:
+		// The token bucket rate limiter would not allow any events as burst is less than 1, so replace it with a custom
+		// rate limiter that always returns a constant delay.
+		// Also, delay the first request when starting the scenario.
+		every := time.Duration(1 / float64(r.Rate) * float64(time.Second))
+		rateLimiter = constantDelayRateLimiter(every)
+		initialDelay = every
+		workers = 1
+	}
+
 	return builder.ControllerManagedBy(mgr).
 		Named(r.Name).
 		WithOptions(controller.Options{
 			MaxConcurrentReconciles: workers,
-			RateLimiter:             &workqueue.TypedBucketRateLimiter[reconcile.Request]{Limiter: rate.NewLimiter(r.Rate, int(r.Rate))},
+			RateLimiter:             rateLimiter,
 		}).
-		WatchesRawSource(EmitN(workers, 0)).
+		WatchesRawSource(EmitN(workers, initialDelay)).
 		Complete(StopOnContextCanceled(r))
 }
 

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

@@ -166,3 +166,12 @@ func CreateClusterScopedOwnerObject(ctx context.Context, c client.Client, opts .
 
 	return ownerObject, metav1.NewControllerRef(ownerObject, rbacv1.SchemeGroupVersion.WithKind("ClusterRole")), nil
 }
+
+var _ workqueue.TypedRateLimiter[reconcile.Request] = constantDelayRateLimiter(0)
+
+// constantDelayRateLimiter delays all requests with a constant duration.
+type constantDelayRateLimiter time.Duration
+
+func (d constantDelayRateLimiter) When(reconcile.Request) time.Duration { return time.Duration(d) }
+func (d constantDelayRateLimiter) Forget(reconcile.Request)             {}
+func (d constantDelayRateLimiter) NumRequeues(reconcile.Request) int    { return 0 }