Clear scalers cache correctly both in Operator and Metrics Server

CHANGELOG.md

@@ -31,7 +31,7 @@
 ### Improvements
 
 - **General:** `keda-operator` Cluster Role: add `list` and `watch` access to service accounts ([#2406](https://github.com/kedacore/keda/pull/2406))|([#2410](https://github.com/kedacore/keda/pull/2410))
-- **General:** Delete the cache entry when a ScaledObject is deleted ([#2408](https://github.com/kedacore/keda/pull/2408))
+- **General:** Delete the cache entry when a ScaledObject is deleted ([#2564](https://github.com/kedacore/keda/pull/2564))
 - **General:** Sign KEDA images published on GitHub Container Registry ([#2501](https://github.com/kedacore/keda/pull/2501))|([#2502](https://github.com/kedacore/keda/pull/2502))|([#2504](https://github.com/kedacore/keda/pull/2504))
 - **Azure Pipelines Scaler:** support `poolName` or `poolID` validation ([#2370](https://github.com/kedacore/keda/pull/2370))
 - **Graphite Scaler:** use the latest datapoint returned, not the earliest ([#2365](https://github.com/kedacore/keda/pull/2365))

controllers/keda/metrics_adapter_controller.go

@@ -57,9 +57,12 @@ func (r *MetricsScaledObjectReconciler) Reconcile(ctx context.Context, req ctrl.
 			// Request object not found, could have been deleted after reconcile request.
 			// Owned objects are automatically garbage collected. For additional cleanup logic use finalizers.
 			// Return and don't requeue
-
-			r.removeFromCache(req.NamespacedName.String())
-			return ctrl.Result{}, nil
+			err := r.ScaleHandler.ClearScalersCache(ctx, scaledObject)
+			if err != nil {
+				reqLogger.Error(err, "error clearing scalers cache")
+			}
+			r.removeFromMetricsCache(req.NamespacedName.String())
+			return ctrl.Result{}, err
 		}
 		// Error reading the object - requeue the request.
 		reqLogger.Error(err, "Failed to get ScaledObject")
@@ -70,8 +73,12 @@ func (r *MetricsScaledObjectReconciler) Reconcile(ctx context.Context, req ctrl.
 	// indicated by the deletion timestamp being set.
 	// This depends on the preexisting finalizer setup in ScaledObjectController.
 	if scaledObject.GetDeletionTimestamp() != nil {
-		r.removeFromCache(req.NamespacedName.String())
-		return ctrl.Result{}, nil
+		err := r.ScaleHandler.ClearScalersCache(ctx, scaledObject)
+		if err != nil {
+			reqLogger.Error(err, "error clearing scalers cache")
+		}
+		r.removeFromMetricsCache(req.NamespacedName.String())
+		return ctrl.Result{}, err
 	}
 
 	reqLogger.V(1).Info("Reconciling ScaledObject", "externalMetricNames", scaledObject.Status.ExternalMetricNames)
@@ -82,8 +89,11 @@ func (r *MetricsScaledObjectReconciler) Reconcile(ctx context.Context, req ctrl.
 	}
 
 	r.addToMetricsCache(req.NamespacedName.String(), scaledObject.Status.ExternalMetricNames)
-	r.ScaleHandler.ClearScalersCache(ctx, req.Name, req.Namespace)
-	return ctrl.Result{}, nil
+	err = r.ScaleHandler.ClearScalersCache(ctx, scaledObject)
+	if err != nil {
+		reqLogger.Error(err, "error clearing scalers cache")
+	}
+	return ctrl.Result{}, err
 }
 
 func (r *MetricsScaledObjectReconciler) SetupWithManager(mgr ctrl.Manager, options controller.Options) error {
@@ -105,7 +115,7 @@ func (r *MetricsScaledObjectReconciler) addToMetricsCache(namespacedName string,
 	(*r.ExternalMetricsInfo) = extMetrics
 }
 
-func (r *MetricsScaledObjectReconciler) removeFromCache(namespacedName string) {
+func (r *MetricsScaledObjectReconciler) removeFromMetricsCache(namespacedName string) {
 	scaledObjectsMetricsLock.Lock()
 	defer scaledObjectsMetricsLock.Unlock()
 	delete(scaledObjectsMetrics, namespacedName)

pkg/provider/provider.go

@@ -77,7 +77,7 @@ func (p *KedaProvider) GetExternalMetric(ctx context.Context, namespace string,
 	logger.V(1).Info("KEDA Metrics Server received request for external metrics", "namespace", namespace, "metric name", info.Metric, "metricSelector", metricSelector.String())
 	selector, err := labels.ConvertSelectorToLabelsMap(metricSelector.String())
 	if err != nil {
-		logger.Error(err, "Error converting Selector to Labels Map")
+		logger.Error(err, "error converting Selector to Labels Map")
 		return nil, err
 	}
 
@@ -96,16 +96,15 @@ func (p *KedaProvider) GetExternalMetric(ctx context.Context, namespace string,
 
 	scaledObject := &scaledObjects.Items[0]
 	var matchingMetrics []external_metrics.ExternalMetricValue
-	cache, err := p.scaleHandler.GetScalersCache(ctx, scaledObject)
-	if err != nil {
-		return nil, err
-	}
 
+	cache, err := p.scaleHandler.GetScalersCache(ctx, scaledObject)
 	metricsServer.RecordScalerObjectError(scaledObject.Namespace, scaledObject.Name, err)
 	if err != nil {
 		return nil, fmt.Errorf("error when getting scalers %s", err)
 	}
 
+	scalerError := false
+
 	for scalerIndex, scaler := range cache.GetScalers() {
 		metricSpecs := scaler.GetMetricSpecForScaling(ctx)
 		scalerName := strings.Replace(fmt.Sprintf("%T", scaler), "*scalers.", "", 1)
@@ -121,6 +120,7 @@ func (p *KedaProvider) GetExternalMetric(ctx context.Context, namespace string,
 				metrics, err = p.getMetricsWithFallback(ctx, metrics, err, info.Metric, scaledObject, metricSpec)
 
 				if err != nil {
+					scalerError = true
 					logger.Error(err, "error getting metric for scaler", "scaledObject.Namespace", scaledObject.Namespace, "scaledObject.Name", scaledObject.Name, "scaler", scaler)
 				} else {
 					for _, metric := range metrics {
@@ -134,8 +134,18 @@ func (p *KedaProvider) GetExternalMetric(ctx context.Context, namespace string,
 		}
 	}
 
+	// invalidate the cache for the ScaledObject, if we hit an error in any scaler
+	// in this case we try to build all scalers (and resolve all secrets/creds) again in the next call
+	if scalerError {
+		err := p.scaleHandler.ClearScalersCache(ctx, scaledObject)
+		if err != nil {
+			logger.Error(err, "error clearing scalers cache")
+		}
+		logger.V(1).Info("scaler error encountered, clearing scaler cache")
+	}
+
 	if len(matchingMetrics) == 0 {
-		return nil, fmt.Errorf("No matching metrics found for " + info.Metric)
+		return nil, fmt.Errorf("no matching metrics found for " + info.Metric)
 	}
 
 	return &external_metrics.ExternalMetricValueList{
@@ -164,7 +174,7 @@ func (p *KedaProvider) GetMetricByName(ctx context.Context, name types.Namespace
 // GetMetricBySelector fetches a particular metric for a set of objects matching
 // the given label selector.  The namespace will be empty if the metric is root-scoped.
 func (p *KedaProvider) GetMetricBySelector(ctx context.Context, namespace string, selector labels.Selector, info provider.CustomMetricInfo, metricSelector labels.Selector) (*custom_metrics.MetricValueList, error) {
-	logger.V(0).Info("Received request for custom metric", "groupresource", info.GroupResource.String(), "namespace", namespace, "metric name", info.Metric, "selector", selector.String())
+	logger.V(0).Info("Received request for custom metric, which is not supported by this adapter", "groupresource", info.GroupResource.String(), "namespace", namespace, "metric name", info.Metric, "selector", selector.String())
 	return nil, apiErrors.NewServiceUnavailable("not implemented yet")
 }
 

pkg/scaling/scale_handler.go

@@ -19,7 +19,6 @@ package scaling
 import (
 	"context"
 	"fmt"
-	"strings"
 	"sync"
 	"time"
 
@@ -46,7 +45,7 @@ type ScaleHandler interface {
 	HandleScalableObject(ctx context.Context, scalableObject interface{}) error
 	DeleteScalableObject(ctx context.Context, scalableObject interface{}) error
 	GetScalersCache(ctx context.Context, scalableObject interface{}) (*cache.ScalersCache, error)
-	ClearScalersCache(ctx context.Context, name, namespace string)
+	ClearScalersCache(ctx context.Context, scalableObject interface{}) error
 }
 
 type scaleHandler struct {
@@ -126,7 +125,10 @@ func (h *scaleHandler) DeleteScalableObject(ctx context.Context, scalableObject
 			cancel()
 		}
 		h.scaleLoopContexts.Delete(key)
-		delete(h.scalerCaches, key)
+		err := h.ClearScalersCache(ctx, scalableObject)
+		if err != nil {
+			h.logger.Error(err, "error clearing scalers cache")
+		}
 		h.recorder.Event(withTriggers, corev1.EventTypeNormal, eventreason.KEDAScalersStopped, "Stopped scalers watch")
 	} else {
 		h.logger.V(1).Info("ScaleObject was not found in controller cache", "key", key)
@@ -151,7 +153,10 @@ func (h *scaleHandler) startScaleLoop(ctx context.Context, withTriggers *kedav1a
 			tmr.Stop()
 		case <-ctx.Done():
 			logger.V(1).Info("Context canceled")
-			h.ClearScalersCache(ctx, withTriggers.Name, withTriggers.Namespace)
+			err := h.ClearScalersCache(ctx, scalableObject)
+			if err != nil {
+				logger.Error(err, "error clearing scalers cache")
+			}
 			tmr.Stop()
 			return
 		}
@@ -201,15 +206,23 @@ func (h *scaleHandler) GetScalersCache(ctx context.Context, scalableObject inter
 	return h.scalerCaches[key], nil
 }
 
-func (h *scaleHandler) ClearScalersCache(ctx context.Context, name, namespace string) {
+func (h *scaleHandler) ClearScalersCache(ctx context.Context, scalableObject interface{}) error {
+	withTriggers, err := asDuckWithTriggers(scalableObject)
+	if err != nil {
+		return err
+	}
+
+	key := withTriggers.GenerateIdenitifier()
+
 	h.lock.Lock()
 	defer h.lock.Unlock()
 
-	key := strings.ToLower(fmt.Sprintf("%s.%s", name, namespace))
 	if cache, ok := h.scalerCaches[key]; ok {
 		cache.Close(ctx)
 		delete(h.scalerCaches, key)
 	}
+
+	return nil
 }
 
 func (h *scaleHandler) startPushScalers(ctx context.Context, withTriggers *kedav1alpha1.WithTriggers, scalableObject interface{}, scalingMutex sync.Locker) {