helmrepo: Delete cache metrics on object delete

The cache event metrics for a given helmrepo continues to be exported
even after the object is deleted.

This change deletes the cache event metrics when the object is deleted.

Signed-off-by: Sunny <darkowlzz@protonmail.com>

internal/cache/metrics.go

@@ -67,6 +67,11 @@ func (r *CacheRecorder) IncCacheEvents(event, name, namespace string) {
 	r.cacheEventsCounter.WithLabelValues(event, name, namespace).Inc()
 }
 
+// DeleteCacheEvent deletes the cache event metric.
+func (r *CacheRecorder) DeleteCacheEvent(event, name, namespace string) {
+	r.cacheEventsCounter.DeleteLabelValues(event, name, namespace)
+}
+
 // MustMakeMetrics creates a new CacheRecorder, and registers the metrics collectors in the controller-runtime metrics registry.
 func MustMakeMetrics() *CacheRecorder {
 	r := NewCacheRecorder()

internal/controller/helmrepository_controller.go

@@ -618,6 +618,10 @@ func (r *HelmRepositoryReconciler) reconcileDelete(ctx context.Context, obj *hel
 		controllerutil.RemoveFinalizer(obj, sourcev1.SourceFinalizer)
 	}
 
+	// Delete cache metrics.
+	r.DeleteCacheEvent(cache.CacheEventTypeHit, obj.Name, obj.Namespace)
+	r.DeleteCacheEvent(cache.CacheEventTypeMiss, obj.Name, obj.Namespace)
+
 	// Stop reconciliation as the object is being deleted
 	return sreconcile.ResultEmpty, nil
 }