feat(controllers): export cached/uncached images metrics

Author: plaffitt

controllers/cachedimage_controller.go

@@ -65,6 +65,7 @@ func (r *CachedImageReconciler) Reconcile(ctx context.Context, req ctrl.Request)
 				return ctrl.Result{}, err
 			}
 			r.Recorder.Eventf(&cachedImage, "Normal", "CleanedUp", "Image %s successfully removed from cache", cachedImage.Spec.SourceImage)
+			IncImageRemovedFromCache()
 
 			log.Info("removing finalizer")
 			controllerutil.RemoveFinalizer(&cachedImage, finalizerName)
@@ -123,6 +124,7 @@ func (r *CachedImageReconciler) Reconcile(ctx context.Context, req ctrl.Request)
 		} else {
 			log.Info("image cached")
 			r.Recorder.Eventf(&cachedImage, "Normal", "Cached", "Successfully cached image %s", cachedImage.Spec.SourceImage)
+			IncImagePutInCache()
 			if err := r.Get(ctx, req.NamespacedName, &cachedImage); err != nil {
 				return ctrl.Result{}, client.IgnoreNotFound(err)
 			}

controllers/collector.go

@@ -0,0 +1,37 @@
+package controllers
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+var (
+	imagePutInCache = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name: "kube_image_keeper_image_put_in_cache",
+			Help: "Number of images put in cache successfully",
+		},
+	)
+	imageRemovedFromCache = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name: "kube_image_keeper_image_removed_from_cache",
+			Help: "Number of images removed from cache successfully",
+		},
+	)
+)
+
+func init() {
+	// Register custom metrics with the global prometheus registry
+	metrics.Registry.MustRegister(
+		imagePutInCache,
+		imageRemovedFromCache,
+	)
+}
+
+func IncImagePutInCache() {
+	imagePutInCache.Inc()
+}
+
+func IncImageRemovedFromCache() {
+	imageRemovedFromCache.Inc()
+}