Add new handler for metrics

changelog/fragments/enqueue-object-handler.yml

@@ -0,0 +1,7 @@
+entries:
+    - description: >
+       Add new handler for metrics which can be registered with controller-runtime registry, 
+       and wraps existing EnqueueResuestForObject, for both Ansible and Helm controllers.      
+
+      kind: "addition"
+      breaking: false

pkg/ansible/controller/controller.go

@@ -20,19 +20,19 @@ import (
 	"strings"
 	"time"
 
-	"github.com/operator-framework/operator-sdk/pkg/ansible/events"
-	"github.com/operator-framework/operator-sdk/pkg/ansible/runner"
-	"github.com/operator-framework/operator-sdk/pkg/predicate"
-
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"sigs.k8s.io/controller-runtime/pkg/controller"
-	crthandler "sigs.k8s.io/controller-runtime/pkg/handler"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
 	"sigs.k8s.io/controller-runtime/pkg/source"
+
+	"github.com/operator-framework/operator-sdk/pkg/ansible/events"
+	"github.com/operator-framework/operator-sdk/pkg/ansible/runner"
+	handler "github.com/operator-framework/operator-sdk/pkg/handler"
+	"github.com/operator-framework/operator-sdk/pkg/predicate"
 )
 
 var log = logf.Log.WithName("ansible-controller")
@@ -106,7 +106,7 @@ func Add(mgr manager.Manager, options Options) *controller.Controller {
 		os.Exit(1)
 	}
 
-	if err := c.Watch(&source.Kind{Type: u}, &crthandler.EnqueueRequestForObject{},
+	if err := c.Watch(&source.Kind{Type: u}, &handler.InstrumentedEnqueueRequestForObject{},
 		predicate.GenerationChangedPredicate{}, filterPredicate); err != nil {
 		log.Error(err, "")
 		os.Exit(1)

pkg/handler/instrumented_enqueue_object.go

@@ -0,0 +1,81 @@
+// Copyright 2020 The Operator-SDK Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package handler
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/util/workqueue"
+	"sigs.k8s.io/controller-runtime/pkg/event"
+	"sigs.k8s.io/controller-runtime/pkg/handler"
+
+	"github.com/operator-framework/operator-sdk/pkg/handler/internal/metrics"
+)
+
+// InstrumentedEnqueueRequestForObject wraps controller-runtime handler for "EnqueueRequestForObject", and
+// sets up primary resource metrics on event handlers. The main objective of this handler is to set
+// prometheues metrics when create/update/delete events occur. These metrics contain below information on resource.
+//
+// resource_created_at_seconds{"name", "namespace", "group", "version", "kind"}
+//
+// '&handler.InstrumentedEnqueueRequestForObject{}' is used to call the handler.
+type InstrumentedEnqueueRequestForObject struct {
+	handler.EnqueueRequestForObject
+}
+
+// Create implements EventHandler, and creates the metrics.
+func (h InstrumentedEnqueueRequestForObject) Create(e event.CreateEvent, q workqueue.RateLimitingInterface) {
+	setResourceMetric(e.Meta, e.Object)
+	h.EnqueueRequestForObject.Create(e, q)
+}
+
+// Update implements EventHandler, and updates the metrics.
+func (h InstrumentedEnqueueRequestForObject) Update(e event.UpdateEvent, q workqueue.RateLimitingInterface) {
+	setResourceMetric(e.MetaOld, e.ObjectOld)
+	setResourceMetric(e.MetaNew, e.ObjectNew)
+
+	h.EnqueueRequestForObject.Update(e, q)
+}
+
+// Delete implements EventHandler, and deletes metrics.
+func (h InstrumentedEnqueueRequestForObject) Delete(e event.DeleteEvent, q workqueue.RateLimitingInterface) {
+	deleteResourceMetric(e.Meta, e.Object)
+	h.EnqueueRequestForObject.Delete(e, q)
+}
+
+func setResourceMetric(metadata metav1.Object, obj runtime.Object) {
+	if metadata != nil && obj != nil {
+		labels := getResourceLabels(metadata, obj)
+		m, _ := metrics.ResourceCreatedAt.GetMetricWith(labels)
+		m.Set(float64(metadata.GetCreationTimestamp().UTC().Unix()))
+	}
+}
+
+func deleteResourceMetric(metadata metav1.Object, obj runtime.Object) {
+	if metadata != nil && obj != nil {
+		labels := getResourceLabels(metadata, obj)
+		_ = metrics.ResourceCreatedAt.Delete(labels)
+	}
+}
+
+func getResourceLabels(metadata metav1.Object, obj runtime.Object) map[string]string {
+	return map[string]string{
+		"name":      metadata.GetName(),
+		"namespace": metadata.GetNamespace(),
+		"group":     obj.GetObjectKind().GroupVersionKind().Group,
+		"version":   obj.GetObjectKind().GroupVersionKind().Version,
+		"kind":      obj.GetObjectKind().GroupVersionKind().Kind,
+	}
+}

pkg/handler/internal/metrics/metrics.go

@@ -0,0 +1,33 @@
+// Copyright 2020 The Operator-SDK Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+// ResourceCreatedAt creates new prometheus metrics for primary resource,
+// with information {"name", "namespace", "group", "version", "kind"}
+var ResourceCreatedAt = prometheus.NewGaugeVec(prometheus.GaugeOpts{
+	Name: "resource_created_at_seconds",
+	Help: "Timestamp at which a resource was created",
+}, []string{"name", "namespace", "group", "version", "kind"})
+
+func init() {
+	metrics.Registry.MustRegister(
+		ResourceCreatedAt,
+	)
+}

pkg/helm/controller/controller.go

@@ -79,7 +79,7 @@ func Add(mgr manager.Manager, options WatchOptions) error {
 
 	o := &unstructured.Unstructured{}
 	o.SetGroupVersionKind(options.GVK)
-	if err := c.Watch(&source.Kind{Type: o}, &crthandler.EnqueueRequestForObject{}); err != nil {
+	if err := c.Watch(&source.Kind{Type: o}, &handler.InstrumentedEnqueueRequestForObject{}); err != nil {
 		return err
 	}