Metrics Adapter: use gRPC connection to get metrics from Operator

Signed-off-by: Zbynek Roubalik <[email protected]>

CREATE-NEW-SCALER.md

@@ -40,7 +40,6 @@ KEDA works in conjunction with Kubernetes Horizontal Pod Autoscaler (HPA). When
 
 The return type of this function is `MetricSpec`, but in KEDA's case we will mostly write External metrics. So the property that should be filled is `ExternalMetricSource`, where the:
 - `MetricName`: the name of our metric we are returning in this scaler. The name should be unique, to allow setting multiple (even the same type) Triggers in one ScaledObject, but each function call should return the same name.
-- `MetricSelector`: //TODO
 - `TargetValue`: is the value of the metric we want to reach at all times at all costs. As long as the current metric doesn't match TargetValue, HPA will increase the number of the pods until it reaches the maximum number of pods allowed to scale to.
 - `TargetAverageValue`: the value of the metric for which we require one pod to handle. e.g. if we are have a scaler based on the length of a message queue, and we specificy 10 for `TargetAverageValue`, we are saying that each pod will handle 10 messages. So if the length of the queue becomes 30, we expect that we have 3 pods in our cluster. (`TargetAverage` and `TargetValue` are mutually exclusive)
 

Makefile

@@ -151,6 +151,7 @@ clientset-generate: ## Generate client-go clientset, listers and informers.
 proto-gen: protoc-gen ## Generate Liiklus, ExternalScaler and MetricsService proto
 	PATH=$(LOCALBIN):$(PATH) protoc -I vendor --proto_path=hack LiiklusService.proto --go_out=pkg/scalers/liiklus --go-grpc_out=pkg/scalers/liiklus
 	PATH=$(LOCALBIN):$(PATH) protoc -I vendor --proto_path=pkg/scalers/externalscaler externalscaler.proto --go_out=pkg/scalers/externalscaler --go-grpc_out=pkg/scalers/externalscaler
+	PATH=$(LOCALBIN):$(PATH) protoc -I vendor --proto_path=pkg/metricsservice/api metrics.proto --go_out=pkg/metricsservice/api --go-grpc_out=pkg/metricsservice/api
 
 .PHONY: mockgen-gen
 mockgen-gen: mockgen pkg/mock/mock_scaling/mock_interface.go pkg/mock/mock_scaler/mock_scaler.go pkg/mock/mock_scale/mock_interfaces.go pkg/mock/mock_client/mock_interfaces.go pkg/scalers/liiklus/mocks/mock_liiklus.go

adapter/main.go

@@ -44,6 +44,7 @@ import (
 	generatedopenapi "github.com/kedacore/keda/v2/adapter/generated/openapi"
 	kedav1alpha1 "github.com/kedacore/keda/v2/apis/keda/v1alpha1"
 	kedacontrollers "github.com/kedacore/keda/v2/controllers/keda"
+	"github.com/kedacore/keda/v2/pkg/metricsservice"
 	"github.com/kedacore/keda/v2/pkg/prommetrics"
 	kedaprovider "github.com/kedacore/keda/v2/pkg/provider"
 	"github.com/kedacore/keda/v2/pkg/scaling"
@@ -138,13 +139,20 @@ func (a *Adapter) makeProvider(ctx context.Context, globalHTTPTimeout time.Durat
 
 	prometheusServer := &prommetrics.PrometheusMetricServer{}
 	go func() { prometheusServer.NewServer(fmt.Sprintf(":%v", prometheusMetricsPort), prometheusMetricsPath) }()
-	stopCh := make(chan struct{})
 
-	if err := runScaledObjectController(ctx, mgr, handler, logger, externalMetricsInfo, externalMetricsInfoLock, maxConcurrentReconciles, stopCh); err != nil {
+	grpcServerAddr := "keda-operator.keda.svc.cluster.local:9666"
+	logger.Info("Connecting Metrics Service gRPC client to the server", "address", grpcServerAddr)
+	grpcClient, err := metricsservice.NewGrpcClient(grpcServerAddr)
+	if err != nil {
+		logger.Error(err, "error connecting Metrics Service gRPC client to the server", "address", grpcServerAddr)
 		return nil, nil, err
 	}
 
-	return kedaprovider.NewProvider(ctx, logger, handler, mgr.GetClient(), namespace, externalMetricsInfo, externalMetricsInfoLock), stopCh, nil
+	stopCh := make(chan struct{})
+	if err := runScaledObjectController(ctx, mgr, handler, logger, externalMetricsInfo, externalMetricsInfoLock, maxConcurrentReconciles, stopCh); err != nil {
+		return nil, nil, err
+	}
+	return kedaprovider.NewProvider(ctx, logger, handler, mgr.GetClient(), *grpcClient, namespace, externalMetricsInfo, externalMetricsInfoLock), stopCh, nil
 }
 
 func runScaledObjectController(ctx context.Context, mgr manager.Manager, scaleHandler scaling.ScaleHandler, logger logr.Logger, externalMetricsInfo *[]provider.ExternalMetricInfo, externalMetricsInfoLock *sync.RWMutex, maxConcurrentReconciles int, stopCh chan<- struct{}) error {

apis/keda/v1alpha1/indentifier.go

@@ -0,0 +1,27 @@
+/*
+Copyright 2022 The KEDA 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 v1alpha1
+
+import (
+	"fmt"
+	"strings"
+)
+
+// GenerateIdenitifier returns identifier for the object in for "kind.namespace.name"
+func GenerateIdenitifier(kind, name, namespace string) string {
+	return strings.ToLower(fmt.Sprintf("%s.%s.%s", kind, namespace, name))
+}

apis/keda/v1alpha1/withtriggers_types.go

@@ -17,8 +17,6 @@ limitations under the License.
 package v1alpha1
 
 import (
-	"fmt"
-	"strings"
 	"time"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -91,5 +89,5 @@ func (t *WithTriggers) GetPollingInterval() time.Duration {
 
 // GenerateIdenitifier returns identifier for the object in for "kind.namespace.name"
 func (t *WithTriggers) GenerateIdenitifier() string {
-	return strings.ToLower(fmt.Sprintf("%s.%s.%s", t.Kind, t.Namespace, t.Name))
+	return GenerateIdenitifier(t.Kind, t.Namespace, t.Name)
 }

config/manager/kustomization.yaml

@@ -1,9 +1,10 @@
 resources:
 - manager.yaml
+- service.yaml
 
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 images:
 - name: ghcr.io/kedacore/keda
-  newName: ghcr.io/kedacore/keda
+  newName: quay.io/zroubalik/keda
   newTag: main

config/manager/service.yaml

@@ -0,0 +1,17 @@
+---
+apiVersion: v1
+kind: Service
+metadata:
+  labels:
+    app.kubernetes.io/name: keda-operator
+    app.kubernetes.io/version: latest
+    app.kubernetes.io/part-of: keda-operator
+  name: keda-operator
+  namespace: keda
+spec:
+  ports:
+  - name: metricsservice
+    port: 9666
+    targetPort: 9666
+  selector:
+    app: keda-operator

config/metrics-server/kustomization.yaml

@@ -10,5 +10,5 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 images:
 - name: ghcr.io/kedacore/keda-metrics-apiserver
-  newName: ghcr.io/kedacore/keda-metrics-apiserver
+  newName: quay.io/zroubalik/keda-metrics-apiserver
   newTag: main

controllers/keda/hpa.go

@@ -197,7 +197,7 @@ func (r *ScaledObjectReconciler) getScaledObjectMetricSpecs(ctx context.Context,
 	var externalMetricNames []string
 	var resourceMetricNames []string
 
-	cache, err := r.scaleHandler.GetScalersCache(ctx, scaledObject)
+	cache, err := r.ScaleHandler.GetScalersCache(ctx, scaledObject)
 	if err != nil {
 		logger.Error(err, "Error getting scalers")
 		return nil, err

controllers/keda/hpa_test.go

@@ -54,7 +54,7 @@ var _ = Describe("hpa", func() {
 		logger = logr.Discard()
 		reconciler = ScaledObjectReconciler{
 			Client:       client,
-			scaleHandler: scaleHandler,
+			ScaleHandler: scaleHandler,
 		}
 	})
 

controllers/keda/scaledobject_controller.go

@@ -20,7 +20,6 @@ import (
 	"context"
 	"fmt"
 	"sync"
-	"time"
 
 	"github.com/go-logr/logr"
 	autoscalingv1 "k8s.io/api/autoscaling/v1"
@@ -32,8 +31,6 @@ import (
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/types"
-	"k8s.io/client-go/discovery"
-	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/scale"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/record"
@@ -42,7 +39,6 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller"
 	"sigs.k8s.io/controller-runtime/pkg/log"
-	"sigs.k8s.io/controller-runtime/pkg/manager"
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 
 	kedav1alpha1 "github.com/kedacore/keda/v2/apis/keda/v1alpha1"
@@ -65,16 +61,14 @@ import (
 
 // ScaledObjectReconciler reconciles a ScaledObject object
 type ScaledObjectReconciler struct {
-	Client            client.Client
-	Scheme            *runtime.Scheme
-	GlobalHTTPTimeout time.Duration
-	Recorder          record.EventRecorder
+	Client       client.Client
+	Scheme       *runtime.Scheme
+	Recorder     record.EventRecorder
+	ScaleClient  scale.ScalesGetter
+	ScaleHandler scaling.ScaleHandler
 
-	scaleClient              scale.ScalesGetter
 	restMapper               meta.RESTMapper
 	scaledObjectsGenerations *sync.Map
-	scaleHandler             scaling.ScaleHandler
-	kubeVersion              kedautil.K8sVersion
 }
 
 type scaledObjectMetricsData struct {
@@ -102,33 +96,12 @@ func init() {
 
 // SetupWithManager initializes the ScaledObjectReconciler instance and starts a new controller managed by the passed Manager instance.
 func (r *ScaledObjectReconciler) SetupWithManager(mgr ctrl.Manager, options controller.Options) error {
-	setupLog := log.Log.WithName("setup")
-
-	// create Discovery clientset
-	// TODO If we need to increase the QPS of scaling API calls, copy and tweak this RESTConfig.
-	clientset, err := discovery.NewDiscoveryClientForConfig(mgr.GetConfig())
-	if err != nil {
-		setupLog.Error(err, "Not able to create Discovery clientset")
-		return err
-	}
-
-	// Find out Kubernetes version
-	version, err := clientset.ServerVersion()
-	if err == nil {
-		r.kubeVersion = kedautil.NewK8sVersion(version)
-		setupLog.Info("Running on Kubernetes "+r.kubeVersion.PrettyVersion, "version", version)
-	} else {
-		setupLog.Error(err, "Not able to get Kubernetes version")
-	}
-
-	// Create Scale Client
-	scaleClient := initScaleClient(mgr, clientset)
-	r.scaleClient = scaleClient
-
-	// Init the rest of ScaledObjectReconciler
 	r.restMapper = mgr.GetRESTMapper()
 	r.scaledObjectsGenerations = &sync.Map{}
-	r.scaleHandler = scaling.NewScaleHandler(mgr.GetClient(), r.scaleClient, mgr.GetScheme(), r.GlobalHTTPTimeout, r.Recorder)
+
+	if r.ScaleHandler == nil {
+		return fmt.Errorf("ScaleHandler is not initialized")
+	}
 
 	// Start controller
 	return ctrl.NewControllerManagedBy(mgr).
@@ -147,15 +120,6 @@ func (r *ScaledObjectReconciler) SetupWithManager(mgr ctrl.Manager, options cont
 		Complete(r)
 }
 
-func initScaleClient(mgr manager.Manager, clientset *discovery.DiscoveryClient) scale.ScalesGetter {
-	scaleKindResolver := scale.NewDiscoveryScaleKindResolver(clientset)
-	return scale.New(
-		clientset.RESTClient(), mgr.GetRESTMapper(),
-		dynamic.LegacyAPIPathResolverFunc,
-		scaleKindResolver,
-	)
-}
-
 // Reconcile performs reconciliation on the identified ScaledObject resource based on the request information passed, returns the result and an error (if any).
 func (r *ScaledObjectReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
 	reqLogger := log.FromContext(ctx)
@@ -319,7 +283,7 @@ func (r *ScaledObjectReconciler) checkTargetResourceIsScalable(ctx context.Conte
 		// not cached, let's try to detect /scale subresource
 		// also rechecks when we need to update the status.
 		var errScale error
-		scale, errScale = (r.scaleClient).Scales(scaledObject.Namespace).Get(ctx, gr, scaledObject.Spec.ScaleTargetRef.Name, metav1.GetOptions{})
+		scale, errScale = (r.ScaleClient).Scales(scaledObject.Namespace).Get(ctx, gr, scaledObject.Spec.ScaleTargetRef.Name, metav1.GetOptions{})
 		if errScale != nil {
 			// not able to get /scale subresource -> let's check if the resource even exist in the cluster
 			unstruct := &unstructured.Unstructured{}
@@ -467,7 +431,7 @@ func (r *ScaledObjectReconciler) requestScaleLoop(ctx context.Context, logger lo
 		return err
 	}
 
-	if err = r.scaleHandler.HandleScalableObject(ctx, scaledObject); err != nil {
+	if err = r.ScaleHandler.HandleScalableObject(ctx, scaledObject); err != nil {
 		return err
 	}
 
@@ -485,7 +449,7 @@ func (r *ScaledObjectReconciler) stopScaleLoop(ctx context.Context, logger logr.
 		return err
 	}
 
-	if err := r.scaleHandler.DeleteScalableObject(ctx, scaledObject); err != nil {
+	if err := r.ScaleHandler.DeleteScalableObject(ctx, scaledObject); err != nil {
 		return err
 	}
 	// delete ScaledObject's current Generation

controllers/keda/scaledobject_controller_test.go

@@ -76,7 +76,7 @@ var _ = Describe("ScaledObjectController", func() {
 			mockStatusWriter = mock_client.NewMockStatusWriter(ctrl)
 
 			metricNameTestReconciler = ScaledObjectReconciler{
-				scaleHandler: mockScaleHandler,
+				ScaleHandler: mockScaleHandler,
 				Client:       mockClient,
 			}
 		})

controllers/keda/scaledobject_finalizer.go

@@ -53,7 +53,7 @@ func (r *ScaledObjectReconciler) finalizeScaledObject(ctx context.Context, logge
 				logger.V(1).Info("Failed to restore scaleTarget's replica count back to the original, the scaling haven't been probably initialized yet.")
 			} else {
 				// We have enough information about the scaleTarget, let's proceed.
-				scale, err := r.scaleClient.Scales(scaledObject.Namespace).Get(ctx, scaledObject.Status.ScaleTargetGVKR.GroupResource(), scaledObject.Spec.ScaleTargetRef.Name, metav1.GetOptions{})
+				scale, err := r.ScaleClient.Scales(scaledObject.Namespace).Get(ctx, scaledObject.Status.ScaleTargetGVKR.GroupResource(), scaledObject.Spec.ScaleTargetRef.Name, metav1.GetOptions{})
 				if err != nil {
 					if errors.IsNotFound(err) {
 						logger.V(1).Info("Failed to get scaleTarget's scale status, because it was probably deleted", "error", err)
@@ -62,7 +62,7 @@ func (r *ScaledObjectReconciler) finalizeScaledObject(ctx context.Context, logge
 					}
 				} else {
 					scale.Spec.Replicas = *scaledObject.Status.OriginalReplicaCount
-					_, err = r.scaleClient.Scales(scaledObject.Namespace).Update(ctx, scaledObject.Status.ScaleTargetGVKR.GroupResource(), scale, metav1.UpdateOptions{})
+					_, err = r.ScaleClient.Scales(scaledObject.Namespace).Update(ctx, scaledObject.Status.ScaleTargetGVKR.GroupResource(), scale, metav1.UpdateOptions{})
 					if err != nil {
 						logger.Error(err, "Failed to restore scaleTarget's replica count back to the original", "finalizer", scaledObjectFinalizer)
 					}