feat: Use HorizontalRunnerAutoscaler for autoscaling

controllers/horizontalrunnerautoscaler_controller.go

@@ -0,0 +1,184 @@
+/*
+Copyright 2020 The actions-runner-controller 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 controllers
+
+import (
+	"context"
+	"time"
+
+	"github.com/summerwind/actions-runner-controller/github"
+	"k8s.io/apimachinery/pkg/types"
+
+	"github.com/go-logr/logr"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/tools/record"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	"github.com/summerwind/actions-runner-controller/api/v1alpha1"
+)
+
+const (
+	DefaultScaleDownDelay = 10 * time.Minute
+)
+
+// HorizontalRunnerAutoscalerReconciler reconciles a HorizontalRunnerAutoscaler object
+type HorizontalRunnerAutoscalerReconciler struct {
+	client.Client
+	GitHubClient *github.Client
+	Log          logr.Logger
+	Recorder     record.EventRecorder
+	Scheme       *runtime.Scheme
+}
+
+// +kubebuilder:rbac:groups=actions.summerwind.dev,resources=runnerdeployments,verbs=get;list;watch;update;patch
+// +kubebuilder:rbac:groups=actions.summerwind.dev,resources=horizontalrunnerautoscalers,verbs=get;list;watch;create;update;patch;delete
+// +kubebuilder:rbac:groups=actions.summerwind.dev,resources=horizontalrunnerautoscalers/status,verbs=get;update;patch
+// +kubebuilder:rbac:groups=core,resources=events,verbs=create;patch
+
+func (r *HorizontalRunnerAutoscalerReconciler) Reconcile(req ctrl.Request) (ctrl.Result, error) {
+	ctx := context.Background()
+	log := r.Log.WithValues("horizontalrunnerautoscaler", req.NamespacedName)
+
+	var hra v1alpha1.HorizontalRunnerAutoscaler
+	if err := r.Get(ctx, req.NamespacedName, &hra); err != nil {
+		return ctrl.Result{}, client.IgnoreNotFound(err)
+	}
+
+	if !hra.ObjectMeta.DeletionTimestamp.IsZero() {
+		return ctrl.Result{}, nil
+	}
+
+	var rd v1alpha1.RunnerDeployment
+	if err := r.Get(ctx, types.NamespacedName{
+		Namespace: req.Namespace,
+		Name:      hra.Spec.ScaleTargetRef.Name,
+	}, &rd); err != nil {
+		return ctrl.Result{}, client.IgnoreNotFound(err)
+	}
+
+	if !rd.ObjectMeta.DeletionTimestamp.IsZero() {
+		return ctrl.Result{}, nil
+	}
+
+	replicas, err := r.computeReplicas(rd, hra)
+	if err != nil {
+		r.Recorder.Event(&hra, corev1.EventTypeNormal, "RunnerAutoscalingFailure", err.Error())
+
+		log.Error(err, "Could not compute replicas")
+
+		return ctrl.Result{}, err
+	}
+
+	const defaultReplicas = 1
+
+	currentDesiredReplicas := getIntOrDefault(rd.Spec.Replicas, defaultReplicas)
+	newDesiredReplicas := getIntOrDefault(replicas, defaultReplicas)
+
+	// Please add more conditions that we can in-place update the newest runnerreplicaset without disruption
+	if currentDesiredReplicas != newDesiredReplicas {
+		copy := rd.DeepCopy()
+		copy.Spec.Replicas = &newDesiredReplicas
+
+		if err := r.Client.Update(ctx, copy); err != nil {
+			log.Error(err, "Failed to update runnerderployment resource")
+
+			return ctrl.Result{}, err
+		}
+
+		return ctrl.Result{}, err
+	}
+
+	if hra.Status.DesiredReplicas == nil || *hra.Status.DesiredReplicas != *replicas {
+		updated := hra.DeepCopy()
+
+		if (hra.Status.DesiredReplicas == nil && *replicas > 1) ||
+			(hra.Status.DesiredReplicas != nil && *replicas > *hra.Status.DesiredReplicas) {
+
+			updated.Status.LastSuccessfulScaleOutTime = &metav1.Time{Time: time.Now()}
+		}
+
+		updated.Status.DesiredReplicas = replicas
+
+		if err := r.Status().Update(ctx, updated); err != nil {
+			log.Error(err, "Failed to update horizontalrunnerautoscaler status")
+
+			return ctrl.Result{}, err
+		}
+	}
+
+	return ctrl.Result{}, nil
+}
+
+func (r *HorizontalRunnerAutoscalerReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	r.Recorder = mgr.GetEventRecorderFor("runnerdeployment-controller")
+
+	if err := mgr.GetFieldIndexer().IndexField(&v1alpha1.RunnerReplicaSet{}, runnerSetOwnerKey, func(rawObj runtime.Object) []string {
+		runnerSet := rawObj.(*v1alpha1.RunnerReplicaSet)
+		owner := metav1.GetControllerOf(runnerSet)
+		if owner == nil {
+			return nil
+		}
+
+		if owner.APIVersion != v1alpha1.GroupVersion.String() || owner.Kind != "RunnerDeployment" {
+			return nil
+		}
+
+		return []string{owner.Name}
+	}); err != nil {
+		return err
+	}
+
+	return ctrl.NewControllerManagedBy(mgr).
+		For(&v1alpha1.RunnerDeployment{}).
+		Owns(&v1alpha1.RunnerReplicaSet{}).
+		Complete(r)
+}
+
+func (r *HorizontalRunnerAutoscalerReconciler) computeReplicas(rd v1alpha1.RunnerDeployment, hra v1alpha1.HorizontalRunnerAutoscaler) (*int, error) {
+	var computedReplicas *int
+
+	replicas, err := r.determineDesiredReplicas(rd, hra)
+	if err != nil {
+		return nil, err
+	}
+
+	var scaleDownDelay time.Duration
+
+	if hra.Spec.ScaleDownDelaySecondsAfterScaleUp != nil {
+		scaleDownDelay = time.Duration(*hra.Spec.ScaleDownDelaySecondsAfterScaleUp) * time.Second
+	} else {
+		scaleDownDelay = DefaultScaleDownDelay
+	}
+
+	now := time.Now()
+
+	if hra.Status.DesiredReplicas == nil ||
+		*hra.Status.DesiredReplicas < *replicas ||
+		hra.Status.LastSuccessfulScaleOutTime == nil ||
+		hra.Status.LastSuccessfulScaleOutTime.Add(scaleDownDelay).Before(now) {
+
+		computedReplicas = replicas
+	} else {
+		computedReplicas = hra.Status.DesiredReplicas
+	}
+
+	return computedReplicas, nil
+}