init hpa controller framework (#141)

Signed-off-by: chenxianpao <chenxianpao@huawei.com>

cmd/controller-manager/app/controllermanager.go

@@ -16,6 +16,7 @@ import (
 	"github.com/karmada-io/karmada/pkg/controllers/binding"
 	"github.com/karmada-io/karmada/pkg/controllers/cluster"
 	"github.com/karmada-io/karmada/pkg/controllers/execution"
+	"github.com/karmada-io/karmada/pkg/controllers/hpa"
 	"github.com/karmada-io/karmada/pkg/controllers/propagationpolicy"
 	"github.com/karmada-io/karmada/pkg/controllers/status"
 	"github.com/karmada-io/karmada/pkg/util/gclient"
@@ -101,6 +102,14 @@ func setupControllers(mgr controllerruntime.Manager, stopChan <-chan struct{}) {
 		klog.Fatalf("Failed to setup clusterstatus controller: %v", err)
 	}
 
+	hpaController := &hpa.HorizontalPodAutoscalerController{
+		Client:        mgr.GetClient(),
+		EventRecorder: mgr.GetEventRecorderFor(hpa.ControllerName),
+	}
+	if err := hpaController.SetupWithManager(mgr); err != nil {
+		klog.Fatalf("Failed to setup hpa controller: %v", err)
+	}
+
 	policyController := &propagationpolicy.Controller{
 		Client:        mgr.GetClient(),
 		DynamicClient: dynamicClientSet,

pkg/controllers/hpa/hpa_controller.go

@@ -0,0 +1,50 @@
+package hpa
+
+import (
+	"context"
+
+	autoscalingv1 "k8s.io/api/autoscaling/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/klog/v2"
+	controllerruntime "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+// ControllerName is the controller name that will be used when reporting events.
+const ControllerName = "hpa-controller"
+
+// HorizontalPodAutoscalerController is to sync HorizontalPodAutoscaler.
+type HorizontalPodAutoscalerController struct {
+	client.Client // used to operate HorizontalPodAutoscaler resources.
+	EventRecorder record.EventRecorder
+}
+
+// Reconcile performs a full reconciliation for the object referred to by the Request.
+// The Controller will requeue the Request to be processed again if an error is non-nil or
+// Result.Requeue is true, otherwise upon completion it will remove the work from the queue.
+func (c *HorizontalPodAutoscalerController) Reconcile(req controllerruntime.Request) (controllerruntime.Result, error) {
+	klog.V(4).Infof("Reconciling HorizontalPodAutoscaler %s.", req.NamespacedName.String())
+
+	hpa := &autoscalingv1.HorizontalPodAutoscaler{}
+	if err := c.Client.Get(context.TODO(), req.NamespacedName, hpa); err != nil {
+		// The resource may no longer exist, in which case we stop processing.
+		if errors.IsNotFound(err) {
+			return controllerruntime.Result{}, nil
+		}
+
+		return controllerruntime.Result{Requeue: true}, err
+	}
+
+	if !hpa.DeletionTimestamp.IsZero() {
+		// Do nothing, just return.
+		return controllerruntime.Result{}, nil
+	}
+
+	return controllerruntime.Result{}, nil
+}
+
+// SetupWithManager creates a controller and register to controller manager.
+func (c *HorizontalPodAutoscalerController) SetupWithManager(mgr controllerruntime.Manager) error {
+	return controllerruntime.NewControllerManagedBy(mgr).For(&autoscalingv1.HorizontalPodAutoscaler{}).Complete(c)
+}