Add binding controller

pkg/controllers/binding/binding_controller.go

@@ -0,0 +1,243 @@
+package binding
+
+import (
+	"fmt"
+	"time"
+
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/kubernetes/scheme"
+	typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
+	"k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/client-go/util/workqueue"
+	"k8s.io/klog/v2"
+
+	"github.com/huawei-cloudnative/karmada/pkg/controllers/util"
+	clientset "github.com/huawei-cloudnative/karmada/pkg/generated/clientset/versioned"
+	karmadaScheme "github.com/huawei-cloudnative/karmada/pkg/generated/clientset/versioned/scheme"
+	informers "github.com/huawei-cloudnative/karmada/pkg/generated/informers/externalversions"
+	listers "github.com/huawei-cloudnative/karmada/pkg/generated/listers/propagationstrategy/v1alpha1"
+)
+
+const controllerAgentName = "binding-controller"
+
+// Controller is the controller implementation for binding resources
+type Controller struct {
+	// karmadaClientSet is the clientset for our own API group.
+	karmadaClientSet clientset.Interface
+
+	// kubeClientSet is a standard kubernetes clientset.
+	kubeClientSet kubernetes.Interface
+
+	propagationBindingLister listers.PropagationBindingLister
+	propagationBindingSynced cache.InformerSynced
+	// workqueue is a rate limited work queue. This is used to queue work to be
+	// processed instead of performing it as soon as a change happens. This
+	// means we can ensure we only process a fixed amount of resources at a
+	// time, and makes it easy to ensure we are never processing the same item
+	// simultaneously in two different workers.
+	workqueue workqueue.RateLimitingInterface
+
+	// recorder is an event recorder for recording Event resources to the
+	// Kubernetes API.
+	eventRecorder record.EventRecorder
+}
+
+// StartPropagationBindingController starts a new binding controller.
+func StartPropagationBindingController(config *util.ControllerConfig, stopChan <-chan struct{}) error {
+	controller, err := newPropagationBindingController(config)
+	if err != nil {
+		return err
+	}
+	klog.Infof("Starting PropagationBinding controller")
+
+	go wait.Until(func() {
+		if err := controller.Run(1, stopChan); err != nil {
+			klog.Errorf("controller exit unexpected! will restart later, controller: %s, error: %v", controllerAgentName, err)
+		}
+	}, 1*time.Second, stopChan)
+
+	return nil
+}
+
+// newPropagationBindingController returns a new controller.
+func newPropagationBindingController(config *util.ControllerConfig) (*Controller, error) {
+
+	headClusterConfig := rest.CopyConfig(config.HeadClusterConfig)
+	kubeClientSet := kubernetes.NewForConfigOrDie(headClusterConfig)
+
+	karmadaClientSet := clientset.NewForConfigOrDie(headClusterConfig)
+	propagationBindingInformer := informers.NewSharedInformerFactory(karmadaClientSet, 0).Propagationstrategy().V1alpha1().PropagationBindings()
+
+	// Add karmada types to the default Kubernetes Scheme so Events can be logged for karmada types.
+	utilruntime.Must(karmadaScheme.AddToScheme(scheme.Scheme))
+
+	// Create event broadcaster
+	klog.V(1).Infof("Creating event broadcaster for %s", controllerAgentName)
+	eventBroadcaster := record.NewBroadcaster()
+	eventBroadcaster.StartRecordingToSink(&typedcorev1.EventSinkImpl{Interface: kubeClientSet.CoreV1().Events("")})
+
+	controller := &Controller{
+		karmadaClientSet:         karmadaClientSet,
+		kubeClientSet:            kubeClientSet,
+		propagationBindingLister: propagationBindingInformer.Lister(),
+		propagationBindingSynced: propagationBindingInformer.Informer().HasSynced,
+		workqueue:                workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), controllerAgentName),
+		eventRecorder:            eventBroadcaster.NewRecorder(scheme.Scheme, corev1.EventSource{Component: controllerAgentName}),
+	}
+
+	klog.Info("Setting up event handlers")
+	propagationBindingInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc: func(obj interface{}) {
+			klog.Infof("Received add event. just add to queue.")
+			controller.enqueueEventResource(obj)
+		},
+		UpdateFunc: func(old, new interface{}) {
+			klog.Infof("Received update event. just add to queue.")
+			controller.enqueueEventResource(new)
+		},
+		DeleteFunc: func(obj interface{}) {
+			klog.Infof("Received delete event. Do nothing just log.")
+		},
+	})
+
+	return controller, nil
+}
+
+// Run will set up the event handlers for types we are interested in, as well
+// as syncing informer caches and starting workers. It will block until stopCh
+// is closed, at which point it will shutdown the workqueue and wait for
+// workers to finish processing their current work items.
+func (c *Controller) Run(workerNumber int, stopCh <-chan struct{}) error {
+	defer utilruntime.HandleCrash()
+	defer c.workqueue.ShutDown()
+
+	klog.Infof("Starting controller: %s", controllerAgentName)
+
+	// Wait for the caches to be synced before starting workers
+	klog.Info("Waiting for informer caches to sync")
+	if ok := cache.WaitForCacheSync(stopCh, c.propagationBindingSynced); !ok {
+		return fmt.Errorf("failed to wait for caches to sync")
+	}
+
+	klog.Infof("Starting workers for controller. worker number: %d, controller: %s", workerNumber, controllerAgentName)
+	for i := 0; i < workerNumber; i++ {
+		go wait.Until(c.runWorker, time.Second, stopCh)
+	}
+
+	// Controller will block here until stopCh is closed.
+	<-stopCh
+	klog.Info("Shutting down workers")
+
+	return nil
+}
+
+// runWorker is a long-running function that will continually call the
+// processNextWorkItem function in order to read and process a message on the
+// workqueue.
+func (c *Controller) runWorker() {
+	for c.processNextWorkItem() {
+	}
+}
+
+// processNextWorkItem will read a single work item off the workqueue and
+// attempt to process it, by calling the syncHandler.
+func (c *Controller) processNextWorkItem() bool {
+	obj, shutdown := c.workqueue.Get()
+
+	if shutdown {
+		return false
+	}
+
+	// We wrap this block in a func so we can defer c.workqueue.Done.
+	err := func(obj interface{}) error {
+		// We call Done here so the workqueue knows we have finished
+		// processing this item. We also must remember to call Forget if we
+		// do not want this work item being re-queued. For example, we do
+		// not call Forget if a transient error occurs, instead the item is
+		// put back on the workqueue and attempted again after a back-off
+		// period.
+		defer c.workqueue.Done(obj)
+		var key string
+		var ok bool
+		// We expect strings to come off the workqueue. These are of the
+		// form namespace/name. We do this as the delayed nature of the
+		// workqueue means the items in the informer cache may actually be
+		// more up to date that when the item was initially put onto the
+		// workqueue.
+		if key, ok = obj.(string); !ok {
+			// As the item in the workqueue is actually invalid, we call
+			// Forget here else we'd go into a loop of attempting to
+			// process a work item that is invalid.
+			c.workqueue.Forget(obj)
+			utilruntime.HandleError(fmt.Errorf("expected string in workqueue but got %#v", obj))
+			return nil
+		}
+		// Run the syncHandler, passing it the namespace/name string of the
+		// PropagateStrategy resource to be synced.
+		if err := c.syncHandler(key); err != nil {
+			// Put the item back on the workqueue to handle any transient errors.
+			c.workqueue.AddRateLimited(key)
+			return fmt.Errorf("error syncing '%s': %s, requeuing", key, err.Error())
+		}
+		// Finally, if no error occurs we Forget this item so it does not
+		// get queued again until another change happens.
+		c.workqueue.Forget(obj)
+		klog.Infof("Successfully synced '%s'", key)
+		return nil
+	}(obj)
+
+	if err != nil {
+		utilruntime.HandleError(err)
+		return true
+	}
+
+	return true
+}
+
+// syncHandler compares the actual state with the desired, and attempts to
+// converge the two. It then updates the Status block of the PropagateStrategy resource
+// with the current status of the resource.
+func (c *Controller) syncHandler(key string) error {
+	// Convert the namespace/name string into a distinct namespace and name
+	namespace, name, err := cache.SplitMetaNamespaceKey(key)
+	if err != nil {
+		utilruntime.HandleError(fmt.Errorf("invalid resource key: %s", key))
+		return nil
+	}
+
+	// Get the resource with this namespace/name
+	propagationBinding, err := c.propagationBindingLister.PropagationBindings(namespace).Get(name)
+	if err != nil {
+		// The propagationBinding resource may no longer exist, in which case we stop
+		// processing.
+		if errors.IsNotFound(err) {
+			utilruntime.HandleError(fmt.Errorf("propagationBinding '%s' in work queue no longer exists", key))
+			return nil
+		}
+
+		return err
+	}
+
+	klog.Infof("Sync propagationBinding: %s/%s", propagationBinding.Namespace, propagationBinding.Name)
+
+	return nil
+}
+
+// enqueueFoo takes a resource and converts it into a namespace/name
+// string which is then put onto the work queue. This method should *not* be
+// passed resources of any type other than propagationBinding.
+func (c *Controller) enqueueEventResource(obj interface{}) {
+	var key string
+	var err error
+	if key, err = cache.MetaNamespaceKeyFunc(obj); err != nil {
+		utilruntime.HandleError(err)
+		return
+	}
+	c.workqueue.Add(key)
+}