feat(): switch to informer

internal/informer.go

@@ -0,0 +1,97 @@
+package internal
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	v1 "k8s.io/api/coordination/v1"
+	"k8s.io/client-go/informers"
+	"k8s.io/client-go/tools/cache"
+)
+
+// StartLeaseInformer starts a long-running informer watching Lease objects in the kube-system namespace.
+// It will react to Add/Update events for leases whose name starts with "cilium-l2announce" and label
+// the corresponding node.
+func StartLeaseInformer(cfg *Config, stopCh <-chan struct{}) error {
+	log.WithFields(log.Fields{"Caller": "StartLeaseInformer"}).Info("Starting lease informer")
+
+	client, err := generateClient()
+	if err != nil {
+		return fmt.Errorf("Could not generate client for informer: %s", err.Error())
+	}
+
+	factory := informers.NewSharedInformerFactoryWithOptions(&client, 0, informers.WithNamespace("kube-system"))
+	leaseInformer := factory.Coordination().V1().Leases().Informer()
+
+	leaseInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc: func(obj interface{}) {
+			handleLease(obj, cfg)
+		},
+		UpdateFunc: func(oldObj, newObj interface{}) {
+			handleLease(newObj, cfg)
+		},
+		DeleteFunc: func(obj interface{}) {
+			// nothing to do on delete for now
+		},
+	})
+
+	factory.Start(stopCh)
+
+	// wait for cache sync with timeout
+	synced := make(chan struct{})
+	go func() {
+		if !cache.WaitForCacheSync(stopCh, leaseInformer.HasSynced) {
+			close(synced)
+			return
+		}
+		close(synced)
+	}()
+
+	select {
+	case <-synced:
+		// proceed
+	case <-time.After(15 * time.Second):
+		return fmt.Errorf("timed out waiting for informer cache sync")
+	}
+
+	log.WithFields(log.Fields{"Caller": "StartLeaseInformer"}).Info("Lease informer running")
+	return nil
+}
+
+func handleLease(obj interface{}, cfg *Config) {
+	lease, ok := obj.(*v1.Lease)
+	if !ok {
+		log.WithFields(log.Fields{"Caller": "handleLease"}).Warn("Could not cast object to Lease")
+		return
+	}
+
+	if lease == nil {
+		return
+	}
+
+	if lease.Name == "" || len(lease.Name) < 1 {
+		return
+	}
+
+	if !strings.HasPrefix(lease.Name, "cilium-l2announce") {
+		return
+	}
+
+	node, err := GetNodeNameFromLease(*lease)
+	if err != nil {
+		log.WithFields(log.Fields{"Caller": "handleLease", "Lease": lease.Name}).Errorf("Error parsing lease: %s", err.Error())
+		return
+	}
+
+	if cfg.DryRun {
+		log.WithFields(log.Fields{"Caller": "handleLease"}).Infof("Dry run: would label node %s with %s=true (lease %s)", node, cfg.CiliumLabel, lease.Name)
+		return
+	}
+
+	err = LabelNode(node, lease.Name, cfg)
+	if err != nil {
+		log.WithFields(log.Fields{"Caller": "handleLease", "Node": node, "Lease": lease.Name}).Errorf("Error labeling node: %s", err.Error())
+	}
+}

internal/kube.go

@@ -92,36 +92,36 @@ func RemoveLabelFromNode(nodeName string) error {
 	return nil
 }
 
-func GetCiliumL2Leases() ([]v1.Lease, error) {
-	client, err := generateClient()
-	if err != nil {
-		log.WithFields(log.Fields{"Caller": "GetCiliumL2Leases"}).Errorf("Could not generate client: %s", err.Error())
-		return nil, err
-	}
+// func GetCiliumL2Leases() ([]v1.Lease, error) {
+// 	client, err := generateClient()
+// 	if err != nil {
+// 		log.WithFields(log.Fields{"Caller": "GetCiliumL2Leases"}).Errorf("Could not generate client: %s", err.Error())
+// 		return nil, err
+// 	}
 
-	leases, err := client.CoordinationV1().Leases("kube-system").List(context.TODO(), metav1.ListOptions{})
-	if err != nil {
-		log.WithFields(log.Fields{"Caller": "GetCiliumL2Leases"}).Errorf("Could not list leases: %s", err.Error())
-		return nil, err
-	}
+// 	leases, err := client.CoordinationV1().Leases("kube-system").List(context.TODO(), metav1.ListOptions{})
+// 	if err != nil {
+// 		log.WithFields(log.Fields{"Caller": "GetCiliumL2Leases"}).Errorf("Could not list leases: %s", err.Error())
+// 		return nil, err
+// 	}
 
-	ciliumLeases := []v1.Lease{}
+// 	ciliumLeases := []v1.Lease{}
 
-	for _, l := range leases.Items {
-		if strings.HasPrefix(l.Name, "cilium-l2announce") {
-			log.WithFields(log.Fields{
-				"Caller": "GetCiliumL2Leases",
-				"Lease":  l.Name,
-			}).Info("Found Cilium L2 lease")
-			// Pretty-print a couple of fields for debugging
-			if l.Spec.HolderIdentity != nil {
-				log.WithFields(log.Fields{"HolderIdentity": *l.Spec.HolderIdentity}).Debug("HolderIdentity")
-			}
-			ciliumLeases = append(ciliumLeases, l)
-		}
-	}
-	return ciliumLeases, nil
-}
+// 	for _, l := range leases.Items {
+// 		if strings.HasPrefix(l.Name, "cilium-l2announce") {
+// 			log.WithFields(log.Fields{
+// 				"Caller": "GetCiliumL2Leases",
+// 				"Lease":  l.Name,
+// 			}).Info("Found Cilium L2 lease")
+// 			// Pretty-print a couple of fields for debugging
+// 			if l.Spec.HolderIdentity != nil {
+// 				log.WithFields(log.Fields{"HolderIdentity": *l.Spec.HolderIdentity}).Debug("HolderIdentity")
+// 			}
+// 			ciliumLeases = append(ciliumLeases, l)
+// 		}
+// 	}
+// 	return ciliumLeases, nil
+// }
 
 func GetNodeNameFromLease(lease v1.Lease) (string, error) {
 	if lease.Spec.HolderIdentity == nil {