Fixing Potential Race Condition in EndpointSlice Controller.

This adds a new EndpointSlice tracker to keep track of the expected resource versions of EndpointSlices associated with each Service managed by the EndpointSlice controller. This should prevent a potential race where a syncService call could happen with an incomplete view of EndpointSlices if additions or deletions hadn't fully propagated to the cache yet. Additionally, this ensures that external changes to EndpointSlices will be handled by the EndpointSlice controller.

pkg/controller/endpointslice/utils.go

@@ -26,6 +26,8 @@ import (
 	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/client-go/tools/cache"
 	"k8s.io/klog"
 	podutil "k8s.io/kubernetes/pkg/api/v1/pod"
 	api "k8s.io/kubernetes/pkg/apis/core"
@@ -236,6 +238,27 @@ func getSliceToFill(endpointSlices []*discovery.EndpointSlice, numEndpoints, max
 	return closestSlice
 }
 
+// getEndpointSliceFromDeleteAction parses an EndpointSlice from a delete action.
+func getEndpointSliceFromDeleteAction(obj interface{}) *discovery.EndpointSlice {
+	if endpointSlice, ok := obj.(*discovery.EndpointSlice); ok {
+		// Enqueue all the services that the pod used to be a member of.
+		// This is the same thing we do when we add a pod.
+		return endpointSlice
+	}
+	// If we reached here it means the pod was deleted but its final state is unrecorded.
+	tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
+	if !ok {
+		utilruntime.HandleError(fmt.Errorf("Couldn't get object from tombstone %#v", obj))
+		return nil
+	}
+	endpointSlice, ok := tombstone.Obj.(*discovery.EndpointSlice)
+	if !ok {
+		utilruntime.HandleError(fmt.Errorf("Tombstone contained object that is not a EndpointSlice: %#v", obj))
+		return nil
+	}
+	return endpointSlice
+}
+
 // addTriggerTimeAnnotation adds a triggerTime annotation to an EndpointSlice
 func addTriggerTimeAnnotation(endpointSlice *discovery.EndpointSlice, triggerTime time.Time) {
 	if endpointSlice.Annotations == nil {
@@ -249,6 +272,19 @@ func addTriggerTimeAnnotation(endpointSlice *discovery.EndpointSlice, triggerTim
 	}
 }
 
+// serviceControllerKey returns a controller key for a Service but derived from
+// an EndpointSlice.
+func serviceControllerKey(endpointSlice *discovery.EndpointSlice) (string, error) {
+	if endpointSlice == nil {
+		return "", fmt.Errorf("nil EndpointSlice passed to serviceControllerKey()")
+	}
+	serviceName, ok := endpointSlice.Labels[discovery.LabelServiceName]
+	if !ok || serviceName == "" {
+		return "", fmt.Errorf("EndpointSlice missing %s label", discovery.LabelServiceName)
+	}
+	return fmt.Sprintf("%s/%s", endpointSlice.Namespace, serviceName), nil
+}
+
 // endpointSliceEndpointLen helps sort endpoint slices by the number of
 // endpoints they contain.
 type endpointSliceEndpointLen []*discovery.EndpointSlice