StatefulSet: Use ControllerRef to route watch events.

This is part of the completion of ControllerRef, as described here:

https://github.com/kubernetes/community/blob/master/contributors/design-proposals/controller-ref.md#watches

pkg/controller/statefulset/stateful_set.go

@@ -19,7 +19,6 @@ package statefulset
 import (
 	"fmt"
 	"reflect"
-	"sort"
 	"time"
 
 	"k8s.io/apimachinery/pkg/api/errors"
@@ -50,6 +49,9 @@ const (
 	statefulSetResyncPeriod = 30 * time.Second
 )
 
+// controllerKind contains the schema.GroupVersionKind for this controller type.
+var controllerKind = apps.SchemeGroupVersion.WithKind("StatefulSet")
+
 // StatefulSetController controls statefulsets.
 type StatefulSetController struct {
 	// client interface
@@ -158,15 +160,36 @@ func (ssc *StatefulSetController) Run(workers int, stopCh <-chan struct{}) {
 func (ssc *StatefulSetController) addPod(obj interface{}) {
 	pod := obj.(*v1.Pod)
 	glog.V(4).Infof("Pod %s created, labels: %+v", pod.Name, pod.Labels)
-	set := ssc.getStatefulSetForPod(pod)
-	if set == nil {
+
+	if pod.DeletionTimestamp != nil {
+		// on a restart of the controller manager, it's possible a new pod shows up in a state that
+		// is already pending deletion. Prevent the pod from being a creation observation.
+		ssc.deletePod(pod)
 		return
 	}
-	ssc.enqueueStatefulSet(set)
+
+	// If it has a ControllerRef, that's all that matters.
+	if controllerRef := controller.GetControllerOf(pod); controllerRef != nil {
+		if controllerRef.Kind != controllerKind.Kind {
+			// It's controlled by a different type of controller.
+			return
+		}
+		set, err := ssc.setLister.StatefulSets(pod.Namespace).Get(controllerRef.Name)
+		if err != nil {
+			return
+		}
+		ssc.enqueueStatefulSet(set)
+		return
+	}
+
+	// Otherwise, it's an orphan. Get a list of all matching controllers and sync
+	// them to see if anyone wants to adopt it.
+	for _, set := range ssc.getStatefulSetsForPod(pod) {
+		ssc.enqueueStatefulSet(set)
+	}
 }
 
 // updatePod adds the statefulset for the current and old pods to the sync queue.
-// If the labels of the pod didn't change, this method enqueues a single statefulset.
 func (ssc *StatefulSetController) updatePod(old, cur interface{}) {
 	curPod := cur.(*v1.Pod)
 	oldPod := old.(*v1.Pod)
@@ -175,15 +198,41 @@ func (ssc *StatefulSetController) updatePod(old, cur interface{}) {
 		// Two different versions of the same pod will always have different RVs.
 		return
 	}
-	set := ssc.getStatefulSetForPod(curPod)
-	if set == nil {
+	glog.V(4).Infof("Pod %s updated, objectMeta %+v -> %+v.", curPod.Name, oldPod.ObjectMeta, curPod.ObjectMeta)
+
+	labelChanged := !reflect.DeepEqual(curPod.Labels, oldPod.Labels)
+
+	curControllerRef := controller.GetControllerOf(curPod)
+	oldControllerRef := controller.GetControllerOf(oldPod)
+	controllerRefChanged := !reflect.DeepEqual(curControllerRef, oldControllerRef)
+	if controllerRefChanged &&
+		oldControllerRef != nil && oldControllerRef.Kind == controllerKind.Kind {
+		// The ControllerRef was changed. Sync the old controller, if any.
+		set, err := ssc.setLister.StatefulSets(oldPod.Namespace).Get(oldControllerRef.Name)
+		if err == nil {
+			ssc.enqueueStatefulSet(set)
+		}
+	}
+
+	// If it has a ControllerRef, that's all that matters.
+	if curControllerRef != nil {
+		if curControllerRef.Kind != controllerKind.Kind {
+			// It's controlled by a different type of controller.
+			return
+		}
+		set, err := ssc.setLister.StatefulSets(curPod.Namespace).Get(curControllerRef.Name)
+		if err != nil {
+			return
+		}
+		ssc.enqueueStatefulSet(set)
 		return
 	}
-	ssc.enqueueStatefulSet(set)
-	// TODO will we need this going forward with controller ref impl?
-	if !reflect.DeepEqual(curPod.Labels, oldPod.Labels) {
-		if oldSet := ssc.getStatefulSetForPod(oldPod); oldSet != nil {
-			ssc.enqueueStatefulSet(oldSet)
+
+	// Otherwise, it's an orphan. If anything changed, sync matching controllers
+	// to see if anyone wants to adopt it now.
+	if labelChanged || controllerRefChanged {
+		for _, set := range ssc.getStatefulSetsForPod(curPod) {
+			ssc.enqueueStatefulSet(set)
 		}
 	}
 }
@@ -209,9 +258,22 @@ func (ssc *StatefulSetController) deletePod(obj interface{}) {
 		}
 	}
 	glog.V(4).Infof("Pod %s/%s deleted through %v.", pod.Namespace, pod.Name, utilruntime.GetCaller())
-	if set := ssc.getStatefulSetForPod(pod); set != nil {
-		ssc.enqueueStatefulSet(set)
+
+	controllerRef := controller.GetControllerOf(pod)
+	if controllerRef == nil {
+		// No controller should care about orphans being deleted.
+		return
 	}
+	if controllerRef.Kind != controllerKind.Kind {
+		// It's controlled by a different type of controller.
+		return
+	}
+
+	set, err := ssc.setLister.StatefulSets(pod.Namespace).Get(controllerRef.Name)
+	if err != nil {
+		return
+	}
+	ssc.enqueueStatefulSet(set)
 }
 
 // getPodsForStatefulSet returns the Pods that a given StatefulSet should manage.
@@ -232,12 +294,13 @@ func (ssc *StatefulSetController) getPodsForStatefulSet(set *apps.StatefulSet, s
 		return isMemberOf(set, pod)
 	}
 
-	cm := controller.NewPodControllerRefManager(ssc.podControl, set, selector, getSSKind())
+	cm := controller.NewPodControllerRefManager(ssc.podControl, set, selector, controllerKind)
 	return cm.ClaimPods(pods, filter)
 }
 
-// getStatefulSetForPod returns the StatefulSet managing the given pod.
-func (ssc *StatefulSetController) getStatefulSetForPod(pod *v1.Pod) *apps.StatefulSet {
+// getStatefulSetsForPod returns a list of StatefulSets that potentially match
+// a given pod.
+func (ssc *StatefulSetController) getStatefulSetsForPod(pod *v1.Pod) []*apps.StatefulSet {
 	sets, err := ssc.setLister.GetPodStatefulSets(pod)
 	if err != nil {
 		glog.V(4).Infof("No StatefulSets found for pod %v, StatefulSet controller will avoid syncing", pod.Name)
@@ -245,24 +308,14 @@ func (ssc *StatefulSetController) getStatefulSetForPod(pod *v1.Pod) *apps.Statef
 	}
 	// More than one set is selecting the same Pod
 	if len(sets) > 1 {
+		// ControllerRef will ensure we don't do anything crazy, but more than one
+		// item in this list nevertheless constitutes user error.
 		utilruntime.HandleError(
 			fmt.Errorf(
 				"user error: more than one StatefulSet is selecting pods with labels: %+v",
 				pod.Labels))
-		// The timestamp sort should not be necessary because we will enforce the CreatedBy requirement by
-		// name
-		sort.Sort(overlappingStatefulSets(sets))
-		// return the first created set for which pod is a member
-		for i := range sets {
-			if isMemberOf(sets[i], pod) {
-				return sets[i]
-			}
-		}
-		glog.V(4).Infof("No StatefulSets found for pod %v, StatefulSet controller will avoid syncing", pod.Name)
-		return nil
 	}
-	return sets[0]
-
+	return sets
 }
 
 // enqueueStatefulSet enqueues the given statefulset in the work queue.