DRA scheduler: use assume cache to list claims

This finishes the transition to the assume cache as source of truth for the
current set of claims.

The tests have to be adapted. It's not enough anymore to directly put objects
into the informer store because that doesn't change the assume cache
content. Instead, normal Create/Update calls and waiting for the cache update
are needed.

pkg/scheduler/framework/plugins/dynamicresources/dynamicresources.go

@@ -272,7 +272,6 @@ type dynamicResources struct {
 	enabled                    bool
 	fh                         framework.Handle
 	clientset                  kubernetes.Interface
-	claimLister                resourcev1alpha2listers.ResourceClaimLister
 	classLister                resourcev1alpha2listers.ResourceClassLister
 	podSchedulingContextLister resourcev1alpha2listers.PodSchedulingContextLister
 	claimParametersLister      resourcev1alpha2listers.ResourceClaimParametersLister
@@ -347,7 +346,6 @@ func New(ctx context.Context, plArgs runtime.Object, fh framework.Handle, fts fe
 		enabled:                    true,
 		fh:                         fh,
 		clientset:                  fh.ClientSet(),
-		claimLister:                fh.SharedInformerFactory().Resource().V1alpha2().ResourceClaims().Lister(),
 		classLister:                fh.SharedInformerFactory().Resource().V1alpha2().ResourceClasses().Lister(),
 		podSchedulingContextLister: fh.SharedInformerFactory().Resource().V1alpha2().PodSchedulingContexts().Lister(),
 		claimParametersLister:      fh.SharedInformerFactory().Resource().V1alpha2().ResourceClaimParameters().Lister(),
@@ -791,11 +789,16 @@ func (pl *dynamicResources) foreachPodResourceClaim(pod *v1.Pod, cb func(podReso
 		if claimName == nil {
 			continue
 		}
-		claim, err := pl.claimLister.ResourceClaims(pod.Namespace).Get(*claimName)
+		obj, err := pl.claimAssumeCache.Get(pod.Namespace + "/" + *claimName)
 		if err != nil {
 			return err
 		}
 
+		claim, ok := obj.(*resourcev1alpha2.ResourceClaim)
+		if !ok {
+			return fmt.Errorf("unexpected object type %T for assumed object %s/%s", obj, pod.Namespace, *claimName)
+		}
+
 		if claim.DeletionTimestamp != nil {
 			return fmt.Errorf("resourceclaim %q is being deleted", claim.Name)
 		}

pkg/scheduler/framework/plugins/dynamicresources/dynamicresources_test.go

@@ -1149,12 +1149,13 @@ func TestPlugin(t *testing.T) {
 }
 
 type testContext struct {
-	ctx             context.Context
-	client          *fake.Clientset
-	informerFactory informers.SharedInformerFactory
-	p               *dynamicResources
-	nodeInfos       []*framework.NodeInfo
-	state           *framework.CycleState
+	ctx              context.Context
+	client           *fake.Clientset
+	informerFactory  informers.SharedInformerFactory
+	claimAssumeCache *assumecache.AssumeCache
+	p                *dynamicResources
+	nodeInfos        []*framework.NodeInfo
+	state            *framework.CycleState
 }
 
 func (tc *testContext) verify(t *testing.T, expected result, initialObjects []metav1.Object, result interface{}, status *framework.Status) {
@@ -1320,11 +1321,11 @@ func setup(t *testing.T, nodes []*v1.Node, claims []*resourcev1alpha2.ResourceCl
 	tc.client.PrependReactor("list", "resourceclassparameters", createListReactor(tc.client.Tracker(), "ResourceClassParameters"))
 
 	tc.informerFactory = informers.NewSharedInformerFactory(tc.client, 0)
-	assumeCache := assumecache.NewAssumeCache(tCtx.Logger(), tc.informerFactory.Resource().V1alpha2().ResourceClaims().Informer(), "resource claim", "", nil)
+	tc.claimAssumeCache = assumecache.NewAssumeCache(tCtx.Logger(), tc.informerFactory.Resource().V1alpha2().ResourceClaims().Informer(), "resource claim", "", nil)
 	opts := []runtime.Option{
 		runtime.WithClientSet(tc.client),
 		runtime.WithInformerFactory(tc.informerFactory),
-		runtime.WithResourceClaimCache(assumeCache),
+		runtime.WithResourceClaimCache(tc.claimAssumeCache),
 	}
 	fh, err := runtime.NewFramework(tCtx, nil, nil, opts...)
 	if err != nil {
@@ -1491,6 +1492,7 @@ func Test_isSchedulableAfterClaimChange(t *testing.T) {
 		},
 		"backoff-wrong-old-object": {
 			pod:         podWithClaimName,
+			claims:      []*resourcev1alpha2.ResourceClaim{pendingDelayedClaim},
 			oldObj:      "not-a-claim",
 			newObj:      pendingImmediateClaim,
 			expectedErr: true,
@@ -1519,15 +1521,10 @@ func Test_isSchedulableAfterClaimChange(t *testing.T) {
 		},
 		"structured-claim-deallocate": {
 			pod:    podWithClaimName,
-			claims: []*resourcev1alpha2.ResourceClaim{pendingDelayedClaim},
-			oldObj: func() *resourcev1alpha2.ResourceClaim {
-				claim := structuredAllocatedClaim.DeepCopy()
-				claim.Name += "-other"
-				return claim
-			}(),
+			claims: []*resourcev1alpha2.ResourceClaim{pendingDelayedClaim, otherStructuredAllocatedClaim},
+			oldObj: otherStructuredAllocatedClaim,
 			newObj: func() *resourcev1alpha2.ResourceClaim {
-				claim := structuredAllocatedClaim.DeepCopy()
-				claim.Name += "-other"
+				claim := otherStructuredAllocatedClaim.DeepCopy()
 				claim.Status.Allocation = nil
 				return claim
 			}(),
@@ -1539,18 +1536,48 @@ func Test_isSchedulableAfterClaimChange(t *testing.T) {
 
 	for name, tc := range testcases {
 		t.Run(name, func(t *testing.T) {
-			logger, _ := ktesting.NewTestContext(t)
+			logger, tCtx := ktesting.NewTestContext(t)
 			testCtx := setup(t, nil, tc.claims, nil, nil, nil)
+			oldObj := tc.oldObj
+			newObj := tc.newObj
 			if claim, ok := tc.newObj.(*resourcev1alpha2.ResourceClaim); ok {
-				// Update the informer because the lister gets called and must have the claim.
-				store := testCtx.informerFactory.Resource().V1alpha2().ResourceClaims().Informer().GetStore()
+				// Add or update through the client and wait until the event is processed.
+				claimKey := claim.Namespace + "/" + claim.Name
 				if tc.oldObj == nil {
-					require.NoError(t, store.Add(claim))
+					// Some test claims already have it. Clear for create.
+					createClaim := claim.DeepCopy()
+					createClaim.UID = ""
+					storedClaim, err := testCtx.client.ResourceV1alpha2().ResourceClaims(createClaim.Namespace).Create(tCtx, createClaim, metav1.CreateOptions{})
+					require.NoError(t, err, "create claim")
+					claim = storedClaim
 				} else {
-					require.NoError(t, store.Update(claim))
+					cachedClaim, err := testCtx.claimAssumeCache.Get(claimKey)
+					require.NoError(t, err, "retrieve old claim")
+					updateClaim := claim.DeepCopy()
+					// The test claim doesn't have those (generated dynamically), so copy them.
+					updateClaim.UID = cachedClaim.(*resourcev1alpha2.ResourceClaim).UID
+					updateClaim.ResourceVersion = cachedClaim.(*resourcev1alpha2.ResourceClaim).ResourceVersion
+
+					storedClaim, err := testCtx.client.ResourceV1alpha2().ResourceClaims(updateClaim.Namespace).Update(tCtx, updateClaim, metav1.UpdateOptions{})
+					require.NoError(t, err, "update claim")
+					claim = storedClaim
 				}
+
+				// Eventually the assume cache will have it, too.
+				require.EventuallyWithT(t, func(t *assert.CollectT) {
+					cachedClaim, err := testCtx.claimAssumeCache.Get(claimKey)
+					require.NoError(t, err, "retrieve claim")
+					if cachedClaim.(*resourcev1alpha2.ResourceClaim).ResourceVersion != claim.ResourceVersion {
+						t.Errorf("cached claim not updated yet")
+					}
+				}, time.Minute, time.Second, "claim assume cache must have new or updated claim")
+
+				// This has the actual UID and ResourceVersion,
+				// which is relevant for
+				// isSchedulableAfterClaimChange.
+				newObj = claim
 			}
-			actualHint, err := testCtx.p.isSchedulableAfterClaimChange(logger, tc.pod, tc.oldObj, tc.newObj)
+			actualHint, err := testCtx.p.isSchedulableAfterClaimChange(logger, tc.pod, oldObj, newObj)
 			if tc.expectedErr {
 				require.Error(t, err)
 				return

pkg/scheduler/util/assumecache/assume_cache.go

@@ -125,7 +125,8 @@ type AssumeCache struct {
 	rwMutex sync.RWMutex
 
 	// All registered event handlers.
-	eventHandlers []cache.ResourceEventHandler
+	eventHandlers       []cache.ResourceEventHandler
+	handlerRegistration cache.ResourceEventHandlerRegistration
 
 	// The eventQueue contains functions which deliver an event to one
 	// event handler.
@@ -203,7 +204,7 @@ func NewAssumeCache(logger klog.Logger, informer Informer, description, indexNam
 	// Unit tests don't use informers
 	if informer != nil {
 		// Cannot fail in practice?! No-one bothers checking the error.
-		_, _ = informer.AddEventHandler(
+		c.handlerRegistration, _ = informer.AddEventHandler(
 			cache.ResourceEventHandlerFuncs{
 				AddFunc:    c.add,
 				UpdateFunc: c.update,
@@ -257,18 +258,7 @@ func (c *AssumeCache) add(obj interface{}) {
 		c.logger.Info("Error occurred while updating stored object", "err", err)
 	} else {
 		c.logger.V(10).Info("Adding object to assume cache", "description", c.description, "cacheKey", name, "assumeCache", obj)
-		for _, handler := range c.eventHandlers {
-			handler := handler
-			if oldObj == nil {
-				c.eventQueue.Push(func() {
-					handler.OnAdd(obj, false)
-				})
-			} else {
-				c.eventQueue.Push(func() {
-					handler.OnUpdate(oldObj, obj)
-				})
-			}
-		}
+		c.pushEvent(oldObj, obj)
 	}
 }
 
@@ -304,11 +294,32 @@ func (c *AssumeCache) delete(obj interface{}) {
 		c.logger.Error(err, "Failed to delete", "description", c.description, "cacheKey", name)
 	}
 
+	c.pushEvent(oldObj, nil)
+}
+
+// pushEvent gets called while the mutex is locked for writing.
+// It ensures that all currently registered event handlers get
+// notified about a change when the caller starts delivering
+// those with emitEvents.
+//
+// For a delete event, newObj is nil. For an add, oldObj is nil.
+// An update has both as non-nil.
+func (c *AssumeCache) pushEvent(oldObj, newObj interface{}) {
 	for _, handler := range c.eventHandlers {
 		handler := handler
-		c.eventQueue.Push(func() {
-			handler.OnDelete(oldObj)
-		})
+		if oldObj == nil {
+			c.eventQueue.Push(func() {
+				handler.OnAdd(newObj, false)
+			})
+		} else if newObj == nil {
+			c.eventQueue.Push(func() {
+				handler.OnDelete(oldObj)
+			})
+		} else {
+			c.eventQueue.Push(func() {
+				handler.OnUpdate(oldObj, newObj)
+			})
+		}
 	}
 }
 
@@ -441,13 +452,7 @@ func (c *AssumeCache) Assume(obj interface{}) error {
 		return fmt.Errorf("%v %q is out of sync (stored: %d, assume: %d)", c.description, name, storedVersion, newVersion)
 	}
 
-	for _, handler := range c.eventHandlers {
-		handler := handler
-		oldObj := objInfo.latestObj
-		c.eventQueue.Push(func() {
-			handler.OnUpdate(oldObj, obj)
-		})
-	}
+	c.pushEvent(objInfo.latestObj, obj)
 
 	// Only update the cached object
 	objInfo.latestObj = obj
@@ -467,14 +472,7 @@ func (c *AssumeCache) Restore(objName string) {
 		c.logger.V(5).Info("Restore object", "description", c.description, "cacheKey", objName, "err", err)
 	} else {
 		if objInfo.latestObj != objInfo.apiObj {
-			for _, handler := range c.eventHandlers {
-				handler := handler
-				oldObj, obj := objInfo.latestObj, objInfo.apiObj
-				c.eventQueue.Push(func() {
-					handler.OnUpdate(oldObj, obj)
-				})
-			}
-
+			c.pushEvent(objInfo.latestObj, objInfo.apiObj)
 			objInfo.latestObj = objInfo.apiObj
 		}
 		c.logger.V(4).Info("Restored object", "description", c.description, "cacheKey", objName)
@@ -485,7 +483,9 @@ func (c *AssumeCache) Restore(objName string) {
 // single handler are delivered sequentially, but there is no
 // coordination between different handlers. A handler may use the
 // cache.
-func (c *AssumeCache) AddEventHandler(handler cache.ResourceEventHandler) {
+//
+// The return value can be used to wait for cache synchronization.
+func (c *AssumeCache) AddEventHandler(handler cache.ResourceEventHandler) cache.ResourceEventHandlerRegistration {
 	defer c.emitEvents()
 	c.rwMutex.Lock()
 	defer c.rwMutex.Unlock()
@@ -497,6 +497,13 @@ func (c *AssumeCache) AddEventHandler(handler cache.ResourceEventHandler) {
 			handler.OnAdd(obj, true)
 		})
 	}
+
+	if c.handlerRegistration == nil {
+		// No informer, so immediately synced.
+		return syncedHandlerRegistration{}
+	}
+
+	return c.handlerRegistration
 }
 
 // emitEvents delivers all pending events that are in the queue, in the order
@@ -516,3 +523,9 @@ func (c *AssumeCache) emitEvents() {
 		}()
 	}
 }
+
+// syncedHandlerRegistration is an implementation of ResourceEventHandlerRegistration
+// which always returns true.
+type syncedHandlerRegistration struct{}
+
+func (syncedHandlerRegistration) HasSynced() bool { return true }

pkg/scheduler/util/assumecache/assume_cache_test.go

@@ -290,7 +290,7 @@ func TestRestore(t *testing.T) {
 		events.verifyAndFlush(tCtx, []event{{What: "add", Obj: oldObj}})
 	})
 
-	// Restore object.
+	// Restore the same object.
 	ktesting.Step(tCtx, "initial Restore", func(tCtx ktesting.TContext) {
 		cache.Restore(oldObj.GetName())
 		verify(tCtx, cache, oldObj.GetName(), oldObj, oldObj)
@@ -306,7 +306,7 @@ func TestRestore(t *testing.T) {
 		events.verifyAndFlush(tCtx, []event{{What: "update", OldObj: oldObj, Obj: newObj}})
 	})
 
-	// Restore object.
+	// Restore the same object.
 	ktesting.Step(tCtx, "second Restore", func(tCtx ktesting.TContext) {
 		cache.Restore(oldObj.GetName())
 		verify(tCtx, cache, oldObj.GetName(), oldObj, oldObj)
@@ -346,6 +346,7 @@ func TestEvents(t *testing.T) {
 	ktesting.Step(tCtx, "nil add", func(tCtx ktesting.TContext) {
 		informer.add(nil)
 		verify(tCtx, cache, key, newObj, newObj)
+		events.verifyAndFlush(tCtx, nil)
 	})
 	ktesting.Step(tCtx, "nop update", func(tCtx ktesting.TContext) {
 		informer.update(oldObj)
@@ -378,7 +379,7 @@ func TestEventHandlers(t *testing.T) {
 	tCtx, cache, informer := newTest(t)
 	handlers := make([]mockEventHandler, 5)
 
-	objs := make([]metav1.Object, 0, 20)
+	var objs []metav1.Object
 	for i := 0; i < 5; i++ {
 		objs = append(objs, makeObj(fmt.Sprintf("test-pvc%v", i), "1", ""))
 		informer.add(objs[i])
@@ -437,7 +438,7 @@ func TestEventHandlerConcurrency(t *testing.T) {
 	tCtx, cache, informer := newTest(t)
 	handlers := make([]mockEventHandler, 5)
 
-	objs := make([]metav1.Object, 0, 20)
+	var objs []metav1.Object
 	for i := 0; i < 5; i++ {
 		objs = append(objs, makeObj(fmt.Sprintf("test-pvc%v", i), "1", ""))
 	}
@@ -487,7 +488,7 @@ func TestListNoIndexer(t *testing.T) {
 	tCtx, cache, informer := newTest(t)
 
 	// Add a bunch of objects.
-	objs := make([]interface{}, 0, 10)
+	var objs []interface{}
 	for i := 0; i < 10; i++ {
 		obj := makeObj(fmt.Sprintf("test-pvc%v", i), "1", "")
 		objs = append(objs, obj)
@@ -526,7 +527,7 @@ func TestListWithIndexer(t *testing.T) {
 
 	// Add a bunch of objects.
 	ns := "ns1"
-	objs := make([]interface{}, 0, 10)
+	var objs []interface{}
 	for i := 0; i < 10; i++ {
 		obj := makeObj(fmt.Sprintf("test-pvc%v", i), "1", ns)
 		objs = append(objs, obj)