Merge pull request kubernetes#127500 from p0lyn0mial/upstream-assign-rv-to-watchCacheInterval

cacher: prevents sending events with ResourceVersion < RequiredResourceVersion

Author: k8s-ci-robot

staging/src/k8s.io/apiserver/pkg/storage/cacher/cache_watcher.go

@@ -454,6 +454,13 @@ func (c *cacheWatcher) processInterval(ctx context.Context, cacheInterval *watch
 	const initProcessThreshold = 500 * time.Millisecond
 	startTime := time.Now()
 
+	// cacheInterval may be created from a version being more fresh than requested
+	// (e.g. for NotOlderThan semantic). In such a case, we need to prevent watch event
+	// with lower resourceVersion from being delivered to ensure watch contract.
+	if cacheInterval.resourceVersion > resourceVersion {
+		resourceVersion = cacheInterval.resourceVersion
+	}
+
 	initEventCount := 0
 	for {
 		event, err := cacheInterval.Next()

staging/src/k8s.io/apiserver/pkg/storage/cacher/watch_cache.go

@@ -746,7 +746,7 @@ func (w *watchCache) getAllEventsSinceLocked(resourceVersion uint64, key string,
 	indexerFunc := func(i int) *watchCacheEvent {
 		return w.cache[i%w.capacity]
 	}
-	ci := newCacheInterval(w.startIndex+first, w.endIndex, indexerFunc, w.indexValidator, w.RWMutex.RLocker())
+	ci := newCacheInterval(w.startIndex+first, w.endIndex, indexerFunc, w.indexValidator, resourceVersion, w.RWMutex.RLocker())
 	return ci, nil
 }
 

staging/src/k8s.io/apiserver/pkg/storage/cacher/watch_cache_interval.go

@@ -91,6 +91,10 @@ type watchCacheInterval struct {
 	// lock on each invocation of Next().
 	buffer *watchCacheIntervalBuffer
 
+	// resourceVersion is the resourceVersion from which
+	// the interval was constructed.
+	resourceVersion uint64
+
 	// lock effectively protects access to the underlying source
 	// of events through - indexer and indexValidator.
 	//
@@ -103,14 +107,15 @@ type attrFunc func(runtime.Object) (labels.Set, fields.Set, error)
 type indexerFunc func(int) *watchCacheEvent
 type indexValidator func(int) bool
 
-func newCacheInterval(startIndex, endIndex int, indexer indexerFunc, indexValidator indexValidator, locker sync.Locker) *watchCacheInterval {
+func newCacheInterval(startIndex, endIndex int, indexer indexerFunc, indexValidator indexValidator, resourceVersion uint64, locker sync.Locker) *watchCacheInterval {
 	return &watchCacheInterval{
-		startIndex:     startIndex,
-		endIndex:       endIndex,
-		indexer:        indexer,
-		indexValidator: indexValidator,
-		buffer:         &watchCacheIntervalBuffer{buffer: make([]*watchCacheEvent, bufferSize)},
-		lock:           locker,
+		startIndex:      startIndex,
+		endIndex:        endIndex,
+		indexer:         indexer,
+		indexValidator:  indexValidator,
+		buffer:          &watchCacheIntervalBuffer{buffer: make([]*watchCacheEvent, bufferSize)},
+		resourceVersion: resourceVersion,
+		lock:            locker,
 	}
 }
 
@@ -172,8 +177,9 @@ func newCacheIntervalFromStore(resourceVersion uint64, store storeIndexer, getAt
 	ci := &watchCacheInterval{
 		startIndex: 0,
 		// Simulate that we already have all the events we're looking for.
-		endIndex: 0,
-		buffer:   buffer,
+		endIndex:        0,
+		buffer:          buffer,
+		resourceVersion: resourceVersion,
 	}
 
 	return ci, nil

staging/src/k8s.io/apiserver/pkg/storage/cacher/watch_cache_interval_test.go

@@ -41,7 +41,7 @@ func intervalFromEvents(events []*watchCacheEvent) *watchCacheInterval {
 	}
 	indexValidator := func(_ int) bool { return true }
 
-	return newCacheInterval(startIndex, endIndex, indexer, indexValidator, locker)
+	return newCacheInterval(startIndex, endIndex, indexer, indexValidator, 0, locker)
 }
 
 func bufferFromEvents(events []*watchCacheEvent) *watchCacheIntervalBuffer {
@@ -300,6 +300,7 @@ func TestCacheIntervalNextFromWatchCache(t *testing.T) {
 				wc.endIndex,
 				indexerFunc,
 				wc.isIndexValidLocked,
+				wc.resourceVersion,
 				&wc.RWMutex,
 			)
 

staging/src/k8s.io/apiserver/pkg/storage/testing/watcher_tests.go

@@ -1460,6 +1460,21 @@ func RunWatchSemantics(ctx context.Context, t *testing.T, store storage.Interfac
 				createdPods = append(createdPods, out)
 			}
 
+			if len(createdPods) > 0 {
+				// this list call ensures that the cache has seen the created pods.
+				// this makes the watch request below deterministic.
+				listObject := &example.PodList{}
+				opts := storage.ListOptions{
+					Predicate:            storage.Everything,
+					Recursive:            true,
+					ResourceVersion:      createdPods[len(createdPods)-1].ResourceVersion,
+					ResourceVersionMatch: metav1.ResourceVersionMatchNotOlderThan,
+				}
+				err := store.GetList(ctx, fmt.Sprintf("/pods/%s", ns), opts, listObject)
+				require.NoError(t, err)
+				require.Len(t, listObject.Items, len(createdPods))
+			}
+
 			if scenario.useCurrentRV {
 				currentStorageRV, err := storage.GetCurrentResourceVersionFromStorage(ctx, store, func() runtime.Object { return &example.PodList{} }, "/pods", "")
 				require.NoError(t, err)