integration/apimachinery: add TestReflectorWatchListFallback integration test

test/integration/apimachinery/watchlist_test.go

@@ -0,0 +1,158 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package apimachinery
+
+import (
+	"context"
+	"fmt"
+	"sort"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/google/go-cmp/cmp"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/cache"
+	kubeapiservertesting "k8s.io/kubernetes/cmd/kube-apiserver/app/testing"
+	"k8s.io/kubernetes/test/integration/framework"
+)
+
+func TestReflectorWatchListFallback(t *testing.T) {
+	ctx := context.TODO()
+
+	t.Log("Starting etcd that will be used by two different instances of kube-apiserver")
+	etcdURL, etcdTearDownFn, err := framework.RunCustomEtcd("etcd_watchlist", []string{"--experimental-watch-progress-notify-interval", "1s"}, nil)
+	require.NoError(t, err)
+	defer etcdTearDownFn()
+	etcdOptions := framework.DefaultEtcdOptions()
+	etcdOptions.StorageConfig.Transport.ServerList = []string{etcdURL}
+
+	t.Log("Starting the first server with the WatchList feature enabled")
+	server1 := kubeapiservertesting.StartTestServerOrDie(t, nil, []string{"--feature-gates=WatchList=true"}, &etcdOptions.StorageConfig)
+	defer server1.TearDownFn()
+	clientSet, err := kubernetes.NewForConfig(server1.ClientConfig)
+	require.NoError(t, err)
+
+	ns := framework.CreateNamespaceOrDie(clientSet, "reflector-fallback-watchlist", t)
+	defer framework.DeleteNamespaceOrDie(clientSet, ns, t)
+
+	t.Logf("Adding 5 secrets to %s namespace", ns.Name)
+	for i := 1; i <= 5; i++ {
+		_, err := clientSet.CoreV1().Secrets(ns.Name).Create(ctx, newSecret(fmt.Sprintf("secret-%d", i)), metav1.CreateOptions{})
+		require.NoError(t, err)
+	}
+
+	t.Log("Creating a secret reflector that will use the WatchList feature to synchronise the store")
+	store := &wrappedStore{Store: cache.NewStore(cache.DeletionHandlingMetaNamespaceKeyFunc)}
+	lw := &wrappedListWatch{&cache.ListWatch{}}
+	lw.SetClient(ctx, clientSet, ns)
+	target := cache.NewReflector(lw, &v1.Secret{}, store, time.Duration(0))
+	target.UseWatchList = true
+
+	t.Log("Waiting until the secret reflector synchronises to the store (call to the Replace method)")
+	reflectorCtx, reflectorCtxCancel := context.WithCancel(context.Background())
+	defer reflectorCtxCancel()
+	store.setCancelOnReplace(reflectorCtxCancel)
+	err = target.ListAndWatch(reflectorCtx.Done())
+	require.NoError(t, err)
+
+	t.Log("Verifying if the secret reflector was properly synchronised")
+	verifyStore(t, ctx, clientSet, store, ns)
+
+	t.Log("Starting the second server with the WatchList feature disabled")
+	server2 := kubeapiservertesting.StartTestServerOrDie(t, nil, []string{"--feature-gates=WatchList=false"}, &etcdOptions.StorageConfig)
+	defer server2.TearDownFn()
+	clientSet2, err := kubernetes.NewForConfig(server2.ClientConfig)
+	require.NoError(t, err)
+
+	t.Log("Pointing the ListWatcher used by the secret reflector to the second server (with the WatchList feature disabled)")
+	lw.SetClient(ctx, clientSet2, ns)
+	reflectorCtx, reflectorCtxCancel = context.WithCancel(context.Background())
+	defer reflectorCtxCancel()
+	store.setCancelOnReplace(reflectorCtxCancel)
+	err = target.ListAndWatch(reflectorCtx.Done())
+	require.NoError(t, err)
+
+	t.Log("Verifying if the secret reflector was properly synchronised")
+	verifyStore(t, ctx, clientSet, store, ns)
+}
+
+// TODO(#115478): refactor with e2e/apimachinery/watchlist
+func verifyStore(t *testing.T, ctx context.Context, clientSet kubernetes.Interface, store cache.Store, namespace *v1.Namespace) {
+	t.Logf("Listing secrets directly from the server from %s namespace", namespace.Name)
+	expectedSecretsList, err := clientSet.CoreV1().Secrets(namespace.Name).List(ctx, metav1.ListOptions{})
+	require.NoError(t, err)
+	expectedSecrets := expectedSecretsList.Items
+
+	err = wait.PollUntilContextTimeout(ctx, 100*time.Millisecond, wait.ForeverTestTimeout, true, func(ctx context.Context) (done bool, err error) {
+		t.Log("Comparing secrets retrieved directly from the server with the ones that have been streamed to the secret reflector")
+		rawStreamedSecrets := store.List()
+		streamedSecrets := make([]v1.Secret, 0, len(rawStreamedSecrets))
+		for _, rawSecret := range rawStreamedSecrets {
+			streamedSecrets = append(streamedSecrets, *rawSecret.(*v1.Secret))
+		}
+		sort.Sort(byName(expectedSecrets))
+		sort.Sort(byName(streamedSecrets))
+		return cmp.Equal(expectedSecrets, streamedSecrets), nil
+	})
+	require.NoError(t, err)
+}
+
+type byName []v1.Secret
+
+func (a byName) Len() int           { return len(a) }
+func (a byName) Less(i, j int) bool { return a[i].Name < a[j].Name }
+func (a byName) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+
+func newSecret(name string) *v1.Secret {
+	return &v1.Secret{
+		ObjectMeta: metav1.ObjectMeta{Name: name},
+	}
+}
+
+type wrappedStore struct {
+	cache.Store
+	ctxCancel context.CancelFunc
+}
+
+func (s *wrappedStore) Replace(items []interface{}, rv string) error {
+	s.ctxCancel()
+	return s.Store.Replace(items, rv)
+}
+
+func (s *wrappedStore) setCancelOnReplace(ctxCancel context.CancelFunc) {
+	s.ctxCancel = ctxCancel
+}
+
+type wrappedListWatch struct {
+	*cache.ListWatch
+}
+
+func (lw *wrappedListWatch) SetClient(ctx context.Context, clientSet kubernetes.Interface, ns *v1.Namespace) {
+	lw.ListFunc = func(options metav1.ListOptions) (runtime.Object, error) {
+		return clientSet.CoreV1().Secrets(ns.Name).List(ctx, options)
+	}
+	lw.WatchFunc = func(options metav1.ListOptions) (watch.Interface, error) {
+		return clientSet.CoreV1().Secrets(ns.Name).Watch(ctx, options)
+	}
+}