opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/ShardTest.java

   1 package org.opendaylight.controller.cluster.datastore;
   2
   3 import static org.junit.Assert.assertEquals;
   4 import static org.junit.Assert.assertFalse;
   5 import static org.junit.Assert.assertNotNull;
   6 import static org.junit.Assert.assertNull;
   7 import static org.junit.Assert.assertTrue;
   8 import static org.junit.Assert.fail;
   9 import static org.mockito.Mockito.doAnswer;
  10 import static org.mockito.Mockito.doReturn;
  11 import static org.mockito.Mockito.inOrder;
  12 import static org.mockito.Mockito.mock;
  13 import static org.opendaylight.controller.cluster.datastore.DataStoreVersions.CURRENT_VERSION;
  14 import akka.actor.ActorRef;
  15 import akka.actor.PoisonPill;
  16 import akka.actor.Props;
  17 import akka.dispatch.Dispatchers;
  18 import akka.dispatch.OnComplete;
  19 import akka.japi.Creator;
  20 import akka.pattern.Patterns;
  21 import akka.testkit.TestActorRef;
  22 import akka.util.Timeout;
  23 import com.google.common.base.Function;
  24 import com.google.common.base.Optional;
  25 import com.google.common.util.concurrent.CheckedFuture;
  26 import com.google.common.util.concurrent.Futures;
  27 import com.google.common.util.concurrent.ListenableFuture;
  28 import com.google.common.util.concurrent.MoreExecutors;
  29 import com.google.common.util.concurrent.Uninterruptibles;
  30 import java.io.IOException;
  31 import java.util.Collections;
  32 import java.util.HashSet;
  33 import java.util.Map;
  34 import java.util.Set;
  35 import java.util.concurrent.CountDownLatch;
  36 import java.util.concurrent.ExecutionException;
  37 import java.util.concurrent.TimeUnit;
  38 import java.util.concurrent.atomic.AtomicInteger;
  39 import java.util.concurrent.atomic.AtomicReference;
  40 import org.junit.After;
  41 import org.junit.Before;
  42 import org.junit.Test;
  43 import org.mockito.InOrder;
  44 import org.mockito.invocation.InvocationOnMock;
  45 import org.mockito.stubbing.Answer;
  46 import org.opendaylight.controller.cluster.datastore.DatastoreContext.Builder;
  47 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  48 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  49 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
  50 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  51 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransactionReply;
  52 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  53 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
  54 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  55 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  56 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  57 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
  58 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  59 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListenerReply;
  60 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  61 import org.opendaylight.controller.cluster.datastore.modification.MergeModification;
  62 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  63 import org.opendaylight.controller.cluster.datastore.modification.MutableCompositeModification;
  64 import org.opendaylight.controller.cluster.datastore.modification.WriteModification;
  65 import org.opendaylight.controller.cluster.datastore.node.NormalizedNodeToNodeCodec;
  66 import org.opendaylight.controller.cluster.datastore.utils.InMemoryJournal;
  67 import org.opendaylight.controller.cluster.datastore.utils.InMemorySnapshotStore;
  68 import org.opendaylight.controller.cluster.datastore.utils.MockDataChangeListener;
  69 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
  70 import org.opendaylight.controller.cluster.raft.ReplicatedLogImplEntry;
  71 import org.opendaylight.controller.cluster.raft.Snapshot;
  72 import org.opendaylight.controller.cluster.raft.base.messages.ApplyLogEntries;
  73 import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot;
  74 import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
  75 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot;
  76 import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
  77 import org.opendaylight.controller.cluster.raft.client.messages.FindLeader;
  78 import org.opendaylight.controller.cluster.raft.client.messages.FindLeaderReply;
  79 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationByteStringPayload;
  80 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationPayload;
  81 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  82 import org.opendaylight.controller.md.cluster.datastore.model.SchemaContextHelper;
  83 import org.opendaylight.controller.md.cluster.datastore.model.TestModel;
  84 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker;
  85 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeEvent;
  86 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener;
  87 import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
  88 import org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStore;
  89 import org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStoreFactory;
  90 import org.opendaylight.controller.protobuff.messages.common.NormalizedNodeMessages;
  91 import org.opendaylight.controller.protobuff.messages.transaction.ShardTransactionMessages.CreateTransactionReply;
  92 import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadTransaction;
  93 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  94 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
  95 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  96 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
  97 import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild;
  98 import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
  99 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
 100 import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes;
 101 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 102 import scala.concurrent.Await;
 103 import scala.concurrent.Future;
 104 import scala.concurrent.duration.FiniteDuration;
 105
 106 public class ShardTest extends AbstractActorTest {
 107
 108     private static final SchemaContext SCHEMA_CONTEXT = TestModel.createTestContext();
 109
 110     private static final AtomicInteger NEXT_SHARD_NUM = new AtomicInteger();
 111
 112     private final ShardIdentifier shardID = ShardIdentifier.builder().memberName("member-1")
 113             .shardName("inventory").type("config" + NEXT_SHARD_NUM.getAndIncrement()).build();
 114
 115     private final Builder dataStoreContextBuilder = DatastoreContext.newBuilder().
 116             shardJournalRecoveryLogBatchSize(3).shardSnapshotBatchCount(5000).
 117             shardHeartbeatIntervalInMillis(100);
 118
 119     @Before
 120     public void setUp() {
 121         Builder newBuilder = DatastoreContext.newBuilder();
 122         InMemorySnapshotStore.clear();
 123         InMemoryJournal.clear();
 124     }
 125
 126     @After
 127     public void tearDown() {
 128         InMemorySnapshotStore.clear();
 129         InMemoryJournal.clear();
 130     }
 131
 132     private DatastoreContext newDatastoreContext() {
 133         return dataStoreContextBuilder.build();
 134     }
 135
 136     private Props newShardProps() {
 137         return Shard.props(shardID, Collections.<ShardIdentifier,String>emptyMap(),
 138                 newDatastoreContext(), SCHEMA_CONTEXT);
 139     }
 140
 141     @Test
 142     public void testRegisterChangeListener() throws Exception {
 143         new ShardTestKit(getSystem()) {{
 144             TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 145                     newShardProps(),  "testRegisterChangeListener");
 146
 147             waitUntilLeader(shard);
 148
 149             shard.tell(new UpdateSchemaContext(SchemaContextHelper.full()), ActorRef.noSender());
 150
 151             MockDataChangeListener listener = new MockDataChangeListener(1);
 152             ActorRef dclActor = getSystem().actorOf(DataChangeListener.props(listener),
 153                     "testRegisterChangeListener-DataChangeListener");
 154
 155             shard.tell(new RegisterChangeListener(TestModel.TEST_PATH,
 156                     dclActor.path(), AsyncDataBroker.DataChangeScope.BASE), getRef());
 157
 158             RegisterChangeListenerReply reply = expectMsgClass(duration("3 seconds"),
 159                     RegisterChangeListenerReply.class);
 160             String replyPath = reply.getListenerRegistrationPath().toString();
 161             assertTrue("Incorrect reply path: " + replyPath, replyPath.matches(
 162                     "akka:\\/\\/test\\/user\\/testRegisterChangeListener\\/\\$.*"));
 163
 164             YangInstanceIdentifier path = TestModel.TEST_PATH;
 165             writeToStore(shard, path, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 166
 167             listener.waitForChangeEvents(path);
 168
 169             dclActor.tell(PoisonPill.getInstance(), ActorRef.noSender());
 170             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 171         }};
 172     }
 173
 174     @SuppressWarnings("serial")
 175     @Test
 176     public void testChangeListenerNotifiedWhenNotTheLeaderOnRegistration() throws Exception {
 177         // This test tests the timing window in which a change listener is registered before the
 178         // shard becomes the leader. We verify that the listener is registered and notified of the
 179         // existing data when the shard becomes the leader.
 180         new ShardTestKit(getSystem()) {{
 181             // For this test, we want to send the RegisterChangeListener message after the shard
 182             // has recovered from persistence and before it becomes the leader. So we subclass
 183             // Shard to override onReceiveCommand and, when the first ElectionTimeout is received,
 184             // we know that the shard has been initialized to a follower and has started the
 185             // election process. The following 2 CountDownLatches are used to coordinate the
 186             // ElectionTimeout with the sending of the RegisterChangeListener message.
 187             final CountDownLatch onFirstElectionTimeout = new CountDownLatch(1);
 188             final CountDownLatch onChangeListenerRegistered = new CountDownLatch(1);
 189             Creator<Shard> creator = new Creator<Shard>() {
 190                 boolean firstElectionTimeout = true;
 191
 192                 @Override
 193                 public Shard create() throws Exception {
 194                     return new Shard(shardID, Collections.<ShardIdentifier,String>emptyMap(),
 195                             newDatastoreContext(), SCHEMA_CONTEXT) {
 196                         @Override
 197                         public void onReceiveCommand(final Object message) throws Exception {
 198                             if(message instanceof ElectionTimeout && firstElectionTimeout) {
 199                                 // Got the first ElectionTimeout. We don't forward it to the
 200                                 // base Shard yet until we've sent the RegisterChangeListener
 201                                 // message. So we signal the onFirstElectionTimeout latch to tell
 202                                 // the main thread to send the RegisterChangeListener message and
 203                                 // start a thread to wait on the onChangeListenerRegistered latch,
 204                                 // which the main thread signals after it has sent the message.
 205                                 // After the onChangeListenerRegistered is triggered, we send the
 206                                 // original ElectionTimeout message to proceed with the election.
 207                                 firstElectionTimeout = false;
 208                                 final ActorRef self = getSelf();
 209                                 new Thread() {
 210                                     @Override
 211                                     public void run() {
 212                                         Uninterruptibles.awaitUninterruptibly(
 213                                                 onChangeListenerRegistered, 5, TimeUnit.SECONDS);
 214                                         self.tell(message, self);
 215                                     }
 216                                 }.start();
 217
 218                                 onFirstElectionTimeout.countDown();
 219                             } else {
 220                                 super.onReceiveCommand(message);
 221                             }
 222                         }
 223                     };
 224                 }
 225             };
 226
 227             MockDataChangeListener listener = new MockDataChangeListener(1);
 228             ActorRef dclActor = getSystem().actorOf(DataChangeListener.props(listener),
 229                     "testRegisterChangeListenerWhenNotLeaderInitially-DataChangeListener");
 230
 231             TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 232                     Props.create(new DelegatingShardCreator(creator)),
 233                     "testRegisterChangeListenerWhenNotLeaderInitially");
 234
 235             // Write initial data into the in-memory store.
 236             YangInstanceIdentifier path = TestModel.TEST_PATH;
 237             writeToStore(shard, path, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 238
 239             // Wait until the shard receives the first ElectionTimeout message.
 240             assertEquals("Got first ElectionTimeout", true,
 241                     onFirstElectionTimeout.await(5, TimeUnit.SECONDS));
 242
 243             // Now send the RegisterChangeListener and wait for the reply.
 244             shard.tell(new RegisterChangeListener(path, dclActor.path(),
 245                     AsyncDataBroker.DataChangeScope.SUBTREE), getRef());
 246
 247             RegisterChangeListenerReply reply = expectMsgClass(duration("5 seconds"),
 248                     RegisterChangeListenerReply.class);
 249             assertNotNull("getListenerRegistrationPath", reply.getListenerRegistrationPath());
 250
 251             // Sanity check - verify the shard is not the leader yet.
 252             shard.tell(new FindLeader(), getRef());
 253             FindLeaderReply findLeadeReply =
 254                     expectMsgClass(duration("5 seconds"), FindLeaderReply.class);
 255             assertNull("Expected the shard not to be the leader", findLeadeReply.getLeaderActor());
 256
 257             // Signal the onChangeListenerRegistered latch to tell the thread above to proceed
 258             // with the election process.
 259             onChangeListenerRegistered.countDown();
 260
 261             // Wait for the shard to become the leader and notify our listener with the existing
 262             // data in the store.
 263             listener.waitForChangeEvents(path);
 264
 265             dclActor.tell(PoisonPill.getInstance(), ActorRef.noSender());
 266             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 267         }};
 268     }
 269
 270     @Test
 271     public void testCreateTransaction(){
 272         new ShardTestKit(getSystem()) {{
 273             ActorRef shard = getSystem().actorOf(newShardProps(), "testCreateTransaction");
 274
 275             waitUntilLeader(shard);
 276
 277             shard.tell(new UpdateSchemaContext(TestModel.createTestContext()), getRef());
 278
 279             shard.tell(new CreateTransaction("txn-1",
 280                     TransactionProxy.TransactionType.READ_ONLY.ordinal() ).toSerializable(), getRef());
 281
 282             CreateTransactionReply reply = expectMsgClass(duration("3 seconds"),
 283                     CreateTransactionReply.class);
 284
 285             String path = reply.getTransactionActorPath().toString();
 286             assertTrue("Unexpected transaction path " + path,
 287                     path.contains("akka://test/user/testCreateTransaction/shard-txn-1"));
 288
 289             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 290         }};
 291     }
 292
 293     @Test
 294     public void testCreateTransactionOnChain(){
 295         new ShardTestKit(getSystem()) {{
 296             final ActorRef shard = getSystem().actorOf(newShardProps(), "testCreateTransactionOnChain");
 297
 298             waitUntilLeader(shard);
 299
 300             shard.tell(new CreateTransaction("txn-1",
 301                     TransactionProxy.TransactionType.READ_ONLY.ordinal() , "foobar").toSerializable(),
 302                     getRef());
 303
 304             CreateTransactionReply reply = expectMsgClass(duration("3 seconds"),
 305                     CreateTransactionReply.class);
 306
 307             String path = reply.getTransactionActorPath().toString();
 308             assertTrue("Unexpected transaction path " + path,
 309                     path.contains("akka://test/user/testCreateTransactionOnChain/shard-txn-1"));
 310
 311             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 312         }};
 313     }
 314
 315     @SuppressWarnings("serial")
 316     @Test
 317     public void testPeerAddressResolved() throws Exception {
 318         new ShardTestKit(getSystem()) {{
 319             final CountDownLatch recoveryComplete = new CountDownLatch(1);
 320             class TestShard extends Shard {
 321                 TestShard() {
 322                     super(shardID, Collections.<ShardIdentifier, String>singletonMap(shardID, null),
 323                             newDatastoreContext(), SCHEMA_CONTEXT);
 324                 }
 325
 326                 Map<String, String> getPeerAddresses() {
 327                     return getRaftActorContext().getPeerAddresses();
 328                 }
 329
 330                 @Override
 331                 protected void onRecoveryComplete() {
 332                     try {
 333                         super.onRecoveryComplete();
 334                     } finally {
 335                         recoveryComplete.countDown();
 336                     }
 337                 }
 338             }
 339
 340             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 341                     Props.create(new DelegatingShardCreator(new Creator<Shard>() {
 342                         @Override
 343                         public TestShard create() throws Exception {
 344                             return new TestShard();
 345                         }
 346                     })), "testPeerAddressResolved");
 347
 348             //waitUntilLeader(shard);
 349             assertEquals("Recovery complete", true,
 350                     Uninterruptibles.awaitUninterruptibly(recoveryComplete, 5, TimeUnit.SECONDS));
 351
 352             String address = "akka://foobar";
 353             shard.underlyingActor().onReceiveCommand(new PeerAddressResolved(shardID, address));
 354
 355             assertEquals("getPeerAddresses", address,
 356                     ((TestShard)shard.underlyingActor()).getPeerAddresses().get(shardID.toString()));
 357
 358             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 359         }};
 360     }
 361
 362     @Test
 363     public void testApplySnapshot() throws Exception {
 364         TestActorRef<Shard> shard = TestActorRef.create(getSystem(), newShardProps(),
 365                 "testApplySnapshot");
 366
 367         NormalizedNodeToNodeCodec codec =
 368             new NormalizedNodeToNodeCodec(SCHEMA_CONTEXT);
 369
 370         writeToStore(shard, TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 371
 372         YangInstanceIdentifier root = YangInstanceIdentifier.builder().build();
 373         NormalizedNode<?,?> expected = readStore(shard, root);
 374
 375         NormalizedNodeMessages.Container encode = codec.encode(expected);
 376
 377         ApplySnapshot applySnapshot = new ApplySnapshot(Snapshot.create(
 378                 encode.getNormalizedNode().toByteString().toByteArray(),
 379                 Collections.<ReplicatedLogEntry>emptyList(), 1, 2, 3, 4));
 380
 381         shard.underlyingActor().onReceiveCommand(applySnapshot);
 382
 383         NormalizedNode<?,?> actual = readStore(shard, root);
 384
 385         assertEquals(expected, actual);
 386
 387         shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 388     }
 389
 390     @Test
 391     public void testApplyState() throws Exception {
 392
 393         TestActorRef<Shard> shard = TestActorRef.create(getSystem(), newShardProps(), "testApplyState");
 394
 395         NormalizedNode<?, ?> node = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 396
 397         MutableCompositeModification compMod = new MutableCompositeModification();
 398         compMod.addModification(new WriteModification(TestModel.TEST_PATH, node, SCHEMA_CONTEXT));
 399         Payload payload = new CompositeModificationPayload(compMod.toSerializable());
 400         ApplyState applyState = new ApplyState(null, "test",
 401                 new ReplicatedLogImplEntry(1, 2, payload));
 402
 403         shard.underlyingActor().onReceiveCommand(applyState);
 404
 405         NormalizedNode<?,?> actual = readStore(shard, TestModel.TEST_PATH);
 406         assertEquals("Applied state", node, actual);
 407
 408         shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 409     }
 410
 411     @SuppressWarnings("serial")
 412     @Test
 413     public void testRecovery() throws Exception {
 414
 415         // Set up the InMemorySnapshotStore.
 416
 417         InMemoryDOMDataStore testStore = InMemoryDOMDataStoreFactory.create("Test", null, null);
 418         testStore.onGlobalContextUpdated(SCHEMA_CONTEXT);
 419
 420         DOMStoreWriteTransaction writeTx = testStore.newWriteOnlyTransaction();
 421         writeTx.write(TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 422         DOMStoreThreePhaseCommitCohort commitCohort = writeTx.ready();
 423         commitCohort.preCommit().get();
 424         commitCohort.commit().get();
 425
 426         DOMStoreReadTransaction readTx = testStore.newReadOnlyTransaction();
 427         NormalizedNode<?, ?> root = readTx.read(YangInstanceIdentifier.builder().build()).get().get();
 428
 429         InMemorySnapshotStore.addSnapshot(shardID.toString(), Snapshot.create(
 430                 new NormalizedNodeToNodeCodec(SCHEMA_CONTEXT).encode(
 431                         root).
 432                                 getNormalizedNode().toByteString().toByteArray(),
 433                                 Collections.<ReplicatedLogEntry>emptyList(), 0, 1, -1, -1));
 434
 435         // Set up the InMemoryJournal.
 436
 437         InMemoryJournal.addEntry(shardID.toString(), 0, new ReplicatedLogImplEntry(0, 1, newPayload(
 438                   new WriteModification(TestModel.OUTER_LIST_PATH,
 439                           ImmutableNodes.mapNodeBuilder(TestModel.OUTER_LIST_QNAME).build(),
 440                           SCHEMA_CONTEXT))));
 441
 442         int nListEntries = 16;
 443         Set<Integer> listEntryKeys = new HashSet<>();
 444         for(int i = 1; i <= nListEntries-5; i++) {
 445             listEntryKeys.add(Integer.valueOf(i));
 446             YangInstanceIdentifier path = YangInstanceIdentifier.builder(TestModel.OUTER_LIST_PATH)
 447                     .nodeWithKey(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, i).build();
 448             Modification mod = new MergeModification(path,
 449                     ImmutableNodes.mapEntry(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, i),
 450                     SCHEMA_CONTEXT);
 451             InMemoryJournal.addEntry(shardID.toString(), i, new ReplicatedLogImplEntry(i, 1,
 452                     newPayload(mod)));
 453         }
 454
 455         // Add some of the new CompositeModificationByteStringPayload
 456         for(int i = 11; i <= nListEntries; i++) {
 457             listEntryKeys.add(Integer.valueOf(i));
 458             YangInstanceIdentifier path = YangInstanceIdentifier.builder(TestModel.OUTER_LIST_PATH)
 459                     .nodeWithKey(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, i).build();
 460             Modification mod = new MergeModification(path,
 461                     ImmutableNodes.mapEntry(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, i),
 462                     SCHEMA_CONTEXT);
 463             InMemoryJournal.addEntry(shardID.toString(), i, new ReplicatedLogImplEntry(i, 1,
 464                     newByteStringPayload(mod)));
 465         }
 466
 467
 468         InMemoryJournal.addEntry(shardID.toString(), nListEntries + 1,
 469                 new ApplyLogEntries(nListEntries));
 470
 471         // Create the actor and wait for recovery complete.
 472
 473         final CountDownLatch recoveryComplete = new CountDownLatch(1);
 474
 475         Creator<Shard> creator = new Creator<Shard>() {
 476             @Override
 477             public Shard create() throws Exception {
 478                 return new Shard(shardID, Collections.<ShardIdentifier,String>emptyMap(),
 479                         newDatastoreContext(), SCHEMA_CONTEXT) {
 480                     @Override
 481                     protected void onRecoveryComplete() {
 482                         try {
 483                             super.onRecoveryComplete();
 484                         } finally {
 485                             recoveryComplete.countDown();
 486                         }
 487                     }
 488                 };
 489             }
 490         };
 491
 492         TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 493                 Props.create(new DelegatingShardCreator(creator)), "testRecovery");
 494
 495         assertEquals("Recovery complete", true, recoveryComplete.await(5, TimeUnit.SECONDS));
 496
 497         // Verify data in the data store.
 498
 499         NormalizedNode<?, ?> outerList = readStore(shard, TestModel.OUTER_LIST_PATH);
 500         assertNotNull(TestModel.OUTER_LIST_QNAME.getLocalName() + " not found", outerList);
 501         assertTrue(TestModel.OUTER_LIST_QNAME.getLocalName() + " value is not Iterable",
 502                 outerList.getValue() instanceof Iterable);
 503         for(Object entry: (Iterable<?>) outerList.getValue()) {
 504             assertTrue(TestModel.OUTER_LIST_QNAME.getLocalName() + " entry is not MapEntryNode",
 505                     entry instanceof MapEntryNode);
 506             MapEntryNode mapEntry = (MapEntryNode)entry;
 507             Optional<DataContainerChild<? extends PathArgument, ?>> idLeaf =
 508                     mapEntry.getChild(new YangInstanceIdentifier.NodeIdentifier(TestModel.ID_QNAME));
 509             assertTrue("Missing leaf " + TestModel.ID_QNAME.getLocalName(), idLeaf.isPresent());
 510             Object value = idLeaf.get().getValue();
 511             assertTrue("Unexpected value for leaf "+ TestModel.ID_QNAME.getLocalName() + ": " + value,
 512                     listEntryKeys.remove(value));
 513         }
 514
 515         if(!listEntryKeys.isEmpty()) {
 516             fail("Missing " + TestModel.OUTER_LIST_QNAME.getLocalName() + " entries with keys: " +
 517                     listEntryKeys);
 518         }
 519
 520         assertEquals("Last log index", nListEntries,
 521                 shard.underlyingActor().getShardMBean().getLastLogIndex());
 522         assertEquals("Commit index", nListEntries,
 523                 shard.underlyingActor().getShardMBean().getCommitIndex());
 524         assertEquals("Last applied", nListEntries,
 525                 shard.underlyingActor().getShardMBean().getLastApplied());
 526
 527         shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 528     }
 529
 530     private CompositeModificationPayload newPayload(final Modification... mods) {
 531         MutableCompositeModification compMod = new MutableCompositeModification();
 532         for(Modification mod: mods) {
 533             compMod.addModification(mod);
 534         }
 535
 536         return new CompositeModificationPayload(compMod.toSerializable());
 537     }
 538
 539     private CompositeModificationByteStringPayload newByteStringPayload(final Modification... mods) {
 540         MutableCompositeModification compMod = new MutableCompositeModification();
 541         for(Modification mod: mods) {
 542             compMod.addModification(mod);
 543         }
 544
 545         return new CompositeModificationByteStringPayload(compMod.toSerializable());
 546     }
 547
 548
 549     private DOMStoreThreePhaseCommitCohort setupMockWriteTransaction(final String cohortName,
 550             final InMemoryDOMDataStore dataStore, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data,
 551             final MutableCompositeModification modification) {
 552         return setupMockWriteTransaction(cohortName, dataStore, path, data, modification, null);
 553     }
 554
 555     private DOMStoreThreePhaseCommitCohort setupMockWriteTransaction(final String cohortName,
 556             final InMemoryDOMDataStore dataStore, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data,
 557             final MutableCompositeModification modification,
 558             final Function<DOMStoreThreePhaseCommitCohort,ListenableFuture<Void>> preCommit) {
 559
 560         DOMStoreWriteTransaction tx = dataStore.newWriteOnlyTransaction();
 561         tx.write(path, data);
 562         final DOMStoreThreePhaseCommitCohort realCohort = tx.ready();
 563         DOMStoreThreePhaseCommitCohort cohort = mock(DOMStoreThreePhaseCommitCohort.class, cohortName);
 564
 565         doAnswer(new Answer<ListenableFuture<Boolean>>() {
 566             @Override
 567             public ListenableFuture<Boolean> answer(final InvocationOnMock invocation) {
 568                 return realCohort.canCommit();
 569             }
 570         }).when(cohort).canCommit();
 571
 572         doAnswer(new Answer<ListenableFuture<Void>>() {
 573             @Override
 574             public ListenableFuture<Void> answer(final InvocationOnMock invocation) throws Throwable {
 575                 if(preCommit != null) {
 576                     return preCommit.apply(realCohort);
 577                 } else {
 578                     return realCohort.preCommit();
 579                 }
 580             }
 581         }).when(cohort).preCommit();
 582
 583         doAnswer(new Answer<ListenableFuture<Void>>() {
 584             @Override
 585             public ListenableFuture<Void> answer(final InvocationOnMock invocation) throws Throwable {
 586                 return realCohort.commit();
 587             }
 588         }).when(cohort).commit();
 589
 590         doAnswer(new Answer<ListenableFuture<Void>>() {
 591             @Override
 592             public ListenableFuture<Void> answer(final InvocationOnMock invocation) throws Throwable {
 593                 return realCohort.abort();
 594             }
 595         }).when(cohort).abort();
 596
 597         modification.addModification(new WriteModification(path, data, SCHEMA_CONTEXT));
 598
 599         return cohort;
 600     }
 601
 602     @SuppressWarnings({ "unchecked" })
 603     @Test
 604     public void testConcurrentThreePhaseCommits() throws Throwable {
 605         new ShardTestKit(getSystem()) {{
 606             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 607                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
 608                     "testConcurrentThreePhaseCommits");
 609
 610             waitUntilLeader(shard);
 611
 612             // Setup 3 simulated transactions with mock cohorts backed by real cohorts.
 613
 614             InMemoryDOMDataStore dataStore = shard.underlyingActor().getDataStore();
 615
 616             String transactionID1 = "tx1";
 617             MutableCompositeModification modification1 = new MutableCompositeModification();
 618             DOMStoreThreePhaseCommitCohort cohort1 = setupMockWriteTransaction("cohort1", dataStore,
 619                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification1);
 620
 621             String transactionID2 = "tx2";
 622             MutableCompositeModification modification2 = new MutableCompositeModification();
 623             DOMStoreThreePhaseCommitCohort cohort2 = setupMockWriteTransaction("cohort2", dataStore,
 624                     TestModel.OUTER_LIST_PATH,
 625                     ImmutableNodes.mapNodeBuilder(TestModel.OUTER_LIST_QNAME).build(),
 626                     modification2);
 627
 628             String transactionID3 = "tx3";
 629             MutableCompositeModification modification3 = new MutableCompositeModification();
 630             DOMStoreThreePhaseCommitCohort cohort3 = setupMockWriteTransaction("cohort3", dataStore,
 631                     YangInstanceIdentifier.builder(TestModel.OUTER_LIST_PATH)
 632                         .nodeWithKey(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, 1).build(),
 633                     ImmutableNodes.mapEntry(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, 1),
 634                     modification3);
 635
 636             long timeoutSec = 5;
 637             final FiniteDuration duration = FiniteDuration.create(timeoutSec, TimeUnit.SECONDS);
 638             final Timeout timeout = new Timeout(duration);
 639
 640             // Simulate the ForwardedReadyTransaction message for the first Tx that would be sent
 641             // by the ShardTransaction.
 642
 643             shard.tell(new ForwardedReadyTransaction(transactionID1, CURRENT_VERSION,
 644                     cohort1, modification1, true), getRef());
 645             ReadyTransactionReply readyReply = ReadyTransactionReply.fromSerializable(
 646                     expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS));
 647             assertEquals("Cohort path", shard.path().toString(), readyReply.getCohortPath());
 648
 649             // Send the CanCommitTransaction message for the first Tx.
 650
 651             shard.tell(new CanCommitTransaction(transactionID1).toSerializable(), getRef());
 652             CanCommitTransactionReply canCommitReply = CanCommitTransactionReply.fromSerializable(
 653                     expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS));
 654             assertEquals("Can commit", true, canCommitReply.getCanCommit());
 655
 656             // Send the ForwardedReadyTransaction for the next 2 Tx's.
 657
 658             shard.tell(new ForwardedReadyTransaction(transactionID2, CURRENT_VERSION,
 659                     cohort2, modification2, true), getRef());
 660             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
 661
 662             shard.tell(new ForwardedReadyTransaction(transactionID3, CURRENT_VERSION,
 663                     cohort3, modification3, true), getRef());
 664             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
 665
 666             // Send the CanCommitTransaction message for the next 2 Tx's. These should get queued and
 667             // processed after the first Tx completes.
 668
 669             Future<Object> canCommitFuture1 = Patterns.ask(shard,
 670                     new CanCommitTransaction(transactionID2).toSerializable(), timeout);
 671
 672             Future<Object> canCommitFuture2 = Patterns.ask(shard,
 673                     new CanCommitTransaction(transactionID3).toSerializable(), timeout);
 674
 675             // Send the CommitTransaction message for the first Tx. After it completes, it should
 676             // trigger the 2nd Tx to proceed which should in turn then trigger the 3rd.
 677
 678             shard.tell(new CommitTransaction(transactionID1).toSerializable(), getRef());
 679             expectMsgClass(duration, CommitTransactionReply.SERIALIZABLE_CLASS);
 680
 681             // Wait for the next 2 Tx's to complete.
 682
 683             final AtomicReference<Throwable> caughtEx = new AtomicReference<>();
 684             final CountDownLatch commitLatch = new CountDownLatch(2);
 685
 686             class OnFutureComplete extends OnComplete<Object> {
 687                 private final Class<?> expRespType;
 688
 689                 OnFutureComplete(final Class<?> expRespType) {
 690                     this.expRespType = expRespType;
 691                 }
 692
 693                 @Override
 694                 public void onComplete(final Throwable error, final Object resp) {
 695                     if(error != null) {
 696                         caughtEx.set(new AssertionError(getClass().getSimpleName() + " failure", error));
 697                     } else {
 698                         try {
 699                             assertEquals("Commit response type", expRespType, resp.getClass());
 700                             onSuccess(resp);
 701                         } catch (Exception e) {
 702                             caughtEx.set(e);
 703                         }
 704                     }
 705                 }
 706
 707                 void onSuccess(final Object resp) throws Exception {
 708                 }
 709             }
 710
 711             class OnCommitFutureComplete extends OnFutureComplete {
 712                 OnCommitFutureComplete() {
 713                     super(CommitTransactionReply.SERIALIZABLE_CLASS);
 714                 }
 715
 716                 @Override
 717                 public void onComplete(final Throwable error, final Object resp) {
 718                     super.onComplete(error, resp);
 719                     commitLatch.countDown();
 720                 }
 721             }
 722
 723             class OnCanCommitFutureComplete extends OnFutureComplete {
 724                 private final String transactionID;
 725
 726                 OnCanCommitFutureComplete(final String transactionID) {
 727                     super(CanCommitTransactionReply.SERIALIZABLE_CLASS);
 728                     this.transactionID = transactionID;
 729                 }
 730
 731                 @Override
 732                 void onSuccess(final Object resp) throws Exception {
 733                     CanCommitTransactionReply canCommitReply =
 734                             CanCommitTransactionReply.fromSerializable(resp);
 735                     assertEquals("Can commit", true, canCommitReply.getCanCommit());
 736
 737                     Future<Object> commitFuture = Patterns.ask(shard,
 738                             new CommitTransaction(transactionID).toSerializable(), timeout);
 739                     commitFuture.onComplete(new OnCommitFutureComplete(), getSystem().dispatcher());
 740                 }
 741             }
 742
 743             canCommitFuture1.onComplete(new OnCanCommitFutureComplete(transactionID2),
 744                     getSystem().dispatcher());
 745
 746             canCommitFuture2.onComplete(new OnCanCommitFutureComplete(transactionID3),
 747                     getSystem().dispatcher());
 748
 749             boolean done = commitLatch.await(timeoutSec, TimeUnit.SECONDS);
 750
 751             if(caughtEx.get() != null) {
 752                 throw caughtEx.get();
 753             }
 754
 755             assertEquals("Commits complete", true, done);
 756
 757             InOrder inOrder = inOrder(cohort1, cohort2, cohort3);
 758             inOrder.verify(cohort1).canCommit();
 759             inOrder.verify(cohort1).preCommit();
 760             inOrder.verify(cohort1).commit();
 761             inOrder.verify(cohort2).canCommit();
 762             inOrder.verify(cohort2).preCommit();
 763             inOrder.verify(cohort2).commit();
 764             inOrder.verify(cohort3).canCommit();
 765             inOrder.verify(cohort3).preCommit();
 766             inOrder.verify(cohort3).commit();
 767
 768             // Verify data in the data store.
 769
 770             NormalizedNode<?, ?> outerList = readStore(shard, TestModel.OUTER_LIST_PATH);
 771             assertNotNull(TestModel.OUTER_LIST_QNAME.getLocalName() + " not found", outerList);
 772             assertTrue(TestModel.OUTER_LIST_QNAME.getLocalName() + " value is not Iterable",
 773                     outerList.getValue() instanceof Iterable);
 774             Object entry = ((Iterable<Object>)outerList.getValue()).iterator().next();
 775             assertTrue(TestModel.OUTER_LIST_QNAME.getLocalName() + " entry is not MapEntryNode",
 776                        entry instanceof MapEntryNode);
 777             MapEntryNode mapEntry = (MapEntryNode)entry;
 778             Optional<DataContainerChild<? extends PathArgument, ?>> idLeaf =
 779                     mapEntry.getChild(new YangInstanceIdentifier.NodeIdentifier(TestModel.ID_QNAME));
 780             assertTrue("Missing leaf " + TestModel.ID_QNAME.getLocalName(), idLeaf.isPresent());
 781             assertEquals(TestModel.ID_QNAME.getLocalName() + " value", 1, idLeaf.get().getValue());
 782
 783             verifyLastLogIndex(shard, 2);
 784
 785             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 786         }};
 787     }
 788
 789     private void verifyLastLogIndex(TestActorRef<Shard> shard, long expectedValue) {
 790         for(int i = 0; i < 20 * 5; i++) {
 791             long lastLogIndex = shard.underlyingActor().getShardMBean().getLastLogIndex();
 792             if(lastLogIndex == expectedValue) {
 793                 break;
 794             }
 795             Uninterruptibles.sleepUninterruptibly(50, TimeUnit.MILLISECONDS);
 796         }
 797
 798         assertEquals("Last log index", expectedValue, shard.underlyingActor().getShardMBean().getLastLogIndex());
 799     }
 800
 801     @Test
 802     public void testCommitWithPersistenceDisabled() throws Throwable {
 803         dataStoreContextBuilder.persistent(false);
 804         new ShardTestKit(getSystem()) {{
 805             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 806                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
 807                     "testCommitPhaseFailure");
 808
 809             waitUntilLeader(shard);
 810
 811             InMemoryDOMDataStore dataStore = shard.underlyingActor().getDataStore();
 812
 813             // Setup a simulated transactions with a mock cohort.
 814
 815             String transactionID = "tx";
 816             MutableCompositeModification modification = new MutableCompositeModification();
 817             NormalizedNode<?, ?> containerNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
 818             DOMStoreThreePhaseCommitCohort cohort = setupMockWriteTransaction("cohort", dataStore,
 819                     TestModel.TEST_PATH, containerNode, modification);
 820
 821             FiniteDuration duration = duration("5 seconds");
 822
 823             // Simulate the ForwardedReadyTransaction messages that would be sent
 824             // by the ShardTransaction.
 825
 826             shard.tell(new ForwardedReadyTransaction(transactionID, CURRENT_VERSION,
 827                     cohort, modification, true), getRef());
 828             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
 829
 830             // Send the CanCommitTransaction message.
 831
 832             shard.tell(new CanCommitTransaction(transactionID).toSerializable(), getRef());
 833             CanCommitTransactionReply canCommitReply = CanCommitTransactionReply.fromSerializable(
 834                     expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS));
 835             assertEquals("Can commit", true, canCommitReply.getCanCommit());
 836
 837             // Send the CanCommitTransaction message.
 838
 839             shard.tell(new CommitTransaction(transactionID).toSerializable(), getRef());
 840             expectMsgClass(duration, CommitTransactionReply.SERIALIZABLE_CLASS);
 841
 842             InOrder inOrder = inOrder(cohort);
 843             inOrder.verify(cohort).canCommit();
 844             inOrder.verify(cohort).preCommit();
 845             inOrder.verify(cohort).commit();
 846
 847             NormalizedNode<?, ?> actualNode = readStore(shard, TestModel.TEST_PATH);
 848             assertEquals(TestModel.TEST_QNAME.getLocalName(), containerNode, actualNode);
 849
 850             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 851         }};
 852     }
 853
 854     @Test
 855     public void testCommitPhaseFailure() throws Throwable {
 856         new ShardTestKit(getSystem()) {{
 857             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 858                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
 859                     "testCommitPhaseFailure");
 860
 861             waitUntilLeader(shard);
 862
 863             // Setup 2 simulated transactions with mock cohorts. The first one fails in the
 864             // commit phase.
 865
 866             String transactionID1 = "tx1";
 867             MutableCompositeModification modification1 = new MutableCompositeModification();
 868             DOMStoreThreePhaseCommitCohort cohort1 = mock(DOMStoreThreePhaseCommitCohort.class, "cohort1");
 869             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort1).canCommit();
 870             doReturn(Futures.immediateFuture(null)).when(cohort1).preCommit();
 871             doReturn(Futures.immediateFailedFuture(new IllegalStateException("mock"))).when(cohort1).commit();
 872
 873             String transactionID2 = "tx2";
 874             MutableCompositeModification modification2 = new MutableCompositeModification();
 875             DOMStoreThreePhaseCommitCohort cohort2 = mock(DOMStoreThreePhaseCommitCohort.class, "cohort2");
 876             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort2).canCommit();
 877
 878             FiniteDuration duration = duration("5 seconds");
 879             final Timeout timeout = new Timeout(duration);
 880
 881             // Simulate the ForwardedReadyTransaction messages that would be sent
 882             // by the ShardTransaction.
 883
 884             shard.tell(new ForwardedReadyTransaction(transactionID1, CURRENT_VERSION,
 885                     cohort1, modification1, true), getRef());
 886             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
 887
 888             shard.tell(new ForwardedReadyTransaction(transactionID2, CURRENT_VERSION,
 889                     cohort2, modification2, true), getRef());
 890             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
 891
 892             // Send the CanCommitTransaction message for the first Tx.
 893
 894             shard.tell(new CanCommitTransaction(transactionID1).toSerializable(), getRef());
 895             CanCommitTransactionReply canCommitReply = CanCommitTransactionReply.fromSerializable(
 896                     expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS));
 897             assertEquals("Can commit", true, canCommitReply.getCanCommit());
 898
 899             // Send the CanCommitTransaction message for the 2nd Tx. This should get queued and
 900             // processed after the first Tx completes.
 901
 902             Future<Object> canCommitFuture = Patterns.ask(shard,
 903                     new CanCommitTransaction(transactionID2).toSerializable(), timeout);
 904
 905             // Send the CommitTransaction message for the first Tx. This should send back an error
 906             // and trigger the 2nd Tx to proceed.
 907
 908             shard.tell(new CommitTransaction(transactionID1).toSerializable(), getRef());
 909             expectMsgClass(duration, akka.actor.Status.Failure.class);
 910
 911             // Wait for the 2nd Tx to complete the canCommit phase.
 912
 913             final CountDownLatch latch = new CountDownLatch(1);
 914             canCommitFuture.onComplete(new OnComplete<Object>() {
 915                 @Override
 916                 public void onComplete(final Throwable t, final Object resp) {
 917                     latch.countDown();
 918                 }
 919             }, getSystem().dispatcher());
 920
 921             assertEquals("2nd CanCommit complete", true, latch.await(5, TimeUnit.SECONDS));
 922
 923             InOrder inOrder = inOrder(cohort1, cohort2);
 924             inOrder.verify(cohort1).canCommit();
 925             inOrder.verify(cohort1).preCommit();
 926             inOrder.verify(cohort1).commit();
 927             inOrder.verify(cohort2).canCommit();
 928
 929             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 930         }};
 931     }
 932
 933     @Test
 934     public void testPreCommitPhaseFailure() throws Throwable {
 935         new ShardTestKit(getSystem()) {{
 936             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 937                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
 938                     "testPreCommitPhaseFailure");
 939
 940             waitUntilLeader(shard);
 941
 942             String transactionID = "tx1";
 943             MutableCompositeModification modification = new MutableCompositeModification();
 944             DOMStoreThreePhaseCommitCohort cohort = mock(DOMStoreThreePhaseCommitCohort.class, "cohort1");
 945             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort).canCommit();
 946             doReturn(Futures.immediateFailedFuture(new IllegalStateException("mock"))).when(cohort).preCommit();
 947
 948             FiniteDuration duration = duration("5 seconds");
 949
 950             // Simulate the ForwardedReadyTransaction messages that would be sent
 951             // by the ShardTransaction.
 952
 953             shard.tell(new ForwardedReadyTransaction(transactionID, CURRENT_VERSION,
 954                     cohort, modification, true), getRef());
 955             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
 956
 957             // Send the CanCommitTransaction message.
 958
 959             shard.tell(new CanCommitTransaction(transactionID).toSerializable(), getRef());
 960             CanCommitTransactionReply canCommitReply = CanCommitTransactionReply.fromSerializable(
 961                     expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS));
 962             assertEquals("Can commit", true, canCommitReply.getCanCommit());
 963
 964             // Send the CommitTransaction message. This should send back an error
 965             // for preCommit failure.
 966
 967             shard.tell(new CommitTransaction(transactionID).toSerializable(), getRef());
 968             expectMsgClass(duration, akka.actor.Status.Failure.class);
 969
 970             InOrder inOrder = inOrder(cohort);
 971             inOrder.verify(cohort).canCommit();
 972             inOrder.verify(cohort).preCommit();
 973
 974             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 975         }};
 976     }
 977
 978     @Test
 979     public void testCanCommitPhaseFailure() throws Throwable {
 980         new ShardTestKit(getSystem()) {{
 981             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 982                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
 983                     "testCanCommitPhaseFailure");
 984
 985             waitUntilLeader(shard);
 986
 987             final FiniteDuration duration = duration("5 seconds");
 988
 989             String transactionID = "tx1";
 990             MutableCompositeModification modification = new MutableCompositeModification();
 991             DOMStoreThreePhaseCommitCohort cohort = mock(DOMStoreThreePhaseCommitCohort.class, "cohort1");
 992             doReturn(Futures.immediateFailedFuture(new IllegalStateException("mock"))).when(cohort).canCommit();
 993
 994             // Simulate the ForwardedReadyTransaction messages that would be sent
 995             // by the ShardTransaction.
 996
 997             shard.tell(new ForwardedReadyTransaction(transactionID, CURRENT_VERSION,
 998                     cohort, modification, true), getRef());
 999             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1000
1001             // Send the CanCommitTransaction message.
1002
1003             shard.tell(new CanCommitTransaction(transactionID).toSerializable(), getRef());
1004             expectMsgClass(duration, akka.actor.Status.Failure.class);
1005
1006             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
1007         }};
1008     }
1009
1010     @Test
1011     public void testAbortBeforeFinishCommit() throws Throwable {
1012         new ShardTestKit(getSystem()) {{
1013             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
1014                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
1015                     "testAbortBeforeFinishCommit");
1016
1017             waitUntilLeader(shard);
1018
1019             final FiniteDuration duration = duration("5 seconds");
1020             InMemoryDOMDataStore dataStore = shard.underlyingActor().getDataStore();
1021
1022             final String transactionID = "tx1";
1023             Function<DOMStoreThreePhaseCommitCohort,ListenableFuture<Void>> preCommit =
1024                           new Function<DOMStoreThreePhaseCommitCohort,ListenableFuture<Void>>() {
1025                 @Override
1026                 public ListenableFuture<Void> apply(final DOMStoreThreePhaseCommitCohort cohort) {
1027                     ListenableFuture<Void> preCommitFuture = cohort.preCommit();
1028
1029                     // Simulate an AbortTransaction message occurring during replication, after
1030                     // persisting and before finishing the commit to the in-memory store.
1031                     // We have no followers so due to optimizations in the RaftActor, it does not
1032                     // attempt replication and thus we can't send an AbortTransaction message b/c
1033                     // it would be processed too late after CommitTransaction completes. So we'll
1034                     // simulate an AbortTransaction message occurring during replication by calling
1035                     // the shard directly.
1036                     //
1037                     shard.underlyingActor().doAbortTransaction(transactionID, null);
1038
1039                     return preCommitFuture;
1040                 }
1041             };
1042
1043             MutableCompositeModification modification = new MutableCompositeModification();
1044             DOMStoreThreePhaseCommitCohort cohort = setupMockWriteTransaction("cohort1", dataStore,
1045                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME),
1046                     modification, preCommit);
1047
1048             shard.tell(new ForwardedReadyTransaction(transactionID, CURRENT_VERSION,
1049                     cohort, modification, true), getRef());
1050             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1051
1052             shard.tell(new CanCommitTransaction(transactionID).toSerializable(), getRef());
1053             CanCommitTransactionReply canCommitReply = CanCommitTransactionReply.fromSerializable(
1054                     expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS));
1055             assertEquals("Can commit", true, canCommitReply.getCanCommit());
1056
1057             shard.tell(new CommitTransaction(transactionID).toSerializable(), getRef());
1058             expectMsgClass(duration, CommitTransactionReply.SERIALIZABLE_CLASS);
1059
1060             NormalizedNode<?, ?> node = readStore(shard, TestModel.TEST_PATH);
1061
1062             // Since we're simulating an abort occurring during replication and before finish commit,
1063             // the data should still get written to the in-memory store since we've gotten past
1064             // canCommit and preCommit and persisted the data.
1065             assertNotNull(TestModel.TEST_QNAME.getLocalName() + " not found", node);
1066
1067             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
1068         }};
1069     }
1070
1071     @Test
1072     public void testTransactionCommitTimeout() throws Throwable {
1073         dataStoreContextBuilder.shardTransactionCommitTimeoutInSeconds(1);
1074
1075         new ShardTestKit(getSystem()) {{
1076             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
1077                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
1078                     "testTransactionCommitTimeout");
1079
1080             waitUntilLeader(shard);
1081
1082             final FiniteDuration duration = duration("5 seconds");
1083
1084             InMemoryDOMDataStore dataStore = shard.underlyingActor().getDataStore();
1085
1086             writeToStore(shard, TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
1087             writeToStore(shard, TestModel.OUTER_LIST_PATH,
1088                     ImmutableNodes.mapNodeBuilder(TestModel.OUTER_LIST_QNAME).build());
1089
1090             // Create 1st Tx - will timeout
1091
1092             String transactionID1 = "tx1";
1093             MutableCompositeModification modification1 = new MutableCompositeModification();
1094             DOMStoreThreePhaseCommitCohort cohort1 = setupMockWriteTransaction("cohort1", dataStore,
1095                     YangInstanceIdentifier.builder(TestModel.OUTER_LIST_PATH)
1096                         .nodeWithKey(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, 1).build(),
1097                     ImmutableNodes.mapEntry(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, 1),
1098                     modification1);
1099
1100             // Create 2nd Tx
1101
1102             String transactionID2 = "tx3";
1103             MutableCompositeModification modification2 = new MutableCompositeModification();
1104             YangInstanceIdentifier listNodePath = YangInstanceIdentifier.builder(TestModel.OUTER_LIST_PATH)
1105                 .nodeWithKey(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, 2).build();
1106             DOMStoreThreePhaseCommitCohort cohort2 = setupMockWriteTransaction("cohort3", dataStore,
1107                     listNodePath,
1108                     ImmutableNodes.mapEntry(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, 2),
1109                     modification2);
1110
1111             // Ready the Tx's
1112
1113             shard.tell(new ForwardedReadyTransaction(transactionID1, CURRENT_VERSION,
1114                     cohort1, modification1, true), getRef());
1115             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1116
1117             shard.tell(new ForwardedReadyTransaction(transactionID2, CURRENT_VERSION,
1118                     cohort2, modification2, true), getRef());
1119             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1120
1121             // canCommit 1st Tx. We don't send the commit so it should timeout.
1122
1123             shard.tell(new CanCommitTransaction(transactionID1).toSerializable(), getRef());
1124             expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS);
1125
1126             // canCommit the 2nd Tx - it should complete after the 1st Tx times out.
1127
1128             shard.tell(new CanCommitTransaction(transactionID2).toSerializable(), getRef());
1129             expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS);
1130
1131             // Commit the 2nd Tx.
1132
1133             shard.tell(new CommitTransaction(transactionID2).toSerializable(), getRef());
1134             expectMsgClass(duration, CommitTransactionReply.SERIALIZABLE_CLASS);
1135
1136             NormalizedNode<?, ?> node = readStore(shard, listNodePath);
1137             assertNotNull(listNodePath + " not found", node);
1138
1139             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
1140         }};
1141     }
1142
1143     @Test
1144     public void testTransactionCommitQueueCapacityExceeded() throws Throwable {
1145         dataStoreContextBuilder.shardTransactionCommitQueueCapacity(1);
1146
1147         new ShardTestKit(getSystem()) {{
1148             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
1149                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
1150                     "testTransactionCommitQueueCapacityExceeded");
1151
1152             waitUntilLeader(shard);
1153
1154             final FiniteDuration duration = duration("5 seconds");
1155
1156             InMemoryDOMDataStore dataStore = shard.underlyingActor().getDataStore();
1157
1158             String transactionID1 = "tx1";
1159             MutableCompositeModification modification1 = new MutableCompositeModification();
1160             DOMStoreThreePhaseCommitCohort cohort1 = setupMockWriteTransaction("cohort1", dataStore,
1161                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification1);
1162
1163             String transactionID2 = "tx2";
1164             MutableCompositeModification modification2 = new MutableCompositeModification();
1165             DOMStoreThreePhaseCommitCohort cohort2 = setupMockWriteTransaction("cohort2", dataStore,
1166                     TestModel.OUTER_LIST_PATH,
1167                     ImmutableNodes.mapNodeBuilder(TestModel.OUTER_LIST_QNAME).build(),
1168                     modification2);
1169
1170             String transactionID3 = "tx3";
1171             MutableCompositeModification modification3 = new MutableCompositeModification();
1172             DOMStoreThreePhaseCommitCohort cohort3 = setupMockWriteTransaction("cohort3", dataStore,
1173                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification3);
1174
1175             // Ready the Tx's
1176
1177             shard.tell(new ForwardedReadyTransaction(transactionID1, CURRENT_VERSION,
1178                     cohort1, modification1, true), getRef());
1179             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1180
1181             shard.tell(new ForwardedReadyTransaction(transactionID2, CURRENT_VERSION,
1182                     cohort2, modification2, true), getRef());
1183             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1184
1185             shard.tell(new ForwardedReadyTransaction(transactionID3, CURRENT_VERSION,
1186                     cohort3, modification3, true), getRef());
1187             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1188
1189             // canCommit 1st Tx.
1190
1191             shard.tell(new CanCommitTransaction(transactionID1).toSerializable(), getRef());
1192             expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS);
1193
1194             // canCommit the 2nd Tx - it should get queued.
1195
1196             shard.tell(new CanCommitTransaction(transactionID2).toSerializable(), getRef());
1197
1198             // canCommit the 3rd Tx - should exceed queue capacity and fail.
1199
1200             shard.tell(new CanCommitTransaction(transactionID3).toSerializable(), getRef());
1201             expectMsgClass(duration, akka.actor.Status.Failure.class);
1202
1203             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
1204         }};
1205     }
1206
1207     @Test
1208     public void testCanCommitBeforeReadyFailure() throws Throwable {
1209         new ShardTestKit(getSystem()) {{
1210             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
1211                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
1212                     "testCanCommitBeforeReadyFailure");
1213
1214             shard.tell(new CanCommitTransaction("tx").toSerializable(), getRef());
1215             expectMsgClass(duration("5 seconds"), akka.actor.Status.Failure.class);
1216
1217             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
1218         }};
1219     }
1220
1221     @Test
1222     public void testAbortTransaction() throws Throwable {
1223         new ShardTestKit(getSystem()) {{
1224             final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
1225                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
1226                     "testAbortTransaction");
1227
1228             waitUntilLeader(shard);
1229
1230             // Setup 2 simulated transactions with mock cohorts. The first one will be aborted.
1231
1232             String transactionID1 = "tx1";
1233             MutableCompositeModification modification1 = new MutableCompositeModification();
1234             DOMStoreThreePhaseCommitCohort cohort1 = mock(DOMStoreThreePhaseCommitCohort.class, "cohort1");
1235             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort1).canCommit();
1236             doReturn(Futures.immediateFuture(null)).when(cohort1).abort();
1237
1238             String transactionID2 = "tx2";
1239             MutableCompositeModification modification2 = new MutableCompositeModification();
1240             DOMStoreThreePhaseCommitCohort cohort2 = mock(DOMStoreThreePhaseCommitCohort.class, "cohort2");
1241             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort2).canCommit();
1242
1243             FiniteDuration duration = duration("5 seconds");
1244             final Timeout timeout = new Timeout(duration);
1245
1246             // Simulate the ForwardedReadyTransaction messages that would be sent
1247             // by the ShardTransaction.
1248
1249             shard.tell(new ForwardedReadyTransaction(transactionID1, CURRENT_VERSION,
1250                     cohort1, modification1, true), getRef());
1251             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1252
1253             shard.tell(new ForwardedReadyTransaction(transactionID2, CURRENT_VERSION,
1254                     cohort2, modification2, true), getRef());
1255             expectMsgClass(duration, ReadyTransactionReply.SERIALIZABLE_CLASS);
1256
1257             // Send the CanCommitTransaction message for the first Tx.
1258
1259             shard.tell(new CanCommitTransaction(transactionID1).toSerializable(), getRef());
1260             CanCommitTransactionReply canCommitReply = CanCommitTransactionReply.fromSerializable(
1261                     expectMsgClass(duration, CanCommitTransactionReply.SERIALIZABLE_CLASS));
1262             assertEquals("Can commit", true, canCommitReply.getCanCommit());
1263
1264             // Send the CanCommitTransaction message for the 2nd Tx. This should get queued and
1265             // processed after the first Tx completes.
1266
1267             Future<Object> canCommitFuture = Patterns.ask(shard,
1268                     new CanCommitTransaction(transactionID2).toSerializable(), timeout);
1269
1270             // Send the AbortTransaction message for the first Tx. This should trigger the 2nd
1271             // Tx to proceed.
1272
1273             shard.tell(new AbortTransaction(transactionID1).toSerializable(), getRef());
1274             expectMsgClass(duration, AbortTransactionReply.SERIALIZABLE_CLASS);
1275
1276             // Wait for the 2nd Tx to complete the canCommit phase.
1277
1278             Await.ready(canCommitFuture, duration);
1279
1280             InOrder inOrder = inOrder(cohort1, cohort2);
1281             inOrder.verify(cohort1).canCommit();
1282             inOrder.verify(cohort2).canCommit();
1283
1284             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
1285         }};
1286     }
1287
1288     @Test
1289     public void testCreateSnapshot() throws IOException, InterruptedException {
1290             testCreateSnapshot(true, "testCreateSnapshot");
1291     }
1292
1293     @Test
1294     public void testCreateSnapshotWithNonPersistentData() throws IOException, InterruptedException {
1295         testCreateSnapshot(false, "testCreateSnapshotWithNonPersistentData");
1296     }
1297
1298     @SuppressWarnings("serial")
1299     public void testCreateSnapshot(final boolean persistent, final String shardActorName) throws IOException, InterruptedException {
1300         final DatastoreContext dataStoreContext = DatastoreContext.newBuilder().
1301                 shardJournalRecoveryLogBatchSize(3).shardSnapshotBatchCount(5000).persistent(persistent).build();
1302
1303         new ShardTestKit(getSystem()) {{
1304             final AtomicReference<CountDownLatch> latch = new AtomicReference<>(new CountDownLatch(1));
1305             Creator<Shard> creator = new Creator<Shard>() {
1306                 @Override
1307                 public Shard create() throws Exception {
1308                     return new Shard(shardID, Collections.<ShardIdentifier,String>emptyMap(),
1309                             newDatastoreContext(), SCHEMA_CONTEXT) {
1310                         @Override
1311                         protected void commitSnapshot(final long sequenceNumber) {
1312                             super.commitSnapshot(sequenceNumber);
1313                             latch.get().countDown();
1314                         }
1315                     };
1316                 }
1317             };
1318
1319             TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
1320                     Props.create(new DelegatingShardCreator(creator)), shardActorName);
1321
1322             waitUntilLeader(shard);
1323
1324             shard.tell(new CaptureSnapshot(-1,-1,-1,-1), getRef());
1325
1326             assertEquals("Snapshot saved", true, latch.get().await(5, TimeUnit.SECONDS));
1327
1328             latch.set(new CountDownLatch(1));
1329             shard.tell(new CaptureSnapshot(-1,-1,-1,-1), getRef());
1330
1331             assertEquals("Snapshot saved", true, latch.get().await(5, TimeUnit.SECONDS));
1332
1333             shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
1334         }};
1335     }
1336
1337     /**
1338      * This test simply verifies that the applySnapShot logic will work
1339      * @throws ReadFailedException
1340      */
1341     @Test
1342     public void testInMemoryDataStoreRestore() throws ReadFailedException {
1343         InMemoryDOMDataStore store = new InMemoryDOMDataStore("test", MoreExecutors.sameThreadExecutor());
1344
1345         store.onGlobalContextUpdated(SCHEMA_CONTEXT);
1346
1347         DOMStoreWriteTransaction putTransaction = store.newWriteOnlyTransaction();
1348         putTransaction.write(TestModel.TEST_PATH,
1349             ImmutableNodes.containerNode(TestModel.TEST_QNAME));
1350         commitTransaction(putTransaction);
1351
1352
1353         NormalizedNode<?, ?> expected = readStore(store);
1354
1355         DOMStoreWriteTransaction writeTransaction = store.newWriteOnlyTransaction();
1356
1357         writeTransaction.delete(YangInstanceIdentifier.builder().build());
1358         writeTransaction.write(YangInstanceIdentifier.builder().build(), expected);
1359
1360         commitTransaction(writeTransaction);
1361
1362         NormalizedNode<?, ?> actual = readStore(store);
1363
1364         assertEquals(expected, actual);
1365     }
1366
1367     @Test
1368     public void testRecoveryApplicable(){
1369
1370         final DatastoreContext persistentContext = DatastoreContext.newBuilder().
1371                 shardJournalRecoveryLogBatchSize(3).shardSnapshotBatchCount(5000).persistent(true).build();
1372
1373         final Props persistentProps = Shard.props(shardID, Collections.<ShardIdentifier, String>emptyMap(),
1374                 persistentContext, SCHEMA_CONTEXT);
1375
1376         final DatastoreContext nonPersistentContext = DatastoreContext.newBuilder().
1377                 shardJournalRecoveryLogBatchSize(3).shardSnapshotBatchCount(5000).persistent(false).build();
1378
1379         final Props nonPersistentProps = Shard.props(shardID, Collections.<ShardIdentifier, String>emptyMap(),
1380                 nonPersistentContext, SCHEMA_CONTEXT);
1381
1382         new ShardTestKit(getSystem()) {{
1383             TestActorRef<Shard> shard1 = TestActorRef.create(getSystem(),
1384                     persistentProps, "testPersistence1");
1385
1386             assertTrue("Recovery Applicable", shard1.underlyingActor().getDataPersistenceProvider().isRecoveryApplicable());
1387
1388             shard1.tell(PoisonPill.getInstance(), ActorRef.noSender());
1389
1390             TestActorRef<Shard> shard2 = TestActorRef.create(getSystem(),
1391                     nonPersistentProps, "testPersistence2");
1392
1393             assertFalse("Recovery Not Applicable", shard2.underlyingActor().getDataPersistenceProvider().isRecoveryApplicable());
1394
1395             shard2.tell(PoisonPill.getInstance(), ActorRef.noSender());
1396
1397         }};
1398
1399     }
1400
1401
1402     private NormalizedNode<?, ?> readStore(final InMemoryDOMDataStore store) throws ReadFailedException {
1403         DOMStoreReadTransaction transaction = store.newReadOnlyTransaction();
1404         CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> read =
1405             transaction.read(YangInstanceIdentifier.builder().build());
1406
1407         Optional<NormalizedNode<?, ?>> optional = read.checkedGet();
1408
1409         NormalizedNode<?, ?> normalizedNode = optional.get();
1410
1411         transaction.close();
1412
1413         return normalizedNode;
1414     }
1415
1416     private void commitTransaction(final DOMStoreWriteTransaction transaction) {
1417         DOMStoreThreePhaseCommitCohort commitCohort = transaction.ready();
1418         ListenableFuture<Void> future =
1419             commitCohort.preCommit();
1420         try {
1421             future.get();
1422             future = commitCohort.commit();
1423             future.get();
1424         } catch (InterruptedException | ExecutionException e) {
1425         }
1426     }
1427
1428     private AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>> noOpDataChangeListener() {
1429         return new AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>() {
1430             @Override
1431             public void onDataChanged(
1432                 final AsyncDataChangeEvent<YangInstanceIdentifier, NormalizedNode<?, ?>> change) {
1433
1434             }
1435         };
1436     }
1437
1438     static NormalizedNode<?,?> readStore(final TestActorRef<Shard> shard, final YangInstanceIdentifier id)
1439             throws ExecutionException, InterruptedException {
1440         DOMStoreReadTransaction transaction = shard.underlyingActor().getDataStore().newReadOnlyTransaction();
1441
1442         CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> future =
1443             transaction.read(id);
1444
1445         Optional<NormalizedNode<?, ?>> optional = future.get();
1446         NormalizedNode<?, ?> node = optional.isPresent()? optional.get() : null;
1447
1448         transaction.close();
1449
1450         return node;
1451     }
1452
1453     private void writeToStore(final TestActorRef<Shard> shard, final YangInstanceIdentifier id, final NormalizedNode<?,?> node)
1454         throws ExecutionException, InterruptedException {
1455         DOMStoreWriteTransaction transaction = shard.underlyingActor().getDataStore().newWriteOnlyTransaction();
1456
1457         transaction.write(id, node);
1458
1459         DOMStoreThreePhaseCommitCohort commitCohort = transaction.ready();
1460         commitCohort.preCommit().get();
1461         commitCohort.commit().get();
1462     }
1463
1464     @SuppressWarnings("serial")
1465     private static final class DelegatingShardCreator implements Creator<Shard> {
1466         private final Creator<Shard> delegate;
1467
1468         DelegatingShardCreator(final Creator<Shard> delegate) {
1469             this.delegate = delegate;
1470         }
1471
1472         @Override
1473         public Shard create() throws Exception {
1474             return delegate.create();
1475         }
1476     }
1477 }