opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/Shard.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.controller.cluster.datastore;
  10
  11 import akka.actor.ActorRef;
  12 import akka.actor.ActorSelection;
  13 import akka.actor.Cancellable;
  14 import akka.actor.Props;
  15 import akka.actor.Status;
  16 import akka.actor.Status.Failure;
  17 import akka.serialization.Serialization;
  18 import com.google.common.annotations.VisibleForTesting;
  19 import com.google.common.base.Optional;
  20 import com.google.common.base.Preconditions;
  21 import com.google.common.base.Ticker;
  22 import com.google.common.base.Verify;
  23 import com.google.common.collect.ImmutableList;
  24 import com.google.common.collect.ImmutableMap;
  25 import com.google.common.collect.Range;
  26 import java.io.IOException;
  27 import java.util.Arrays;
  28 import java.util.Collection;
  29 import java.util.Collections;
  30 import java.util.Map;
  31 import java.util.concurrent.TimeUnit;
  32 import javax.annotation.Nonnull;
  33 import javax.annotation.Nullable;
  34 import org.opendaylight.controller.cluster.access.ABIVersion;
  35 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  36 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  37 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
  38 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
  39 import org.opendaylight.controller.cluster.access.commands.OutOfSequenceEnvelopeException;
  40 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  41 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  42 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
  43 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  44 import org.opendaylight.controller.cluster.access.concepts.Request;
  45 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  46 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  47 import org.opendaylight.controller.cluster.access.concepts.RequestSuccess;
  48 import org.opendaylight.controller.cluster.access.concepts.RetiredGenerationException;
  49 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
  50 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  51 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  52 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  53 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  54 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
  55 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  56 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  57 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  58 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  59 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  60 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  61 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  62 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  63 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  64 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  65 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  66 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  67 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  68 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  69 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  70 import org.opendaylight.controller.cluster.datastore.messages.MakeLeaderLocal;
  71 import org.opendaylight.controller.cluster.datastore.messages.OnDemandShardState;
  72 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  73 import org.opendaylight.controller.cluster.datastore.messages.PersistAbortTransactionPayload;
  74 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  75 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  76 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  77 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  78 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  79 import org.opendaylight.controller.cluster.datastore.persisted.AbortTransactionPayload;
  80 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot;
  81 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot.ShardSnapshot;
  82 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  83 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  84 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  85 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  86 import org.opendaylight.controller.cluster.raft.LeadershipTransferFailedException;
  87 import org.opendaylight.controller.cluster.raft.RaftActor;
  88 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  89 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
  90 import org.opendaylight.controller.cluster.raft.RaftState;
  91 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  92 import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
  93 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  94 import org.opendaylight.controller.cluster.raft.messages.RequestLeadership;
  95 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
  96 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  97 import org.opendaylight.yangtools.concepts.Identifier;
  98 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  99 import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree;
 100 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
 101 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 102 import org.opendaylight.yangtools.yang.model.api.SchemaContextProvider;
 103 import scala.concurrent.duration.Duration;
 104 import scala.concurrent.duration.FiniteDuration;
 105
 106 /**
 107  * A Shard represents a portion of the logical data tree.
 108  *
 109  * <p>
 110  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
 111  */
 112 public class Shard extends RaftActor {
 113
 114     @VisibleForTesting
 115     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
 116         @Override
 117         public String toString() {
 118             return "txCommitTimeoutCheck";
 119         }
 120     };
 121
 122     @VisibleForTesting
 123     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
 124         @Override
 125         public String toString() {
 126             return "getShardMBeanMessage";
 127         }
 128     };
 129
 130     static final Object RESUME_NEXT_PENDING_TRANSACTION = new Object() {
 131         @Override
 132         public String toString() {
 133             return "resumeNextPendingTransaction";
 134         }
 135     };
 136
 137     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
 138     public static final String DEFAULT_NAME = "default";
 139
 140     private static final Collection<ABIVersion> SUPPORTED_ABIVERSIONS;
 141
 142     static {
 143         final ABIVersion[] values = ABIVersion.values();
 144         final ABIVersion[] real = Arrays.copyOfRange(values, 1, values.length - 1);
 145         SUPPORTED_ABIVERSIONS = ImmutableList.copyOf(real).reverse();
 146     }
 147
 148     // FIXME: make this a dynamic property based on mailbox size and maximum number of clients
 149     private static final int CLIENT_MAX_MESSAGES = 1000;
 150
 151     // The state of this Shard
 152     private final ShardDataTree store;
 153
 154     /// The name of this shard
 155     private final String name;
 156
 157     private final ShardStats shardMBean;
 158
 159     private DatastoreContext datastoreContext;
 160
 161     private final ShardCommitCoordinator commitCoordinator;
 162
 163     private long transactionCommitTimeout;
 164
 165     private Cancellable txCommitTimeoutCheckSchedule;
 166
 167     private final Optional<ActorRef> roleChangeNotifier;
 168
 169     private final MessageTracker appendEntriesReplyTracker;
 170
 171     private final ShardTransactionActorFactory transactionActorFactory;
 172
 173     private final ShardSnapshotCohort snapshotCohort;
 174
 175     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 176     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 177
 178
 179     private ShardSnapshot restoreFromSnapshot;
 180
 181     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 182
 183     private final FrontendMetadata frontendMetadata;
 184     private Map<FrontendIdentifier, LeaderFrontendState> knownFrontends = ImmutableMap.of();
 185     private boolean paused;
 186
 187     protected Shard(final AbstractBuilder<?, ?> builder) {
 188         super(builder.getId().toString(), builder.getPeerAddresses(),
 189                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 190
 191         this.name = builder.getId().toString();
 192         this.datastoreContext = builder.getDatastoreContext();
 193         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 194         this.frontendMetadata = new FrontendMetadata(name);
 195
 196         setPersistence(datastoreContext.isPersistent());
 197
 198         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 199
 200         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 201                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher", name);
 202         ShardDataChangeListenerPublisherActorProxy dataChangeListenerPublisher =
 203                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher", name);
 204         if (builder.getDataTree() != null) {
 205             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 206                     treeChangeListenerPublisher, dataChangeListenerPublisher, name, frontendMetadata);
 207         } else {
 208             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 209                     builder.getDatastoreContext().getStoreRoot(), treeChangeListenerPublisher,
 210                     dataChangeListenerPublisher, name, frontendMetadata);
 211         }
 212
 213         shardMBean = ShardMBeanFactory.getShardStatsMBean(name, datastoreContext.getDataStoreMXBeanType(), this);
 214
 215         if (isMetricsCaptureEnabled()) {
 216             getContext().become(new MeteringBehavior(this));
 217         }
 218
 219         commitCoordinator = new ShardCommitCoordinator(store, LOG, this.name);
 220
 221         setTransactionCommitTimeout();
 222
 223         // create a notifier actor for each cluster member
 224         roleChangeNotifier = createRoleChangeNotifier(name);
 225
 226         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 227                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 228
 229         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 230             new Dispatchers(context().system().dispatchers()).getDispatcherPath(Dispatchers.DispatcherType.Transaction),
 231                 self(), getContext(), shardMBean, builder.getId().getShardName());
 232
 233         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 234             this.name);
 235
 236         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 237     }
 238
 239     private void setTransactionCommitTimeout() {
 240         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 241                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 242     }
 243
 244     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 245         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 246             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 247         return Optional.of(shardRoleChangeNotifier);
 248     }
 249
 250     @Override
 251     public void postStop() {
 252         LOG.info("Stopping Shard {}", persistenceId());
 253
 254         super.postStop();
 255
 256         messageRetrySupport.close();
 257
 258         if (txCommitTimeoutCheckSchedule != null) {
 259             txCommitTimeoutCheckSchedule.cancel();
 260         }
 261
 262         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 263
 264         shardMBean.unregisterMBean();
 265     }
 266
 267     @Override
 268     protected void handleRecover(final Object message) {
 269         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 270             getSender());
 271
 272         super.handleRecover(message);
 273         if (LOG.isTraceEnabled()) {
 274             appendEntriesReplyTracker.begin();
 275         }
 276     }
 277
 278     @SuppressWarnings("checkstyle:IllegalCatch")
 279     @Override
 280     protected void handleNonRaftCommand(final Object message) {
 281         try (MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 282             final Optional<Error> maybeError = context.error();
 283             if (maybeError.isPresent()) {
 284                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 285                     maybeError.get());
 286             }
 287
 288             store.resetTransactionBatch();
 289
 290             if (message instanceof RequestEnvelope) {
 291                 final long now = ticker().read();
 292                 final RequestEnvelope envelope = (RequestEnvelope)message;
 293
 294                 try {
 295                     final RequestSuccess<?, ?> success = handleRequest(envelope, now);
 296                     if (success != null) {
 297                         envelope.sendSuccess(success, ticker().read() - now);
 298                     }
 299                 } catch (RequestException e) {
 300                     LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
 301                     envelope.sendFailure(e, ticker().read() - now);
 302                 } catch (Exception e) {
 303                     LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
 304                     envelope.sendFailure(new RuntimeRequestException("Request failed to process", e),
 305                         ticker().read() - now);
 306                 }
 307             } else if (message instanceof ConnectClientRequest) {
 308                 handleConnectClient((ConnectClientRequest)message);
 309             } else if (CreateTransaction.isSerializedType(message)) {
 310                 handleCreateTransaction(message);
 311             } else if (message instanceof BatchedModifications) {
 312                 handleBatchedModifications((BatchedModifications)message);
 313             } else if (message instanceof ForwardedReadyTransaction) {
 314                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 315             } else if (message instanceof ReadyLocalTransaction) {
 316                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 317             } else if (CanCommitTransaction.isSerializedType(message)) {
 318                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 319             } else if (CommitTransaction.isSerializedType(message)) {
 320                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 321             } else if (AbortTransaction.isSerializedType(message)) {
 322                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 323             } else if (CloseTransactionChain.isSerializedType(message)) {
 324                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 325             } else if (message instanceof RegisterChangeListener) {
 326                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 327             } else if (message instanceof RegisterDataTreeChangeListener) {
 328                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 329             } else if (message instanceof UpdateSchemaContext) {
 330                 updateSchemaContext((UpdateSchemaContext) message);
 331             } else if (message instanceof PeerAddressResolved) {
 332                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 333                 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
 334             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 335                 commitTimeoutCheck();
 336             } else if (message instanceof DatastoreContext) {
 337                 onDatastoreContext((DatastoreContext)message);
 338             } else if (message instanceof RegisterRoleChangeListener) {
 339                 roleChangeNotifier.get().forward(message, context());
 340             } else if (message instanceof FollowerInitialSyncUpStatus) {
 341                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 342                 context().parent().tell(message, self());
 343             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 344                 sender().tell(getShardMBean(), self());
 345             } else if (message instanceof GetShardDataTree) {
 346                 sender().tell(store.getDataTree(), self());
 347             } else if (message instanceof ServerRemoved) {
 348                 context().parent().forward(message, context());
 349             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 350                 messageRetrySupport.onTimerMessage(message);
 351             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 352                 store.processCohortRegistryCommand(getSender(),
 353                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 354             } else if (message instanceof PersistAbortTransactionPayload) {
 355                 final TransactionIdentifier txId = ((PersistAbortTransactionPayload) message).getTransactionId();
 356                 persistPayload(txId, AbortTransactionPayload.create(txId), true);
 357             } else if (message instanceof MakeLeaderLocal) {
 358                 onMakeLeaderLocal();
 359             } else if (RESUME_NEXT_PENDING_TRANSACTION.equals(message)) {
 360                 store.resumeNextPendingTransaction();
 361             } else {
 362                 super.handleNonRaftCommand(message);
 363             }
 364         }
 365     }
 366
 367     private void commitTimeoutCheck() {
 368         store.checkForExpiredTransactions(transactionCommitTimeout, this::updateAccess);
 369         commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 370     }
 371
 372     private Optional<Long> updateAccess(final SimpleShardDataTreeCohort cohort) {
 373         final FrontendIdentifier frontend = cohort.getIdentifier().getHistoryId().getClientId().getFrontendId();
 374         final LeaderFrontendState state = knownFrontends.get(frontend);
 375         if (state == null) {
 376             // Not tell-based protocol, do nothing
 377             return Optional.absent();
 378         }
 379
 380         if (isIsolatedLeader()) {
 381             // We are isolated and no new request can come through until we emerge from it. We are still updating
 382             // liveness of frontend when we see it attempting to communicate. Use the last access timer.
 383             return Optional.of(state.getLastSeenTicks());
 384         }
 385
 386         // If this frontend has freshly connected, give it some time to catch up before killing its transactions.
 387         return Optional.of(state.getLastConnectTicks());
 388     }
 389
 390     private void onMakeLeaderLocal() {
 391         LOG.debug("{}: onMakeLeaderLocal received", persistenceId());
 392         if (isLeader()) {
 393             getSender().tell(new Status.Success(null), getSelf());
 394             return;
 395         }
 396
 397         final ActorSelection leader = getLeader();
 398
 399         if (leader == null) {
 400             // Leader is not present. The cluster is most likely trying to
 401             // elect a leader and we should let that run its normal course
 402
 403             // TODO we can wait for the election to complete and retry the
 404             // request. We can also let the caller retry by sending a flag
 405             // in the response indicating the request is "reTryable".
 406             getSender().tell(new Failure(
 407                     new LeadershipTransferFailedException("We cannot initiate leadership transfer to local node. "
 408                             + "Currently there is no leader for " + persistenceId())),
 409                     getSelf());
 410             return;
 411         }
 412
 413         leader.tell(new RequestLeadership(getId(), getSender()), getSelf());
 414     }
 415
 416     // Acquire our frontend tracking handle and verify generation matches
 417     @Nullable
 418     private LeaderFrontendState findFrontend(final ClientIdentifier clientId) throws RequestException {
 419         final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
 420         if (existing != null) {
 421             final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
 422             if (cmp == 0) {
 423                 existing.touch();
 424                 return existing;
 425             }
 426             if (cmp > 0) {
 427                 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
 428                 throw new RetiredGenerationException(existing.getIdentifier().getGeneration());
 429             }
 430
 431             LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
 432             existing.retire();
 433             knownFrontends.remove(clientId.getFrontendId());
 434         } else {
 435             LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
 436         }
 437
 438         return null;
 439     }
 440
 441     private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
 442         final LeaderFrontendState ret = findFrontend(clientId);
 443         if (ret != null) {
 444             return ret;
 445         }
 446
 447         // TODO: a dedicated exception would be better, but this is technically true, too
 448         throw new OutOfSequenceEnvelopeException(0);
 449     }
 450
 451     private static @Nonnull ABIVersion selectVersion(final ConnectClientRequest message) {
 452         final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
 453         for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
 454             if (clientRange.contains(v)) {
 455                 return v;
 456             }
 457         }
 458
 459         throw new IllegalArgumentException(String.format(
 460             "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
 461             clientRange));
 462     }
 463
 464     @SuppressWarnings("checkstyle:IllegalCatch")
 465     private void handleConnectClient(final ConnectClientRequest message) {
 466         try {
 467             final ClientIdentifier clientId = message.getTarget();
 468             final LeaderFrontendState existing = findFrontend(clientId);
 469             if (existing != null) {
 470                 existing.touch();
 471             }
 472
 473             if (!isLeader() || !isLeaderActive()) {
 474                 LOG.info("{}: not currently leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 475                                 + "isLeadershipTransferInProgress: {}.",
 476                         persistenceId(), message, isLeader(), isLeaderActive(), isLeadershipTransferInProgress());
 477                 throw new NotLeaderException(getSelf());
 478             }
 479
 480             final ABIVersion selectedVersion = selectVersion(message);
 481             final LeaderFrontendState frontend;
 482             if (existing == null) {
 483                 frontend = new LeaderFrontendState(persistenceId(), clientId, store);
 484                 knownFrontends.put(clientId.getFrontendId(), frontend);
 485                 LOG.debug("{}: created state {} for client {}", persistenceId(), frontend, clientId);
 486             } else {
 487                 frontend = existing;
 488             }
 489
 490             frontend.reconnect();
 491             message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
 492                 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
 493                 ActorRef.noSender());
 494         } catch (RequestException | RuntimeException e) {
 495             message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
 496         }
 497     }
 498
 499     private @Nullable RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope, final long now)
 500             throws RequestException {
 501         // We are not the leader, hence we want to fail-fast.
 502         if (!isLeader() || paused || !isLeaderActive()) {
 503             LOG.debug("{}: not currently active leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 504                             + "isLeadershipTransferInProgress: {}, paused: {}",
 505                     persistenceId(), envelope, isLeader(), isLeaderActive(), isLeadershipTransferInProgress(), paused);
 506             throw new NotLeaderException(getSelf());
 507         }
 508
 509         final Request<?, ?> request = envelope.getMessage();
 510         if (request instanceof TransactionRequest) {
 511             final TransactionRequest<?> txReq = (TransactionRequest<?>)request;
 512             final ClientIdentifier clientId = txReq.getTarget().getHistoryId().getClientId();
 513             return getFrontend(clientId).handleTransactionRequest(txReq, envelope, now);
 514         } else if (request instanceof LocalHistoryRequest) {
 515             final LocalHistoryRequest<?> lhReq = (LocalHistoryRequest<?>)request;
 516             final ClientIdentifier clientId = lhReq.getTarget().getClientId();
 517             return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope, now);
 518         } else {
 519             LOG.warn("{}: rejecting unsupported request {}", persistenceId(), request);
 520             throw new UnsupportedRequestException(request);
 521         }
 522     }
 523
 524     private boolean hasLeader() {
 525         return getLeaderId() != null;
 526     }
 527
 528     public int getPendingTxCommitQueueSize() {
 529         return store.getQueueSize();
 530     }
 531
 532     public int getCohortCacheSize() {
 533         return commitCoordinator.getCohortCacheSize();
 534     }
 535
 536     @Override
 537     protected Optional<ActorRef> getRoleChangeNotifier() {
 538         return roleChangeNotifier;
 539     }
 540
 541     @Override
 542     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 543             final short leaderPayloadVersion) {
 544         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 545                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 546     }
 547
 548     protected void onDatastoreContext(final DatastoreContext context) {
 549         datastoreContext = context;
 550
 551         setTransactionCommitTimeout();
 552
 553         setPersistence(datastoreContext.isPersistent());
 554
 555         updateConfigParams(datastoreContext.getShardRaftConfig());
 556     }
 557
 558     // applyState() will be invoked once consensus is reached on the payload
 559     void persistPayload(final Identifier id, final Payload payload, final boolean batchHint) {
 560         boolean canSkipPayload = !hasFollowers() && !persistence().isRecoveryApplicable();
 561         if (canSkipPayload) {
 562             applyState(self(), id, payload);
 563         } else {
 564             // We are faking the sender
 565             persistData(self(), id, payload, batchHint);
 566         }
 567     }
 568
 569     private void handleCommitTransaction(final CommitTransaction commit) {
 570         if (isLeader()) {
 571             commitCoordinator.handleCommit(commit.getTransactionId(), getSender(), this);
 572         } else {
 573             ActorSelection leader = getLeader();
 574             if (leader == null) {
 575                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 576                         "Could not commit transaction " + commit.getTransactionId());
 577             } else {
 578                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 579                 leader.forward(commit, getContext());
 580             }
 581         }
 582     }
 583
 584     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 585         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionId());
 586
 587         if (isLeader()) {
 588             commitCoordinator.handleCanCommit(canCommit.getTransactionId(), getSender(), this);
 589         } else {
 590             ActorSelection leader = getLeader();
 591             if (leader == null) {
 592                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 593                         "Could not canCommit transaction " + canCommit.getTransactionId());
 594             } else {
 595                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 596                 leader.forward(canCommit, getContext());
 597             }
 598         }
 599     }
 600
 601     @SuppressWarnings("checkstyle:IllegalCatch")
 602     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 603         try {
 604             commitCoordinator.handleBatchedModifications(batched, sender, this);
 605         } catch (Exception e) {
 606             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 607                     batched.getTransactionId(), e);
 608             sender.tell(new Failure(e), getSelf());
 609         }
 610     }
 611
 612     private void handleBatchedModifications(final BatchedModifications batched) {
 613         // This message is sent to prepare the modifications transaction directly on the Shard as an
 614         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 615         // BatchedModifications message, the caller sets the ready flag in the message indicating
 616         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 617         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 618         // ReadyTransaction message.
 619
 620         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 621         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 622         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 623         // window where it could have a stale leader during leadership transitions.
 624         //
 625         boolean isLeaderActive = isLeaderActive();
 626         if (isLeader() && isLeaderActive) {
 627             handleBatchedModificationsLocal(batched, getSender());
 628         } else {
 629             ActorSelection leader = getLeader();
 630             if (!isLeaderActive || leader == null) {
 631                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 632                         "Could not commit transaction " + batched.getTransactionId());
 633             } else {
 634                 // If this is not the first batch and leadership changed in between batched messages,
 635                 // we need to reconstruct previous BatchedModifications from the transaction
 636                 // DataTreeModification, honoring the max batched modification count, and forward all the
 637                 // previous BatchedModifications to the new leader.
 638                 Collection<BatchedModifications> newModifications = commitCoordinator
 639                         .createForwardedBatchedModifications(batched,
 640                                 datastoreContext.getShardBatchedModificationCount());
 641
 642                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 643                         newModifications.size(), leader);
 644
 645                 for (BatchedModifications bm : newModifications) {
 646                     leader.forward(bm, getContext());
 647                 }
 648             }
 649         }
 650     }
 651
 652     private boolean failIfIsolatedLeader(final ActorRef sender) {
 653         if (isIsolatedLeader()) {
 654             sender.tell(new Failure(new NoShardLeaderException(String.format(
 655                     "Shard %s was the leader but has lost contact with all of its followers. Either all"
 656                     + " other follower nodes are down or this node is isolated by a network partition.",
 657                     persistenceId()))), getSelf());
 658             return true;
 659         }
 660
 661         return false;
 662     }
 663
 664     protected boolean isIsolatedLeader() {
 665         return getRaftState() == RaftState.IsolatedLeader;
 666     }
 667
 668     @SuppressWarnings("checkstyle:IllegalCatch")
 669     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 670         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionId());
 671
 672         boolean isLeaderActive = isLeaderActive();
 673         if (isLeader() && isLeaderActive) {
 674             try {
 675                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 676             } catch (Exception e) {
 677                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 678                         message.getTransactionId(), e);
 679                 getSender().tell(new Failure(e), getSelf());
 680             }
 681         } else {
 682             ActorSelection leader = getLeader();
 683             if (!isLeaderActive || leader == null) {
 684                 messageRetrySupport.addMessageToRetry(message, getSender(),
 685                         "Could not commit transaction " + message.getTransactionId());
 686             } else {
 687                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 688                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 689                 leader.forward(message, getContext());
 690             }
 691         }
 692     }
 693
 694     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 695         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
 696
 697         boolean isLeaderActive = isLeaderActive();
 698         if (isLeader() && isLeaderActive) {
 699             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 700         } else {
 701             ActorSelection leader = getLeader();
 702             if (!isLeaderActive || leader == null) {
 703                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 704                         "Could not commit transaction " + forwardedReady.getTransactionId());
 705             } else {
 706                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 707
 708                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
 709                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 710                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 711                 leader.forward(readyLocal, getContext());
 712             }
 713         }
 714     }
 715
 716     private void handleAbortTransaction(final AbortTransaction abort) {
 717         doAbortTransaction(abort.getTransactionId(), getSender());
 718     }
 719
 720     void doAbortTransaction(final Identifier transactionID, final ActorRef sender) {
 721         commitCoordinator.handleAbort(transactionID, sender, this);
 722     }
 723
 724     private void handleCreateTransaction(final Object message) {
 725         if (isLeader()) {
 726             createTransaction(CreateTransaction.fromSerializable(message));
 727         } else if (getLeader() != null) {
 728             getLeader().forward(message, getContext());
 729         } else {
 730             getSender().tell(new Failure(new NoShardLeaderException(
 731                     "Could not create a shard transaction", persistenceId())), getSelf());
 732         }
 733     }
 734
 735     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 736         final LocalHistoryIdentifier id = closeTransactionChain.getIdentifier();
 737         store.closeTransactionChain(id, null);
 738         store.purgeTransactionChain(id, null);
 739     }
 740
 741     @SuppressWarnings("checkstyle:IllegalCatch")
 742     private void createTransaction(final CreateTransaction createTransaction) {
 743         try {
 744             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 745                     && failIfIsolatedLeader(getSender())) {
 746                 return;
 747             }
 748
 749             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 750                 createTransaction.getTransactionId());
 751
 752             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 753                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 754         } catch (Exception e) {
 755             getSender().tell(new Failure(e), getSelf());
 756         }
 757     }
 758
 759     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 760         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 761         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 762             transactionId);
 763     }
 764
 765     private void updateSchemaContext(final UpdateSchemaContext message) {
 766         updateSchemaContext(message.getSchemaContext());
 767     }
 768
 769     @VisibleForTesting
 770     void updateSchemaContext(final SchemaContext schemaContext) {
 771         store.updateSchemaContext(schemaContext);
 772     }
 773
 774     private boolean isMetricsCaptureEnabled() {
 775         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 776         return config.isMetricCaptureEnabled();
 777     }
 778
 779     @Override
 780     @VisibleForTesting
 781     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 782         return snapshotCohort;
 783     }
 784
 785     @Override
 786     @Nonnull
 787     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 788         return new ShardRecoveryCoordinator(store,
 789             restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 790     }
 791
 792     @Override
 793     protected void onRecoveryComplete() {
 794         restoreFromSnapshot = null;
 795
 796         //notify shard manager
 797         getContext().parent().tell(new ActorInitialized(), getSelf());
 798
 799         // Being paranoid here - this method should only be called once but just in case...
 800         if (txCommitTimeoutCheckSchedule == null) {
 801             // Schedule a message to be periodically sent to check if the current in-progress
 802             // transaction should be expired and aborted.
 803             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 804             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 805                     period, period, getSelf(),
 806                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 807         }
 808     }
 809
 810     @Override
 811     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 812         if (data instanceof Payload) {
 813             try {
 814                 store.applyReplicatedPayload(identifier, (Payload)data);
 815             } catch (DataValidationFailedException | IOException e) {
 816                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 817             }
 818         } else {
 819             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 820         }
 821     }
 822
 823     @Override
 824     protected void onStateChanged() {
 825         boolean isLeader = isLeader();
 826         boolean hasLeader = hasLeader();
 827         changeSupport.onLeadershipChange(isLeader, hasLeader);
 828         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 829
 830         // If this actor is no longer the leader close all the transaction chains
 831         if (!isLeader) {
 832             if (LOG.isDebugEnabled()) {
 833                 LOG.debug(
 834                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 835                     persistenceId(), getId());
 836             }
 837
 838             paused = false;
 839             store.purgeLeaderState();
 840         }
 841
 842         if (hasLeader && !isIsolatedLeader()) {
 843             messageRetrySupport.retryMessages();
 844         }
 845     }
 846
 847     @Override
 848     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 849         shardMBean.incrementLeadershipChangeCount();
 850         paused = false;
 851
 852         if (!isLeader()) {
 853             if (!knownFrontends.isEmpty()) {
 854                 LOG.debug("{}: removing frontend state for {}", persistenceId(), knownFrontends.keySet());
 855                 knownFrontends = ImmutableMap.of();
 856             }
 857
 858             if (!hasLeader()) {
 859                 // No leader anywhere, nothing else to do
 860                 return;
 861             }
 862
 863             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 864             // them to transaction messages and send to the new leader.
 865             ActorSelection leader = getLeader();
 866             if (leader != null) {
 867                 Collection<?> messagesToForward = convertPendingTransactionsToMessages();
 868
 869                 if (!messagesToForward.isEmpty()) {
 870                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 871                             messagesToForward.size(), leader);
 872
 873                     for (Object message : messagesToForward) {
 874                         leader.tell(message, self());
 875                     }
 876                 }
 877             } else {
 878                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
 879                         + "change and the leader address isn't available.", this);
 880             }
 881         } else {
 882             // We have become the leader, we need to reconstruct frontend state
 883             knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
 884             LOG.debug("{}: became leader with frontend state for {}", persistenceId(), knownFrontends.keySet());
 885         }
 886
 887         if (!isIsolatedLeader()) {
 888             messageRetrySupport.retryMessages();
 889         }
 890     }
 891
 892     /**
 893      * Clears all pending transactions and converts them to messages to be forwarded to a new leader.
 894      *
 895      * @return the converted messages
 896      */
 897     public Collection<?> convertPendingTransactionsToMessages() {
 898         return commitCoordinator.convertPendingTransactionsToMessages(
 899                 datastoreContext.getShardBatchedModificationCount());
 900     }
 901
 902     @Override
 903     protected void pauseLeader(final Runnable operation) {
 904         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 905         paused = true;
 906
 907         // Tell-based protocol can replay transaction state, so it is safe to blow it up when we are paused.
 908         knownFrontends.values().forEach(LeaderFrontendState::retire);
 909         knownFrontends = ImmutableMap.of();
 910
 911         store.setRunOnPendingTransactionsComplete(operation);
 912     }
 913
 914     @Override
 915     protected void unpauseLeader() {
 916         LOG.debug("{}: In unpauseLeader", persistenceId());
 917         paused = false;
 918
 919         store.setRunOnPendingTransactionsComplete(null);
 920
 921         // Restore tell-based protocol state as if we were becoming the leader
 922         knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
 923     }
 924
 925     @Override
 926     protected OnDemandRaftState.AbstractBuilder<?> newOnDemandRaftStateBuilder() {
 927         return OnDemandShardState.newBuilder().treeChangeListenerActors(treeChangeSupport.getListenerActors())
 928                 .dataChangeListenerActors(changeSupport.getListenerActors())
 929                 .commitCohortActors(store.getCohortActors());
 930     }
 931
 932     @Override
 933     public String persistenceId() {
 934         return this.name;
 935     }
 936
 937     @VisibleForTesting
 938     ShardCommitCoordinator getCommitCoordinator() {
 939         return commitCoordinator;
 940     }
 941
 942     public DatastoreContext getDatastoreContext() {
 943         return datastoreContext;
 944     }
 945
 946     @VisibleForTesting
 947     public ShardDataTree getDataStore() {
 948         return store;
 949     }
 950
 951     @VisibleForTesting
 952     ShardStats getShardMBean() {
 953         return shardMBean;
 954     }
 955
 956     public static Builder builder() {
 957         return new Builder();
 958     }
 959
 960     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 961         private final Class<S> shardClass;
 962         private ShardIdentifier id;
 963         private Map<String, String> peerAddresses = Collections.emptyMap();
 964         private DatastoreContext datastoreContext;
 965         private SchemaContextProvider schemaContextProvider;
 966         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 967         private TipProducingDataTree dataTree;
 968         private volatile boolean sealed;
 969
 970         protected AbstractBuilder(final Class<S> shardClass) {
 971             this.shardClass = shardClass;
 972         }
 973
 974         protected void checkSealed() {
 975             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 976         }
 977
 978         @SuppressWarnings("unchecked")
 979         private T self() {
 980             return (T) this;
 981         }
 982
 983         public T id(final ShardIdentifier newId) {
 984             checkSealed();
 985             this.id = newId;
 986             return self();
 987         }
 988
 989         public T peerAddresses(final Map<String, String> newPeerAddresses) {
 990             checkSealed();
 991             this.peerAddresses = newPeerAddresses;
 992             return self();
 993         }
 994
 995         public T datastoreContext(final DatastoreContext newDatastoreContext) {
 996             checkSealed();
 997             this.datastoreContext = newDatastoreContext;
 998             return self();
 999         }
1000
1001         public T schemaContextProvider(final SchemaContextProvider schemaContextProvider) {
1002             checkSealed();
1003             this.schemaContextProvider = Preconditions.checkNotNull(schemaContextProvider);
1004             return self();
1005         }
1006
1007         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
1008             checkSealed();
1009             this.restoreFromSnapshot = newRestoreFromSnapshot;
1010             return self();
1011         }
1012
1013         public T dataTree(final TipProducingDataTree newDataTree) {
1014             checkSealed();
1015             this.dataTree = newDataTree;
1016             return self();
1017         }
1018
1019         public ShardIdentifier getId() {
1020             return id;
1021         }
1022
1023         public Map<String, String> getPeerAddresses() {
1024             return peerAddresses;
1025         }
1026
1027         public DatastoreContext getDatastoreContext() {
1028             return datastoreContext;
1029         }
1030
1031         public SchemaContext getSchemaContext() {
1032             return Verify.verifyNotNull(schemaContextProvider.getSchemaContext());
1033         }
1034
1035         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
1036             return restoreFromSnapshot;
1037         }
1038
1039         public TipProducingDataTree getDataTree() {
1040             return dataTree;
1041         }
1042
1043         public TreeType getTreeType() {
1044             switch (datastoreContext.getLogicalStoreType()) {
1045                 case CONFIGURATION:
1046                     return TreeType.CONFIGURATION;
1047                 case OPERATIONAL:
1048                     return TreeType.OPERATIONAL;
1049                 default:
1050                     throw new IllegalStateException("Unhandled logical store type "
1051                             + datastoreContext.getLogicalStoreType());
1052             }
1053         }
1054
1055         protected void verify() {
1056             Preconditions.checkNotNull(id, "id should not be null");
1057             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
1058             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
1059             Preconditions.checkNotNull(schemaContextProvider, "schemaContextProvider should not be null");
1060         }
1061
1062         public Props props() {
1063             sealed = true;
1064             verify();
1065             return Props.create(shardClass, this);
1066         }
1067     }
1068
1069     public static class Builder extends AbstractBuilder<Builder, Shard> {
1070         private Builder() {
1071             super(Shard.class);
1072         }
1073     }
1074
1075     Ticker ticker() {
1076         return Ticker.systemTicker();
1077     }
1078
1079     void scheduleNextPendingTransaction() {
1080         self().tell(RESUME_NEXT_PENDING_TRANSACTION, ActorRef.noSender());
1081     }
1082 }