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 static com.google.common.base.Verify.verify;
  12
  13 import akka.actor.ActorRef;
  14 import akka.actor.ActorSelection;
  15 import akka.actor.Cancellable;
  16 import akka.actor.ExtendedActorSystem;
  17 import akka.actor.Props;
  18 import akka.actor.Status;
  19 import akka.actor.Status.Failure;
  20 import akka.serialization.JavaSerializer;
  21 import akka.serialization.Serialization;
  22 import com.google.common.annotations.VisibleForTesting;
  23 import com.google.common.base.Optional;
  24 import com.google.common.base.Preconditions;
  25 import com.google.common.base.Ticker;
  26 import com.google.common.base.Verify;
  27 import com.google.common.collect.ImmutableList;
  28 import com.google.common.collect.ImmutableMap;
  29 import com.google.common.collect.Range;
  30 import java.io.IOException;
  31 import java.util.Arrays;
  32 import java.util.Collection;
  33 import java.util.Collections;
  34 import java.util.Map;
  35 import java.util.concurrent.TimeUnit;
  36 import javax.annotation.Nonnull;
  37 import javax.annotation.Nullable;
  38 import org.opendaylight.controller.cluster.access.ABIVersion;
  39 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  40 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  41 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
  42 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
  43 import org.opendaylight.controller.cluster.access.commands.OutOfSequenceEnvelopeException;
  44 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  45 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  46 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
  47 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  48 import org.opendaylight.controller.cluster.access.concepts.Request;
  49 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  50 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  51 import org.opendaylight.controller.cluster.access.concepts.RequestSuccess;
  52 import org.opendaylight.controller.cluster.access.concepts.RetiredGenerationException;
  53 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
  54 import org.opendaylight.controller.cluster.access.concepts.SliceableMessage;
  55 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  56 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  57 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  58 import org.opendaylight.controller.cluster.common.actor.Dispatchers;
  59 import org.opendaylight.controller.cluster.common.actor.Dispatchers.DispatcherType;
  60 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  61 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
  62 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  63 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  64 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  65 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardDataTreeListenerInfoMXBeanImpl;
  66 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  67 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  68 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  69 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  70 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  71 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  72 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  73 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  74 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  75 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  76 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  77 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  78 import org.opendaylight.controller.cluster.datastore.messages.MakeLeaderLocal;
  79 import org.opendaylight.controller.cluster.datastore.messages.OnDemandShardState;
  80 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  81 import org.opendaylight.controller.cluster.datastore.messages.PersistAbortTransactionPayload;
  82 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  83 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  84 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  85 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  86 import org.opendaylight.controller.cluster.datastore.persisted.AbortTransactionPayload;
  87 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot;
  88 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot.ShardSnapshot;
  89 import org.opendaylight.controller.cluster.datastore.persisted.DisableTrackingPayload;
  90 import org.opendaylight.controller.cluster.datastore.persisted.PurgeTransactionPayload;
  91 import org.opendaylight.controller.cluster.messaging.MessageAssembler;
  92 import org.opendaylight.controller.cluster.messaging.MessageSlicer;
  93 import org.opendaylight.controller.cluster.messaging.SliceOptions;
  94 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  95 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  96 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  97 import org.opendaylight.controller.cluster.raft.LeadershipTransferFailedException;
  98 import org.opendaylight.controller.cluster.raft.RaftActor;
  99 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
 100 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
 101 import org.opendaylight.controller.cluster.raft.RaftState;
 102 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
 103 import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
 104 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
 105 import org.opendaylight.controller.cluster.raft.messages.RequestLeadership;
 106 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
 107 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
 108 import org.opendaylight.yangtools.concepts.Identifier;
 109 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree;
 110 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
 111 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
 112 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 113 import org.opendaylight.yangtools.yang.model.api.SchemaContextProvider;
 114 import scala.concurrent.duration.Duration;
 115 import scala.concurrent.duration.FiniteDuration;
 116
 117 /**
 118  * A Shard represents a portion of the logical data tree.
 119  *
 120  * <p>
 121  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
 122  */
 123 public class Shard extends RaftActor {
 124
 125     @VisibleForTesting
 126     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
 127         @Override
 128         public String toString() {
 129             return "txCommitTimeoutCheck";
 130         }
 131     };
 132
 133     @VisibleForTesting
 134     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
 135         @Override
 136         public String toString() {
 137             return "getShardMBeanMessage";
 138         }
 139     };
 140
 141     static final Object RESUME_NEXT_PENDING_TRANSACTION = new Object() {
 142         @Override
 143         public String toString() {
 144             return "resumeNextPendingTransaction";
 145         }
 146     };
 147
 148     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
 149     public static final String DEFAULT_NAME = "default";
 150
 151     private static final Collection<ABIVersion> SUPPORTED_ABIVERSIONS;
 152
 153     static {
 154         final ABIVersion[] values = ABIVersion.values();
 155         final ABIVersion[] real = Arrays.copyOfRange(values, 1, values.length - 1);
 156         SUPPORTED_ABIVERSIONS = ImmutableList.copyOf(real).reverse();
 157     }
 158
 159     // FIXME: make this a dynamic property based on mailbox size and maximum number of clients
 160     private static final int CLIENT_MAX_MESSAGES = 1000;
 161
 162     // The state of this Shard
 163     private final ShardDataTree store;
 164
 165     /// The name of this shard
 166     private final String name;
 167
 168     private final String shardName;
 169
 170     private final ShardStats shardMBean;
 171
 172     private final ShardDataTreeListenerInfoMXBeanImpl listenerInfoMXBean;
 173
 174     private DatastoreContext datastoreContext;
 175
 176     private final ShardCommitCoordinator commitCoordinator;
 177
 178     private long transactionCommitTimeout;
 179
 180     private Cancellable txCommitTimeoutCheckSchedule;
 181
 182     private final Optional<ActorRef> roleChangeNotifier;
 183
 184     private final MessageTracker appendEntriesReplyTracker;
 185
 186     private final ShardTransactionActorFactory transactionActorFactory;
 187
 188     private final ShardSnapshotCohort snapshotCohort;
 189
 190     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 191
 192     private ShardSnapshot restoreFromSnapshot;
 193
 194     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 195
 196     private final FrontendMetadata frontendMetadata;
 197     private Map<FrontendIdentifier, LeaderFrontendState> knownFrontends = ImmutableMap.of();
 198     private boolean paused;
 199
 200     private final MessageSlicer responseMessageSlicer;
 201     private final Dispatchers dispatchers;
 202
 203     private final MessageAssembler requestMessageAssembler;
 204
 205     protected Shard(final AbstractBuilder<?, ?> builder) {
 206         super(builder.getId().toString(), builder.getPeerAddresses(),
 207                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 208
 209         this.name = builder.getId().toString();
 210         this.shardName = builder.getId().getShardName();
 211         this.datastoreContext = builder.getDatastoreContext();
 212         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 213         this.frontendMetadata = new FrontendMetadata(name);
 214
 215         setPersistence(datastoreContext.isPersistent());
 216
 217         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 218
 219         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 220                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher", name);
 221         if (builder.getDataTree() != null) {
 222             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 223                     treeChangeListenerPublisher, name, frontendMetadata);
 224         } else {
 225             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 226                     builder.getDatastoreContext().getStoreRoot(), treeChangeListenerPublisher, name, frontendMetadata);
 227         }
 228
 229         shardMBean = ShardMBeanFactory.getShardStatsMBean(name, datastoreContext.getDataStoreMXBeanType(), this);
 230
 231         if (isMetricsCaptureEnabled()) {
 232             getContext().become(new MeteringBehavior(this));
 233         }
 234
 235         commitCoordinator = new ShardCommitCoordinator(store, LOG, this.name);
 236
 237         setTransactionCommitTimeout();
 238
 239         // create a notifier actor for each cluster member
 240         roleChangeNotifier = createRoleChangeNotifier(name);
 241
 242         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 243                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 244
 245         dispatchers = new Dispatchers(context().system().dispatchers());
 246         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 247             dispatchers.getDispatcherPath(Dispatchers.DispatcherType.Transaction),
 248                 self(), getContext(), shardMBean, builder.getId().getShardName());
 249
 250         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 251             this.name);
 252
 253         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 254
 255         responseMessageSlicer = MessageSlicer.builder().logContext(this.name)
 256                 .messageSliceSize(datastoreContext.getMaximumMessageSliceSize())
 257                 .fileBackedStreamFactory(getRaftActorContext().getFileBackedOutputStreamFactory())
 258                 .expireStateAfterInactivity(2, TimeUnit.MINUTES).build();
 259
 260         requestMessageAssembler = MessageAssembler.builder().logContext(this.name)
 261                 .fileBackedStreamFactory(getRaftActorContext().getFileBackedOutputStreamFactory())
 262                 .assembledMessageCallback((message, sender) -> self().tell(message, sender))
 263                 .expireStateAfterInactivity(datastoreContext.getRequestTimeout(), TimeUnit.NANOSECONDS).build();
 264
 265         listenerInfoMXBean = new ShardDataTreeListenerInfoMXBeanImpl(name, datastoreContext.getDataStoreMXBeanType(),
 266                 self());
 267         listenerInfoMXBean.register();
 268     }
 269
 270     private void setTransactionCommitTimeout() {
 271         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 272                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 273     }
 274
 275     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 276         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 277             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 278         return Optional.of(shardRoleChangeNotifier);
 279     }
 280
 281     @Override
 282     public void postStop() {
 283         LOG.info("Stopping Shard {}", persistenceId());
 284
 285         super.postStop();
 286
 287         messageRetrySupport.close();
 288
 289         if (txCommitTimeoutCheckSchedule != null) {
 290             txCommitTimeoutCheckSchedule.cancel();
 291         }
 292
 293         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 294
 295         shardMBean.unregisterMBean();
 296         listenerInfoMXBean.unregister();
 297     }
 298
 299     @Override
 300     protected void handleRecover(final Object message) {
 301         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 302             getSender());
 303
 304         super.handleRecover(message);
 305         if (LOG.isTraceEnabled()) {
 306             appendEntriesReplyTracker.begin();
 307         }
 308     }
 309
 310     @Override
 311     protected void handleNonRaftCommand(final Object message) {
 312         try (MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 313             final Optional<Error> maybeError = context.error();
 314             if (maybeError.isPresent()) {
 315                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 316                     maybeError.get());
 317             }
 318
 319             store.resetTransactionBatch();
 320
 321             if (message instanceof RequestEnvelope) {
 322                 handleRequestEnvelope((RequestEnvelope)message);
 323             } else if (MessageAssembler.isHandledMessage(message)) {
 324                 handleRequestAssemblerMessage(message);
 325             } else if (message instanceof ConnectClientRequest) {
 326                 handleConnectClient((ConnectClientRequest)message);
 327             } else if (CreateTransaction.isSerializedType(message)) {
 328                 handleCreateTransaction(message);
 329             } else if (message instanceof BatchedModifications) {
 330                 handleBatchedModifications((BatchedModifications)message);
 331             } else if (message instanceof ForwardedReadyTransaction) {
 332                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 333             } else if (message instanceof ReadyLocalTransaction) {
 334                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 335             } else if (CanCommitTransaction.isSerializedType(message)) {
 336                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 337             } else if (CommitTransaction.isSerializedType(message)) {
 338                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 339             } else if (AbortTransaction.isSerializedType(message)) {
 340                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 341             } else if (CloseTransactionChain.isSerializedType(message)) {
 342                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 343             } else if (message instanceof RegisterDataTreeChangeListener) {
 344                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 345             } else if (message instanceof UpdateSchemaContext) {
 346                 updateSchemaContext((UpdateSchemaContext) message);
 347             } else if (message instanceof PeerAddressResolved) {
 348                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 349                 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
 350             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 351                 commitTimeoutCheck();
 352             } else if (message instanceof DatastoreContext) {
 353                 onDatastoreContext((DatastoreContext)message);
 354             } else if (message instanceof RegisterRoleChangeListener) {
 355                 roleChangeNotifier.get().forward(message, context());
 356             } else if (message instanceof FollowerInitialSyncUpStatus) {
 357                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 358                 context().parent().tell(message, self());
 359             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 360                 sender().tell(getShardMBean(), self());
 361             } else if (message instanceof GetShardDataTree) {
 362                 sender().tell(store.getDataTree(), self());
 363             } else if (message instanceof ServerRemoved) {
 364                 context().parent().forward(message, context());
 365             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 366                 messageRetrySupport.onTimerMessage(message);
 367             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 368                 store.processCohortRegistryCommand(getSender(),
 369                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 370             } else if (message instanceof PersistAbortTransactionPayload) {
 371                 final TransactionIdentifier txId = ((PersistAbortTransactionPayload) message).getTransactionId();
 372                 persistPayload(txId, AbortTransactionPayload.create(txId,
 373                     datastoreContext.getInitialPayloadSerializedBufferCapacity()), true);
 374                 persistPayload(txId, PurgeTransactionPayload.create(txId,
 375                     datastoreContext.getInitialPayloadSerializedBufferCapacity()), false);
 376             } else if (message instanceof MakeLeaderLocal) {
 377                 onMakeLeaderLocal();
 378             } else if (RESUME_NEXT_PENDING_TRANSACTION.equals(message)) {
 379                 store.resumeNextPendingTransaction();
 380             } else if (!responseMessageSlicer.handleMessage(message)) {
 381                 super.handleNonRaftCommand(message);
 382             }
 383         }
 384     }
 385
 386     private void handleRequestAssemblerMessage(final Object message) {
 387         dispatchers.getDispatcher(DispatcherType.Serialization).execute(() -> {
 388             JavaSerializer.currentSystem().value_$eq((ExtendedActorSystem) context().system());
 389             requestMessageAssembler.handleMessage(message, self());
 390         });
 391     }
 392
 393     @SuppressWarnings("checkstyle:IllegalCatch")
 394     private void handleRequestEnvelope(final RequestEnvelope envelope) {
 395         final long now = ticker().read();
 396         try {
 397             final RequestSuccess<?, ?> success = handleRequest(envelope, now);
 398             if (success != null) {
 399                 final long executionTimeNanos = ticker().read() - now;
 400                 if (success instanceof SliceableMessage) {
 401                     dispatchers.getDispatcher(DispatcherType.Serialization).execute(() ->
 402                         responseMessageSlicer.slice(SliceOptions.builder().identifier(success.getTarget())
 403                             .message(envelope.newSuccessEnvelope(success, executionTimeNanos))
 404                             .sendTo(envelope.getMessage().getReplyTo()).replyTo(self())
 405                             .onFailureCallback(t -> LOG.warn("Error slicing response {}", success, t)).build()));
 406                 } else {
 407                     envelope.sendSuccess(success, executionTimeNanos);
 408                 }
 409             }
 410         } catch (RequestException e) {
 411             LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
 412             envelope.sendFailure(e, ticker().read() - now);
 413         } catch (Exception e) {
 414             LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
 415             envelope.sendFailure(new RuntimeRequestException("Request failed to process", e),
 416                 ticker().read() - now);
 417         }
 418     }
 419
 420     private void commitTimeoutCheck() {
 421         store.checkForExpiredTransactions(transactionCommitTimeout, this::updateAccess);
 422         commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 423         requestMessageAssembler.checkExpiredAssembledMessageState();
 424     }
 425
 426     private Optional<Long> updateAccess(final SimpleShardDataTreeCohort cohort) {
 427         final FrontendIdentifier frontend = cohort.getIdentifier().getHistoryId().getClientId().getFrontendId();
 428         final LeaderFrontendState state = knownFrontends.get(frontend);
 429         if (state == null) {
 430             // Not tell-based protocol, do nothing
 431             return Optional.absent();
 432         }
 433
 434         if (isIsolatedLeader()) {
 435             // We are isolated and no new request can come through until we emerge from it. We are still updating
 436             // liveness of frontend when we see it attempting to communicate. Use the last access timer.
 437             return Optional.of(state.getLastSeenTicks());
 438         }
 439
 440         // If this frontend has freshly connected, give it some time to catch up before killing its transactions.
 441         return Optional.of(state.getLastConnectTicks());
 442     }
 443
 444     private void disableTracking(final DisableTrackingPayload payload) {
 445         final ClientIdentifier clientId = payload.getIdentifier();
 446         LOG.debug("{}: disabling tracking of {}", persistenceId(), clientId);
 447         frontendMetadata.disableTracking(clientId);
 448
 449         if (isLeader()) {
 450             final FrontendIdentifier frontendId = clientId.getFrontendId();
 451             final LeaderFrontendState frontend = knownFrontends.get(frontendId);
 452             if (frontend != null) {
 453                 if (clientId.equals(frontend.getIdentifier())) {
 454                     if (!(frontend instanceof LeaderFrontendState.Disabled)) {
 455                         verify(knownFrontends.replace(frontendId, frontend,
 456                             new LeaderFrontendState.Disabled(persistenceId(), clientId, store)));
 457                         LOG.debug("{}: leader state for {} disabled", persistenceId(), clientId);
 458                     } else {
 459                         LOG.debug("{}: leader state {} is already disabled", persistenceId(), frontend);
 460                     }
 461                 } else {
 462                     LOG.debug("{}: leader state {} does not match {}", persistenceId(), frontend, clientId);
 463                 }
 464             } else {
 465                 LOG.debug("{}: leader state for {} not found", persistenceId(), clientId);
 466             }
 467         }
 468     }
 469
 470     private void onMakeLeaderLocal() {
 471         LOG.debug("{}: onMakeLeaderLocal received", persistenceId());
 472         if (isLeader()) {
 473             getSender().tell(new Status.Success(null), getSelf());
 474             return;
 475         }
 476
 477         final ActorSelection leader = getLeader();
 478
 479         if (leader == null) {
 480             // Leader is not present. The cluster is most likely trying to
 481             // elect a leader and we should let that run its normal course
 482
 483             // TODO we can wait for the election to complete and retry the
 484             // request. We can also let the caller retry by sending a flag
 485             // in the response indicating the request is "reTryable".
 486             getSender().tell(new Failure(
 487                     new LeadershipTransferFailedException("We cannot initiate leadership transfer to local node. "
 488                             + "Currently there is no leader for " + persistenceId())),
 489                     getSelf());
 490             return;
 491         }
 492
 493         leader.tell(new RequestLeadership(getId(), getSender()), getSelf());
 494     }
 495
 496     // Acquire our frontend tracking handle and verify generation matches
 497     @Nullable
 498     private LeaderFrontendState findFrontend(final ClientIdentifier clientId) throws RequestException {
 499         final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
 500         if (existing != null) {
 501             final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
 502             if (cmp == 0) {
 503                 existing.touch();
 504                 return existing;
 505             }
 506             if (cmp > 0) {
 507                 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
 508                 throw new RetiredGenerationException(clientId.getGeneration(),
 509                     existing.getIdentifier().getGeneration());
 510             }
 511
 512             LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
 513             existing.retire();
 514             knownFrontends.remove(clientId.getFrontendId());
 515         } else {
 516             LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
 517         }
 518
 519         return null;
 520     }
 521
 522     private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
 523         final LeaderFrontendState ret = findFrontend(clientId);
 524         if (ret != null) {
 525             return ret;
 526         }
 527
 528         // TODO: a dedicated exception would be better, but this is technically true, too
 529         throw new OutOfSequenceEnvelopeException(0);
 530     }
 531
 532     @Nonnull
 533     private static ABIVersion selectVersion(final ConnectClientRequest message) {
 534         final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
 535         for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
 536             if (clientRange.contains(v)) {
 537                 return v;
 538             }
 539         }
 540
 541         throw new IllegalArgumentException(String.format(
 542             "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
 543             clientRange));
 544     }
 545
 546     @SuppressWarnings("checkstyle:IllegalCatch")
 547     private void handleConnectClient(final ConnectClientRequest message) {
 548         try {
 549             final ClientIdentifier clientId = message.getTarget();
 550             final LeaderFrontendState existing = findFrontend(clientId);
 551             if (existing != null) {
 552                 existing.touch();
 553             }
 554
 555             if (!isLeader() || !isLeaderActive()) {
 556                 LOG.info("{}: not currently leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 557                                 + "isLeadershipTransferInProgress: {}.",
 558                         persistenceId(), message, isLeader(), isLeaderActive(), isLeadershipTransferInProgress());
 559                 throw new NotLeaderException(getSelf());
 560             }
 561
 562             final ABIVersion selectedVersion = selectVersion(message);
 563             final LeaderFrontendState frontend;
 564             if (existing == null) {
 565                 frontend = new LeaderFrontendState.Enabled(persistenceId(), clientId, store);
 566                 knownFrontends.put(clientId.getFrontendId(), frontend);
 567                 LOG.debug("{}: created state {} for client {}", persistenceId(), frontend, clientId);
 568             } else {
 569                 frontend = existing;
 570             }
 571
 572             frontend.reconnect();
 573             message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
 574                 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
 575                 ActorRef.noSender());
 576         } catch (RequestException | RuntimeException e) {
 577             message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
 578         }
 579     }
 580
 581     @Nullable
 582     private RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope, final long now)
 583             throws RequestException {
 584         // We are not the leader, hence we want to fail-fast.
 585         if (!isLeader() || paused || !isLeaderActive()) {
 586             LOG.debug("{}: not currently active leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 587                             + "isLeadershipTransferInProgress: {}, paused: {}",
 588                     persistenceId(), envelope, isLeader(), isLeaderActive(), isLeadershipTransferInProgress(), paused);
 589             throw new NotLeaderException(getSelf());
 590         }
 591
 592         final Request<?, ?> request = envelope.getMessage();
 593         if (request instanceof TransactionRequest) {
 594             final TransactionRequest<?> txReq = (TransactionRequest<?>)request;
 595             final ClientIdentifier clientId = txReq.getTarget().getHistoryId().getClientId();
 596             return getFrontend(clientId).handleTransactionRequest(txReq, envelope, now);
 597         } else if (request instanceof LocalHistoryRequest) {
 598             final LocalHistoryRequest<?> lhReq = (LocalHistoryRequest<?>)request;
 599             final ClientIdentifier clientId = lhReq.getTarget().getClientId();
 600             return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope, now);
 601         } else {
 602             LOG.warn("{}: rejecting unsupported request {}", persistenceId(), request);
 603             throw new UnsupportedRequestException(request);
 604         }
 605     }
 606
 607     private boolean hasLeader() {
 608         return getLeaderId() != null;
 609     }
 610
 611     public int getPendingTxCommitQueueSize() {
 612         return store.getQueueSize();
 613     }
 614
 615     public int getCohortCacheSize() {
 616         return commitCoordinator.getCohortCacheSize();
 617     }
 618
 619     @Override
 620     protected Optional<ActorRef> getRoleChangeNotifier() {
 621         return roleChangeNotifier;
 622     }
 623
 624     String getShardName() {
 625         return shardName;
 626     }
 627
 628     @Override
 629     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 630             final short leaderPayloadVersion) {
 631         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 632                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 633     }
 634
 635     protected void onDatastoreContext(final DatastoreContext context) {
 636         datastoreContext = context;
 637
 638         setTransactionCommitTimeout();
 639
 640         setPersistence(datastoreContext.isPersistent());
 641
 642         updateConfigParams(datastoreContext.getShardRaftConfig());
 643     }
 644
 645     // applyState() will be invoked once consensus is reached on the payload
 646     void persistPayload(final Identifier id, final Payload payload, final boolean batchHint) {
 647         boolean canSkipPayload = !hasFollowers() && !persistence().isRecoveryApplicable();
 648         if (canSkipPayload) {
 649             applyState(self(), id, payload);
 650         } else {
 651             // We are faking the sender
 652             persistData(self(), id, payload, batchHint);
 653         }
 654     }
 655
 656     private void handleCommitTransaction(final CommitTransaction commit) {
 657         final TransactionIdentifier txId = commit.getTransactionId();
 658         if (isLeader()) {
 659             askProtocolEncountered(txId);
 660             commitCoordinator.handleCommit(txId, getSender(), this);
 661         } else {
 662             ActorSelection leader = getLeader();
 663             if (leader == null) {
 664                 messageRetrySupport.addMessageToRetry(commit, getSender(), "Could not commit transaction " + txId);
 665             } else {
 666                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 667                 leader.forward(commit, getContext());
 668             }
 669         }
 670     }
 671
 672     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 673         final TransactionIdentifier txId = canCommit.getTransactionId();
 674         LOG.debug("{}: Can committing transaction {}", persistenceId(), txId);
 675
 676         if (isLeader()) {
 677             askProtocolEncountered(txId);
 678             commitCoordinator.handleCanCommit(txId, getSender(), this);
 679         } else {
 680             ActorSelection leader = getLeader();
 681             if (leader == null) {
 682                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 683                         "Could not canCommit transaction " + txId);
 684             } else {
 685                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 686                 leader.forward(canCommit, getContext());
 687             }
 688         }
 689     }
 690
 691     @SuppressWarnings("checkstyle:IllegalCatch")
 692     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 693         askProtocolEncountered(batched.getTransactionId());
 694
 695         try {
 696             commitCoordinator.handleBatchedModifications(batched, sender, this);
 697         } catch (Exception e) {
 698             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 699                     batched.getTransactionId(), e);
 700             sender.tell(new Failure(e), getSelf());
 701         }
 702     }
 703
 704     private void handleBatchedModifications(final BatchedModifications batched) {
 705         // This message is sent to prepare the modifications transaction directly on the Shard as an
 706         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 707         // BatchedModifications message, the caller sets the ready flag in the message indicating
 708         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 709         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 710         // ReadyTransaction message.
 711
 712         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 713         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 714         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 715         // window where it could have a stale leader during leadership transitions.
 716         //
 717         boolean isLeaderActive = isLeaderActive();
 718         if (isLeader() && isLeaderActive) {
 719             handleBatchedModificationsLocal(batched, getSender());
 720         } else {
 721             ActorSelection leader = getLeader();
 722             if (!isLeaderActive || leader == null) {
 723                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 724                         "Could not process BatchedModifications " + batched.getTransactionId());
 725             } else {
 726                 // If this is not the first batch and leadership changed in between batched messages,
 727                 // we need to reconstruct previous BatchedModifications from the transaction
 728                 // DataTreeModification, honoring the max batched modification count, and forward all the
 729                 // previous BatchedModifications to the new leader.
 730                 Collection<BatchedModifications> newModifications = commitCoordinator
 731                         .createForwardedBatchedModifications(batched,
 732                                 datastoreContext.getShardBatchedModificationCount());
 733
 734                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 735                         newModifications.size(), leader);
 736
 737                 for (BatchedModifications bm : newModifications) {
 738                     leader.forward(bm, getContext());
 739                 }
 740             }
 741         }
 742     }
 743
 744     private boolean failIfIsolatedLeader(final ActorRef sender) {
 745         if (isIsolatedLeader()) {
 746             sender.tell(new Failure(new NoShardLeaderException(String.format(
 747                     "Shard %s was the leader but has lost contact with all of its followers. Either all"
 748                     + " other follower nodes are down or this node is isolated by a network partition.",
 749                     persistenceId()))), getSelf());
 750             return true;
 751         }
 752
 753         return false;
 754     }
 755
 756     protected boolean isIsolatedLeader() {
 757         return getRaftState() == RaftState.IsolatedLeader;
 758     }
 759
 760     @SuppressWarnings("checkstyle:IllegalCatch")
 761     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 762         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionId());
 763
 764         boolean isLeaderActive = isLeaderActive();
 765         if (isLeader() && isLeaderActive) {
 766             try {
 767                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 768             } catch (Exception e) {
 769                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 770                         message.getTransactionId(), e);
 771                 getSender().tell(new Failure(e), getSelf());
 772             }
 773         } else {
 774             ActorSelection leader = getLeader();
 775             if (!isLeaderActive || leader == null) {
 776                 messageRetrySupport.addMessageToRetry(message, getSender(),
 777                         "Could not process ready local transaction " + message.getTransactionId());
 778             } else {
 779                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 780                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 781                 leader.forward(message, getContext());
 782             }
 783         }
 784     }
 785
 786     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 787         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
 788
 789         boolean isLeaderActive = isLeaderActive();
 790         if (isLeader() && isLeaderActive) {
 791             askProtocolEncountered(forwardedReady.getTransactionId());
 792             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 793         } else {
 794             ActorSelection leader = getLeader();
 795             if (!isLeaderActive || leader == null) {
 796                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 797                         "Could not process forwarded ready transaction " + forwardedReady.getTransactionId());
 798             } else {
 799                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 800
 801                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
 802                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit(),
 803                         forwardedReady.getParticipatingShardNames());
 804                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 805                 leader.forward(readyLocal, getContext());
 806             }
 807         }
 808     }
 809
 810     private void handleAbortTransaction(final AbortTransaction abort) {
 811         final TransactionIdentifier transactionId = abort.getTransactionId();
 812         askProtocolEncountered(transactionId);
 813         doAbortTransaction(transactionId, getSender());
 814     }
 815
 816     void doAbortTransaction(final Identifier transactionID, final ActorRef sender) {
 817         commitCoordinator.handleAbort(transactionID, sender, this);
 818     }
 819
 820     private void handleCreateTransaction(final Object message) {
 821         if (isLeader()) {
 822             createTransaction(CreateTransaction.fromSerializable(message));
 823         } else if (getLeader() != null) {
 824             getLeader().forward(message, getContext());
 825         } else {
 826             getSender().tell(new Failure(new NoShardLeaderException(
 827                     "Could not create a shard transaction", persistenceId())), getSelf());
 828         }
 829     }
 830
 831     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 832         if (isLeader()) {
 833             final LocalHistoryIdentifier id = closeTransactionChain.getIdentifier();
 834             askProtocolEncountered(id.getClientId());
 835
 836             // FIXME: CONTROLLER-1628: stage purge once no transactions are present
 837             store.closeTransactionChain(id, null);
 838             store.purgeTransactionChain(id, null);
 839         } else if (getLeader() != null) {
 840             getLeader().forward(closeTransactionChain, getContext());
 841         } else {
 842             LOG.warn("{}: Could not close transaction {}", persistenceId(), closeTransactionChain.getIdentifier());
 843         }
 844     }
 845
 846     @SuppressWarnings("checkstyle:IllegalCatch")
 847     private void createTransaction(final CreateTransaction createTransaction) {
 848         askProtocolEncountered(createTransaction.getTransactionId());
 849
 850         try {
 851             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 852                     && failIfIsolatedLeader(getSender())) {
 853                 return;
 854             }
 855
 856             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 857                 createTransaction.getTransactionId());
 858
 859             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 860                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 861         } catch (Exception e) {
 862             getSender().tell(new Failure(e), getSelf());
 863         }
 864     }
 865
 866     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 867         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 868         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 869             transactionId);
 870     }
 871
 872     // Called on leader only
 873     private void askProtocolEncountered(final TransactionIdentifier transactionId) {
 874         askProtocolEncountered(transactionId.getHistoryId().getClientId());
 875     }
 876
 877     // Called on leader only
 878     private void askProtocolEncountered(final ClientIdentifier clientId) {
 879         final LeaderFrontendState state = knownFrontends.get(clientId.getFrontendId());
 880         if (state instanceof LeaderFrontendState.Enabled) {
 881             LOG.debug("{}: encountered ask-based client {}, disabling transaction tracking", persistenceId(), clientId);
 882             persistPayload(clientId, DisableTrackingPayload.create(clientId,
 883                 datastoreContext.getInitialPayloadSerializedBufferCapacity()), false);
 884         }
 885     }
 886
 887     private void updateSchemaContext(final UpdateSchemaContext message) {
 888         updateSchemaContext(message.getSchemaContext());
 889     }
 890
 891     @VisibleForTesting
 892     void updateSchemaContext(final SchemaContext schemaContext) {
 893         store.updateSchemaContext(schemaContext);
 894     }
 895
 896     private boolean isMetricsCaptureEnabled() {
 897         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 898         return config.isMetricCaptureEnabled();
 899     }
 900
 901     @Override
 902     @VisibleForTesting
 903     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 904         return snapshotCohort;
 905     }
 906
 907     @Override
 908     @Nonnull
 909     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 910         if (restoreFromSnapshot == null) {
 911             return ShardRecoveryCoordinator.create(store, persistenceId(), LOG);
 912         }
 913
 914         return ShardRecoveryCoordinator.forSnapshot(store, persistenceId(), LOG, restoreFromSnapshot.getSnapshot());
 915     }
 916
 917     @Override
 918     protected void onRecoveryComplete() {
 919         restoreFromSnapshot = null;
 920
 921         //notify shard manager
 922         getContext().parent().tell(new ActorInitialized(), getSelf());
 923
 924         // Being paranoid here - this method should only be called once but just in case...
 925         if (txCommitTimeoutCheckSchedule == null) {
 926             // Schedule a message to be periodically sent to check if the current in-progress
 927             // transaction should be expired and aborted.
 928             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 929             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 930                     period, period, getSelf(),
 931                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 932         }
 933     }
 934
 935     @Override
 936     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 937         if (data instanceof Payload) {
 938             if (data instanceof DisableTrackingPayload) {
 939                 disableTracking((DisableTrackingPayload) data);
 940                 return;
 941             }
 942
 943             try {
 944                 store.applyReplicatedPayload(identifier, (Payload)data);
 945             } catch (DataValidationFailedException | IOException e) {
 946                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 947             }
 948         } else {
 949             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 950         }
 951     }
 952
 953     @Override
 954     protected void onStateChanged() {
 955         boolean isLeader = isLeader();
 956         boolean hasLeader = hasLeader();
 957         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 958
 959         // If this actor is no longer the leader close all the transaction chains
 960         if (!isLeader) {
 961             if (LOG.isDebugEnabled()) {
 962                 LOG.debug(
 963                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 964                     persistenceId(), getId());
 965             }
 966
 967             paused = false;
 968             store.purgeLeaderState();
 969         }
 970
 971         if (hasLeader && !isIsolatedLeader()) {
 972             messageRetrySupport.retryMessages();
 973         }
 974     }
 975
 976     @Override
 977     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 978         shardMBean.incrementLeadershipChangeCount();
 979         paused = false;
 980
 981         if (!isLeader()) {
 982             if (!knownFrontends.isEmpty()) {
 983                 LOG.debug("{}: removing frontend state for {}", persistenceId(), knownFrontends.keySet());
 984                 knownFrontends = ImmutableMap.of();
 985             }
 986
 987             requestMessageAssembler.close();
 988
 989             if (!hasLeader()) {
 990                 // No leader anywhere, nothing else to do
 991                 return;
 992             }
 993
 994             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 995             // them to transaction messages and send to the new leader.
 996             ActorSelection leader = getLeader();
 997             if (leader != null) {
 998                 Collection<?> messagesToForward = convertPendingTransactionsToMessages();
 999
1000                 if (!messagesToForward.isEmpty()) {
1001                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
1002                             messagesToForward.size(), leader);
1003
1004                     for (Object message : messagesToForward) {
1005                         LOG.debug("{}: Forwarding pending transaction message {}", persistenceId(), message);
1006
1007                         leader.tell(message, self());
1008                     }
1009                 }
1010             } else {
1011                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
1012                         + "change and the leader address isn't available.", this);
1013             }
1014         } else {
1015             // We have become the leader, we need to reconstruct frontend state
1016             knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
1017             LOG.debug("{}: became leader with frontend state for {}", persistenceId(), knownFrontends.keySet());
1018         }
1019
1020         if (!isIsolatedLeader()) {
1021             messageRetrySupport.retryMessages();
1022         }
1023     }
1024
1025     /**
1026      * Clears all pending transactions and converts them to messages to be forwarded to a new leader.
1027      *
1028      * @return the converted messages
1029      */
1030     public Collection<?> convertPendingTransactionsToMessages() {
1031         return commitCoordinator.convertPendingTransactionsToMessages(
1032                 datastoreContext.getShardBatchedModificationCount());
1033     }
1034
1035     @Override
1036     protected void pauseLeader(final Runnable operation) {
1037         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
1038         paused = true;
1039
1040         // Tell-based protocol can replay transaction state, so it is safe to blow it up when we are paused.
1041         knownFrontends.values().forEach(LeaderFrontendState::retire);
1042         knownFrontends = ImmutableMap.of();
1043
1044         store.setRunOnPendingTransactionsComplete(operation);
1045     }
1046
1047     @Override
1048     protected void unpauseLeader() {
1049         LOG.debug("{}: In unpauseLeader", persistenceId());
1050         paused = false;
1051
1052         store.setRunOnPendingTransactionsComplete(null);
1053
1054         // Restore tell-based protocol state as if we were becoming the leader
1055         knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
1056     }
1057
1058     @Override
1059     protected OnDemandRaftState.AbstractBuilder<?, ?> newOnDemandRaftStateBuilder() {
1060         return OnDemandShardState.newBuilder().treeChangeListenerActors(treeChangeSupport.getListenerActors())
1061                 .commitCohortActors(store.getCohortActors());
1062     }
1063
1064     @Override
1065     public String persistenceId() {
1066         return this.name;
1067     }
1068
1069     @VisibleForTesting
1070     ShardCommitCoordinator getCommitCoordinator() {
1071         return commitCoordinator;
1072     }
1073
1074     public DatastoreContext getDatastoreContext() {
1075         return datastoreContext;
1076     }
1077
1078     @VisibleForTesting
1079     public ShardDataTree getDataStore() {
1080         return store;
1081     }
1082
1083     @VisibleForTesting
1084     ShardStats getShardMBean() {
1085         return shardMBean;
1086     }
1087
1088     public static Builder builder() {
1089         return new Builder();
1090     }
1091
1092     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
1093         private final Class<S> shardClass;
1094         private ShardIdentifier id;
1095         private Map<String, String> peerAddresses = Collections.emptyMap();
1096         private DatastoreContext datastoreContext;
1097         private SchemaContextProvider schemaContextProvider;
1098         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
1099         private DataTree dataTree;
1100         private volatile boolean sealed;
1101
1102         protected AbstractBuilder(final Class<S> shardClass) {
1103             this.shardClass = shardClass;
1104         }
1105
1106         protected void checkSealed() {
1107             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
1108         }
1109
1110         @SuppressWarnings("unchecked")
1111         private T self() {
1112             return (T) this;
1113         }
1114
1115         public T id(final ShardIdentifier newId) {
1116             checkSealed();
1117             this.id = newId;
1118             return self();
1119         }
1120
1121         public T peerAddresses(final Map<String, String> newPeerAddresses) {
1122             checkSealed();
1123             this.peerAddresses = newPeerAddresses;
1124             return self();
1125         }
1126
1127         public T datastoreContext(final DatastoreContext newDatastoreContext) {
1128             checkSealed();
1129             this.datastoreContext = newDatastoreContext;
1130             return self();
1131         }
1132
1133         public T schemaContextProvider(final SchemaContextProvider newSchemaContextProvider) {
1134             checkSealed();
1135             this.schemaContextProvider = Preconditions.checkNotNull(newSchemaContextProvider);
1136             return self();
1137         }
1138
1139         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
1140             checkSealed();
1141             this.restoreFromSnapshot = newRestoreFromSnapshot;
1142             return self();
1143         }
1144
1145         public T dataTree(final DataTree newDataTree) {
1146             checkSealed();
1147             this.dataTree = newDataTree;
1148             return self();
1149         }
1150
1151         public ShardIdentifier getId() {
1152             return id;
1153         }
1154
1155         public Map<String, String> getPeerAddresses() {
1156             return peerAddresses;
1157         }
1158
1159         public DatastoreContext getDatastoreContext() {
1160             return datastoreContext;
1161         }
1162
1163         public SchemaContext getSchemaContext() {
1164             return Verify.verifyNotNull(schemaContextProvider.getSchemaContext());
1165         }
1166
1167         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
1168             return restoreFromSnapshot;
1169         }
1170
1171         public DataTree getDataTree() {
1172             return dataTree;
1173         }
1174
1175         public TreeType getTreeType() {
1176             switch (datastoreContext.getLogicalStoreType()) {
1177                 case CONFIGURATION:
1178                     return TreeType.CONFIGURATION;
1179                 case OPERATIONAL:
1180                     return TreeType.OPERATIONAL;
1181                 default:
1182                     throw new IllegalStateException("Unhandled logical store type "
1183                             + datastoreContext.getLogicalStoreType());
1184             }
1185         }
1186
1187         protected void verify() {
1188             Preconditions.checkNotNull(id, "id should not be null");
1189             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
1190             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
1191             Preconditions.checkNotNull(schemaContextProvider, "schemaContextProvider should not be null");
1192         }
1193
1194         public Props props() {
1195             sealed = true;
1196             verify();
1197             return Props.create(shardClass, this);
1198         }
1199     }
1200
1201     public static class Builder extends AbstractBuilder<Builder, Shard> {
1202         Builder() {
1203             super(Shard.class);
1204         }
1205     }
1206
1207     Ticker ticker() {
1208         return Ticker.systemTicker();
1209     }
1210
1211     void scheduleNextPendingTransaction() {
1212         self().tell(RESUME_NEXT_PENDING_TRANSACTION, ActorRef.noSender());
1213     }
1214 }