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.serialization.Serialization;
  16 import com.google.common.annotations.VisibleForTesting;
  17 import com.google.common.base.Optional;
  18 import com.google.common.base.Preconditions;
  19 import com.google.common.base.Ticker;
  20 import java.io.IOException;
  21 import java.util.Collection;
  22 import java.util.Collections;
  23 import java.util.Map;
  24 import java.util.concurrent.TimeUnit;
  25 import javax.annotation.Nonnull;
  26 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  27 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  28 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  29 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
  30 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  31 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  32 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  33 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  34 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  35 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  36 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  37 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  38 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  39 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  40 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  41 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  42 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  43 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot;
  44 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot.ShardSnapshot;
  45 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  46 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  47 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  48 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  49 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  50 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  51 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  52 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  53 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  54 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  55 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  56 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  57 import org.opendaylight.controller.cluster.raft.RaftActor;
  58 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  59 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
  60 import org.opendaylight.controller.cluster.raft.RaftState;
  61 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  62 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  63 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
  64 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  65 import org.opendaylight.yangtools.concepts.Identifier;
  66 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  67 import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree;
  68 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
  69 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  70 import scala.concurrent.duration.Duration;
  71 import scala.concurrent.duration.FiniteDuration;
  72
  73 /**
  74  * A Shard represents a portion of the logical data tree <br/>
  75  * <p>
  76  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
  77  * </p>
  78  */
  79 public class Shard extends RaftActor {
  80
  81     @VisibleForTesting
  82     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
  83         @Override
  84         public String toString() {
  85             return "txCommitTimeoutCheck";
  86         }
  87     };
  88
  89     @VisibleForTesting
  90     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
  91         @Override
  92         public String toString() {
  93             return "getShardMBeanMessage";
  94         }
  95     };
  96
  97     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
  98     public static final String DEFAULT_NAME = "default";
  99
 100     // The state of this Shard
 101     private final ShardDataTree store;
 102
 103     /// The name of this shard
 104     private final String name;
 105
 106     private final ShardStats shardMBean;
 107
 108     private DatastoreContext datastoreContext;
 109
 110     private final ShardCommitCoordinator commitCoordinator;
 111
 112     private long transactionCommitTimeout;
 113
 114     private Cancellable txCommitTimeoutCheckSchedule;
 115
 116     private final Optional<ActorRef> roleChangeNotifier;
 117
 118     private final MessageTracker appendEntriesReplyTracker;
 119
 120     private final ShardTransactionActorFactory transactionActorFactory;
 121
 122     private final ShardSnapshotCohort snapshotCohort;
 123
 124     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 125     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 126
 127
 128     private ShardSnapshot restoreFromSnapshot;
 129
 130     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 131
 132     protected Shard(final AbstractBuilder<?, ?> builder) {
 133         super(builder.getId().toString(), builder.getPeerAddresses(),
 134                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 135
 136         this.name = builder.getId().toString();
 137         this.datastoreContext = builder.getDatastoreContext();
 138         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 139
 140         setPersistence(datastoreContext.isPersistent());
 141
 142         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 143
 144         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 145                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher");
 146         ShardDataChangeListenerPublisherActorProxy dataChangeListenerPublisher =
 147                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher");
 148         if(builder.getDataTree() != null) {
 149             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 150                     treeChangeListenerPublisher, dataChangeListenerPublisher, name);
 151         } else {
 152             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 153                     treeChangeListenerPublisher, dataChangeListenerPublisher, name);
 154         }
 155
 156         shardMBean = ShardMBeanFactory.getShardStatsMBean(name.toString(),
 157                 datastoreContext.getDataStoreMXBeanType());
 158         shardMBean.setShard(this);
 159
 160         if (isMetricsCaptureEnabled()) {
 161             getContext().become(new MeteringBehavior(this));
 162         }
 163
 164         commitCoordinator = new ShardCommitCoordinator(store, LOG, this.name);
 165
 166         setTransactionCommitTimeout();
 167
 168         // create a notifier actor for each cluster member
 169         roleChangeNotifier = createRoleChangeNotifier(name.toString());
 170
 171         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 172                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 173
 174         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 175                 new Dispatchers(context().system().dispatchers()).getDispatcherPath(
 176                         Dispatchers.DispatcherType.Transaction), self(), getContext(), shardMBean);
 177
 178         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 179             this.name);
 180
 181         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 182     }
 183
 184     private void setTransactionCommitTimeout() {
 185         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 186                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 187     }
 188
 189     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 190         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 191             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 192         return Optional.of(shardRoleChangeNotifier);
 193     }
 194
 195     @Override
 196     public void postStop() {
 197         LOG.info("Stopping Shard {}", persistenceId());
 198
 199         super.postStop();
 200
 201         messageRetrySupport.close();
 202
 203         if (txCommitTimeoutCheckSchedule != null) {
 204             txCommitTimeoutCheckSchedule.cancel();
 205         }
 206
 207         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 208
 209         shardMBean.unregisterMBean();
 210     }
 211
 212     @Override
 213     protected void handleRecover(final Object message) {
 214         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 215             getSender());
 216
 217         super.handleRecover(message);
 218         if (LOG.isTraceEnabled()) {
 219             appendEntriesReplyTracker.begin();
 220         }
 221     }
 222
 223     @Override
 224     protected void handleNonRaftCommand(final Object message) {
 225         try (final MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 226             final Optional<Error> maybeError = context.error();
 227             if (maybeError.isPresent()) {
 228                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 229                     maybeError.get());
 230             }
 231
 232             if (CreateTransaction.isSerializedType(message)) {
 233                 handleCreateTransaction(message);
 234             } else if (message instanceof BatchedModifications) {
 235                 handleBatchedModifications((BatchedModifications)message);
 236             } else if (message instanceof ForwardedReadyTransaction) {
 237                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 238             } else if (message instanceof ReadyLocalTransaction) {
 239                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 240             } else if (CanCommitTransaction.isSerializedType(message)) {
 241                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 242             } else if (CommitTransaction.isSerializedType(message)) {
 243                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 244             } else if (AbortTransaction.isSerializedType(message)) {
 245                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 246             } else if (CloseTransactionChain.isSerializedType(message)) {
 247                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 248             } else if (message instanceof RegisterChangeListener) {
 249                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 250             } else if (message instanceof RegisterDataTreeChangeListener) {
 251                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 252             } else if (message instanceof UpdateSchemaContext) {
 253                 updateSchemaContext((UpdateSchemaContext) message);
 254             } else if (message instanceof PeerAddressResolved) {
 255                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 256                 setPeerAddress(resolved.getPeerId().toString(),
 257                         resolved.getPeerAddress());
 258             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 259                 store.checkForExpiredTransactions(transactionCommitTimeout);
 260                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 261             } else if (message instanceof DatastoreContext) {
 262                 onDatastoreContext((DatastoreContext)message);
 263             } else if (message instanceof RegisterRoleChangeListener){
 264                 roleChangeNotifier.get().forward(message, context());
 265             } else if (message instanceof FollowerInitialSyncUpStatus) {
 266                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 267                 context().parent().tell(message, self());
 268             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)){
 269                 sender().tell(getShardMBean(), self());
 270             } else if (message instanceof GetShardDataTree) {
 271                 sender().tell(store.getDataTree(), self());
 272             } else if (message instanceof ServerRemoved){
 273                 context().parent().forward(message, context());
 274             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 275                 messageRetrySupport.onTimerMessage(message);
 276             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 277                 store.processCohortRegistryCommand(getSender(),
 278                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 279             } else {
 280                 super.handleNonRaftCommand(message);
 281             }
 282         }
 283     }
 284
 285     private boolean hasLeader() {
 286         return getLeaderId() != null;
 287     }
 288
 289     public int getPendingTxCommitQueueSize() {
 290         return store.getQueueSize();
 291     }
 292
 293     public int getCohortCacheSize() {
 294         return commitCoordinator.getCohortCacheSize();
 295     }
 296
 297     @Override
 298     protected Optional<ActorRef> getRoleChangeNotifier() {
 299         return roleChangeNotifier;
 300     }
 301
 302     @Override
 303     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId, final short leaderPayloadVersion) {
 304         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 305                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 306     }
 307
 308     protected void onDatastoreContext(final DatastoreContext context) {
 309         datastoreContext = context;
 310
 311         setTransactionCommitTimeout();
 312
 313         if (datastoreContext.isPersistent() && !persistence().isRecoveryApplicable()) {
 314             setPersistence(true);
 315         } else if (!datastoreContext.isPersistent() && persistence().isRecoveryApplicable()) {
 316             setPersistence(false);
 317         }
 318
 319         updateConfigParams(datastoreContext.getShardRaftConfig());
 320     }
 321
 322     boolean canSkipPayload() {
 323         // If we do not have any followers and we are not using persistence we can apply modification to the state
 324         // immediately
 325         return !hasFollowers() && !persistence().isRecoveryApplicable();
 326     }
 327
 328     // applyState() will be invoked once consensus is reached on the payload
 329     void persistPayload(final TransactionIdentifier transactionId, final Payload payload) {
 330         // We are faking the sender
 331         persistData(self(), transactionId, payload);
 332     }
 333
 334     private void handleCommitTransaction(final CommitTransaction commit) {
 335         if (isLeader()) {
 336             commitCoordinator.handleCommit(commit.getTransactionID(), getSender(), this);
 337         } else {
 338             ActorSelection leader = getLeader();
 339             if (leader == null) {
 340                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 341                         "Could not commit transaction " + commit.getTransactionID());
 342             } else {
 343                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 344                 leader.forward(commit, getContext());
 345             }
 346         }
 347     }
 348
 349     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 350         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionID());
 351
 352         if (isLeader()) {
 353         commitCoordinator.handleCanCommit(canCommit.getTransactionID(), getSender(), this);
 354         } else {
 355             ActorSelection leader = getLeader();
 356             if (leader == null) {
 357                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 358                         "Could not canCommit transaction " + canCommit.getTransactionID());
 359             } else {
 360                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 361                 leader.forward(canCommit, getContext());
 362             }
 363         }
 364     }
 365
 366     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 367         try {
 368             commitCoordinator.handleBatchedModifications(batched, sender, this);
 369         } catch (Exception e) {
 370             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 371                     batched.getTransactionID(), e);
 372             sender.tell(new akka.actor.Status.Failure(e), getSelf());
 373         }
 374     }
 375
 376     private void handleBatchedModifications(final BatchedModifications batched) {
 377         // This message is sent to prepare the modifications transaction directly on the Shard as an
 378         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 379         // BatchedModifications message, the caller sets the ready flag in the message indicating
 380         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 381         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 382         // ReadyTransaction message.
 383
 384         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 385         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 386         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 387         // window where it could have a stale leader during leadership transitions.
 388         //
 389         boolean isLeaderActive = isLeaderActive();
 390         if (isLeader() && isLeaderActive) {
 391             handleBatchedModificationsLocal(batched, getSender());
 392         } else {
 393             ActorSelection leader = getLeader();
 394             if (!isLeaderActive || leader == null) {
 395                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 396                         "Could not commit transaction " + batched.getTransactionID());
 397             } else {
 398                 // If this is not the first batch and leadership changed in between batched messages,
 399                 // we need to reconstruct previous BatchedModifications from the transaction
 400                 // DataTreeModification, honoring the max batched modification count, and forward all the
 401                 // previous BatchedModifications to the new leader.
 402                 Collection<BatchedModifications> newModifications = commitCoordinator.createForwardedBatchedModifications(
 403                         batched, datastoreContext.getShardBatchedModificationCount());
 404
 405                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 406                         newModifications.size(), leader);
 407
 408                 for (BatchedModifications bm : newModifications) {
 409                     leader.forward(bm, getContext());
 410                 }
 411             }
 412         }
 413     }
 414
 415     private boolean failIfIsolatedLeader(final ActorRef sender) {
 416         if (isIsolatedLeader()) {
 417             sender.tell(new akka.actor.Status.Failure(new NoShardLeaderException(String.format(
 418                     "Shard %s was the leader but has lost contact with all of its followers. Either all" +
 419                     " other follower nodes are down or this node is isolated by a network partition.",
 420                     persistenceId()))), getSelf());
 421             return true;
 422         }
 423
 424         return false;
 425     }
 426
 427     protected boolean isIsolatedLeader() {
 428         return getRaftState() == RaftState.IsolatedLeader;
 429     }
 430
 431     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 432         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionID());
 433
 434         boolean isLeaderActive = isLeaderActive();
 435         if (isLeader() && isLeaderActive) {
 436             try {
 437                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 438             } catch (Exception e) {
 439                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 440                         message.getTransactionID(), e);
 441                 getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 442             }
 443         } else {
 444             ActorSelection leader = getLeader();
 445             if (!isLeaderActive || leader == null) {
 446                 messageRetrySupport.addMessageToRetry(message, getSender(),
 447                         "Could not commit transaction " + message.getTransactionID());
 448             } else {
 449                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 450                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 451                 leader.forward(message, getContext());
 452             }
 453         }
 454     }
 455
 456     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 457         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionID());
 458
 459         boolean isLeaderActive = isLeaderActive();
 460         if (isLeader() && isLeaderActive) {
 461             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 462         } else {
 463             ActorSelection leader = getLeader();
 464             if (!isLeaderActive || leader == null) {
 465                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 466                         "Could not commit transaction " + forwardedReady.getTransactionID());
 467             } else {
 468                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 469
 470                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionID(),
 471                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 472                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 473                 leader.forward(readyLocal, getContext());
 474             }
 475         }
 476     }
 477
 478     private void handleAbortTransaction(final AbortTransaction abort) {
 479         doAbortTransaction(abort.getTransactionID(), getSender());
 480     }
 481
 482     void doAbortTransaction(final TransactionIdentifier transactionID, final ActorRef sender) {
 483         commitCoordinator.handleAbort(transactionID, sender, this);
 484     }
 485
 486     private void handleCreateTransaction(final Object message) {
 487         if (isLeader()) {
 488             createTransaction(CreateTransaction.fromSerializable(message));
 489         } else if (getLeader() != null) {
 490             getLeader().forward(message, getContext());
 491         } else {
 492             getSender().tell(new akka.actor.Status.Failure(new NoShardLeaderException(
 493                     "Could not create a shard transaction", persistenceId())), getSelf());
 494         }
 495     }
 496
 497     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 498         store.closeTransactionChain(closeTransactionChain.getIdentifier());
 499     }
 500
 501     private void createTransaction(final CreateTransaction createTransaction) {
 502         try {
 503             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY &&
 504                     failIfIsolatedLeader(getSender())) {
 505                 return;
 506             }
 507
 508             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 509                 createTransaction.getTransactionId());
 510
 511             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 512                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 513         } catch (Exception e) {
 514             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 515         }
 516     }
 517
 518     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 519         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 520         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 521             transactionId);
 522     }
 523
 524     private void updateSchemaContext(final UpdateSchemaContext message) {
 525         updateSchemaContext(message.getSchemaContext());
 526     }
 527
 528     @VisibleForTesting
 529     void updateSchemaContext(final SchemaContext schemaContext) {
 530         store.updateSchemaContext(schemaContext);
 531     }
 532
 533     private boolean isMetricsCaptureEnabled() {
 534         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 535         return config.isMetricCaptureEnabled();
 536     }
 537
 538     @Override
 539     @VisibleForTesting
 540     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 541         return snapshotCohort;
 542     }
 543
 544     @Override
 545     @Nonnull
 546     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 547         return new ShardRecoveryCoordinator(store,
 548             restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 549     }
 550
 551     @Override
 552     protected void onRecoveryComplete() {
 553         restoreFromSnapshot = null;
 554
 555         //notify shard manager
 556         getContext().parent().tell(new ActorInitialized(), getSelf());
 557
 558         // Being paranoid here - this method should only be called once but just in case...
 559         if (txCommitTimeoutCheckSchedule == null) {
 560             // Schedule a message to be periodically sent to check if the current in-progress
 561             // transaction should be expired and aborted.
 562             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 563             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 564                     period, period, getSelf(),
 565                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 566         }
 567     }
 568
 569     @Override
 570     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 571         if (data instanceof Payload) {
 572             try {
 573                 store.applyReplicatedPayload(identifier, (Payload)data);
 574             } catch (DataValidationFailedException | IOException e) {
 575                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 576             }
 577         } else {
 578             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 579         }
 580     }
 581
 582     @Override
 583     protected void onStateChanged() {
 584         boolean isLeader = isLeader();
 585         boolean hasLeader = hasLeader();
 586         changeSupport.onLeadershipChange(isLeader, hasLeader);
 587         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 588
 589         // If this actor is no longer the leader close all the transaction chains
 590         if (!isLeader) {
 591             if (LOG.isDebugEnabled()) {
 592                 LOG.debug(
 593                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 594                     persistenceId(), getId());
 595             }
 596
 597             store.closeAllTransactionChains();
 598         }
 599
 600         if (hasLeader && !isIsolatedLeader()) {
 601             messageRetrySupport.retryMessages();
 602         }
 603     }
 604
 605     @Override
 606     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 607         shardMBean.incrementLeadershipChangeCount();
 608
 609         boolean hasLeader = hasLeader();
 610         if (hasLeader && !isLeader()) {
 611             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 612             // them to transaction messages and send to the new leader.
 613             ActorSelection leader = getLeader();
 614             if (leader != null) {
 615                 Collection<?> messagesToForward = commitCoordinator.convertPendingTransactionsToMessages(
 616                             datastoreContext.getShardBatchedModificationCount());
 617
 618                 if (!messagesToForward.isEmpty()) {
 619                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 620                             messagesToForward.size(), leader);
 621
 622                     for (Object message : messagesToForward) {
 623                         leader.tell(message, self());
 624                     }
 625                 }
 626             } else {
 627                 commitCoordinator.abortPendingTransactions(
 628                         "The transacton was aborted due to inflight leadership change and the leader address isn't available.",
 629                         this);
 630             }
 631         }
 632
 633         if (hasLeader && !isIsolatedLeader()) {
 634             messageRetrySupport.retryMessages();
 635         }
 636     }
 637
 638     @Override
 639     protected void pauseLeader(final Runnable operation) {
 640         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 641         store.setRunOnPendingTransactionsComplete(operation);
 642     }
 643
 644     @Override
 645     public String persistenceId() {
 646         return this.name;
 647     }
 648
 649     @VisibleForTesting
 650     ShardCommitCoordinator getCommitCoordinator() {
 651         return commitCoordinator;
 652     }
 653
 654     public DatastoreContext getDatastoreContext() {
 655         return datastoreContext;
 656     }
 657
 658     @VisibleForTesting
 659     public ShardDataTree getDataStore() {
 660         return store;
 661     }
 662
 663     @VisibleForTesting
 664     ShardStats getShardMBean() {
 665         return shardMBean;
 666     }
 667
 668     public static Builder builder() {
 669         return new Builder();
 670     }
 671
 672     public static abstract class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 673         private final Class<S> shardClass;
 674         private ShardIdentifier id;
 675         private Map<String, String> peerAddresses = Collections.emptyMap();
 676         private DatastoreContext datastoreContext;
 677         private SchemaContext schemaContext;
 678         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 679         private TipProducingDataTree dataTree;
 680         private volatile boolean sealed;
 681
 682         protected AbstractBuilder(final Class<S> shardClass) {
 683             this.shardClass = shardClass;
 684         }
 685
 686         protected void checkSealed() {
 687             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 688         }
 689
 690         @SuppressWarnings("unchecked")
 691         private T self() {
 692             return (T) this;
 693         }
 694
 695         public T id(final ShardIdentifier id) {
 696             checkSealed();
 697             this.id = id;
 698             return self();
 699         }
 700
 701         public T peerAddresses(final Map<String, String> peerAddresses) {
 702             checkSealed();
 703             this.peerAddresses = peerAddresses;
 704             return self();
 705         }
 706
 707         public T datastoreContext(final DatastoreContext datastoreContext) {
 708             checkSealed();
 709             this.datastoreContext = datastoreContext;
 710             return self();
 711         }
 712
 713         public T schemaContext(final SchemaContext schemaContext) {
 714             checkSealed();
 715             this.schemaContext = schemaContext;
 716             return self();
 717         }
 718
 719         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot restoreFromSnapshot) {
 720             checkSealed();
 721             this.restoreFromSnapshot = restoreFromSnapshot;
 722             return self();
 723         }
 724
 725         public T dataTree(final TipProducingDataTree dataTree) {
 726             checkSealed();
 727             this.dataTree = dataTree;
 728             return self();
 729         }
 730
 731         public ShardIdentifier getId() {
 732             return id;
 733         }
 734
 735         public Map<String, String> getPeerAddresses() {
 736             return peerAddresses;
 737         }
 738
 739         public DatastoreContext getDatastoreContext() {
 740             return datastoreContext;
 741         }
 742
 743         public SchemaContext getSchemaContext() {
 744             return schemaContext;
 745         }
 746
 747         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
 748             return restoreFromSnapshot;
 749         }
 750
 751         public TipProducingDataTree getDataTree() {
 752             return dataTree;
 753         }
 754
 755         public TreeType getTreeType() {
 756             switch (datastoreContext.getLogicalStoreType()) {
 757             case CONFIGURATION:
 758                 return TreeType.CONFIGURATION;
 759             case OPERATIONAL:
 760                 return TreeType.OPERATIONAL;
 761             }
 762
 763             throw new IllegalStateException("Unhandled logical store type " + datastoreContext.getLogicalStoreType());
 764         }
 765
 766         protected void verify() {
 767             Preconditions.checkNotNull(id, "id should not be null");
 768             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
 769             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
 770             Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
 771         }
 772
 773         public Props props() {
 774             sealed = true;
 775             verify();
 776             return Props.create(shardClass, this);
 777         }
 778     }
 779
 780     public static class Builder extends AbstractBuilder<Builder, Shard> {
 781         private Builder() {
 782             super(Shard.class);
 783         }
 784     }
 785
 786     Ticker ticker() {
 787         return Ticker.systemTicker();
 788     }
 789 }