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.
  75  * <p/>
  76  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
  77  */
  78 public class Shard extends RaftActor {
  79
  80     @VisibleForTesting
  81     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
  82         @Override
  83         public String toString() {
  84             return "txCommitTimeoutCheck";
  85         }
  86     };
  87
  88     @VisibleForTesting
  89     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
  90         @Override
  91         public String toString() {
  92             return "getShardMBeanMessage";
  93         }
  94     };
  95
  96     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
  97     public static final String DEFAULT_NAME = "default";
  98
  99     // The state of this Shard
 100     private final ShardDataTree store;
 101
 102     /// The name of this shard
 103     private final String name;
 104
 105     private final ShardStats shardMBean;
 106
 107     private DatastoreContext datastoreContext;
 108
 109     private final ShardCommitCoordinator commitCoordinator;
 110
 111     private long transactionCommitTimeout;
 112
 113     private Cancellable txCommitTimeoutCheckSchedule;
 114
 115     private final Optional<ActorRef> roleChangeNotifier;
 116
 117     private final MessageTracker appendEntriesReplyTracker;
 118
 119     private final ShardTransactionActorFactory transactionActorFactory;
 120
 121     private final ShardSnapshotCohort snapshotCohort;
 122
 123     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 124     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 125
 126
 127     private ShardSnapshot restoreFromSnapshot;
 128
 129     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 130
 131     private final FrontendMetadata frontendMetadata = new FrontendMetadata();
 132
 133     protected Shard(final AbstractBuilder<?, ?> builder) {
 134         super(builder.getId().toString(), builder.getPeerAddresses(),
 135                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 136
 137         this.name = builder.getId().toString();
 138         this.datastoreContext = builder.getDatastoreContext();
 139         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 140
 141         setPersistence(datastoreContext.isPersistent());
 142
 143         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 144
 145         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 146                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher");
 147         ShardDataChangeListenerPublisherActorProxy dataChangeListenerPublisher =
 148                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher");
 149         if (builder.getDataTree() != null) {
 150             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 151                     treeChangeListenerPublisher, dataChangeListenerPublisher, name);
 152         } else {
 153             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 154                     treeChangeListenerPublisher, dataChangeListenerPublisher, name);
 155         }
 156
 157         shardMBean = ShardMBeanFactory.getShardStatsMBean(name.toString(),
 158                 datastoreContext.getDataStoreMXBeanType());
 159         shardMBean.setShard(this);
 160
 161         if (isMetricsCaptureEnabled()) {
 162             getContext().become(new MeteringBehavior(this));
 163         }
 164
 165         commitCoordinator = new ShardCommitCoordinator(store, LOG, this.name);
 166
 167         setTransactionCommitTimeout();
 168
 169         // create a notifier actor for each cluster member
 170         roleChangeNotifier = createRoleChangeNotifier(name.toString());
 171
 172         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 173                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 174
 175         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 176                 new Dispatchers(context().system().dispatchers()).getDispatcherPath(
 177                         Dispatchers.DispatcherType.Transaction), self(), getContext(), shardMBean);
 178
 179         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 180             this.name);
 181
 182         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 183     }
 184
 185     private void setTransactionCommitTimeout() {
 186         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 187                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 188     }
 189
 190     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 191         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 192             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 193         return Optional.of(shardRoleChangeNotifier);
 194     }
 195
 196     @Override
 197     public void postStop() {
 198         LOG.info("Stopping Shard {}", persistenceId());
 199
 200         super.postStop();
 201
 202         messageRetrySupport.close();
 203
 204         if (txCommitTimeoutCheckSchedule != null) {
 205             txCommitTimeoutCheckSchedule.cancel();
 206         }
 207
 208         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 209
 210         shardMBean.unregisterMBean();
 211     }
 212
 213     @Override
 214     protected void handleRecover(final Object message) {
 215         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 216             getSender());
 217
 218         super.handleRecover(message);
 219         if (LOG.isTraceEnabled()) {
 220             appendEntriesReplyTracker.begin();
 221         }
 222     }
 223
 224     @Override
 225     protected void handleNonRaftCommand(final Object message) {
 226         try (final MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 227             final Optional<Error> maybeError = context.error();
 228             if (maybeError.isPresent()) {
 229                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 230                     maybeError.get());
 231             }
 232
 233             if (CreateTransaction.isSerializedType(message)) {
 234                 handleCreateTransaction(message);
 235             } else if (message instanceof BatchedModifications) {
 236                 handleBatchedModifications((BatchedModifications)message);
 237             } else if (message instanceof ForwardedReadyTransaction) {
 238                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 239             } else if (message instanceof ReadyLocalTransaction) {
 240                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 241             } else if (CanCommitTransaction.isSerializedType(message)) {
 242                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 243             } else if (CommitTransaction.isSerializedType(message)) {
 244                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 245             } else if (AbortTransaction.isSerializedType(message)) {
 246                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 247             } else if (CloseTransactionChain.isSerializedType(message)) {
 248                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 249             } else if (message instanceof RegisterChangeListener) {
 250                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 251             } else if (message instanceof RegisterDataTreeChangeListener) {
 252                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 253             } else if (message instanceof UpdateSchemaContext) {
 254                 updateSchemaContext((UpdateSchemaContext) message);
 255             } else if (message instanceof PeerAddressResolved) {
 256                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 257                 setPeerAddress(resolved.getPeerId().toString(),
 258                         resolved.getPeerAddress());
 259             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 260                 store.checkForExpiredTransactions(transactionCommitTimeout);
 261                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 262             } else if (message instanceof DatastoreContext) {
 263                 onDatastoreContext((DatastoreContext)message);
 264             } else if (message instanceof RegisterRoleChangeListener) {
 265                 roleChangeNotifier.get().forward(message, context());
 266             } else if (message instanceof FollowerInitialSyncUpStatus) {
 267                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 268                 context().parent().tell(message, self());
 269             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 270                 sender().tell(getShardMBean(), self());
 271             } else if (message instanceof GetShardDataTree) {
 272                 sender().tell(store.getDataTree(), self());
 273             } else if (message instanceof ServerRemoved) {
 274                 context().parent().forward(message, context());
 275             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 276                 messageRetrySupport.onTimerMessage(message);
 277             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 278                 store.processCohortRegistryCommand(getSender(),
 279                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 280             } else {
 281                 super.handleNonRaftCommand(message);
 282             }
 283         }
 284     }
 285
 286     private boolean hasLeader() {
 287         return getLeaderId() != null;
 288     }
 289
 290     public int getPendingTxCommitQueueSize() {
 291         return store.getQueueSize();
 292     }
 293
 294     public int getCohortCacheSize() {
 295         return commitCoordinator.getCohortCacheSize();
 296     }
 297
 298     @Override
 299     protected Optional<ActorRef> getRoleChangeNotifier() {
 300         return roleChangeNotifier;
 301     }
 302
 303     @Override
 304     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 305             final short leaderPayloadVersion) {
 306         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 307                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 308     }
 309
 310     protected void onDatastoreContext(final DatastoreContext context) {
 311         datastoreContext = context;
 312
 313         setTransactionCommitTimeout();
 314
 315         setPersistence(datastoreContext.isPersistent());
 316
 317         updateConfigParams(datastoreContext.getShardRaftConfig());
 318     }
 319
 320     boolean canSkipPayload() {
 321         // If we do not have any followers and we are not using persistence we can apply modification to the state
 322         // immediately
 323         return !hasFollowers() && !persistence().isRecoveryApplicable();
 324     }
 325
 326     // applyState() will be invoked once consensus is reached on the payload
 327     void persistPayload(final TransactionIdentifier transactionId, final Payload payload) {
 328         // We are faking the sender
 329         persistData(self(), transactionId, payload);
 330     }
 331
 332     private void handleCommitTransaction(final CommitTransaction commit) {
 333         if (isLeader()) {
 334             commitCoordinator.handleCommit(commit.getTransactionID(), getSender(), this);
 335         } else {
 336             ActorSelection leader = getLeader();
 337             if (leader == null) {
 338                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 339                         "Could not commit transaction " + commit.getTransactionID());
 340             } else {
 341                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 342                 leader.forward(commit, getContext());
 343             }
 344         }
 345     }
 346
 347     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 348         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionID());
 349
 350         if (isLeader()) {
 351             commitCoordinator.handleCanCommit(canCommit.getTransactionID(), getSender(), this);
 352         } else {
 353             ActorSelection leader = getLeader();
 354             if (leader == null) {
 355                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 356                         "Could not canCommit transaction " + canCommit.getTransactionID());
 357             } else {
 358                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 359                 leader.forward(canCommit, getContext());
 360             }
 361         }
 362     }
 363
 364     @SuppressWarnings("checkstyle:IllegalCatch")
 365     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 366         try {
 367             commitCoordinator.handleBatchedModifications(batched, sender, this);
 368         } catch (Exception e) {
 369             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 370                     batched.getTransactionID(), e);
 371             sender.tell(new akka.actor.Status.Failure(e), getSelf());
 372         }
 373     }
 374
 375     private void handleBatchedModifications(final BatchedModifications batched) {
 376         // This message is sent to prepare the modifications transaction directly on the Shard as an
 377         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 378         // BatchedModifications message, the caller sets the ready flag in the message indicating
 379         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 380         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 381         // ReadyTransaction message.
 382
 383         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 384         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 385         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 386         // window where it could have a stale leader during leadership transitions.
 387         //
 388         boolean isLeaderActive = isLeaderActive();
 389         if (isLeader() && isLeaderActive) {
 390             handleBatchedModificationsLocal(batched, getSender());
 391         } else {
 392             ActorSelection leader = getLeader();
 393             if (!isLeaderActive || leader == null) {
 394                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 395                         "Could not commit transaction " + batched.getTransactionID());
 396             } else {
 397                 // If this is not the first batch and leadership changed in between batched messages,
 398                 // we need to reconstruct previous BatchedModifications from the transaction
 399                 // DataTreeModification, honoring the max batched modification count, and forward all the
 400                 // previous BatchedModifications to the new leader.
 401                 Collection<BatchedModifications> newModifications = commitCoordinator
 402                         .createForwardedBatchedModifications(batched,
 403                                 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     @SuppressWarnings("checkstyle:IllegalCatch")
 432     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 433         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionID());
 434
 435         boolean isLeaderActive = isLeaderActive();
 436         if (isLeader() && isLeaderActive) {
 437             try {
 438                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 439             } catch (Exception e) {
 440                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 441                         message.getTransactionID(), e);
 442                 getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 443             }
 444         } else {
 445             ActorSelection leader = getLeader();
 446             if (!isLeaderActive || leader == null) {
 447                 messageRetrySupport.addMessageToRetry(message, getSender(),
 448                         "Could not commit transaction " + message.getTransactionID());
 449             } else {
 450                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 451                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 452                 leader.forward(message, getContext());
 453             }
 454         }
 455     }
 456
 457     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 458         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionID());
 459
 460         boolean isLeaderActive = isLeaderActive();
 461         if (isLeader() && isLeaderActive) {
 462             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 463         } else {
 464             ActorSelection leader = getLeader();
 465             if (!isLeaderActive || leader == null) {
 466                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 467                         "Could not commit transaction " + forwardedReady.getTransactionID());
 468             } else {
 469                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 470
 471                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionID(),
 472                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 473                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 474                 leader.forward(readyLocal, getContext());
 475             }
 476         }
 477     }
 478
 479     private void handleAbortTransaction(final AbortTransaction abort) {
 480         doAbortTransaction(abort.getTransactionID(), getSender());
 481     }
 482
 483     void doAbortTransaction(final TransactionIdentifier transactionID, final ActorRef sender) {
 484         commitCoordinator.handleAbort(transactionID, sender, this);
 485     }
 486
 487     private void handleCreateTransaction(final Object message) {
 488         if (isLeader()) {
 489             createTransaction(CreateTransaction.fromSerializable(message));
 490         } else if (getLeader() != null) {
 491             getLeader().forward(message, getContext());
 492         } else {
 493             getSender().tell(new akka.actor.Status.Failure(new NoShardLeaderException(
 494                     "Could not create a shard transaction", persistenceId())), getSelf());
 495         }
 496     }
 497
 498     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 499         store.closeTransactionChain(closeTransactionChain.getIdentifier());
 500     }
 501
 502     @SuppressWarnings("checkstyle:IllegalCatch")
 503     private void createTransaction(final CreateTransaction createTransaction) {
 504         try {
 505             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 506                     && failIfIsolatedLeader(getSender())) {
 507                 return;
 508             }
 509
 510             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 511                 createTransaction.getTransactionId());
 512
 513             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 514                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 515         } catch (Exception e) {
 516             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 517         }
 518     }
 519
 520     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 521         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 522         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 523             transactionId);
 524     }
 525
 526     private void updateSchemaContext(final UpdateSchemaContext message) {
 527         updateSchemaContext(message.getSchemaContext());
 528     }
 529
 530     @VisibleForTesting
 531     void updateSchemaContext(final SchemaContext schemaContext) {
 532         store.updateSchemaContext(schemaContext);
 533     }
 534
 535     private boolean isMetricsCaptureEnabled() {
 536         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 537         return config.isMetricCaptureEnabled();
 538     }
 539
 540     @Override
 541     @VisibleForTesting
 542     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 543         return snapshotCohort;
 544     }
 545
 546     @Override
 547     @Nonnull
 548     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 549         return new ShardRecoveryCoordinator(store,
 550             restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 551     }
 552
 553     @Override
 554     protected void onRecoveryComplete() {
 555         restoreFromSnapshot = null;
 556
 557         //notify shard manager
 558         getContext().parent().tell(new ActorInitialized(), getSelf());
 559
 560         // Being paranoid here - this method should only be called once but just in case...
 561         if (txCommitTimeoutCheckSchedule == null) {
 562             // Schedule a message to be periodically sent to check if the current in-progress
 563             // transaction should be expired and aborted.
 564             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 565             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 566                     period, period, getSelf(),
 567                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 568         }
 569     }
 570
 571     @Override
 572     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 573         if (data instanceof Payload) {
 574             try {
 575                 store.applyReplicatedPayload(identifier, (Payload)data);
 576             } catch (DataValidationFailedException | IOException e) {
 577                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 578             }
 579         } else {
 580             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 581         }
 582     }
 583
 584     @Override
 585     protected void onStateChanged() {
 586         boolean isLeader = isLeader();
 587         boolean hasLeader = hasLeader();
 588         changeSupport.onLeadershipChange(isLeader, hasLeader);
 589         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 590
 591         // If this actor is no longer the leader close all the transaction chains
 592         if (!isLeader) {
 593             if (LOG.isDebugEnabled()) {
 594                 LOG.debug(
 595                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 596                     persistenceId(), getId());
 597             }
 598
 599             store.closeAllTransactionChains();
 600         }
 601
 602         if (hasLeader && !isIsolatedLeader()) {
 603             messageRetrySupport.retryMessages();
 604         }
 605     }
 606
 607     @Override
 608     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 609         shardMBean.incrementLeadershipChangeCount();
 610
 611         boolean hasLeader = hasLeader();
 612         if (hasLeader && !isLeader()) {
 613             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 614             // them to transaction messages and send to the new leader.
 615             ActorSelection leader = getLeader();
 616             if (leader != null) {
 617                 Collection<?> messagesToForward = convertPendingTransactionsToMessages();
 618
 619                 if (!messagesToForward.isEmpty()) {
 620                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 621                             messagesToForward.size(), leader);
 622
 623                     for (Object message : messagesToForward) {
 624                         leader.tell(message, self());
 625                     }
 626                 }
 627             } else {
 628                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
 629                         + "change and the leader address isn't available.", this);
 630             }
 631         }
 632
 633         if (hasLeader && !isIsolatedLeader()) {
 634             messageRetrySupport.retryMessages();
 635         }
 636     }
 637
 638     /**
 639      * Clears all pending transactions and converts them to messages to be forwarded to a new leader.
 640      *
 641      * @return the converted messages
 642      */
 643     public Collection<?> convertPendingTransactionsToMessages() {
 644         return commitCoordinator.convertPendingTransactionsToMessages(
 645                 datastoreContext.getShardBatchedModificationCount());
 646     }
 647
 648     @Override
 649     protected void pauseLeader(final Runnable operation) {
 650         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 651         store.setRunOnPendingTransactionsComplete(operation);
 652     }
 653
 654     @Override
 655     public String persistenceId() {
 656         return this.name;
 657     }
 658
 659     @VisibleForTesting
 660     ShardCommitCoordinator getCommitCoordinator() {
 661         return commitCoordinator;
 662     }
 663
 664     public DatastoreContext getDatastoreContext() {
 665         return datastoreContext;
 666     }
 667
 668     @VisibleForTesting
 669     public ShardDataTree getDataStore() {
 670         return store;
 671     }
 672
 673     @VisibleForTesting
 674     ShardStats getShardMBean() {
 675         return shardMBean;
 676     }
 677
 678     public static Builder builder() {
 679         return new Builder();
 680     }
 681
 682     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 683         private final Class<S> shardClass;
 684         private ShardIdentifier id;
 685         private Map<String, String> peerAddresses = Collections.emptyMap();
 686         private DatastoreContext datastoreContext;
 687         private SchemaContext schemaContext;
 688         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 689         private TipProducingDataTree dataTree;
 690         private volatile boolean sealed;
 691
 692         protected AbstractBuilder(final Class<S> shardClass) {
 693             this.shardClass = shardClass;
 694         }
 695
 696         protected void checkSealed() {
 697             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 698         }
 699
 700         @SuppressWarnings("unchecked")
 701         private T self() {
 702             return (T) this;
 703         }
 704
 705         public T id(final ShardIdentifier newId) {
 706             checkSealed();
 707             this.id = newId;
 708             return self();
 709         }
 710
 711         public T peerAddresses(final Map<String, String> newPeerAddresses) {
 712             checkSealed();
 713             this.peerAddresses = newPeerAddresses;
 714             return self();
 715         }
 716
 717         public T datastoreContext(final DatastoreContext newDatastoreContext) {
 718             checkSealed();
 719             this.datastoreContext = newDatastoreContext;
 720             return self();
 721         }
 722
 723         public T schemaContext(final SchemaContext newSchemaContext) {
 724             checkSealed();
 725             this.schemaContext = newSchemaContext;
 726             return self();
 727         }
 728
 729         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
 730             checkSealed();
 731             this.restoreFromSnapshot = newRestoreFromSnapshot;
 732             return self();
 733         }
 734
 735         public T dataTree(final TipProducingDataTree newDataTree) {
 736             checkSealed();
 737             this.dataTree = newDataTree;
 738             return self();
 739         }
 740
 741         public ShardIdentifier getId() {
 742             return id;
 743         }
 744
 745         public Map<String, String> getPeerAddresses() {
 746             return peerAddresses;
 747         }
 748
 749         public DatastoreContext getDatastoreContext() {
 750             return datastoreContext;
 751         }
 752
 753         public SchemaContext getSchemaContext() {
 754             return schemaContext;
 755         }
 756
 757         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
 758             return restoreFromSnapshot;
 759         }
 760
 761         public TipProducingDataTree getDataTree() {
 762             return dataTree;
 763         }
 764
 765         public TreeType getTreeType() {
 766             switch (datastoreContext.getLogicalStoreType()) {
 767                 case CONFIGURATION:
 768                     return TreeType.CONFIGURATION;
 769                 case OPERATIONAL:
 770                     return TreeType.OPERATIONAL;
 771                 default:
 772                     throw new IllegalStateException("Unhandled logical store type "
 773                             + datastoreContext.getLogicalStoreType());
 774             }
 775         }
 776
 777         protected void verify() {
 778             Preconditions.checkNotNull(id, "id should not be null");
 779             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
 780             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
 781             Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
 782         }
 783
 784         public Props props() {
 785             sealed = true;
 786             verify();
 787             return Props.create(shardClass, this);
 788         }
 789     }
 790
 791     public static class Builder extends AbstractBuilder<Builder, Shard> {
 792         private Builder() {
 793             super(Shard.class);
 794         }
 795     }
 796
 797     Ticker ticker() {
 798         return Ticker.systemTicker();
 799     }
 800 }