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.japi.Creator;
  16 import akka.persistence.RecoveryFailure;
  17 import akka.serialization.Serialization;
  18 import com.google.common.annotations.VisibleForTesting;
  19 import com.google.common.base.Optional;
  20 import com.google.common.base.Preconditions;
  21 import com.google.common.util.concurrent.FutureCallback;
  22 import com.google.common.util.concurrent.Futures;
  23 import com.google.common.util.concurrent.ListenableFuture;
  24 import java.io.IOException;
  25 import java.util.HashMap;
  26 import java.util.Map;
  27 import java.util.concurrent.ExecutionException;
  28 import java.util.concurrent.TimeUnit;
  29 import javax.annotation.Nonnull;
  30 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  31 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  32 import org.opendaylight.controller.cluster.datastore.ShardCommitCoordinator.CohortEntry;
  33 import org.opendaylight.controller.cluster.datastore.compat.BackwardsCompatibleThreePhaseCommitCohort;
  34 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  35 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  36 import org.opendaylight.controller.cluster.datastore.identifiers.ShardTransactionIdentifier;
  37 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  38 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  39 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  40 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
  41 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  42 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  43 import org.opendaylight.controller.cluster.datastore.messages.BatchedModificationsReply;
  44 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  45 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  46 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  47 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
  48 import org.opendaylight.controller.cluster.datastore.messages.CreateSnapshot;
  49 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  50 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  51 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  52 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  53 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
  54 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  55 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  56 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  57 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  58 import org.opendaylight.controller.cluster.datastore.modification.ModificationPayload;
  59 import org.opendaylight.controller.cluster.datastore.modification.MutableCompositeModification;
  60 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  61 import org.opendaylight.controller.cluster.datastore.utils.MessageTracker;
  62 import org.opendaylight.controller.cluster.datastore.utils.SerializationUtils;
  63 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  64 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  65 import org.opendaylight.controller.cluster.raft.RaftActor;
  66 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  67 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  68 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  69 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationByteStringPayload;
  70 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationPayload;
  71 import org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStore;
  72 import org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStoreFactory;
  73 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  74 import org.opendaylight.controller.sal.core.spi.data.DOMStoreTransaction;
  75 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
  76 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  77 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  78 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  79 import scala.concurrent.duration.Duration;
  80 import scala.concurrent.duration.FiniteDuration;
  81
  82 /**
  83  * A Shard represents a portion of the logical data tree <br/>
  84  * <p>
  85  * Our Shard uses InMemoryDataStore as it's internal representation and delegates all requests it
  86  * </p>
  87  */
  88 public class Shard extends RaftActor {
  89
  90     private static final YangInstanceIdentifier DATASTORE_ROOT = YangInstanceIdentifier.builder().build();
  91
  92     private static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = "txCommitTimeoutCheck";
  93
  94     @VisibleForTesting
  95     static final String DEFAULT_NAME = "default";
  96
  97     // The state of this Shard
  98     private final InMemoryDOMDataStore store;
  99
 100     /// The name of this shard
 101     private final String name;
 102
 103     private final ShardStats shardMBean;
 104
 105     private DatastoreContext datastoreContext;
 106
 107     private SchemaContext schemaContext;
 108
 109     private int createSnapshotTransactionCounter;
 110
 111     private final ShardCommitCoordinator commitCoordinator;
 112
 113     private long transactionCommitTimeout;
 114
 115     private Cancellable txCommitTimeoutCheckSchedule;
 116
 117     private final Optional<ActorRef> roleChangeNotifier;
 118
 119     private final MessageTracker appendEntriesReplyTracker;
 120
 121     private final ReadyTransactionReply READY_TRANSACTION_REPLY = new ReadyTransactionReply(
 122             Serialization.serializedActorPath(getSelf()));
 123
 124     private final DOMTransactionFactory transactionFactory;
 125
 126     private final String txnDispatcherPath;
 127
 128     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 129     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 130
 131     protected Shard(final ShardIdentifier name, final Map<String, String> peerAddresses,
 132             final DatastoreContext datastoreContext, final SchemaContext schemaContext) {
 133         super(name.toString(), new HashMap<>(peerAddresses), Optional.of(datastoreContext.getShardRaftConfig()));
 134
 135         this.name = name.toString();
 136         this.datastoreContext = datastoreContext;
 137         this.schemaContext = schemaContext;
 138         this.txnDispatcherPath = new Dispatchers(context().system().dispatchers())
 139                 .getDispatcherPath(Dispatchers.DispatcherType.Transaction);
 140
 141         setPersistence(datastoreContext.isPersistent());
 142
 143         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 144
 145         store = InMemoryDOMDataStoreFactory.create(name.toString(), null,
 146                 datastoreContext.getDataStoreProperties());
 147
 148         if (schemaContext != null) {
 149             store.onGlobalContextUpdated(schemaContext);
 150         }
 151
 152         shardMBean = ShardMBeanFactory.getShardStatsMBean(name.toString(),
 153                 datastoreContext.getDataStoreMXBeanType());
 154         shardMBean.setNotificationManager(store.getDataChangeListenerNotificationManager());
 155         shardMBean.setShardActor(getSelf());
 156
 157         if (isMetricsCaptureEnabled()) {
 158             getContext().become(new MeteringBehavior(this));
 159         }
 160
 161         transactionFactory = new DOMTransactionFactory(store, shardMBean, LOG, this.name);
 162
 163         commitCoordinator = new ShardCommitCoordinator(transactionFactory,
 164                 TimeUnit.SECONDS.convert(5, TimeUnit.MINUTES),
 165                 datastoreContext.getShardTransactionCommitQueueCapacity(), self(), 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
 176     private void setTransactionCommitTimeout() {
 177         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 178                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS);
 179     }
 180
 181     public static Props props(final ShardIdentifier name,
 182         final Map<String, String> peerAddresses,
 183         final DatastoreContext datastoreContext, final SchemaContext schemaContext) {
 184         Preconditions.checkNotNull(name, "name should not be null");
 185         Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
 186         Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
 187         Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
 188
 189         return Props.create(new ShardCreator(name, peerAddresses, datastoreContext, schemaContext));
 190     }
 191
 192     private Optional<ActorRef> createRoleChangeNotifier(String shardId) {
 193         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 194             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 195         return Optional.of(shardRoleChangeNotifier);
 196     }
 197
 198     @Override
 199     public void postStop() {
 200         LOG.info("Stopping Shard {}", persistenceId());
 201
 202         super.postStop();
 203
 204         if(txCommitTimeoutCheckSchedule != null) {
 205             txCommitTimeoutCheckSchedule.cancel();
 206         }
 207
 208         shardMBean.unregisterMBean();
 209     }
 210
 211     @Override
 212     public void onReceiveRecover(final Object message) throws Exception {
 213         if(LOG.isDebugEnabled()) {
 214             LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(),
 215                 message.getClass().toString(), getSender());
 216         }
 217
 218         if (message instanceof RecoveryFailure){
 219             LOG.error("{}: Recovery failed because of this cause",
 220                     persistenceId(), ((RecoveryFailure) message).cause());
 221
 222             // Even though recovery failed, we still need to finish our recovery, eg send the
 223             // ActorInitialized message and start the txCommitTimeoutCheckSchedule.
 224             onRecoveryComplete();
 225         } else {
 226             super.onReceiveRecover(message);
 227             if(LOG.isTraceEnabled()) {
 228                 appendEntriesReplyTracker.begin();
 229             }
 230         }
 231     }
 232
 233     @Override
 234     public void onReceiveCommand(final Object message) throws Exception {
 235
 236         MessageTracker.Context context = appendEntriesReplyTracker.received(message);
 237
 238         if(context.error().isPresent()){
 239             LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 240                     context.error());
 241         }
 242
 243         try {
 244             if (CreateTransaction.SERIALIZABLE_CLASS.isInstance(message)) {
 245                 handleCreateTransaction(message);
 246             } else if (BatchedModifications.class.isInstance(message)) {
 247                 handleBatchedModifications((BatchedModifications)message);
 248             } else if (message instanceof ForwardedReadyTransaction) {
 249                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 250             } else if (CanCommitTransaction.SERIALIZABLE_CLASS.isInstance(message)) {
 251                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 252             } else if (CommitTransaction.SERIALIZABLE_CLASS.isInstance(message)) {
 253                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 254             } else if (AbortTransaction.SERIALIZABLE_CLASS.isInstance(message)) {
 255                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 256             } else if (CloseTransactionChain.SERIALIZABLE_CLASS.isInstance(message)) {
 257                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 258             } else if (message instanceof RegisterChangeListener) {
 259                 changeSupport.onMessage((RegisterChangeListener) message, isLeader());
 260             } else if (message instanceof RegisterDataTreeChangeListener) {
 261                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader());
 262             } else if (message instanceof UpdateSchemaContext) {
 263                 updateSchemaContext((UpdateSchemaContext) message);
 264             } else if (message instanceof PeerAddressResolved) {
 265                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 266                 setPeerAddress(resolved.getPeerId().toString(),
 267                         resolved.getPeerAddress());
 268             } else if (message.equals(TX_COMMIT_TIMEOUT_CHECK_MESSAGE)) {
 269                 handleTransactionCommitTimeoutCheck();
 270             } else if(message instanceof DatastoreContext) {
 271                 onDatastoreContext((DatastoreContext)message);
 272             } else if(message instanceof RegisterRoleChangeListener){
 273                 roleChangeNotifier.get().forward(message, context());
 274             } else if (message instanceof FollowerInitialSyncUpStatus){
 275                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 276                 context().parent().tell(message, self());
 277             } else {
 278                 super.onReceiveCommand(message);
 279             }
 280         } finally {
 281             context.done();
 282         }
 283     }
 284
 285     @Override
 286     protected Optional<ActorRef> getRoleChangeNotifier() {
 287         return roleChangeNotifier;
 288     }
 289
 290     private void onDatastoreContext(DatastoreContext context) {
 291         datastoreContext = context;
 292
 293         commitCoordinator.setQueueCapacity(datastoreContext.getShardTransactionCommitQueueCapacity());
 294
 295         setTransactionCommitTimeout();
 296
 297         if(datastoreContext.isPersistent() && !persistence().isRecoveryApplicable()) {
 298             setPersistence(true);
 299         } else if(!datastoreContext.isPersistent() && persistence().isRecoveryApplicable()) {
 300             setPersistence(false);
 301         }
 302
 303         updateConfigParams(datastoreContext.getShardRaftConfig());
 304     }
 305
 306     private void handleTransactionCommitTimeoutCheck() {
 307         CohortEntry cohortEntry = commitCoordinator.getCurrentCohortEntry();
 308         if(cohortEntry != null) {
 309             long elapsed = System.currentTimeMillis() - cohortEntry.getLastAccessTime();
 310             if(elapsed > transactionCommitTimeout) {
 311                 LOG.warn("{}: Current transaction {} has timed out after {} ms - aborting",
 312                         persistenceId(), cohortEntry.getTransactionID(), transactionCommitTimeout);
 313
 314                 doAbortTransaction(cohortEntry.getTransactionID(), null);
 315             }
 316         }
 317     }
 318
 319     private void handleCommitTransaction(final CommitTransaction commit) {
 320         final String transactionID = commit.getTransactionID();
 321
 322         LOG.debug("{}: Committing transaction {}", persistenceId(), transactionID);
 323
 324         // Get the current in-progress cohort entry in the commitCoordinator if it corresponds to
 325         // this transaction.
 326         final CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
 327         if(cohortEntry == null) {
 328             // We're not the current Tx - the Tx was likely expired b/c it took too long in
 329             // between the canCommit and commit messages.
 330             IllegalStateException ex = new IllegalStateException(
 331                     String.format("%s: Cannot commit transaction %s - it is not the current transaction",
 332                             persistenceId(), transactionID));
 333             LOG.error(ex.getMessage());
 334             shardMBean.incrementFailedTransactionsCount();
 335             getSender().tell(new akka.actor.Status.Failure(ex), getSelf());
 336             return;
 337         }
 338
 339         // We perform the preCommit phase here atomically with the commit phase. This is an
 340         // optimization to eliminate the overhead of an extra preCommit message. We lose front-end
 341         // coordination of preCommit across shards in case of failure but preCommit should not
 342         // normally fail since we ensure only one concurrent 3-phase commit.
 343
 344         try {
 345             // We block on the future here so we don't have to worry about possibly accessing our
 346             // state on a different thread outside of our dispatcher. Also, the data store
 347             // currently uses a same thread executor anyway.
 348             cohortEntry.getCohort().preCommit().get();
 349
 350             // If we do not have any followers and we are not using persistence
 351             // or if cohortEntry has no modifications
 352             // we can apply modification to the state immediately
 353             if((!hasFollowers() && !persistence().isRecoveryApplicable()) || (!cohortEntry.hasModifications())){
 354                 applyModificationToState(getSender(), transactionID, cohortEntry.getModification());
 355             } else {
 356                 Shard.this.persistData(getSender(), transactionID,
 357                         new ModificationPayload(cohortEntry.getModification()));
 358             }
 359         } catch (Exception e) {
 360             LOG.error("{} An exception occurred while preCommitting transaction {}",
 361                     persistenceId(), cohortEntry.getTransactionID(), e);
 362             shardMBean.incrementFailedTransactionsCount();
 363             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 364         }
 365
 366         cohortEntry.updateLastAccessTime();
 367     }
 368
 369     private void finishCommit(@Nonnull final ActorRef sender, final @Nonnull String transactionID) {
 370         // With persistence enabled, this method is called via applyState by the leader strategy
 371         // after the commit has been replicated to a majority of the followers.
 372
 373         CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
 374         if(cohortEntry == null) {
 375             // The transaction is no longer the current commit. This can happen if the transaction
 376             // was aborted prior, most likely due to timeout in the front-end. We need to finish
 377             // committing the transaction though since it was successfully persisted and replicated
 378             // however we can't use the original cohort b/c it was already preCommitted and may
 379             // conflict with the current commit or may have been aborted so we commit with a new
 380             // transaction.
 381             cohortEntry = commitCoordinator.getAndRemoveCohortEntry(transactionID);
 382             if(cohortEntry != null) {
 383                 commitWithNewTransaction(cohortEntry.getModification());
 384                 sender.tell(CommitTransactionReply.INSTANCE.toSerializable(), getSelf());
 385             } else {
 386                 // This really shouldn't happen - it likely means that persistence or replication
 387                 // took so long to complete such that the cohort entry was expired from the cache.
 388                 IllegalStateException ex = new IllegalStateException(
 389                         String.format("%s: Could not finish committing transaction %s - no CohortEntry found",
 390                                 persistenceId(), transactionID));
 391                 LOG.error(ex.getMessage());
 392                 sender.tell(new akka.actor.Status.Failure(ex), getSelf());
 393             }
 394
 395             return;
 396         }
 397
 398         LOG.debug("{}: Finishing commit for transaction {}", persistenceId(), cohortEntry.getTransactionID());
 399
 400         try {
 401             // We block on the future here so we don't have to worry about possibly accessing our
 402             // state on a different thread outside of our dispatcher. Also, the data store
 403             // currently uses a same thread executor anyway.
 404             cohortEntry.getCohort().commit().get();
 405
 406             sender.tell(CommitTransactionReply.INSTANCE.toSerializable(), getSelf());
 407
 408             shardMBean.incrementCommittedTransactionCount();
 409             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
 410
 411         } catch (Exception e) {
 412             sender.tell(new akka.actor.Status.Failure(e), getSelf());
 413
 414             LOG.error("{}, An exception occurred while committing transaction {}", persistenceId(),
 415                     transactionID, e);
 416             shardMBean.incrementFailedTransactionsCount();
 417         } finally {
 418             commitCoordinator.currentTransactionComplete(transactionID, true);
 419         }
 420     }
 421
 422     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 423         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionID());
 424         commitCoordinator.handleCanCommit(canCommit, getSender(), self());
 425     }
 426
 427     private void handleBatchedModifications(BatchedModifications batched) {
 428         // This message is sent to prepare the modificationsa transaction directly on the Shard as an
 429         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 430         // BatchedModifications message, the caller sets the ready flag in the message indicating
 431         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 432         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 433         // ReadyTransaction message.
 434
 435         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 436         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 437         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 438         // window where it could have a stale leader during leadership transitions.
 439         //
 440         if(isLeader()) {
 441             try {
 442                 boolean ready = commitCoordinator.handleTransactionModifications(batched);
 443                 if(ready) {
 444                     sender().tell(READY_TRANSACTION_REPLY, self());
 445                 } else {
 446                     sender().tell(new BatchedModificationsReply(batched.getModifications().size()), self());
 447                 }
 448             } catch (Exception e) {
 449                 LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 450                         batched.getTransactionID(), e);
 451                 getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 452             }
 453         } else {
 454             ActorSelection leader = getLeader();
 455             if(leader != null) {
 456                 // TODO: what if this is not the first batch and leadership changed in between batched messages?
 457                 // We could check if the commitCoordinator already has a cached entry and forward all the previous
 458                 // batched modifications.
 459                 LOG.debug("{}: Forwarding BatchedModifications to leader {}", persistenceId(), leader);
 460                 leader.forward(batched, getContext());
 461             } else {
 462                 // TODO: rather than throwing an immediate exception, we could schedule a timer to try again to make
 463                 // it more resilient in case we're in the process of electing a new leader.
 464                 getSender().tell(new akka.actor.Status.Failure(new NoShardLeaderException(String.format(
 465                     "Could not find the leader for shard %s. This typically happens" +
 466                     " when the system is coming up or recovering and a leader is being elected. Try again" +
 467                     " later.", persistenceId()))), getSelf());
 468             }
 469         }
 470     }
 471
 472     private void handleForwardedReadyTransaction(ForwardedReadyTransaction ready) {
 473         LOG.debug("{}: Readying transaction {}, client version {}", persistenceId(),
 474                 ready.getTransactionID(), ready.getTxnClientVersion());
 475
 476         // This message is forwarded by the ShardTransaction on ready. We cache the cohort in the
 477         // commitCoordinator in preparation for the subsequent three phase commit initiated by
 478         // the front-end.
 479         commitCoordinator.transactionReady(ready.getTransactionID(), ready.getCohort(),
 480                 (MutableCompositeModification) ready.getModification());
 481
 482         // Return our actor path as we'll handle the three phase commit, except if the Tx client
 483         // version < 1 (Helium-1 version). This means the Tx was initiated by a base Helium version
 484         // node. In that case, the subsequent 3-phase commit messages won't contain the
 485         // transactionId so to maintain backwards compatibility, we create a separate cohort actor
 486         // to provide the compatible behavior.
 487         if(ready.getTxnClientVersion() < DataStoreVersions.LITHIUM_VERSION) {
 488             ActorRef replyActorPath = getSelf();
 489             if(ready.getTxnClientVersion() < DataStoreVersions.HELIUM_1_VERSION) {
 490                 LOG.debug("{}: Creating BackwardsCompatibleThreePhaseCommitCohort", persistenceId());
 491                 replyActorPath = getContext().actorOf(BackwardsCompatibleThreePhaseCommitCohort.props(
 492                         ready.getTransactionID()));
 493             }
 494
 495             ReadyTransactionReply readyTransactionReply =
 496                     new ReadyTransactionReply(Serialization.serializedActorPath(replyActorPath),
 497                             ready.getTxnClientVersion());
 498             getSender().tell(ready.isReturnSerialized() ? readyTransactionReply.toSerializable() :
 499                 readyTransactionReply, getSelf());
 500         } else {
 501             getSender().tell(READY_TRANSACTION_REPLY, getSelf());
 502         }
 503     }
 504
 505     private void handleAbortTransaction(final AbortTransaction abort) {
 506         doAbortTransaction(abort.getTransactionID(), getSender());
 507     }
 508
 509     void doAbortTransaction(final String transactionID, final ActorRef sender) {
 510         final CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
 511         if(cohortEntry != null) {
 512             LOG.debug("{}: Aborting transaction {}", persistenceId(), transactionID);
 513
 514             // We don't remove the cached cohort entry here (ie pass false) in case the Tx was
 515             // aborted during replication in which case we may still commit locally if replication
 516             // succeeds.
 517             commitCoordinator.currentTransactionComplete(transactionID, false);
 518
 519             final ListenableFuture<Void> future = cohortEntry.getCohort().abort();
 520             final ActorRef self = getSelf();
 521
 522             Futures.addCallback(future, new FutureCallback<Void>() {
 523                 @Override
 524                 public void onSuccess(final Void v) {
 525                     shardMBean.incrementAbortTransactionsCount();
 526
 527                     if(sender != null) {
 528                         sender.tell(AbortTransactionReply.INSTANCE.toSerializable(), self);
 529                     }
 530                 }
 531
 532                 @Override
 533                 public void onFailure(final Throwable t) {
 534                     LOG.error("{}: An exception happened during abort", persistenceId(), t);
 535
 536                     if(sender != null) {
 537                         sender.tell(new akka.actor.Status.Failure(t), self);
 538                     }
 539                 }
 540             });
 541         }
 542     }
 543
 544     private void handleCreateTransaction(final Object message) {
 545         if (isLeader()) {
 546             createTransaction(CreateTransaction.fromSerializable(message));
 547         } else if (getLeader() != null) {
 548             getLeader().forward(message, getContext());
 549         } else {
 550             getSender().tell(new akka.actor.Status.Failure(new NoShardLeaderException(String.format(
 551                 "Could not find leader for shard %s so transaction cannot be created. This typically happens" +
 552                 " when the system is coming up or recovering and a leader is being elected. Try again" +
 553                 " later.", persistenceId()))), getSelf());
 554         }
 555     }
 556
 557     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 558         transactionFactory.closeTransactionChain(closeTransactionChain.getTransactionChainId());
 559     }
 560
 561     private ActorRef createTypedTransactionActor(int transactionType,
 562             ShardTransactionIdentifier transactionId, String transactionChainId,
 563             short clientVersion ) {
 564
 565         DOMStoreTransaction transaction = transactionFactory.newTransaction(
 566                 TransactionProxy.TransactionType.fromInt(transactionType), transactionId.toString(),
 567                 transactionChainId);
 568
 569         return createShardTransaction(transaction, transactionId, clientVersion);
 570     }
 571
 572     private ActorRef createShardTransaction(DOMStoreTransaction transaction, ShardTransactionIdentifier transactionId,
 573                                             short clientVersion){
 574         return getContext().actorOf(
 575                 ShardTransaction.props(transaction, getSelf(),
 576                         schemaContext, datastoreContext, shardMBean,
 577                         transactionId.getRemoteTransactionId(), clientVersion)
 578                         .withDispatcher(txnDispatcherPath),
 579                 transactionId.toString());
 580
 581     }
 582
 583     private void createTransaction(CreateTransaction createTransaction) {
 584         try {
 585             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 586                 createTransaction.getTransactionId(), createTransaction.getTransactionChainId(),
 587                 createTransaction.getVersion());
 588
 589             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 590                     createTransaction.getTransactionId()).toSerializable(), getSelf());
 591         } catch (Exception e) {
 592             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 593         }
 594     }
 595
 596     private ActorRef createTransaction(int transactionType, String remoteTransactionId,
 597             String transactionChainId, short clientVersion) {
 598
 599
 600         ShardTransactionIdentifier transactionId = new ShardTransactionIdentifier(remoteTransactionId);
 601
 602         if(LOG.isDebugEnabled()) {
 603             LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 604         }
 605
 606         ActorRef transactionActor = createTypedTransactionActor(transactionType, transactionId,
 607                 transactionChainId, clientVersion);
 608
 609         return transactionActor;
 610     }
 611
 612     private void syncCommitTransaction(final DOMStoreWriteTransaction transaction)
 613         throws ExecutionException, InterruptedException {
 614         DOMStoreThreePhaseCommitCohort commitCohort = transaction.ready();
 615         commitCohort.preCommit().get();
 616         commitCohort.commit().get();
 617     }
 618
 619     private void commitWithNewTransaction(final Modification modification) {
 620         DOMStoreWriteTransaction tx = store.newWriteOnlyTransaction();
 621         modification.apply(tx);
 622         try {
 623             syncCommitTransaction(tx);
 624             shardMBean.incrementCommittedTransactionCount();
 625             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
 626         } catch (InterruptedException | ExecutionException e) {
 627             shardMBean.incrementFailedTransactionsCount();
 628             LOG.error("{}: Failed to commit", persistenceId(), e);
 629         }
 630     }
 631
 632     private void updateSchemaContext(final UpdateSchemaContext message) {
 633         this.schemaContext = message.getSchemaContext();
 634         updateSchemaContext(message.getSchemaContext());
 635         store.onGlobalContextUpdated(message.getSchemaContext());
 636     }
 637
 638     @VisibleForTesting
 639     void updateSchemaContext(final SchemaContext schemaContext) {
 640         store.onGlobalContextUpdated(schemaContext);
 641     }
 642
 643     private boolean isMetricsCaptureEnabled() {
 644         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 645         return config.isMetricCaptureEnabled();
 646     }
 647
 648     @Override
 649     @Nonnull
 650     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 651         return new ShardRecoveryCoordinator(store, persistenceId(), LOG);
 652     }
 653
 654     @Override
 655     protected void onRecoveryComplete() {
 656         //notify shard manager
 657         getContext().parent().tell(new ActorInitialized(), getSelf());
 658
 659         // Being paranoid here - this method should only be called once but just in case...
 660         if(txCommitTimeoutCheckSchedule == null) {
 661             // Schedule a message to be periodically sent to check if the current in-progress
 662             // transaction should be expired and aborted.
 663             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 664             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 665                     period, period, getSelf(),
 666                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 667         }
 668     }
 669
 670     @Override
 671     protected void applyState(final ActorRef clientActor, final String identifier, final Object data) {
 672
 673         if(data instanceof ModificationPayload) {
 674             try {
 675                 applyModificationToState(clientActor, identifier, ((ModificationPayload) data).getModification());
 676             } catch (ClassNotFoundException | IOException e) {
 677                 LOG.error("{}: Error extracting ModificationPayload", persistenceId(), e);
 678             }
 679         }
 680         else if (data instanceof CompositeModificationPayload) {
 681             Object modification = ((CompositeModificationPayload) data).getModification();
 682
 683             applyModificationToState(clientActor, identifier, modification);
 684         } else if(data instanceof CompositeModificationByteStringPayload ){
 685             Object modification = ((CompositeModificationByteStringPayload) data).getModification();
 686
 687             applyModificationToState(clientActor, identifier, modification);
 688         } else {
 689             LOG.error("{}: Unknown state received {} Class loader = {} CompositeNodeMod.ClassLoader = {}",
 690                     persistenceId(), data, data.getClass().getClassLoader(),
 691                     CompositeModificationPayload.class.getClassLoader());
 692         }
 693     }
 694
 695     private void applyModificationToState(ActorRef clientActor, String identifier, Object modification) {
 696         if(modification == null) {
 697             LOG.error(
 698                     "{}: modification is null - this is very unexpected, clientActor = {}, identifier = {}",
 699                     persistenceId(), identifier, clientActor != null ? clientActor.path().toString() : null);
 700         } else if(clientActor == null) {
 701             // There's no clientActor to which to send a commit reply so we must be applying
 702             // replicated state from the leader.
 703             commitWithNewTransaction(MutableCompositeModification.fromSerializable(modification));
 704         } else {
 705             // This must be the OK to commit after replication consensus.
 706             finishCommit(clientActor, identifier);
 707         }
 708     }
 709
 710     @Override
 711     protected void createSnapshot() {
 712         // Create a transaction actor. We are really going to treat the transaction as a worker
 713         // so that this actor does not get block building the snapshot. THe transaction actor will
 714         // after processing the CreateSnapshot message.
 715
 716         ActorRef createSnapshotTransaction = createTransaction(
 717                 TransactionProxy.TransactionType.READ_ONLY.ordinal(),
 718                 "createSnapshot" + ++createSnapshotTransactionCounter, "",
 719                 DataStoreVersions.CURRENT_VERSION);
 720
 721         createSnapshotTransaction.tell(CreateSnapshot.INSTANCE, self());
 722     }
 723
 724     @VisibleForTesting
 725     @Override
 726     protected void applySnapshot(final byte[] snapshotBytes) {
 727         // Since this will be done only on Recovery or when this actor is a Follower
 728         // we can safely commit everything in here. We not need to worry about event notifications
 729         // as they would have already been disabled on the follower
 730
 731         LOG.info("{}: Applying snapshot", persistenceId());
 732         try {
 733             DOMStoreWriteTransaction transaction = store.newWriteOnlyTransaction();
 734
 735             NormalizedNode<?, ?> node = SerializationUtils.deserializeNormalizedNode(snapshotBytes);
 736
 737             // delete everything first
 738             transaction.delete(DATASTORE_ROOT);
 739
 740             // Add everything from the remote node back
 741             transaction.write(DATASTORE_ROOT, node);
 742             syncCommitTransaction(transaction);
 743         } catch (InterruptedException | ExecutionException e) {
 744             LOG.error("{}: An exception occurred when applying snapshot", persistenceId(), e);
 745         } finally {
 746             LOG.info("{}: Done applying snapshot", persistenceId());
 747         }
 748     }
 749
 750     @Override
 751     protected void onStateChanged() {
 752         boolean isLeader = isLeader();
 753         changeSupport.onLeadershipChange(isLeader);
 754         treeChangeSupport.onLeadershipChange(isLeader);
 755
 756         // If this actor is no longer the leader close all the transaction chains
 757         if (!isLeader) {
 758             if(LOG.isDebugEnabled()) {
 759                 LOG.debug(
 760                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 761                     persistenceId(), getId());
 762             }
 763
 764             transactionFactory.closeAllTransactionChains();
 765         }
 766     }
 767
 768     @Override
 769     public String persistenceId() {
 770         return this.name;
 771     }
 772
 773     @VisibleForTesting
 774     ShardCommitCoordinator getCommitCoordinator() {
 775         return commitCoordinator;
 776     }
 777
 778
 779     private static class ShardCreator implements Creator<Shard> {
 780
 781         private static final long serialVersionUID = 1L;
 782
 783         final ShardIdentifier name;
 784         final Map<String, String> peerAddresses;
 785         final DatastoreContext datastoreContext;
 786         final SchemaContext schemaContext;
 787
 788         ShardCreator(final ShardIdentifier name, final Map<String, String> peerAddresses,
 789                 final DatastoreContext datastoreContext, final SchemaContext schemaContext) {
 790             this.name = name;
 791             this.peerAddresses = peerAddresses;
 792             this.datastoreContext = datastoreContext;
 793             this.schemaContext = schemaContext;
 794         }
 795
 796         @Override
 797         public Shard create() throws Exception {
 798             return new Shard(name, peerAddresses, datastoreContext, schemaContext);
 799         }
 800     }
 801
 802     @VisibleForTesting
 803     public InMemoryDOMDataStore getDataStore() {
 804         return store;
 805     }
 806
 807     @VisibleForTesting
 808     ShardStats getShardMBean() {
 809         return shardMBean;
 810     }
 811 }