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.PoisonPill;
  15 import akka.actor.Props;
  16 import akka.event.Logging;
  17 import akka.event.LoggingAdapter;
  18 import akka.japi.Creator;
  19 import akka.persistence.RecoveryFailure;
  20 import akka.serialization.Serialization;
  21 import com.google.common.annotations.VisibleForTesting;
  22 import com.google.common.base.Optional;
  23 import com.google.common.base.Preconditions;
  24 import com.google.common.collect.Lists;
  25 import com.google.common.util.concurrent.FutureCallback;
  26 import com.google.common.util.concurrent.Futures;
  27 import com.google.common.util.concurrent.ListenableFuture;
  28 import com.google.protobuf.ByteString;
  29 import com.google.protobuf.InvalidProtocolBufferException;
  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.identifiers.ShardIdentifier;
  34 import org.opendaylight.controller.cluster.datastore.identifiers.ShardTransactionIdentifier;
  35 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  36 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  37 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  38 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  39 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
  40 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  41 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  42 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  43 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
  44 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  45 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  46 import org.opendaylight.controller.cluster.datastore.messages.EnableNotification;
  47 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  48 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  49 import org.opendaylight.controller.cluster.datastore.messages.ReadData;
  50 import org.opendaylight.controller.cluster.datastore.messages.ReadDataReply;
  51 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
  52 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  53 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListenerReply;
  54 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  55 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  56 import org.opendaylight.controller.cluster.datastore.modification.MutableCompositeModification;
  57 import org.opendaylight.controller.cluster.datastore.node.NormalizedNodeToNodeCodec;
  58 import org.opendaylight.controller.cluster.raft.RaftActor;
  59 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
  60 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshotReply;
  61 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationPayload;
  62 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  63 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener;
  64 import org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStore;
  65 import org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStoreFactory;
  66 import org.opendaylight.controller.protobuff.messages.common.NormalizedNodeMessages;
  67 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  68 import org.opendaylight.controller.sal.core.spi.data.DOMStoreTransactionChain;
  69 import org.opendaylight.controller.sal.core.spi.data.DOMStoreTransactionFactory;
  70 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
  71 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  72 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  73 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  74 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  75 import scala.concurrent.duration.Duration;
  76 import scala.concurrent.duration.FiniteDuration;
  77 import java.util.ArrayList;
  78 import java.util.Collection;
  79 import java.util.HashMap;
  80 import java.util.List;
  81 import java.util.Map;
  82 import java.util.concurrent.ExecutionException;
  83 import java.util.concurrent.TimeUnit;
  84 import javax.annotation.Nonnull;
  85
  86 /**
  87  * A Shard represents a portion of the logical data tree <br/>
  88  * <p>
  89  * Our Shard uses InMemoryDataStore as it's internal representation and delegates all requests it
  90  * </p>
  91  */
  92 public class Shard extends RaftActor {
  93
  94     private static final Object COMMIT_TRANSACTION_REPLY = new CommitTransactionReply().toSerializable();
  95
  96     private static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = "txCommitTimeoutCheck";
  97
  98     public static final String DEFAULT_NAME = "default";
  99
 100     // The state of this Shard
 101     private final InMemoryDOMDataStore store;
 102
 103     private final LoggingAdapter LOG =
 104         Logging.getLogger(getContext().system(), this);
 105
 106     // By default persistent will be true and can be turned off using the system
 107     // property shard.persistent
 108     private final boolean persistent;
 109
 110     /// The name of this shard
 111     private final ShardIdentifier name;
 112
 113     private final ShardStats shardMBean;
 114
 115     private final List<ActorSelection> dataChangeListeners = new ArrayList<>();
 116
 117     private final DatastoreContext datastoreContext;
 118
 119     private SchemaContext schemaContext;
 120
 121     private ActorRef createSnapshotTransaction;
 122
 123     private int createSnapshotTransactionCounter;
 124
 125     private final ShardCommitCoordinator commitCoordinator;
 126
 127     private final long transactionCommitTimeout;
 128
 129     private Cancellable txCommitTimeoutCheckSchedule;
 130
 131     /**
 132      * Coordinates persistence recovery on startup.
 133      */
 134     private ShardRecoveryCoordinator recoveryCoordinator;
 135     private List<Object> currentLogRecoveryBatch;
 136
 137     private final Map<String, DOMStoreTransactionChain> transactionChains = new HashMap<>();
 138
 139     protected Shard(ShardIdentifier name, Map<ShardIdentifier, String> peerAddresses,
 140             DatastoreContext datastoreContext, SchemaContext schemaContext) {
 141         super(name.toString(), mapPeerAddresses(peerAddresses),
 142                 Optional.of(datastoreContext.getShardRaftConfig()));
 143
 144         this.name = name;
 145         this.datastoreContext = datastoreContext;
 146         this.schemaContext = schemaContext;
 147
 148         String setting = System.getProperty("shard.persistent");
 149
 150         this.persistent = !"false".equals(setting);
 151
 152         LOG.info("Shard created : {} persistent : {}", name, persistent);
 153
 154         store = InMemoryDOMDataStoreFactory.create(name.toString(), null,
 155                 datastoreContext.getDataStoreProperties());
 156
 157         if(schemaContext != null) {
 158             store.onGlobalContextUpdated(schemaContext);
 159         }
 160
 161         shardMBean = ShardMBeanFactory.getShardStatsMBean(name.toString(),
 162                 datastoreContext.getDataStoreMXBeanType());
 163         shardMBean.setDataStoreExecutor(store.getDomStoreExecutor());
 164         shardMBean.setNotificationManager(store.getDataChangeListenerNotificationManager());
 165
 166         if (isMetricsCaptureEnabled()) {
 167             getContext().become(new MeteringBehavior(this));
 168         }
 169
 170         commitCoordinator = new ShardCommitCoordinator(TimeUnit.SECONDS.convert(1, TimeUnit.MINUTES),
 171                 datastoreContext.getShardTransactionCommitQueueCapacity());
 172
 173         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 174                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS);
 175     }
 176
 177     private static Map<String, String> mapPeerAddresses(
 178         Map<ShardIdentifier, String> peerAddresses) {
 179         Map<String, String> map = new HashMap<>();
 180
 181         for (Map.Entry<ShardIdentifier, String> entry : peerAddresses
 182             .entrySet()) {
 183             map.put(entry.getKey().toString(), entry.getValue());
 184         }
 185
 186         return map;
 187     }
 188
 189     public static Props props(final ShardIdentifier name,
 190         final Map<ShardIdentifier, String> peerAddresses,
 191         DatastoreContext datastoreContext, SchemaContext schemaContext) {
 192         Preconditions.checkNotNull(name, "name should not be null");
 193         Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
 194         Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
 195         Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
 196
 197         return Props.create(new ShardCreator(name, peerAddresses, datastoreContext, schemaContext));
 198     }
 199
 200     @Override
 201     public void postStop() {
 202         super.postStop();
 203
 204         if(txCommitTimeoutCheckSchedule != null) {
 205             txCommitTimeoutCheckSchedule.cancel();
 206         }
 207     }
 208
 209     @Override
 210     public void onReceiveRecover(Object message) {
 211         if(LOG.isDebugEnabled()) {
 212             LOG.debug("onReceiveRecover: Received message {} from {}",
 213                 message.getClass().toString(),
 214                 getSender());
 215         }
 216
 217         if (message instanceof RecoveryFailure){
 218             LOG.error(((RecoveryFailure) message).cause(), "Recovery failed because of this cause");
 219         } else {
 220             super.onReceiveRecover(message);
 221         }
 222     }
 223
 224     @Override
 225     public void onReceiveCommand(Object message) {
 226         if(LOG.isDebugEnabled()) {
 227             LOG.debug("onReceiveCommand: Received message {} from {}", message, getSender());
 228         }
 229
 230         if(message.getClass().equals(ReadDataReply.SERIALIZABLE_CLASS)) {
 231             handleReadDataReply(message);
 232         } else if (message.getClass().equals(CreateTransaction.SERIALIZABLE_CLASS)) {
 233             handleCreateTransaction(message);
 234         } else if(message instanceof ForwardedReadyTransaction) {
 235             handleForwardedReadyTransaction((ForwardedReadyTransaction)message);
 236         } else if(message.getClass().equals(CanCommitTransaction.SERIALIZABLE_CLASS)) {
 237             handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 238         } else if(message.getClass().equals(CommitTransaction.SERIALIZABLE_CLASS)) {
 239             handleCommitTransaction(CommitTransaction.fromSerializable(message));
 240         } else if(message.getClass().equals(AbortTransaction.SERIALIZABLE_CLASS)) {
 241             handleAbortTransaction(AbortTransaction.fromSerializable(message));
 242         } else if (message.getClass().equals(CloseTransactionChain.SERIALIZABLE_CLASS)){
 243             closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 244         } else if (message instanceof RegisterChangeListener) {
 245             registerChangeListener((RegisterChangeListener) message);
 246         } else if (message instanceof UpdateSchemaContext) {
 247             updateSchemaContext((UpdateSchemaContext) message);
 248         } else if (message instanceof PeerAddressResolved) {
 249             PeerAddressResolved resolved = (PeerAddressResolved) message;
 250             setPeerAddress(resolved.getPeerId().toString(),
 251                 resolved.getPeerAddress());
 252         } else if(message.equals(TX_COMMIT_TIMEOUT_CHECK_MESSAGE)) {
 253             handleTransactionCommitTimeoutCheck();
 254         } else {
 255             super.onReceiveCommand(message);
 256         }
 257     }
 258
 259     private void handleTransactionCommitTimeoutCheck() {
 260         CohortEntry cohortEntry = commitCoordinator.getCurrentCohortEntry();
 261         if(cohortEntry != null) {
 262             long elapsed = System.currentTimeMillis() - cohortEntry.getLastAccessTime();
 263             if(elapsed > transactionCommitTimeout) {
 264                 LOG.warning("Current transaction {} has timed out after {} ms - aborting",
 265                         cohortEntry.getTransactionID(), transactionCommitTimeout);
 266
 267                 doAbortTransaction(cohortEntry.getTransactionID(), null);
 268             }
 269         }
 270     }
 271
 272     private void handleCommitTransaction(CommitTransaction commit) {
 273         final String transactionID = commit.getTransactionID();
 274
 275         LOG.debug("Committing transaction {}", transactionID);
 276
 277         // Get the current in-progress cohort entry in the commitCoordinator if it corresponds to
 278         // this transaction.
 279         final CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
 280         if(cohortEntry == null) {
 281             // We're not the current Tx - the Tx was likely expired b/c it took too long in
 282             // between the canCommit and commit messages.
 283             IllegalStateException ex = new IllegalStateException(
 284                     String.format("Cannot commit transaction %s - it is not the current transaction",
 285                             transactionID));
 286             LOG.error(ex.getMessage());
 287             shardMBean.incrementFailedTransactionsCount();
 288             getSender().tell(new akka.actor.Status.Failure(ex), getSelf());
 289             return;
 290         }
 291
 292         // We perform the preCommit phase here atomically with the commit phase. This is an
 293         // optimization to eliminate the overhead of an extra preCommit message. We lose front-end
 294         // coordination of preCommit across shards in case of failure but preCommit should not
 295         // normally fail since we ensure only one concurrent 3-phase commit.
 296
 297         try {
 298             // We block on the future here so we don't have to worry about possibly accessing our
 299             // state on a different thread outside of our dispatcher. Also, the data store
 300             // currently uses a same thread executor anyway.
 301             cohortEntry.getCohort().preCommit().get();
 302
 303             if(persistent) {
 304                 Shard.this.persistData(getSender(), transactionID,
 305                         new CompositeModificationPayload(cohortEntry.getModification().toSerializable()));
 306             } else {
 307                 Shard.this.finishCommit(getSender(), transactionID);
 308             }
 309         } catch (InterruptedException | ExecutionException e) {
 310             LOG.error(e, "An exception occurred while preCommitting transaction {}",
 311                     cohortEntry.getTransactionID());
 312             shardMBean.incrementFailedTransactionsCount();
 313             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 314         }
 315
 316         cohortEntry.updateLastAccessTime();
 317     }
 318
 319     private void finishCommit(@Nonnull final ActorRef sender, final @Nonnull String transactionID) {
 320         // With persistence enabled, this method is called via applyState by the leader strategy
 321         // after the commit has been replicated to a majority of the followers.
 322
 323         CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
 324         if(cohortEntry == null) {
 325             // The transaction is no longer the current commit. This can happen if the transaction
 326             // was aborted prior, most likely due to timeout in the front-end. We need to finish
 327             // committing the transaction though since it was successfully persisted and replicated
 328             // however we can't use the original cohort b/c it was already preCommitted and may
 329             // conflict with the current commit or may have been aborted so we commit with a new
 330             // transaction.
 331             cohortEntry = commitCoordinator.getAndRemoveCohortEntry(transactionID);
 332             if(cohortEntry != null) {
 333                 commitWithNewTransaction(cohortEntry.getModification());
 334                 sender.tell(COMMIT_TRANSACTION_REPLY, getSelf());
 335             } else {
 336                 // This really shouldn't happen - it likely means that persistence or replication
 337                 // took so long to complete such that the cohort entry was expired from the cache.
 338                 IllegalStateException ex = new IllegalStateException(
 339                         String.format("Could not finish committing transaction %s - no CohortEntry found",
 340                                 transactionID));
 341                 LOG.error(ex.getMessage());
 342                 sender.tell(new akka.actor.Status.Failure(ex), getSelf());
 343             }
 344
 345             return;
 346         }
 347
 348         LOG.debug("Finishing commit for transaction {}", cohortEntry.getTransactionID());
 349
 350         try {
 351             // We block on the future here so we don't have to worry about possibly accessing our
 352             // state on a different thread outside of our dispatcher. Also, the data store
 353             // currently uses a same thread executor anyway.
 354             cohortEntry.getCohort().commit().get();
 355
 356             sender.tell(COMMIT_TRANSACTION_REPLY, getSelf());
 357
 358             shardMBean.incrementCommittedTransactionCount();
 359             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
 360
 361         } catch (InterruptedException | ExecutionException e) {
 362             sender.tell(new akka.actor.Status.Failure(e), getSelf());
 363
 364             LOG.error(e, "An exception occurred while committing transaction {}", transactionID);
 365             shardMBean.incrementFailedTransactionsCount();
 366         }
 367
 368         commitCoordinator.currentTransactionComplete(transactionID, true);
 369     }
 370
 371     private void handleCanCommitTransaction(CanCommitTransaction canCommit) {
 372         LOG.debug("Can committing transaction {}", canCommit.getTransactionID());
 373         commitCoordinator.handleCanCommit(canCommit, getSender(), self());
 374     }
 375
 376     private void handleForwardedReadyTransaction(ForwardedReadyTransaction ready) {
 377         LOG.debug("Readying transaction {}", ready.getTransactionID());
 378
 379         // This message is forwarded by the ShardTransaction on ready. We cache the cohort in the
 380         // commitCoordinator in preparation for the subsequent three phase commit initiated by
 381         // the front-end.
 382         commitCoordinator.transactionReady(ready.getTransactionID(), ready.getCohort(),
 383                 ready.getModification());
 384
 385         // Return our actor path as we'll handle the three phase commit.
 386         getSender().tell(new ReadyTransactionReply(Serialization.serializedActorPath(self())).
 387                 toSerializable(), getSelf());
 388     }
 389
 390     private void handleAbortTransaction(AbortTransaction abort) {
 391         doAbortTransaction(abort.getTransactionID(), getSender());
 392     }
 393
 394     private void doAbortTransaction(String transactionID, final ActorRef sender) {
 395         final CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
 396         if(cohortEntry != null) {
 397             LOG.debug("Aborting transaction {}", transactionID);
 398
 399             // We don't remove the cached cohort entry here (ie pass false) in case the Tx was
 400             // aborted during replication in which case we may still commit locally if replication
 401             // succeeds.
 402             commitCoordinator.currentTransactionComplete(transactionID, false);
 403
 404             final ListenableFuture<Void> future = cohortEntry.getCohort().abort();
 405             final ActorRef self = getSelf();
 406
 407             Futures.addCallback(future, new FutureCallback<Void>() {
 408                 @Override
 409                 public void onSuccess(Void v) {
 410                     shardMBean.incrementAbortTransactionsCount();
 411
 412                     if(sender != null) {
 413                         sender.tell(new AbortTransactionReply().toSerializable(), self);
 414                     }
 415                 }
 416
 417                 @Override
 418                 public void onFailure(Throwable t) {
 419                     LOG.error(t, "An exception happened during abort");
 420
 421                     if(sender != null) {
 422                         sender.tell(new akka.actor.Status.Failure(t), self);
 423                     }
 424                 }
 425             });
 426         }
 427     }
 428
 429     private void handleCreateTransaction(Object message) {
 430         if (isLeader()) {
 431             createTransaction(CreateTransaction.fromSerializable(message));
 432         } else if (getLeader() != null) {
 433             getLeader().forward(message, getContext());
 434         } else {
 435             getSender().tell(new akka.actor.Status.Failure(new IllegalStateException(
 436                 "Could not find shard leader so transaction cannot be created. This typically happens" +
 437                 " when system is coming up or recovering and a leader is being elected. Try again" +
 438                 " later.")), getSelf());
 439         }
 440     }
 441
 442     private void handleReadDataReply(Object message) {
 443         // This must be for install snapshot. Don't want to open this up and trigger
 444         // deSerialization
 445
 446         self().tell(new CaptureSnapshotReply(ReadDataReply.getNormalizedNodeByteString(message)),
 447                 self());
 448
 449         createSnapshotTransaction = null;
 450
 451         // Send a PoisonPill instead of sending close transaction because we do not really need
 452         // a response
 453         getSender().tell(PoisonPill.getInstance(), self());
 454     }
 455
 456     private void closeTransactionChain(CloseTransactionChain closeTransactionChain) {
 457         DOMStoreTransactionChain chain =
 458             transactionChains.remove(closeTransactionChain.getTransactionChainId());
 459
 460         if(chain != null) {
 461             chain.close();
 462         }
 463     }
 464
 465     private ActorRef createTypedTransactionActor(
 466         int transactionType,
 467         ShardTransactionIdentifier transactionId,
 468         String transactionChainId ) {
 469
 470         DOMStoreTransactionFactory factory = store;
 471
 472         if(!transactionChainId.isEmpty()) {
 473             factory = transactionChains.get(transactionChainId);
 474             if(factory == null){
 475                 DOMStoreTransactionChain transactionChain = store.createTransactionChain();
 476                 transactionChains.put(transactionChainId, transactionChain);
 477                 factory = transactionChain;
 478             }
 479         }
 480
 481         if(this.schemaContext == null){
 482             throw new NullPointerException("schemaContext should not be null");
 483         }
 484
 485         if (transactionType == TransactionProxy.TransactionType.READ_ONLY.ordinal()) {
 486
 487             shardMBean.incrementReadOnlyTransactionCount();
 488
 489             return getContext().actorOf(
 490                 ShardTransaction.props(factory.newReadOnlyTransaction(), getSelf(),
 491                         schemaContext,datastoreContext, shardMBean,
 492                         transactionId.getRemoteTransactionId()), transactionId.toString());
 493
 494         } else if (transactionType == TransactionProxy.TransactionType.READ_WRITE.ordinal()) {
 495
 496             shardMBean.incrementReadWriteTransactionCount();
 497
 498             return getContext().actorOf(
 499                 ShardTransaction.props(factory.newReadWriteTransaction(), getSelf(),
 500                         schemaContext, datastoreContext, shardMBean,
 501                         transactionId.getRemoteTransactionId()), transactionId.toString());
 502
 503
 504         } else if (transactionType == TransactionProxy.TransactionType.WRITE_ONLY.ordinal()) {
 505
 506             shardMBean.incrementWriteOnlyTransactionCount();
 507
 508             return getContext().actorOf(
 509                 ShardTransaction.props(factory.newWriteOnlyTransaction(), getSelf(),
 510                         schemaContext, datastoreContext, shardMBean,
 511                         transactionId.getRemoteTransactionId()), transactionId.toString());
 512         } else {
 513             throw new IllegalArgumentException(
 514                 "Shard="+name + ":CreateTransaction message has unidentified transaction type="
 515                     + transactionType);
 516         }
 517     }
 518
 519     private void createTransaction(CreateTransaction createTransaction) {
 520         createTransaction(createTransaction.getTransactionType(),
 521             createTransaction.getTransactionId(), createTransaction.getTransactionChainId());
 522     }
 523
 524     private ActorRef createTransaction(int transactionType, String remoteTransactionId, String transactionChainId) {
 525
 526         ShardTransactionIdentifier transactionId =
 527             ShardTransactionIdentifier.builder()
 528                 .remoteTransactionId(remoteTransactionId)
 529                 .build();
 530         if(LOG.isDebugEnabled()) {
 531             LOG.debug("Creating transaction : {} ", transactionId);
 532         }
 533         ActorRef transactionActor =
 534             createTypedTransactionActor(transactionType, transactionId, transactionChainId);
 535
 536         getSender()
 537             .tell(new CreateTransactionReply(
 538                     Serialization.serializedActorPath(transactionActor),
 539                     remoteTransactionId).toSerializable(),
 540                 getSelf());
 541
 542         return transactionActor;
 543     }
 544
 545     private void syncCommitTransaction(DOMStoreWriteTransaction transaction)
 546         throws ExecutionException, InterruptedException {
 547         DOMStoreThreePhaseCommitCohort commitCohort = transaction.ready();
 548         commitCohort.preCommit().get();
 549         commitCohort.commit().get();
 550     }
 551
 552     private void commitWithNewTransaction(Modification modification) {
 553         DOMStoreWriteTransaction tx = store.newWriteOnlyTransaction();
 554         modification.apply(tx);
 555         try {
 556             syncCommitTransaction(tx);
 557             shardMBean.incrementCommittedTransactionCount();
 558             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
 559         } catch (InterruptedException | ExecutionException e) {
 560             shardMBean.incrementFailedTransactionsCount();
 561             LOG.error(e, "Failed to commit");
 562         }
 563     }
 564
 565     private void updateSchemaContext(UpdateSchemaContext message) {
 566         this.schemaContext = message.getSchemaContext();
 567         updateSchemaContext(message.getSchemaContext());
 568         store.onGlobalContextUpdated(message.getSchemaContext());
 569     }
 570
 571     @VisibleForTesting void updateSchemaContext(SchemaContext schemaContext) {
 572         store.onGlobalContextUpdated(schemaContext);
 573     }
 574
 575     private void registerChangeListener(
 576         RegisterChangeListener registerChangeListener) {
 577
 578         if(LOG.isDebugEnabled()) {
 579             LOG.debug("registerDataChangeListener for {}", registerChangeListener
 580                 .getPath());
 581         }
 582
 583
 584         ActorSelection dataChangeListenerPath = getContext()
 585             .system().actorSelection(
 586                 registerChangeListener.getDataChangeListenerPath());
 587
 588
 589         // Notify the listener if notifications should be enabled or not
 590         // If this shard is the leader then it will enable notifications else
 591         // it will not
 592         dataChangeListenerPath
 593             .tell(new EnableNotification(isLeader()), getSelf());
 594
 595         // Now store a reference to the data change listener so it can be notified
 596         // at a later point if notifications should be enabled or disabled
 597         dataChangeListeners.add(dataChangeListenerPath);
 598
 599         AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>
 600             listener = new DataChangeListenerProxy(schemaContext, dataChangeListenerPath);
 601
 602         ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>
 603             registration = store.registerChangeListener(registerChangeListener.getPath(),
 604                 listener, registerChangeListener.getScope());
 605         ActorRef listenerRegistration =
 606             getContext().actorOf(
 607                 DataChangeListenerRegistration.props(registration));
 608
 609         if(LOG.isDebugEnabled()) {
 610             LOG.debug(
 611                 "registerDataChangeListener sending reply, listenerRegistrationPath = {} "
 612                 , listenerRegistration.path().toString());
 613         }
 614
 615         getSender()
 616             .tell(new RegisterChangeListenerReply(listenerRegistration.path()),
 617                 getSelf());
 618     }
 619
 620     private boolean isMetricsCaptureEnabled(){
 621         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 622         return config.isMetricCaptureEnabled();
 623     }
 624
 625     @Override
 626     protected
 627     void startLogRecoveryBatch(int maxBatchSize) {
 628         currentLogRecoveryBatch = Lists.newArrayListWithCapacity(maxBatchSize);
 629
 630         if(LOG.isDebugEnabled()) {
 631             LOG.debug("{} : starting log recovery batch with max size {}", persistenceId(), maxBatchSize);
 632         }
 633     }
 634
 635     @Override
 636     protected void appendRecoveredLogEntry(Payload data) {
 637         if (data instanceof CompositeModificationPayload) {
 638             currentLogRecoveryBatch.add(((CompositeModificationPayload) data).getModification());
 639         } else {
 640             LOG.error("Unknown state received {} during recovery", data);
 641         }
 642     }
 643
 644     @Override
 645     protected void applyRecoverySnapshot(ByteString snapshot) {
 646         if(recoveryCoordinator == null) {
 647             recoveryCoordinator = new ShardRecoveryCoordinator(persistenceId(), schemaContext);
 648         }
 649
 650         recoveryCoordinator.submit(snapshot, store.newWriteOnlyTransaction());
 651
 652         if(LOG.isDebugEnabled()) {
 653             LOG.debug("{} : submitted recovery sbapshot", persistenceId());
 654         }
 655     }
 656
 657     @Override
 658     protected void applyCurrentLogRecoveryBatch() {
 659         if(recoveryCoordinator == null) {
 660             recoveryCoordinator = new ShardRecoveryCoordinator(persistenceId(), schemaContext);
 661         }
 662
 663         recoveryCoordinator.submit(currentLogRecoveryBatch, store.newWriteOnlyTransaction());
 664
 665         if(LOG.isDebugEnabled()) {
 666             LOG.debug("{} : submitted log recovery batch with size {}", persistenceId(),
 667                     currentLogRecoveryBatch.size());
 668         }
 669     }
 670
 671     @Override
 672     protected void onRecoveryComplete() {
 673         if(recoveryCoordinator != null) {
 674             Collection<DOMStoreWriteTransaction> txList = recoveryCoordinator.getTransactions();
 675
 676             if(LOG.isDebugEnabled()) {
 677                 LOG.debug("{} : recovery complete - committing {} Tx's", persistenceId(), txList.size());
 678             }
 679
 680             for(DOMStoreWriteTransaction tx: txList) {
 681                 try {
 682                     syncCommitTransaction(tx);
 683                     shardMBean.incrementCommittedTransactionCount();
 684                 } catch (InterruptedException | ExecutionException e) {
 685                     shardMBean.incrementFailedTransactionsCount();
 686                     LOG.error(e, "Failed to commit");
 687                 }
 688             }
 689         }
 690
 691         recoveryCoordinator = null;
 692         currentLogRecoveryBatch = null;
 693         updateJournalStats();
 694
 695         //notify shard manager
 696         getContext().parent().tell(new ActorInitialized(), getSelf());
 697
 698         // Schedule a message to be periodically sent to check if the current in-progress
 699         // transaction should be expired and aborted.
 700         FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 701         txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 702                 period, period, getSelf(),
 703                 TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 704     }
 705
 706     @Override
 707     protected void applyState(ActorRef clientActor, String identifier, Object data) {
 708
 709         if (data instanceof CompositeModificationPayload) {
 710             Object modification = ((CompositeModificationPayload) data).getModification();
 711
 712             if(modification == null) {
 713                 LOG.error(
 714                      "modification is null - this is very unexpected, clientActor = {}, identifier = {}",
 715                      identifier, clientActor != null ? clientActor.path().toString() : null);
 716             } else if(clientActor == null) {
 717                 // There's no clientActor to which to send a commit reply so we must be applying
 718                 // replicated state from the leader.
 719                 commitWithNewTransaction(MutableCompositeModification.fromSerializable(
 720                         modification, schemaContext));
 721             } else {
 722                 // This must be the OK to commit after replication consensus.
 723                 finishCommit(clientActor, identifier);
 724             }
 725         } else {
 726             LOG.error("Unknown state received {} Class loader = {} CompositeNodeMod.ClassLoader = {}",
 727                     data, data.getClass().getClassLoader(),
 728                     CompositeModificationPayload.class.getClassLoader());
 729         }
 730
 731         updateJournalStats();
 732
 733     }
 734
 735     private void updateJournalStats() {
 736         ReplicatedLogEntry lastLogEntry = getLastLogEntry();
 737
 738         if (lastLogEntry != null) {
 739             shardMBean.setLastLogIndex(lastLogEntry.getIndex());
 740             shardMBean.setLastLogTerm(lastLogEntry.getTerm());
 741         }
 742
 743         shardMBean.setCommitIndex(getCommitIndex());
 744         shardMBean.setLastApplied(getLastApplied());
 745     }
 746
 747     @Override
 748     protected void createSnapshot() {
 749         if (createSnapshotTransaction == null) {
 750
 751             // Create a transaction. We are really going to treat the transaction as a worker
 752             // so that this actor does not get block building the snapshot
 753             createSnapshotTransaction = createTransaction(
 754                 TransactionProxy.TransactionType.READ_ONLY.ordinal(),
 755                 "createSnapshot" + ++createSnapshotTransactionCounter, "");
 756
 757             createSnapshotTransaction.tell(
 758                 new ReadData(YangInstanceIdentifier.builder().build()).toSerializable(), self());
 759
 760         }
 761     }
 762
 763     @VisibleForTesting
 764     @Override
 765     protected void applySnapshot(ByteString snapshot) {
 766         // Since this will be done only on Recovery or when this actor is a Follower
 767         // we can safely commit everything in here. We not need to worry about event notifications
 768         // as they would have already been disabled on the follower
 769
 770         LOG.info("Applying snapshot");
 771         try {
 772             DOMStoreWriteTransaction transaction = store.newWriteOnlyTransaction();
 773             NormalizedNodeMessages.Node serializedNode = NormalizedNodeMessages.Node.parseFrom(snapshot);
 774             NormalizedNode<?, ?> node = new NormalizedNodeToNodeCodec(schemaContext)
 775                 .decode(serializedNode);
 776
 777             // delete everything first
 778             transaction.delete(YangInstanceIdentifier.builder().build());
 779
 780             // Add everything from the remote node back
 781             transaction.write(YangInstanceIdentifier.builder().build(), node);
 782             syncCommitTransaction(transaction);
 783         } catch (InvalidProtocolBufferException | InterruptedException | ExecutionException e) {
 784             LOG.error(e, "An exception occurred when applying snapshot");
 785         } finally {
 786             LOG.info("Done applying snapshot");
 787         }
 788     }
 789
 790     @Override protected void onStateChanged() {
 791         for (ActorSelection dataChangeListener : dataChangeListeners) {
 792             dataChangeListener
 793                 .tell(new EnableNotification(isLeader()), getSelf());
 794         }
 795
 796         shardMBean.setRaftState(getRaftState().name());
 797         shardMBean.setCurrentTerm(getCurrentTerm());
 798
 799         // If this actor is no longer the leader close all the transaction chains
 800         if(!isLeader()){
 801             for(Map.Entry<String, DOMStoreTransactionChain> entry : transactionChains.entrySet()){
 802                 if(LOG.isDebugEnabled()) {
 803                     LOG.debug(
 804                         "onStateChanged: Closing transaction chain {} because shard {} is no longer the leader",
 805                         entry.getKey(), getId());
 806                 }
 807                 entry.getValue().close();
 808             }
 809
 810             transactionChains.clear();
 811         }
 812     }
 813
 814     @Override protected void onLeaderChanged(String oldLeader, String newLeader) {
 815         shardMBean.setLeader(newLeader);
 816     }
 817
 818     @Override public String persistenceId() {
 819         return this.name.toString();
 820     }
 821
 822     private static class ShardCreator implements Creator<Shard> {
 823
 824         private static final long serialVersionUID = 1L;
 825
 826         final ShardIdentifier name;
 827         final Map<ShardIdentifier, String> peerAddresses;
 828         final DatastoreContext datastoreContext;
 829         final SchemaContext schemaContext;
 830
 831         ShardCreator(ShardIdentifier name, Map<ShardIdentifier, String> peerAddresses,
 832                 DatastoreContext datastoreContext, SchemaContext schemaContext) {
 833             this.name = name;
 834             this.peerAddresses = peerAddresses;
 835             this.datastoreContext = datastoreContext;
 836             this.schemaContext = schemaContext;
 837         }
 838
 839         @Override
 840         public Shard create() throws Exception {
 841             return new Shard(name, peerAddresses, datastoreContext, schemaContext);
 842         }
 843     }
 844
 845     @VisibleForTesting
 846     InMemoryDOMDataStore getDataStore() {
 847         return store;
 848     }
 849
 850     @VisibleForTesting
 851     ShardStats getShardMBean() {
 852         return shardMBean;
 853     }
 854 }