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 java.io.IOException;
  20 import java.util.Collections;
  21 import java.util.Map;
  22 import java.util.concurrent.TimeUnit;
  23 import javax.annotation.Nonnull;
  24 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  25 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  26 import org.opendaylight.controller.cluster.datastore.ShardCommitCoordinator.CohortEntry;
  27 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  28 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  29 import org.opendaylight.controller.cluster.datastore.identifiers.ShardTransactionIdentifier;
  30 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  31 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  32 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  33 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  34 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  35 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  36 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  37 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  38 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
  39 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  40 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  41 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot;
  42 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot.ShardSnapshot;
  43 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  44 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  45 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  46 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  47 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  48 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  49 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  50 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  51 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  52 import org.opendaylight.controller.cluster.datastore.modification.MutableCompositeModification;
  53 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  54 import org.opendaylight.controller.cluster.datastore.utils.MessageTracker;
  55 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  56 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  57 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  58 import org.opendaylight.controller.cluster.raft.RaftActor;
  59 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  60 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
  61 import org.opendaylight.controller.cluster.raft.RaftState;
  62 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  63 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  64 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
  65 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationByteStringPayload;
  66 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationPayload;
  67 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree;
  68 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  69 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  70 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  71 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
  72 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  73 import scala.concurrent.duration.Duration;
  74 import scala.concurrent.duration.FiniteDuration;
  75
  76 /**
  77  * A Shard represents a portion of the logical data tree <br/>
  78  * <p>
  79  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
  80  * </p>
  81  */
  82 public class Shard extends RaftActor {
  83
  84     protected static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = "txCommitTimeoutCheck";
  85
  86     @VisibleForTesting
  87     static final Object GET_SHARD_MBEAN_MESSAGE = "getShardMBeanMessage";
  88
  89     @VisibleForTesting
  90     static final String DEFAULT_NAME = "default";
  91
  92     // The state of this Shard
  93     private final ShardDataTree store;
  94
  95     /// The name of this shard
  96     private final String name;
  97
  98     private final ShardStats shardMBean;
  99
 100     private DatastoreContext datastoreContext;
 101
 102     private final ShardCommitCoordinator commitCoordinator;
 103
 104     private long transactionCommitTimeout;
 105
 106     private Cancellable txCommitTimeoutCheckSchedule;
 107
 108     private final Optional<ActorRef> roleChangeNotifier;
 109
 110     private final MessageTracker appendEntriesReplyTracker;
 111
 112     private final ShardTransactionActorFactory transactionActorFactory;
 113
 114     private final ShardSnapshotCohort snapshotCohort;
 115
 116     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 117     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 118
 119
 120     private ShardSnapshot restoreFromSnapshot;
 121
 122     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 123
 124     protected Shard(AbstractBuilder<?, ?> builder) {
 125         super(builder.getId().toString(), builder.getPeerAddresses(),
 126                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 127
 128         this.name = builder.getId().toString();
 129         this.datastoreContext = builder.getDatastoreContext();
 130         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 131
 132         setPersistence(datastoreContext.isPersistent());
 133
 134         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 135
 136         store = new ShardDataTree(builder.getSchemaContext(), builder.getTreeType(),
 137                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher"),
 138                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher"), name);
 139
 140         shardMBean = ShardMBeanFactory.getShardStatsMBean(name.toString(),
 141                 datastoreContext.getDataStoreMXBeanType());
 142         shardMBean.setShard(this);
 143
 144         if (isMetricsCaptureEnabled()) {
 145             getContext().become(new MeteringBehavior(this));
 146         }
 147
 148         commitCoordinator = new ShardCommitCoordinator(store,
 149                 datastoreContext.getShardCommitQueueExpiryTimeoutInMillis(),
 150                 datastoreContext.getShardTransactionCommitQueueCapacity(), LOG, this.name);
 151
 152         setTransactionCommitTimeout();
 153
 154         // create a notifier actor for each cluster member
 155         roleChangeNotifier = createRoleChangeNotifier(name.toString());
 156
 157         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 158                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 159
 160         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 161                 new Dispatchers(context().system().dispatchers()).getDispatcherPath(
 162                         Dispatchers.DispatcherType.Transaction), self(), getContext(), shardMBean);
 163
 164         snapshotCohort = new ShardSnapshotCohort(transactionActorFactory, store, LOG, this.name);
 165
 166         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 167     }
 168
 169     private void setTransactionCommitTimeout() {
 170         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 171                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 172     }
 173
 174     private Optional<ActorRef> createRoleChangeNotifier(String shardId) {
 175         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 176             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 177         return Optional.of(shardRoleChangeNotifier);
 178     }
 179
 180     @Override
 181     public void postStop() {
 182         LOG.info("Stopping Shard {}", persistenceId());
 183
 184         super.postStop();
 185
 186         messageRetrySupport.close();
 187
 188         if(txCommitTimeoutCheckSchedule != null) {
 189             txCommitTimeoutCheckSchedule.cancel();
 190         }
 191
 192         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 193
 194         shardMBean.unregisterMBean();
 195     }
 196
 197     @Override
 198     public void onReceiveRecover(final Object message) throws Exception {
 199         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 200             getSender());
 201
 202         super.onReceiveRecover(message);
 203         if (LOG.isTraceEnabled()) {
 204             appendEntriesReplyTracker.begin();
 205         }
 206     }
 207
 208     @Override
 209     public void onReceiveCommand(final Object message) throws Exception {
 210
 211         MessageTracker.Context context = appendEntriesReplyTracker.received(message);
 212
 213         if(context.error().isPresent()){
 214             LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 215                 context.error());
 216         }
 217
 218         try {
 219             if (CreateTransaction.isSerializedType(message)) {
 220                 handleCreateTransaction(message);
 221             } else if (BatchedModifications.class.isInstance(message)) {
 222                 handleBatchedModifications((BatchedModifications)message);
 223             } else if (message instanceof ForwardedReadyTransaction) {
 224                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 225             } else if (message instanceof ReadyLocalTransaction) {
 226                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 227             } else if (CanCommitTransaction.isSerializedType(message)) {
 228                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 229             } else if (CommitTransaction.isSerializedType(message)) {
 230                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 231             } else if (AbortTransaction.isSerializedType(message)) {
 232                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 233             } else if (CloseTransactionChain.isSerializedType(message)) {
 234                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 235             } else if (message instanceof RegisterChangeListener) {
 236                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 237             } else if (message instanceof RegisterDataTreeChangeListener) {
 238                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 239             } else if (message instanceof UpdateSchemaContext) {
 240                 updateSchemaContext((UpdateSchemaContext) message);
 241             } else if (message instanceof PeerAddressResolved) {
 242                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 243                 setPeerAddress(resolved.getPeerId().toString(),
 244                         resolved.getPeerAddress());
 245             } else if (message.equals(TX_COMMIT_TIMEOUT_CHECK_MESSAGE)) {
 246                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 247             } else if(message instanceof DatastoreContext) {
 248                 onDatastoreContext((DatastoreContext)message);
 249             } else if(message instanceof RegisterRoleChangeListener){
 250                 roleChangeNotifier.get().forward(message, context());
 251             } else if (message instanceof FollowerInitialSyncUpStatus) {
 252                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 253                 context().parent().tell(message, self());
 254             } else if(GET_SHARD_MBEAN_MESSAGE.equals(message)){
 255                 sender().tell(getShardMBean(), self());
 256             } else if(message instanceof GetShardDataTree) {
 257                 sender().tell(store.getDataTree(), self());
 258             } else if(message instanceof ServerRemoved){
 259                 context().parent().forward(message, context());
 260             } else if(ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 261                 messageRetrySupport.onTimerMessage(message);
 262             } else {
 263                 super.onReceiveCommand(message);
 264             }
 265         } finally {
 266             context.done();
 267         }
 268     }
 269
 270     private boolean hasLeader() {
 271         return getLeaderId() != null;
 272     }
 273
 274     public int getPendingTxCommitQueueSize() {
 275         return commitCoordinator.getQueueSize();
 276     }
 277
 278     public int getCohortCacheSize() {
 279         return commitCoordinator.getCohortCacheSize();
 280     }
 281
 282     @Override
 283     protected Optional<ActorRef> getRoleChangeNotifier() {
 284         return roleChangeNotifier;
 285     }
 286
 287     @Override
 288     protected LeaderStateChanged newLeaderStateChanged(String memberId, String leaderId, short leaderPayloadVersion) {
 289         return new ShardLeaderStateChanged(memberId, leaderId,
 290                 isLeader() ? Optional.<DataTree>of(store.getDataTree()) : Optional.<DataTree>absent(),
 291                 leaderPayloadVersion);
 292     }
 293
 294     protected void onDatastoreContext(DatastoreContext context) {
 295         datastoreContext = context;
 296
 297         commitCoordinator.setQueueCapacity(datastoreContext.getShardTransactionCommitQueueCapacity());
 298
 299         setTransactionCommitTimeout();
 300
 301         if(datastoreContext.isPersistent() && !persistence().isRecoveryApplicable()) {
 302             setPersistence(true);
 303         } else if(!datastoreContext.isPersistent() && persistence().isRecoveryApplicable()) {
 304             setPersistence(false);
 305         }
 306
 307         updateConfigParams(datastoreContext.getShardRaftConfig());
 308     }
 309
 310     private static boolean isEmptyCommit(final DataTreeCandidate candidate) {
 311         return ModificationType.UNMODIFIED.equals(candidate.getRootNode().getModificationType());
 312     }
 313
 314     void continueCommit(final CohortEntry cohortEntry) {
 315         final DataTreeCandidate candidate = cohortEntry.getCandidate();
 316
 317         // If we do not have any followers and we are not using persistence
 318         // or if cohortEntry has no modifications
 319         // we can apply modification to the state immediately
 320         if ((!hasFollowers() && !persistence().isRecoveryApplicable()) || isEmptyCommit(candidate)) {
 321             applyModificationToState(cohortEntry.getReplySender(), cohortEntry.getTransactionID(), candidate);
 322         } else {
 323             Shard.this.persistData(cohortEntry.getReplySender(), cohortEntry.getTransactionID(),
 324                     DataTreeCandidatePayload.create(candidate));
 325         }
 326     }
 327
 328     private void handleCommitTransaction(final CommitTransaction commit) {
 329         if(!commitCoordinator.handleCommit(commit.getTransactionID(), getSender(), this)) {
 330             shardMBean.incrementFailedTransactionsCount();
 331         }
 332     }
 333
 334     private void finishCommit(@Nonnull final ActorRef sender, @Nonnull final String transactionID, @Nonnull final CohortEntry cohortEntry) {
 335         LOG.debug("{}: Finishing commit for transaction {}", persistenceId(), cohortEntry.getTransactionID());
 336
 337         try {
 338             cohortEntry.commit();
 339
 340             sender.tell(CommitTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(), getSelf());
 341
 342             shardMBean.incrementCommittedTransactionCount();
 343             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
 344
 345         } catch (Exception e) {
 346             sender.tell(new akka.actor.Status.Failure(e), getSelf());
 347
 348             LOG.error("{}, An exception occurred while committing transaction {}", persistenceId(),
 349                     transactionID, e);
 350             shardMBean.incrementFailedTransactionsCount();
 351         } finally {
 352             commitCoordinator.currentTransactionComplete(transactionID, true);
 353         }
 354     }
 355
 356     private void finishCommit(@Nonnull final ActorRef sender, final @Nonnull String transactionID) {
 357         // With persistence enabled, this method is called via applyState by the leader strategy
 358         // after the commit has been replicated to a majority of the followers.
 359
 360         CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
 361         if (cohortEntry == null) {
 362             // The transaction is no longer the current commit. This can happen if the transaction
 363             // was aborted prior, most likely due to timeout in the front-end. We need to finish
 364             // committing the transaction though since it was successfully persisted and replicated
 365             // however we can't use the original cohort b/c it was already preCommitted and may
 366             // conflict with the current commit or may have been aborted so we commit with a new
 367             // transaction.
 368             cohortEntry = commitCoordinator.getAndRemoveCohortEntry(transactionID);
 369             if(cohortEntry != null) {
 370                 try {
 371                     store.applyForeignCandidate(transactionID, cohortEntry.getCandidate());
 372                 } catch (DataValidationFailedException e) {
 373                     shardMBean.incrementFailedTransactionsCount();
 374                     LOG.error("{}: Failed to re-apply transaction {}", persistenceId(), transactionID, e);
 375                 }
 376
 377                 sender.tell(CommitTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(),
 378                         getSelf());
 379             } else {
 380                 // This really shouldn't happen - it likely means that persistence or replication
 381                 // took so long to complete such that the cohort entry was expired from the cache.
 382                 IllegalStateException ex = new IllegalStateException(
 383                         String.format("%s: Could not finish committing transaction %s - no CohortEntry found",
 384                                 persistenceId(), transactionID));
 385                 LOG.error(ex.getMessage());
 386                 sender.tell(new akka.actor.Status.Failure(ex), getSelf());
 387             }
 388         } else {
 389             finishCommit(sender, transactionID, cohortEntry);
 390         }
 391     }
 392
 393     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 394         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionID());
 395         commitCoordinator.handleCanCommit(canCommit.getTransactionID(), getSender(), this);
 396     }
 397
 398     protected void handleBatchedModificationsLocal(BatchedModifications batched, ActorRef sender) {
 399         try {
 400             commitCoordinator.handleBatchedModifications(batched, sender, this);
 401         } catch (Exception e) {
 402             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 403                     batched.getTransactionID(), e);
 404             sender.tell(new akka.actor.Status.Failure(e), getSelf());
 405         }
 406     }
 407
 408     private void handleBatchedModifications(BatchedModifications batched) {
 409         // This message is sent to prepare the modifications transaction directly on the Shard as an
 410         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 411         // BatchedModifications message, the caller sets the ready flag in the message indicating
 412         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 413         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 414         // ReadyTransaction message.
 415
 416         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 417         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 418         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 419         // window where it could have a stale leader during leadership transitions.
 420         //
 421         boolean isLeaderActive = isLeaderActive();
 422         if (isLeader() && isLeaderActive) {
 423             handleBatchedModificationsLocal(batched, getSender());
 424         } else {
 425             ActorSelection leader = getLeader();
 426             if (!isLeaderActive || leader == null) {
 427                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 428                         "Could not commit transaction " + batched.getTransactionID());
 429             } else {
 430                 // TODO: what if this is not the first batch and leadership changed in between batched messages?
 431                 // We could check if the commitCoordinator already has a cached entry and forward all the previous
 432                 // batched modifications.
 433                 LOG.debug("{}: Forwarding BatchedModifications to leader {}", persistenceId(), leader);
 434                 leader.forward(batched, getContext());
 435             }
 436         }
 437     }
 438
 439     private boolean failIfIsolatedLeader(ActorRef sender) {
 440         if(isIsolatedLeader()) {
 441             sender.tell(new akka.actor.Status.Failure(new NoShardLeaderException(String.format(
 442                     "Shard %s was the leader but has lost contact with all of its followers. Either all" +
 443                     " other follower nodes are down or this node is isolated by a network partition.",
 444                     persistenceId()))), getSelf());
 445             return true;
 446         }
 447
 448         return false;
 449     }
 450
 451     protected boolean isIsolatedLeader() {
 452         return getRaftState() == RaftState.IsolatedLeader;
 453     }
 454
 455     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 456         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionID());
 457
 458         boolean isLeaderActive = isLeaderActive();
 459         if (isLeader() && isLeaderActive) {
 460             try {
 461                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 462             } catch (Exception e) {
 463                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 464                         message.getTransactionID(), e);
 465                 getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 466             }
 467         } else {
 468             ActorSelection leader = getLeader();
 469             if (!isLeaderActive || leader == null) {
 470                 messageRetrySupport.addMessageToRetry(message, getSender(),
 471                         "Could not commit transaction " + message.getTransactionID());
 472             } else {
 473                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 474                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 475                 leader.forward(message, getContext());
 476             }
 477         }
 478     }
 479
 480     private void handleForwardedReadyTransaction(ForwardedReadyTransaction forwardedReady) {
 481         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionID());
 482
 483         boolean isLeaderActive = isLeaderActive();
 484         if (isLeader() && isLeaderActive) {
 485             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 486         } else {
 487             ActorSelection leader = getLeader();
 488             if (!isLeaderActive || leader == null) {
 489                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 490                         "Could not commit transaction " + forwardedReady.getTransactionID());
 491             } else {
 492                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 493
 494                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionID(),
 495                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 496                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 497                 leader.forward(readyLocal, getContext());
 498             }
 499         }
 500     }
 501
 502     private void handleAbortTransaction(final AbortTransaction abort) {
 503         doAbortTransaction(abort.getTransactionID(), getSender());
 504     }
 505
 506     void doAbortTransaction(final String transactionID, final ActorRef sender) {
 507         commitCoordinator.handleAbort(transactionID, sender, this);
 508     }
 509
 510     private void handleCreateTransaction(final Object message) {
 511         if (isLeader()) {
 512             createTransaction(CreateTransaction.fromSerializable(message));
 513         } else if (getLeader() != null) {
 514             getLeader().forward(message, getContext());
 515         } else {
 516             getSender().tell(new akka.actor.Status.Failure(new NoShardLeaderException(
 517                     "Could not create a shard transaction", persistenceId())), getSelf());
 518         }
 519     }
 520
 521     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 522         store.closeTransactionChain(closeTransactionChain.getTransactionChainId());
 523     }
 524
 525     private ActorRef createTypedTransactionActor(int transactionType,
 526             ShardTransactionIdentifier transactionId, String transactionChainId) {
 527
 528         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 529                 transactionId, transactionChainId);
 530     }
 531
 532     private void createTransaction(CreateTransaction createTransaction) {
 533         try {
 534             if(TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY &&
 535                     failIfIsolatedLeader(getSender())) {
 536                 return;
 537             }
 538
 539             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 540                 createTransaction.getTransactionId(), createTransaction.getTransactionChainId());
 541
 542             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 543                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 544         } catch (Exception e) {
 545             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 546         }
 547     }
 548
 549     private ActorRef createTransaction(int transactionType, String remoteTransactionId,
 550             String transactionChainId) {
 551
 552
 553         ShardTransactionIdentifier transactionId = new ShardTransactionIdentifier(remoteTransactionId);
 554
 555         if(LOG.isDebugEnabled()) {
 556             LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 557         }
 558
 559         ActorRef transactionActor = createTypedTransactionActor(transactionType, transactionId,
 560                 transactionChainId);
 561
 562         return transactionActor;
 563     }
 564
 565     private void commitWithNewTransaction(final Modification modification) {
 566         ReadWriteShardDataTreeTransaction tx = store.newReadWriteTransaction(modification.toString(), null);
 567         modification.apply(tx.getSnapshot());
 568         try {
 569             snapshotCohort.syncCommitTransaction(tx);
 570             shardMBean.incrementCommittedTransactionCount();
 571             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
 572         } catch (Exception e) {
 573             shardMBean.incrementFailedTransactionsCount();
 574             LOG.error("{}: Failed to commit", persistenceId(), e);
 575         }
 576     }
 577
 578     private void updateSchemaContext(final UpdateSchemaContext message) {
 579         updateSchemaContext(message.getSchemaContext());
 580     }
 581
 582     @VisibleForTesting
 583     void updateSchemaContext(final SchemaContext schemaContext) {
 584         store.updateSchemaContext(schemaContext);
 585     }
 586
 587     private boolean isMetricsCaptureEnabled() {
 588         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 589         return config.isMetricCaptureEnabled();
 590     }
 591
 592     @Override
 593     @VisibleForTesting
 594     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 595         return snapshotCohort;
 596     }
 597
 598     @Override
 599     @Nonnull
 600     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 601         return new ShardRecoveryCoordinator(store, store.getSchemaContext(),
 602                 restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 603     }
 604
 605     @Override
 606     protected void onRecoveryComplete() {
 607         restoreFromSnapshot = null;
 608
 609         //notify shard manager
 610         getContext().parent().tell(new ActorInitialized(), getSelf());
 611
 612         // Being paranoid here - this method should only be called once but just in case...
 613         if(txCommitTimeoutCheckSchedule == null) {
 614             // Schedule a message to be periodically sent to check if the current in-progress
 615             // transaction should be expired and aborted.
 616             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 617             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 618                     period, period, getSelf(),
 619                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 620         }
 621     }
 622
 623     @Override
 624     protected void applyState(final ActorRef clientActor, final String identifier, final Object data) {
 625         if (data instanceof DataTreeCandidatePayload) {
 626             if (clientActor == null) {
 627                 // No clientActor indicates a replica coming from the leader
 628                 try {
 629                     store.applyForeignCandidate(identifier, ((DataTreeCandidatePayload)data).getCandidate());
 630                 } catch (DataValidationFailedException | IOException e) {
 631                     LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 632                 }
 633             } else {
 634                 // Replication consensus reached, proceed to commit
 635                 finishCommit(clientActor, identifier);
 636             }
 637         } else if (data instanceof CompositeModificationPayload) {
 638             Object modification = ((CompositeModificationPayload) data).getModification();
 639
 640             applyModificationToState(clientActor, identifier, modification);
 641         } else if(data instanceof CompositeModificationByteStringPayload ){
 642             Object modification = ((CompositeModificationByteStringPayload) data).getModification();
 643
 644             applyModificationToState(clientActor, identifier, modification);
 645         } else {
 646             LOG.error("{}: Unknown state received {} Class loader = {} CompositeNodeMod.ClassLoader = {}",
 647                     persistenceId(), data, data.getClass().getClassLoader(),
 648                     CompositeModificationPayload.class.getClassLoader());
 649         }
 650     }
 651
 652     private void applyModificationToState(ActorRef clientActor, String identifier, Object modification) {
 653         if(modification == null) {
 654             LOG.error(
 655                     "{}: modification is null - this is very unexpected, clientActor = {}, identifier = {}",
 656                     persistenceId(), identifier, clientActor != null ? clientActor.path().toString() : null);
 657         } else if(clientActor == null) {
 658             // There's no clientActor to which to send a commit reply so we must be applying
 659             // replicated state from the leader.
 660             commitWithNewTransaction(MutableCompositeModification.fromSerializable(modification));
 661         } else {
 662             // This must be the OK to commit after replication consensus.
 663             finishCommit(clientActor, identifier);
 664         }
 665     }
 666
 667     @Override
 668     protected void onStateChanged() {
 669         boolean isLeader = isLeader();
 670         boolean hasLeader = hasLeader();
 671         changeSupport.onLeadershipChange(isLeader, hasLeader);
 672         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 673
 674         // If this actor is no longer the leader close all the transaction chains
 675         if (!isLeader) {
 676             if(LOG.isDebugEnabled()) {
 677                 LOG.debug(
 678                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 679                     persistenceId(), getId());
 680             }
 681
 682             store.closeAllTransactionChains();
 683
 684             commitCoordinator.abortPendingTransactions(
 685                     "The transacton was aborted due to inflight leadership change.", this);
 686         }
 687
 688         if(hasLeader && !isIsolatedLeader()) {
 689             messageRetrySupport.retryMessages();
 690         }
 691     }
 692
 693     @Override
 694     protected void onLeaderChanged(String oldLeader, String newLeader) {
 695         shardMBean.incrementLeadershipChangeCount();
 696
 697         if(hasLeader() && !isIsolatedLeader()) {
 698             messageRetrySupport.retryMessages();
 699         }
 700     }
 701
 702     @Override
 703     protected void pauseLeader(Runnable operation) {
 704         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 705         commitCoordinator.setRunOnPendingTransactionsComplete(operation);
 706     }
 707
 708     @Override
 709     public String persistenceId() {
 710         return this.name;
 711     }
 712
 713     @VisibleForTesting
 714     ShardCommitCoordinator getCommitCoordinator() {
 715         return commitCoordinator;
 716     }
 717
 718     public DatastoreContext getDatastoreContext() {
 719         return datastoreContext;
 720     }
 721
 722     @VisibleForTesting
 723     public ShardDataTree getDataStore() {
 724         return store;
 725     }
 726
 727     @VisibleForTesting
 728     ShardStats getShardMBean() {
 729         return shardMBean;
 730     }
 731
 732     public static Builder builder() {
 733         return new Builder();
 734     }
 735
 736     public static abstract class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 737         private final Class<S> shardClass;
 738         private ShardIdentifier id;
 739         private Map<String, String> peerAddresses = Collections.emptyMap();
 740         private DatastoreContext datastoreContext;
 741         private SchemaContext schemaContext;
 742         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 743         private volatile boolean sealed;
 744
 745         protected AbstractBuilder(Class<S> shardClass) {
 746             this.shardClass = shardClass;
 747         }
 748
 749         protected void checkSealed() {
 750             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 751         }
 752
 753         @SuppressWarnings("unchecked")
 754         private T self() {
 755             return (T) this;
 756         }
 757
 758         public T id(ShardIdentifier id) {
 759             checkSealed();
 760             this.id = id;
 761             return self();
 762         }
 763
 764         public T peerAddresses(Map<String, String> peerAddresses) {
 765             checkSealed();
 766             this.peerAddresses = peerAddresses;
 767             return self();
 768         }
 769
 770         public T datastoreContext(DatastoreContext datastoreContext) {
 771             checkSealed();
 772             this.datastoreContext = datastoreContext;
 773             return self();
 774         }
 775
 776         public T schemaContext(SchemaContext schemaContext) {
 777             checkSealed();
 778             this.schemaContext = schemaContext;
 779             return self();
 780         }
 781
 782         public T restoreFromSnapshot(DatastoreSnapshot.ShardSnapshot restoreFromSnapshot) {
 783             checkSealed();
 784             this.restoreFromSnapshot = restoreFromSnapshot;
 785             return self();
 786         }
 787
 788         public ShardIdentifier getId() {
 789             return id;
 790         }
 791
 792         public Map<String, String> getPeerAddresses() {
 793             return peerAddresses;
 794         }
 795
 796         public DatastoreContext getDatastoreContext() {
 797             return datastoreContext;
 798         }
 799
 800         public SchemaContext getSchemaContext() {
 801             return schemaContext;
 802         }
 803
 804         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
 805             return restoreFromSnapshot;
 806         }
 807
 808         public TreeType getTreeType() {
 809             switch (datastoreContext.getLogicalStoreType()) {
 810             case CONFIGURATION:
 811                 return TreeType.CONFIGURATION;
 812             case OPERATIONAL:
 813                 return TreeType.OPERATIONAL;
 814             }
 815
 816             throw new IllegalStateException("Unhandled logical store type " + datastoreContext.getLogicalStoreType());
 817         }
 818
 819         protected void verify() {
 820             Preconditions.checkNotNull(id, "id should not be null");
 821             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
 822             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
 823             Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
 824         }
 825
 826         public Props props() {
 827             sealed = true;
 828             verify();
 829             return Props.create(shardClass, this);
 830         }
 831     }
 832
 833     public static class Builder extends AbstractBuilder<Builder, Shard> {
 834         private Builder() {
 835             super(Shard.class);
 836         }
 837     }
 838 }