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.Collection;
  21 import java.util.Collections;
  22 import java.util.Map;
  23 import java.util.concurrent.ExecutionException;
  24 import java.util.concurrent.TimeUnit;
  25 import javax.annotation.Nonnull;
  26 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  27 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  28 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
  29 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  30 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  31 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  32 import org.opendaylight.controller.cluster.datastore.identifiers.ShardTransactionIdentifier;
  33 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  34 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  35 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  36 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  37 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  38 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  39 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  40 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  41 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
  42 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  43 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  44 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot;
  45 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot.ShardSnapshot;
  46 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  47 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  48 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  49 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  50 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  51 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  52 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  53 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  54 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  55 import org.opendaylight.controller.cluster.datastore.modification.MutableCompositeModification;
  56 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  57 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  58 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  59 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  60 import org.opendaylight.controller.cluster.raft.RaftActor;
  61 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  62 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
  63 import org.opendaylight.controller.cluster.raft.RaftState;
  64 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  65 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  66 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
  67 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationByteStringPayload;
  68 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationPayload;
  69 import org.opendaylight.yangtools.concepts.Identifier;
  70 import org.opendaylight.yangtools.util.StringIdentifier;
  71 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  72 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  73 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  74 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
  75 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  76 import scala.concurrent.duration.Duration;
  77 import scala.concurrent.duration.FiniteDuration;
  78
  79 /**
  80  * A Shard represents a portion of the logical data tree <br/>
  81  * <p>
  82  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
  83  * </p>
  84  */
  85 public class Shard extends RaftActor {
  86
  87     @VisibleForTesting
  88     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
  89         @Override
  90         public String toString() {
  91             return "txCommitTimeoutCheck";
  92         }
  93     };
  94
  95     @VisibleForTesting
  96     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
  97         @Override
  98         public String toString() {
  99             return "getShardMBeanMessage";
 100         }
 101     };
 102
 103     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
 104     public static final String DEFAULT_NAME = "default";
 105
 106     // The state of this Shard
 107     private final ShardDataTree store;
 108
 109     /// The name of this shard
 110     private final String name;
 111
 112     private final ShardStats shardMBean;
 113
 114     private DatastoreContext datastoreContext;
 115
 116     private final ShardCommitCoordinator commitCoordinator;
 117
 118     private long transactionCommitTimeout;
 119
 120     private Cancellable txCommitTimeoutCheckSchedule;
 121
 122     private final Optional<ActorRef> roleChangeNotifier;
 123
 124     private final MessageTracker appendEntriesReplyTracker;
 125
 126     private final ShardTransactionActorFactory transactionActorFactory;
 127
 128     private final ShardSnapshotCohort snapshotCohort;
 129
 130     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 131     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 132
 133
 134     private ShardSnapshot restoreFromSnapshot;
 135
 136     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 137
 138     protected Shard(AbstractBuilder<?, ?> builder) {
 139         super(builder.getId().toString(), builder.getPeerAddresses(),
 140                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 141
 142         this.name = builder.getId().toString();
 143         this.datastoreContext = builder.getDatastoreContext();
 144         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 145
 146         setPersistence(datastoreContext.isPersistent());
 147
 148         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 149
 150         store = new ShardDataTree(builder.getSchemaContext(), builder.getTreeType(),
 151                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher"),
 152                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher"), name);
 153
 154         shardMBean = ShardMBeanFactory.getShardStatsMBean(name.toString(),
 155                 datastoreContext.getDataStoreMXBeanType());
 156         shardMBean.setShard(this);
 157
 158         if (isMetricsCaptureEnabled()) {
 159             getContext().become(new MeteringBehavior(this));
 160         }
 161
 162         commitCoordinator = new ShardCommitCoordinator(store,
 163                 datastoreContext.getShardCommitQueueExpiryTimeoutInMillis(),
 164                 datastoreContext.getShardTransactionCommitQueueCapacity(), LOG, this.name);
 165
 166         setTransactionCommitTimeout();
 167
 168         // create a notifier actor for each cluster member
 169         roleChangeNotifier = createRoleChangeNotifier(name.toString());
 170
 171         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 172                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 173
 174         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 175                 new Dispatchers(context().system().dispatchers()).getDispatcherPath(
 176                         Dispatchers.DispatcherType.Transaction), self(), getContext(), shardMBean);
 177
 178         snapshotCohort = new ShardSnapshotCohort(transactionActorFactory, store, LOG, this.name);
 179
 180         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 181     }
 182
 183     private void setTransactionCommitTimeout() {
 184         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 185                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 186     }
 187
 188     private Optional<ActorRef> createRoleChangeNotifier(String shardId) {
 189         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 190             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 191         return Optional.of(shardRoleChangeNotifier);
 192     }
 193
 194     @Override
 195     public void postStop() {
 196         LOG.info("Stopping Shard {}", persistenceId());
 197
 198         super.postStop();
 199
 200         messageRetrySupport.close();
 201
 202         if(txCommitTimeoutCheckSchedule != null) {
 203             txCommitTimeoutCheckSchedule.cancel();
 204         }
 205
 206         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 207
 208         shardMBean.unregisterMBean();
 209     }
 210
 211     @Override
 212     protected void handleRecover(final Object message) {
 213         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 214             getSender());
 215
 216         super.handleRecover(message);
 217         if (LOG.isTraceEnabled()) {
 218             appendEntriesReplyTracker.begin();
 219         }
 220     }
 221
 222     @Override
 223     protected void handleNonRaftCommand(final Object message) {
 224         try (final MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 225             final Optional<Error> maybeError = context.error();
 226             if (maybeError.isPresent()) {
 227                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 228                     maybeError.get());
 229             }
 230
 231             if (CreateTransaction.isSerializedType(message)) {
 232                 handleCreateTransaction(message);
 233             } else if (message instanceof BatchedModifications) {
 234                 handleBatchedModifications((BatchedModifications)message);
 235             } else if (message instanceof ForwardedReadyTransaction) {
 236                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 237             } else if (message instanceof ReadyLocalTransaction) {
 238                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 239             } else if (CanCommitTransaction.isSerializedType(message)) {
 240                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 241             } else if (CommitTransaction.isSerializedType(message)) {
 242                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 243             } else if (AbortTransaction.isSerializedType(message)) {
 244                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 245             } else if (CloseTransactionChain.isSerializedType(message)) {
 246                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 247             } else if (message instanceof RegisterChangeListener) {
 248                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 249             } else if (message instanceof RegisterDataTreeChangeListener) {
 250                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 251             } else if (message instanceof UpdateSchemaContext) {
 252                 updateSchemaContext((UpdateSchemaContext) message);
 253             } else if (message instanceof PeerAddressResolved) {
 254                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 255                 setPeerAddress(resolved.getPeerId().toString(),
 256                         resolved.getPeerAddress());
 257             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 258                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 259             } else if(message instanceof DatastoreContext) {
 260                 onDatastoreContext((DatastoreContext)message);
 261             } else if(message instanceof RegisterRoleChangeListener){
 262                 roleChangeNotifier.get().forward(message, context());
 263             } else if (message instanceof FollowerInitialSyncUpStatus) {
 264                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 265                 context().parent().tell(message, self());
 266             } else if(GET_SHARD_MBEAN_MESSAGE.equals(message)){
 267                 sender().tell(getShardMBean(), self());
 268             } else if(message instanceof GetShardDataTree) {
 269                 sender().tell(store.getDataTree(), self());
 270             } else if(message instanceof ServerRemoved){
 271                 context().parent().forward(message, context());
 272             } else if(ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 273                 messageRetrySupport.onTimerMessage(message);
 274             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 275                 commitCoordinator.processCohortRegistryCommand(getSender(),
 276                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 277             } else {
 278                 super.handleNonRaftCommand(message);
 279             }
 280         }
 281     }
 282
 283     private boolean hasLeader() {
 284         return getLeaderId() != null;
 285     }
 286
 287     public int getPendingTxCommitQueueSize() {
 288         return commitCoordinator.getQueueSize();
 289     }
 290
 291     public int getCohortCacheSize() {
 292         return commitCoordinator.getCohortCacheSize();
 293     }
 294
 295     @Override
 296     protected Optional<ActorRef> getRoleChangeNotifier() {
 297         return roleChangeNotifier;
 298     }
 299
 300     @Override
 301     protected LeaderStateChanged newLeaderStateChanged(String memberId, String leaderId, short leaderPayloadVersion) {
 302         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 303                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 304     }
 305
 306     protected void onDatastoreContext(DatastoreContext context) {
 307         datastoreContext = context;
 308
 309         commitCoordinator.setQueueCapacity(datastoreContext.getShardTransactionCommitQueueCapacity());
 310
 311         setTransactionCommitTimeout();
 312
 313         if(datastoreContext.isPersistent() && !persistence().isRecoveryApplicable()) {
 314             setPersistence(true);
 315         } else if(!datastoreContext.isPersistent() && persistence().isRecoveryApplicable()) {
 316             setPersistence(false);
 317         }
 318
 319         updateConfigParams(datastoreContext.getShardRaftConfig());
 320     }
 321
 322     private static boolean isEmptyCommit(final DataTreeCandidate candidate) {
 323         return ModificationType.UNMODIFIED.equals(candidate.getRootNode().getModificationType());
 324     }
 325
 326     void continueCommit(final CohortEntry cohortEntry) {
 327         final DataTreeCandidate candidate = cohortEntry.getCandidate();
 328
 329         // If we do not have any followers and we are not using persistence
 330         // or if cohortEntry has no modifications
 331         // we can apply modification to the state immediately
 332         if ((!hasFollowers() && !persistence().isRecoveryApplicable()) || isEmptyCommit(candidate)) {
 333             applyModificationToState(cohortEntry.getReplySender(), cohortEntry.getTransactionID(), candidate);
 334         } else {
 335             persistData(cohortEntry.getReplySender(), cohortEntry.getTransactionID(),
 336                     DataTreeCandidatePayload.create(candidate));
 337         }
 338     }
 339
 340     private void handleCommitTransaction(final CommitTransaction commit) {
 341         if (isLeader()) {
 342             if(!commitCoordinator.handleCommit(new StringIdentifier(commit.getTransactionID()), getSender(), this)) {
 343                 shardMBean.incrementFailedTransactionsCount();
 344             }
 345         } else {
 346             ActorSelection leader = getLeader();
 347             if (leader == null) {
 348                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 349                         "Could not commit transaction " + commit.getTransactionID());
 350             } else {
 351                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 352                 leader.forward(commit, getContext());
 353             }
 354         }
 355     }
 356
 357     private void finishCommit(@Nonnull final ActorRef sender, @Nonnull final Identifier transactionID,
 358             @Nonnull final CohortEntry cohortEntry) {
 359         LOG.debug("{}: Finishing commit for transaction {}", persistenceId(), cohortEntry.getTransactionID());
 360
 361         try {
 362             try {
 363             cohortEntry.commit();
 364             } catch(ExecutionException e) {
 365                 // We may get a "store tree and candidate base differ" IllegalStateException from commit under
 366                 // certain edge case scenarios so we'll try to re-apply the candidate from scratch as a last
 367                 // resort. Eg, we're a follower and a tx payload is replicated but the leader goes down before
 368                 // applying it to the state. We then become the leader and a second tx is pre-committed and
 369                 // replicated. When consensus occurs, this will cause the first tx to be applied as a foreign
 370                 // candidate via applyState prior to the second tx. Since the second tx has already been
 371                 // pre-committed, when it gets here to commit it will get an IllegalStateException.
 372
 373                 // FIXME - this is not an ideal way to handle this scenario. This is temporary - a cleaner
 374                 // solution will be forthcoming.
 375                 if(e.getCause() instanceof IllegalStateException) {
 376                     LOG.debug("{}: commit failed for transaction {} - retrying as foreign candidate", persistenceId(),
 377                             transactionID, e);
 378                     store.applyForeignCandidate(transactionID, cohortEntry.getCandidate());
 379                 } else {
 380                     throw e;
 381                 }
 382             }
 383
 384             sender.tell(CommitTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(), getSelf());
 385
 386             shardMBean.incrementCommittedTransactionCount();
 387             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
 388
 389         } catch (Exception e) {
 390             sender.tell(new akka.actor.Status.Failure(e), getSelf());
 391
 392             LOG.error("{}, An exception occurred while committing transaction {}", persistenceId(),
 393                     transactionID, e);
 394             shardMBean.incrementFailedTransactionsCount();
 395         } finally {
 396             commitCoordinator.currentTransactionComplete(transactionID, true);
 397         }
 398     }
 399
 400     private void finishCommit(@Nonnull final ActorRef sender, final @Nonnull Identifier transactionID) {
 401         // With persistence enabled, this method is called via applyState by the leader strategy
 402         // after the commit has been replicated to a majority of the followers.
 403
 404         CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
 405         if (cohortEntry == null) {
 406             // The transaction is no longer the current commit. This can happen if the transaction
 407             // was aborted prior, most likely due to timeout in the front-end. We need to finish
 408             // committing the transaction though since it was successfully persisted and replicated
 409             // however we can't use the original cohort b/c it was already preCommitted and may
 410             // conflict with the current commit or may have been aborted so we commit with a new
 411             // transaction.
 412             cohortEntry = commitCoordinator.getAndRemoveCohortEntry(transactionID);
 413             if(cohortEntry != null) {
 414                 try {
 415                     store.applyForeignCandidate(transactionID, cohortEntry.getCandidate());
 416                 } catch (DataValidationFailedException e) {
 417                     shardMBean.incrementFailedTransactionsCount();
 418                     LOG.error("{}: Failed to re-apply transaction {}", persistenceId(), transactionID, e);
 419                 }
 420
 421                 sender.tell(CommitTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(),
 422                         getSelf());
 423             } else {
 424                 // This really shouldn't happen - it likely means that persistence or replication
 425                 // took so long to complete such that the cohort entry was expired from the cache.
 426                 IllegalStateException ex = new IllegalStateException(
 427                         String.format("%s: Could not finish committing transaction %s - no CohortEntry found",
 428                                 persistenceId(), transactionID));
 429                 LOG.error(ex.getMessage());
 430                 sender.tell(new akka.actor.Status.Failure(ex), getSelf());
 431             }
 432         } else {
 433             finishCommit(sender, transactionID, cohortEntry);
 434         }
 435     }
 436
 437     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 438         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionID());
 439
 440         if (isLeader()) {
 441         commitCoordinator.handleCanCommit(new StringIdentifier(canCommit.getTransactionID()), getSender(), this);
 442         } else {
 443             ActorSelection leader = getLeader();
 444             if (leader == null) {
 445                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 446                         "Could not canCommit transaction " + canCommit.getTransactionID());
 447             } else {
 448                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 449                 leader.forward(canCommit, getContext());
 450             }
 451         }
 452     }
 453
 454     protected void handleBatchedModificationsLocal(BatchedModifications batched, ActorRef sender) {
 455         try {
 456             commitCoordinator.handleBatchedModifications(batched, sender, this, store.getSchemaContext());
 457         } catch (Exception e) {
 458             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 459                     batched.getTransactionID(), e);
 460             sender.tell(new akka.actor.Status.Failure(e), getSelf());
 461         }
 462     }
 463
 464     private void handleBatchedModifications(BatchedModifications batched) {
 465         // This message is sent to prepare the modifications transaction directly on the Shard as an
 466         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 467         // BatchedModifications message, the caller sets the ready flag in the message indicating
 468         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 469         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 470         // ReadyTransaction message.
 471
 472         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 473         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 474         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 475         // window where it could have a stale leader during leadership transitions.
 476         //
 477         boolean isLeaderActive = isLeaderActive();
 478         if (isLeader() && isLeaderActive) {
 479             handleBatchedModificationsLocal(batched, getSender());
 480         } else {
 481             ActorSelection leader = getLeader();
 482             if (!isLeaderActive || leader == null) {
 483                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 484                         "Could not commit transaction " + batched.getTransactionID());
 485             } else {
 486                 // If this is not the first batch and leadership changed in between batched messages,
 487                 // we need to reconstruct previous BatchedModifications from the transaction
 488                 // DataTreeModification, honoring the max batched modification count, and forward all the
 489                 // previous BatchedModifications to the new leader.
 490                 Collection<BatchedModifications> newModifications = commitCoordinator.createForwardedBatchedModifications(
 491                         batched, datastoreContext.getShardBatchedModificationCount());
 492
 493                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 494                         newModifications.size(), leader);
 495
 496                 for(BatchedModifications bm: newModifications) {
 497                     leader.forward(bm, getContext());
 498                 }
 499             }
 500         }
 501     }
 502
 503     private boolean failIfIsolatedLeader(ActorRef sender) {
 504         if(isIsolatedLeader()) {
 505             sender.tell(new akka.actor.Status.Failure(new NoShardLeaderException(String.format(
 506                     "Shard %s was the leader but has lost contact with all of its followers. Either all" +
 507                     " other follower nodes are down or this node is isolated by a network partition.",
 508                     persistenceId()))), getSelf());
 509             return true;
 510         }
 511
 512         return false;
 513     }
 514
 515     protected boolean isIsolatedLeader() {
 516         return getRaftState() == RaftState.IsolatedLeader;
 517     }
 518
 519     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 520         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionID());
 521
 522         boolean isLeaderActive = isLeaderActive();
 523         if (isLeader() && isLeaderActive) {
 524             try {
 525                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this, store.getSchemaContext());
 526             } catch (Exception e) {
 527                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 528                         message.getTransactionID(), e);
 529                 getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 530             }
 531         } else {
 532             ActorSelection leader = getLeader();
 533             if (!isLeaderActive || leader == null) {
 534                 messageRetrySupport.addMessageToRetry(message, getSender(),
 535                         "Could not commit transaction " + message.getTransactionID());
 536             } else {
 537                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 538                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 539                 leader.forward(message, getContext());
 540             }
 541         }
 542     }
 543
 544     private void handleForwardedReadyTransaction(ForwardedReadyTransaction forwardedReady) {
 545         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionID());
 546
 547         boolean isLeaderActive = isLeaderActive();
 548         if (isLeader() && isLeaderActive) {
 549             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this,
 550                     store.getSchemaContext());
 551         } else {
 552             ActorSelection leader = getLeader();
 553             if (!isLeaderActive || leader == null) {
 554                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 555                         "Could not commit transaction " + forwardedReady.getTransactionID());
 556             } else {
 557                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 558
 559                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionID(),
 560                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 561                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 562                 leader.forward(readyLocal, getContext());
 563             }
 564         }
 565     }
 566
 567     private void handleAbortTransaction(final AbortTransaction abort) {
 568         doAbortTransaction(abort.getTransactionID(), getSender());
 569     }
 570
 571     void doAbortTransaction(final String transactionID, final ActorRef sender) {
 572         commitCoordinator.handleAbort(new StringIdentifier(transactionID), sender, this);
 573     }
 574
 575     private void handleCreateTransaction(final Object message) {
 576         if (isLeader()) {
 577             createTransaction(CreateTransaction.fromSerializable(message));
 578         } else if (getLeader() != null) {
 579             getLeader().forward(message, getContext());
 580         } else {
 581             getSender().tell(new akka.actor.Status.Failure(new NoShardLeaderException(
 582                     "Could not create a shard transaction", persistenceId())), getSelf());
 583         }
 584     }
 585
 586     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 587         store.closeTransactionChain(closeTransactionChain.getTransactionChainId());
 588     }
 589
 590     private ActorRef createTypedTransactionActor(int transactionType,
 591             ShardTransactionIdentifier transactionId, String transactionChainId) {
 592
 593         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 594                 transactionId, transactionChainId);
 595     }
 596
 597     private void createTransaction(CreateTransaction createTransaction) {
 598         try {
 599             if(TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY &&
 600                     failIfIsolatedLeader(getSender())) {
 601                 return;
 602             }
 603
 604             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 605                 createTransaction.getTransactionId(), createTransaction.getTransactionChainId());
 606
 607             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 608                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 609         } catch (Exception e) {
 610             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
 611         }
 612     }
 613
 614     private ActorRef createTransaction(int transactionType, String remoteTransactionId,
 615             String transactionChainId) {
 616
 617
 618         ShardTransactionIdentifier transactionId = new ShardTransactionIdentifier(remoteTransactionId);
 619
 620         if(LOG.isDebugEnabled()) {
 621             LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 622         }
 623
 624         ActorRef transactionActor = createTypedTransactionActor(transactionType, transactionId,
 625                 transactionChainId);
 626
 627         return transactionActor;
 628     }
 629
 630     private void commitWithNewTransaction(final Modification modification) {
 631         ReadWriteShardDataTreeTransaction tx = store.newReadWriteTransaction(modification.toString(), null);
 632         modification.apply(tx.getSnapshot());
 633         try {
 634             snapshotCohort.syncCommitTransaction(tx);
 635             shardMBean.incrementCommittedTransactionCount();
 636             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
 637         } catch (Exception e) {
 638             shardMBean.incrementFailedTransactionsCount();
 639             LOG.error("{}: Failed to commit", persistenceId(), e);
 640         }
 641     }
 642
 643     private void updateSchemaContext(final UpdateSchemaContext message) {
 644         updateSchemaContext(message.getSchemaContext());
 645     }
 646
 647     @VisibleForTesting
 648     void updateSchemaContext(final SchemaContext schemaContext) {
 649         store.updateSchemaContext(schemaContext);
 650     }
 651
 652     private boolean isMetricsCaptureEnabled() {
 653         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 654         return config.isMetricCaptureEnabled();
 655     }
 656
 657     @Override
 658     @VisibleForTesting
 659     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 660         return snapshotCohort;
 661     }
 662
 663     @Override
 664     @Nonnull
 665     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 666         return new ShardRecoveryCoordinator(store, store.getSchemaContext(),
 667                 restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 668     }
 669
 670     @Override
 671     protected void onRecoveryComplete() {
 672         restoreFromSnapshot = null;
 673
 674         //notify shard manager
 675         getContext().parent().tell(new ActorInitialized(), getSelf());
 676
 677         // Being paranoid here - this method should only be called once but just in case...
 678         if(txCommitTimeoutCheckSchedule == null) {
 679             // Schedule a message to be periodically sent to check if the current in-progress
 680             // transaction should be expired and aborted.
 681             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 682             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 683                     period, period, getSelf(),
 684                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 685         }
 686     }
 687
 688     @Override
 689     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 690         if (data instanceof DataTreeCandidatePayload) {
 691             if (clientActor == null) {
 692                 // No clientActor indicates a replica coming from the leader
 693                 try {
 694                     store.applyForeignCandidate(identifier, ((DataTreeCandidatePayload)data).getCandidate());
 695                 } catch (DataValidationFailedException | IOException e) {
 696                     LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 697                 }
 698             } else {
 699                 // Replication consensus reached, proceed to commit
 700                 finishCommit(clientActor, identifier);
 701             }
 702         } else if (data instanceof CompositeModificationPayload) {
 703             Object modification = ((CompositeModificationPayload) data).getModification();
 704
 705             applyModificationToState(clientActor, identifier, modification);
 706         } else if(data instanceof CompositeModificationByteStringPayload ){
 707             Object modification = ((CompositeModificationByteStringPayload) data).getModification();
 708
 709             applyModificationToState(clientActor, identifier, modification);
 710         } else {
 711             LOG.error("{}: Unknown state received {} Class loader = {} CompositeNodeMod.ClassLoader = {}",
 712                     persistenceId(), data, data.getClass().getClassLoader(),
 713                     CompositeModificationPayload.class.getClassLoader());
 714         }
 715     }
 716
 717     private void applyModificationToState(ActorRef clientActor, Identifier identifier, Object modification) {
 718         if(modification == null) {
 719             LOG.error(
 720                     "{}: modification is null - this is very unexpected, clientActor = {}, identifier = {}",
 721                     persistenceId(), identifier, clientActor != null ? clientActor.path().toString() : null);
 722         } else if(clientActor == null) {
 723             // There's no clientActor to which to send a commit reply so we must be applying
 724             // replicated state from the leader.
 725             commitWithNewTransaction(MutableCompositeModification.fromSerializable(modification));
 726         } else {
 727             // This must be the OK to commit after replication consensus.
 728             finishCommit(clientActor, identifier);
 729         }
 730     }
 731
 732     @Override
 733     protected void onStateChanged() {
 734         boolean isLeader = isLeader();
 735         boolean hasLeader = hasLeader();
 736         changeSupport.onLeadershipChange(isLeader, hasLeader);
 737         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 738
 739         // If this actor is no longer the leader close all the transaction chains
 740         if (!isLeader) {
 741             if(LOG.isDebugEnabled()) {
 742                 LOG.debug(
 743                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 744                     persistenceId(), getId());
 745             }
 746
 747             store.closeAllTransactionChains();
 748         }
 749
 750         if(hasLeader && !isIsolatedLeader()) {
 751             messageRetrySupport.retryMessages();
 752         }
 753     }
 754
 755     @Override
 756     protected void onLeaderChanged(String oldLeader, String newLeader) {
 757         shardMBean.incrementLeadershipChangeCount();
 758
 759         boolean hasLeader = hasLeader();
 760         if(hasLeader && !isLeader()) {
 761             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 762             // them to transaction messages and send to the new leader.
 763             ActorSelection leader = getLeader();
 764             if(leader != null) {
 765                 Collection<Object> messagesToForward = commitCoordinator.convertPendingTransactionsToMessages(
 766                         datastoreContext.getShardBatchedModificationCount());
 767
 768                 if(!messagesToForward.isEmpty()) {
 769                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 770                             messagesToForward.size(), leader);
 771
 772                     for(Object message: messagesToForward) {
 773                         leader.tell(message, self());
 774                     }
 775                 }
 776             } else {
 777                 commitCoordinator.abortPendingTransactions(
 778                         "The transacton was aborted due to inflight leadership change and the leader address isn't available.",
 779                         this);
 780             }
 781         }
 782
 783         if(hasLeader && !isIsolatedLeader()) {
 784             messageRetrySupport.retryMessages();
 785         }
 786     }
 787
 788     @Override
 789     protected void pauseLeader(Runnable operation) {
 790         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 791         commitCoordinator.setRunOnPendingTransactionsComplete(operation);
 792     }
 793
 794     @Override
 795     public String persistenceId() {
 796         return this.name;
 797     }
 798
 799     @VisibleForTesting
 800     ShardCommitCoordinator getCommitCoordinator() {
 801         return commitCoordinator;
 802     }
 803
 804     public DatastoreContext getDatastoreContext() {
 805         return datastoreContext;
 806     }
 807
 808     @VisibleForTesting
 809     public ShardDataTree getDataStore() {
 810         return store;
 811     }
 812
 813     @VisibleForTesting
 814     ShardStats getShardMBean() {
 815         return shardMBean;
 816     }
 817
 818     public static Builder builder() {
 819         return new Builder();
 820     }
 821
 822     public static abstract class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 823         private final Class<S> shardClass;
 824         private ShardIdentifier id;
 825         private Map<String, String> peerAddresses = Collections.emptyMap();
 826         private DatastoreContext datastoreContext;
 827         private SchemaContext schemaContext;
 828         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 829         private volatile boolean sealed;
 830
 831         protected AbstractBuilder(Class<S> shardClass) {
 832             this.shardClass = shardClass;
 833         }
 834
 835         protected void checkSealed() {
 836             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 837         }
 838
 839         @SuppressWarnings("unchecked")
 840         private T self() {
 841             return (T) this;
 842         }
 843
 844         public T id(ShardIdentifier id) {
 845             checkSealed();
 846             this.id = id;
 847             return self();
 848         }
 849
 850         public T peerAddresses(Map<String, String> peerAddresses) {
 851             checkSealed();
 852             this.peerAddresses = peerAddresses;
 853             return self();
 854         }
 855
 856         public T datastoreContext(DatastoreContext datastoreContext) {
 857             checkSealed();
 858             this.datastoreContext = datastoreContext;
 859             return self();
 860         }
 861
 862         public T schemaContext(SchemaContext schemaContext) {
 863             checkSealed();
 864             this.schemaContext = schemaContext;
 865             return self();
 866         }
 867
 868         public T restoreFromSnapshot(DatastoreSnapshot.ShardSnapshot restoreFromSnapshot) {
 869             checkSealed();
 870             this.restoreFromSnapshot = restoreFromSnapshot;
 871             return self();
 872         }
 873
 874         public ShardIdentifier getId() {
 875             return id;
 876         }
 877
 878         public Map<String, String> getPeerAddresses() {
 879             return peerAddresses;
 880         }
 881
 882         public DatastoreContext getDatastoreContext() {
 883             return datastoreContext;
 884         }
 885
 886         public SchemaContext getSchemaContext() {
 887             return schemaContext;
 888         }
 889
 890         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
 891             return restoreFromSnapshot;
 892         }
 893
 894         public TreeType getTreeType() {
 895             switch (datastoreContext.getLogicalStoreType()) {
 896             case CONFIGURATION:
 897                 return TreeType.CONFIGURATION;
 898             case OPERATIONAL:
 899                 return TreeType.OPERATIONAL;
 900             }
 901
 902             throw new IllegalStateException("Unhandled logical store type " + datastoreContext.getLogicalStoreType());
 903         }
 904
 905         protected void verify() {
 906             Preconditions.checkNotNull(id, "id should not be null");
 907             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
 908             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
 909             Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
 910         }
 911
 912         public Props props() {
 913             sealed = true;
 914             verify();
 915             return Props.create(shardClass, this);
 916         }
 917     }
 918
 919     public static class Builder extends AbstractBuilder<Builder, Shard> {
 920         private Builder() {
 921             super(Shard.class);
 922         }
 923     }
 924 }