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