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