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.actor.Status.Failure;
  16 import akka.serialization.Serialization;
  17 import com.google.common.annotations.VisibleForTesting;
  18 import com.google.common.base.Optional;
  19 import com.google.common.base.Preconditions;
  20 import com.google.common.base.Ticker;
  21 import com.google.common.collect.ImmutableList;
  22 import com.google.common.collect.Range;
  23 import java.io.IOException;
  24 import java.util.Arrays;
  25 import java.util.Collection;
  26 import java.util.Collections;
  27 import java.util.HashMap;
  28 import java.util.Map;
  29 import java.util.concurrent.TimeUnit;
  30 import javax.annotation.Nonnull;
  31 import javax.annotation.Nullable;
  32 import org.opendaylight.controller.cluster.access.ABIVersion;
  33 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  34 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  35 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
  36 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
  37 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  38 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  39 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
  40 import org.opendaylight.controller.cluster.access.concepts.Request;
  41 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  42 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  43 import org.opendaylight.controller.cluster.access.concepts.RequestSuccess;
  44 import org.opendaylight.controller.cluster.access.concepts.RetiredGenerationException;
  45 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
  46 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  47 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  48 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  49 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  50 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
  51 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  52 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  53 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  54 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  55 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  56 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  57 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  58 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  59 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  60 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  61 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  62 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  63 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  64 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot;
  65 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot.ShardSnapshot;
  66 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  67 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  68 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  69 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  70 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  71 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  72 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  73 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  74 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  75 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  76 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  77 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  78 import org.opendaylight.controller.cluster.raft.RaftActor;
  79 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  80 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
  81 import org.opendaylight.controller.cluster.raft.RaftState;
  82 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  83 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  84 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
  85 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  86 import org.opendaylight.yangtools.concepts.Identifier;
  87 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  88 import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree;
  89 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
  90 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  91 import scala.concurrent.duration.Duration;
  92 import scala.concurrent.duration.FiniteDuration;
  93
  94 /**
  95  * A Shard represents a portion of the logical data tree.
  96  *
  97  * <p>
  98  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
  99  */
 100 public class Shard extends RaftActor {
 101
 102     @VisibleForTesting
 103     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
 104         @Override
 105         public String toString() {
 106             return "txCommitTimeoutCheck";
 107         }
 108     };
 109
 110     @VisibleForTesting
 111     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
 112         @Override
 113         public String toString() {
 114             return "getShardMBeanMessage";
 115         }
 116     };
 117
 118     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
 119     public static final String DEFAULT_NAME = "default";
 120
 121     private static final Collection<ABIVersion> SUPPORTED_ABIVERSIONS;
 122
 123     static {
 124         final ABIVersion[] values = ABIVersion.values();
 125         final ABIVersion[] real = Arrays.copyOfRange(values, 1, values.length - 1);
 126         SUPPORTED_ABIVERSIONS = ImmutableList.copyOf(real).reverse();
 127     }
 128
 129     // FIXME: make this a dynamic property based on mailbox size and maximum number of clients
 130     private static final int CLIENT_MAX_MESSAGES = 1000;
 131
 132     // The state of this Shard
 133     private final ShardDataTree store;
 134
 135     /// The name of this shard
 136     private final String name;
 137
 138     private final ShardStats shardMBean;
 139
 140     private DatastoreContext datastoreContext;
 141
 142     private final ShardCommitCoordinator commitCoordinator;
 143
 144     private long transactionCommitTimeout;
 145
 146     private Cancellable txCommitTimeoutCheckSchedule;
 147
 148     private final Optional<ActorRef> roleChangeNotifier;
 149
 150     private final MessageTracker appendEntriesReplyTracker;
 151
 152     private final ShardTransactionActorFactory transactionActorFactory;
 153
 154     private final ShardSnapshotCohort snapshotCohort;
 155
 156     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 157     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 158
 159
 160     private ShardSnapshot restoreFromSnapshot;
 161
 162     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 163
 164     private final FrontendMetadata frontendMetadata = new FrontendMetadata();
 165     private final Map<FrontendIdentifier, LeaderFrontendState> knownFrontends = new HashMap<>();
 166
 167     protected Shard(final AbstractBuilder<?, ?> builder) {
 168         super(builder.getId().toString(), builder.getPeerAddresses(),
 169                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 170
 171         this.name = builder.getId().toString();
 172         this.datastoreContext = builder.getDatastoreContext();
 173         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 174
 175         setPersistence(datastoreContext.isPersistent());
 176
 177         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 178
 179         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 180                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher");
 181         ShardDataChangeListenerPublisherActorProxy dataChangeListenerPublisher =
 182                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher");
 183         if (builder.getDataTree() != null) {
 184             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 185                     treeChangeListenerPublisher, dataChangeListenerPublisher, name);
 186         } else {
 187             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 188                     treeChangeListenerPublisher, dataChangeListenerPublisher, name);
 189         }
 190
 191         shardMBean = ShardMBeanFactory.getShardStatsMBean(name, datastoreContext.getDataStoreMXBeanType(), this);
 192
 193         if (isMetricsCaptureEnabled()) {
 194             getContext().become(new MeteringBehavior(this));
 195         }
 196
 197         commitCoordinator = new ShardCommitCoordinator(store, LOG, this.name);
 198
 199         setTransactionCommitTimeout();
 200
 201         // create a notifier actor for each cluster member
 202         roleChangeNotifier = createRoleChangeNotifier(name);
 203
 204         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 205                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 206
 207         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 208                 new Dispatchers(context().system().dispatchers()).getDispatcherPath(
 209                         Dispatchers.DispatcherType.Transaction), self(), getContext(), shardMBean);
 210
 211         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 212             this.name);
 213
 214         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 215     }
 216
 217     private void setTransactionCommitTimeout() {
 218         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 219                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 220     }
 221
 222     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 223         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 224             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 225         return Optional.of(shardRoleChangeNotifier);
 226     }
 227
 228     @Override
 229     public void postStop() {
 230         LOG.info("Stopping Shard {}", persistenceId());
 231
 232         super.postStop();
 233
 234         messageRetrySupport.close();
 235
 236         if (txCommitTimeoutCheckSchedule != null) {
 237             txCommitTimeoutCheckSchedule.cancel();
 238         }
 239
 240         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 241
 242         shardMBean.unregisterMBean();
 243     }
 244
 245     @Override
 246     protected void handleRecover(final Object message) {
 247         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 248             getSender());
 249
 250         super.handleRecover(message);
 251         if (LOG.isTraceEnabled()) {
 252             appendEntriesReplyTracker.begin();
 253         }
 254     }
 255
 256     @SuppressWarnings("checkstyle:IllegalCatch")
 257     @Override
 258     protected void handleNonRaftCommand(final Object message) {
 259         try (final MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 260             final Optional<Error> maybeError = context.error();
 261             if (maybeError.isPresent()) {
 262                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 263                     maybeError.get());
 264             }
 265
 266             if (message instanceof RequestEnvelope) {
 267                 final RequestEnvelope envelope = (RequestEnvelope)message;
 268                 try {
 269                     final RequestSuccess<?, ?> success = handleRequest(envelope);
 270                     if (success != null) {
 271                         envelope.sendSuccess(success);
 272                     }
 273                 } catch (RequestException e) {
 274                     LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
 275                     envelope.sendFailure(e);
 276                 } catch (Exception e) {
 277                     LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
 278                     envelope.sendFailure(new RuntimeRequestException("Request failed to process", e));
 279                 }
 280             } else if (message instanceof ConnectClientRequest) {
 281                 handleConnectClient((ConnectClientRequest)message);
 282             } else if (CreateTransaction.isSerializedType(message)) {
 283                 handleCreateTransaction(message);
 284             } else if (message instanceof BatchedModifications) {
 285                 handleBatchedModifications((BatchedModifications)message);
 286             } else if (message instanceof ForwardedReadyTransaction) {
 287                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 288             } else if (message instanceof ReadyLocalTransaction) {
 289                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 290             } else if (CanCommitTransaction.isSerializedType(message)) {
 291                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 292             } else if (CommitTransaction.isSerializedType(message)) {
 293                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 294             } else if (AbortTransaction.isSerializedType(message)) {
 295                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 296             } else if (CloseTransactionChain.isSerializedType(message)) {
 297                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 298             } else if (message instanceof RegisterChangeListener) {
 299                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 300             } else if (message instanceof RegisterDataTreeChangeListener) {
 301                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 302             } else if (message instanceof UpdateSchemaContext) {
 303                 updateSchemaContext((UpdateSchemaContext) message);
 304             } else if (message instanceof PeerAddressResolved) {
 305                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 306                 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
 307             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 308                 store.checkForExpiredTransactions(transactionCommitTimeout);
 309                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 310             } else if (message instanceof DatastoreContext) {
 311                 onDatastoreContext((DatastoreContext)message);
 312             } else if (message instanceof RegisterRoleChangeListener) {
 313                 roleChangeNotifier.get().forward(message, context());
 314             } else if (message instanceof FollowerInitialSyncUpStatus) {
 315                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 316                 context().parent().tell(message, self());
 317             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 318                 sender().tell(getShardMBean(), self());
 319             } else if (message instanceof GetShardDataTree) {
 320                 sender().tell(store.getDataTree(), self());
 321             } else if (message instanceof ServerRemoved) {
 322                 context().parent().forward(message, context());
 323             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 324                 messageRetrySupport.onTimerMessage(message);
 325             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 326                 store.processCohortRegistryCommand(getSender(),
 327                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 328             } else {
 329                 super.handleNonRaftCommand(message);
 330             }
 331         }
 332     }
 333
 334     // Acquire our frontend tracking handle and verify generation matches
 335     private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
 336         final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
 337         if (existing != null) {
 338             final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
 339             if (cmp == 0) {
 340                 return existing;
 341             }
 342             if (cmp > 0) {
 343                 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
 344                 throw new RetiredGenerationException(existing.getIdentifier().getGeneration());
 345             }
 346
 347             LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
 348             existing.retire();
 349             knownFrontends.remove(clientId.getFrontendId());
 350         } else {
 351             LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
 352         }
 353
 354         final LeaderFrontendState ret = new LeaderFrontendState(persistenceId(), clientId, store);
 355         knownFrontends.put(clientId.getFrontendId(), ret);
 356         LOG.debug("{}: created state {} for client {}", persistenceId(), ret, clientId);
 357         return ret;
 358     }
 359
 360     private static @Nonnull ABIVersion selectVersion(final ConnectClientRequest message) {
 361         final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
 362         for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
 363             if (clientRange.contains(v)) {
 364                 return v;
 365             }
 366         }
 367
 368         throw new IllegalArgumentException(String.format(
 369             "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
 370             clientRange));
 371     }
 372
 373     @SuppressWarnings("checkstyle:IllegalCatch")
 374     private void handleConnectClient(final ConnectClientRequest message) {
 375         try {
 376             if (!isLeader() || !isLeaderActive()) {
 377                 LOG.debug("{}: not currently leader, rejecting request {}", persistenceId(), message);
 378                 throw new NotLeaderException(getSelf());
 379             }
 380
 381             final ABIVersion selectedVersion = selectVersion(message);
 382             final LeaderFrontendState frontend = getFrontend(message.getTarget());
 383             frontend.reconnect();
 384             message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
 385                 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
 386                 ActorRef.noSender());
 387         } catch (RequestException | RuntimeException e) {
 388             message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
 389         }
 390     }
 391
 392     private @Nullable RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope) throws RequestException {
 393         // We are not the leader, hence we want to fail-fast.
 394         if (!isLeader() || !isLeaderActive()) {
 395             LOG.debug("{}: not currently leader, rejecting request {}", persistenceId(), envelope);
 396             throw new NotLeaderException(getSelf());
 397         }
 398
 399         final Request<?, ?> request = envelope.getMessage();
 400         if (request instanceof TransactionRequest) {
 401             final TransactionRequest<?> txReq = (TransactionRequest<?>)request;
 402             final ClientIdentifier clientId = txReq.getTarget().getHistoryId().getClientId();
 403             return getFrontend(clientId).handleTransactionRequest(txReq, envelope);
 404         } else if (request instanceof LocalHistoryRequest) {
 405             final LocalHistoryRequest<?> lhReq = (LocalHistoryRequest<?>)request;
 406             final ClientIdentifier clientId = lhReq.getTarget().getClientId();
 407             return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope);
 408         } else {
 409             LOG.debug("{}: rejecting unsupported request {}", persistenceId(), request);
 410             throw new UnsupportedRequestException(request);
 411         }
 412     }
 413
 414     private boolean hasLeader() {
 415         return getLeaderId() != null;
 416     }
 417
 418     public int getPendingTxCommitQueueSize() {
 419         return store.getQueueSize();
 420     }
 421
 422     public int getCohortCacheSize() {
 423         return commitCoordinator.getCohortCacheSize();
 424     }
 425
 426     @Override
 427     protected Optional<ActorRef> getRoleChangeNotifier() {
 428         return roleChangeNotifier;
 429     }
 430
 431     @Override
 432     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 433             final short leaderPayloadVersion) {
 434         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 435                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 436     }
 437
 438     protected void onDatastoreContext(final DatastoreContext context) {
 439         datastoreContext = context;
 440
 441         setTransactionCommitTimeout();
 442
 443         setPersistence(datastoreContext.isPersistent());
 444
 445         updateConfigParams(datastoreContext.getShardRaftConfig());
 446     }
 447
 448     boolean canSkipPayload() {
 449         // If we do not have any followers and we are not using persistence we can apply modification to the state
 450         // immediately
 451         return !hasFollowers() && !persistence().isRecoveryApplicable();
 452     }
 453
 454     // applyState() will be invoked once consensus is reached on the payload
 455     void persistPayload(final TransactionIdentifier transactionId, final Payload payload) {
 456         // We are faking the sender
 457         persistData(self(), transactionId, payload);
 458     }
 459
 460     private void handleCommitTransaction(final CommitTransaction commit) {
 461         if (isLeader()) {
 462             commitCoordinator.handleCommit(commit.getTransactionId(), getSender(), this);
 463         } else {
 464             ActorSelection leader = getLeader();
 465             if (leader == null) {
 466                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 467                         "Could not commit transaction " + commit.getTransactionId());
 468             } else {
 469                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 470                 leader.forward(commit, getContext());
 471             }
 472         }
 473     }
 474
 475     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 476         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionId());
 477
 478         if (isLeader()) {
 479             commitCoordinator.handleCanCommit(canCommit.getTransactionId(), getSender(), this);
 480         } else {
 481             ActorSelection leader = getLeader();
 482             if (leader == null) {
 483                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 484                         "Could not canCommit transaction " + canCommit.getTransactionId());
 485             } else {
 486                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 487                 leader.forward(canCommit, getContext());
 488             }
 489         }
 490     }
 491
 492     @SuppressWarnings("checkstyle:IllegalCatch")
 493     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 494         try {
 495             commitCoordinator.handleBatchedModifications(batched, sender, this);
 496         } catch (Exception e) {
 497             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 498                     batched.getTransactionId(), e);
 499             sender.tell(new Failure(e), getSelf());
 500         }
 501     }
 502
 503     private void handleBatchedModifications(final BatchedModifications batched) {
 504         // This message is sent to prepare the modifications transaction directly on the Shard as an
 505         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 506         // BatchedModifications message, the caller sets the ready flag in the message indicating
 507         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 508         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 509         // ReadyTransaction message.
 510
 511         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 512         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 513         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 514         // window where it could have a stale leader during leadership transitions.
 515         //
 516         boolean isLeaderActive = isLeaderActive();
 517         if (isLeader() && isLeaderActive) {
 518             handleBatchedModificationsLocal(batched, getSender());
 519         } else {
 520             ActorSelection leader = getLeader();
 521             if (!isLeaderActive || leader == null) {
 522                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 523                         "Could not commit transaction " + batched.getTransactionId());
 524             } else {
 525                 // If this is not the first batch and leadership changed in between batched messages,
 526                 // we need to reconstruct previous BatchedModifications from the transaction
 527                 // DataTreeModification, honoring the max batched modification count, and forward all the
 528                 // previous BatchedModifications to the new leader.
 529                 Collection<BatchedModifications> newModifications = commitCoordinator
 530                         .createForwardedBatchedModifications(batched,
 531                                 datastoreContext.getShardBatchedModificationCount());
 532
 533                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 534                         newModifications.size(), leader);
 535
 536                 for (BatchedModifications bm : newModifications) {
 537                     leader.forward(bm, getContext());
 538                 }
 539             }
 540         }
 541     }
 542
 543     private boolean failIfIsolatedLeader(final ActorRef sender) {
 544         if (isIsolatedLeader()) {
 545             sender.tell(new Failure(new NoShardLeaderException(String.format(
 546                     "Shard %s was the leader but has lost contact with all of its followers. Either all"
 547                     + " other follower nodes are down or this node is isolated by a network partition.",
 548                     persistenceId()))), getSelf());
 549             return true;
 550         }
 551
 552         return false;
 553     }
 554
 555     protected boolean isIsolatedLeader() {
 556         return getRaftState() == RaftState.IsolatedLeader;
 557     }
 558
 559     @SuppressWarnings("checkstyle:IllegalCatch")
 560     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 561         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionId());
 562
 563         boolean isLeaderActive = isLeaderActive();
 564         if (isLeader() && isLeaderActive) {
 565             try {
 566                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 567             } catch (Exception e) {
 568                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 569                         message.getTransactionId(), e);
 570                 getSender().tell(new Failure(e), getSelf());
 571             }
 572         } else {
 573             ActorSelection leader = getLeader();
 574             if (!isLeaderActive || leader == null) {
 575                 messageRetrySupport.addMessageToRetry(message, getSender(),
 576                         "Could not commit transaction " + message.getTransactionId());
 577             } else {
 578                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 579                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 580                 leader.forward(message, getContext());
 581             }
 582         }
 583     }
 584
 585     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 586         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
 587
 588         boolean isLeaderActive = isLeaderActive();
 589         if (isLeader() && isLeaderActive) {
 590             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 591         } else {
 592             ActorSelection leader = getLeader();
 593             if (!isLeaderActive || leader == null) {
 594                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 595                         "Could not commit transaction " + forwardedReady.getTransactionId());
 596             } else {
 597                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 598
 599                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
 600                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 601                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 602                 leader.forward(readyLocal, getContext());
 603             }
 604         }
 605     }
 606
 607     private void handleAbortTransaction(final AbortTransaction abort) {
 608         doAbortTransaction(abort.getTransactionId(), getSender());
 609     }
 610
 611     void doAbortTransaction(final TransactionIdentifier transactionID, final ActorRef sender) {
 612         commitCoordinator.handleAbort(transactionID, sender, this);
 613     }
 614
 615     private void handleCreateTransaction(final Object message) {
 616         if (isLeader()) {
 617             createTransaction(CreateTransaction.fromSerializable(message));
 618         } else if (getLeader() != null) {
 619             getLeader().forward(message, getContext());
 620         } else {
 621             getSender().tell(new Failure(new NoShardLeaderException(
 622                     "Could not create a shard transaction", persistenceId())), getSelf());
 623         }
 624     }
 625
 626     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 627         store.closeTransactionChain(closeTransactionChain.getIdentifier());
 628     }
 629
 630     @SuppressWarnings("checkstyle:IllegalCatch")
 631     private void createTransaction(final CreateTransaction createTransaction) {
 632         try {
 633             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 634                     && failIfIsolatedLeader(getSender())) {
 635                 return;
 636             }
 637
 638             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 639                 createTransaction.getTransactionId());
 640
 641             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 642                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 643         } catch (Exception e) {
 644             getSender().tell(new Failure(e), getSelf());
 645         }
 646     }
 647
 648     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 649         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 650         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 651             transactionId);
 652     }
 653
 654     private void updateSchemaContext(final UpdateSchemaContext message) {
 655         updateSchemaContext(message.getSchemaContext());
 656     }
 657
 658     @VisibleForTesting
 659     void updateSchemaContext(final SchemaContext schemaContext) {
 660         store.updateSchemaContext(schemaContext);
 661     }
 662
 663     private boolean isMetricsCaptureEnabled() {
 664         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 665         return config.isMetricCaptureEnabled();
 666     }
 667
 668     @Override
 669     @VisibleForTesting
 670     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 671         return snapshotCohort;
 672     }
 673
 674     @Override
 675     @Nonnull
 676     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 677         return new ShardRecoveryCoordinator(store,
 678             restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 679     }
 680
 681     @Override
 682     protected void onRecoveryComplete() {
 683         restoreFromSnapshot = null;
 684
 685         //notify shard manager
 686         getContext().parent().tell(new ActorInitialized(), getSelf());
 687
 688         // Being paranoid here - this method should only be called once but just in case...
 689         if (txCommitTimeoutCheckSchedule == null) {
 690             // Schedule a message to be periodically sent to check if the current in-progress
 691             // transaction should be expired and aborted.
 692             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 693             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 694                     period, period, getSelf(),
 695                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 696         }
 697     }
 698
 699     @Override
 700     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 701         if (data instanceof Payload) {
 702             try {
 703                 store.applyReplicatedPayload(identifier, (Payload)data);
 704             } catch (DataValidationFailedException | IOException e) {
 705                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 706             }
 707         } else {
 708             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 709         }
 710     }
 711
 712     @Override
 713     protected void onStateChanged() {
 714         boolean isLeader = isLeader();
 715         boolean hasLeader = hasLeader();
 716         changeSupport.onLeadershipChange(isLeader, hasLeader);
 717         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 718
 719         // If this actor is no longer the leader close all the transaction chains
 720         if (!isLeader) {
 721             if (LOG.isDebugEnabled()) {
 722                 LOG.debug(
 723                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 724                     persistenceId(), getId());
 725             }
 726
 727             store.closeAllTransactionChains();
 728         }
 729
 730         if (hasLeader && !isIsolatedLeader()) {
 731             messageRetrySupport.retryMessages();
 732         }
 733     }
 734
 735     @Override
 736     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 737         shardMBean.incrementLeadershipChangeCount();
 738
 739         boolean hasLeader = hasLeader();
 740         if (hasLeader && !isLeader()) {
 741             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 742             // them to transaction messages and send to the new leader.
 743             ActorSelection leader = getLeader();
 744             if (leader != null) {
 745                 Collection<?> messagesToForward = convertPendingTransactionsToMessages();
 746
 747                 if (!messagesToForward.isEmpty()) {
 748                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 749                             messagesToForward.size(), leader);
 750
 751                     for (Object message : messagesToForward) {
 752                         leader.tell(message, self());
 753                     }
 754                 }
 755             } else {
 756                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
 757                         + "change and the leader address isn't available.", this);
 758             }
 759         }
 760
 761         if (hasLeader && !isIsolatedLeader()) {
 762             messageRetrySupport.retryMessages();
 763         }
 764     }
 765
 766     /**
 767      * Clears all pending transactions and converts them to messages to be forwarded to a new leader.
 768      *
 769      * @return the converted messages
 770      */
 771     public Collection<?> convertPendingTransactionsToMessages() {
 772         return commitCoordinator.convertPendingTransactionsToMessages(
 773                 datastoreContext.getShardBatchedModificationCount());
 774     }
 775
 776     @Override
 777     protected void pauseLeader(final Runnable operation) {
 778         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 779         store.setRunOnPendingTransactionsComplete(operation);
 780     }
 781
 782     @Override
 783     public String persistenceId() {
 784         return this.name;
 785     }
 786
 787     @VisibleForTesting
 788     ShardCommitCoordinator getCommitCoordinator() {
 789         return commitCoordinator;
 790     }
 791
 792     public DatastoreContext getDatastoreContext() {
 793         return datastoreContext;
 794     }
 795
 796     @VisibleForTesting
 797     public ShardDataTree getDataStore() {
 798         return store;
 799     }
 800
 801     @VisibleForTesting
 802     ShardStats getShardMBean() {
 803         return shardMBean;
 804     }
 805
 806     public static Builder builder() {
 807         return new Builder();
 808     }
 809
 810     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 811         private final Class<S> shardClass;
 812         private ShardIdentifier id;
 813         private Map<String, String> peerAddresses = Collections.emptyMap();
 814         private DatastoreContext datastoreContext;
 815         private SchemaContext schemaContext;
 816         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 817         private TipProducingDataTree dataTree;
 818         private volatile boolean sealed;
 819
 820         protected AbstractBuilder(final Class<S> shardClass) {
 821             this.shardClass = shardClass;
 822         }
 823
 824         protected void checkSealed() {
 825             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 826         }
 827
 828         @SuppressWarnings("unchecked")
 829         private T self() {
 830             return (T) this;
 831         }
 832
 833         public T id(final ShardIdentifier newId) {
 834             checkSealed();
 835             this.id = newId;
 836             return self();
 837         }
 838
 839         public T peerAddresses(final Map<String, String> newPeerAddresses) {
 840             checkSealed();
 841             this.peerAddresses = newPeerAddresses;
 842             return self();
 843         }
 844
 845         public T datastoreContext(final DatastoreContext newDatastoreContext) {
 846             checkSealed();
 847             this.datastoreContext = newDatastoreContext;
 848             return self();
 849         }
 850
 851         public T schemaContext(final SchemaContext newSchemaContext) {
 852             checkSealed();
 853             this.schemaContext = newSchemaContext;
 854             return self();
 855         }
 856
 857         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
 858             checkSealed();
 859             this.restoreFromSnapshot = newRestoreFromSnapshot;
 860             return self();
 861         }
 862
 863         public T dataTree(final TipProducingDataTree newDataTree) {
 864             checkSealed();
 865             this.dataTree = newDataTree;
 866             return self();
 867         }
 868
 869         public ShardIdentifier getId() {
 870             return id;
 871         }
 872
 873         public Map<String, String> getPeerAddresses() {
 874             return peerAddresses;
 875         }
 876
 877         public DatastoreContext getDatastoreContext() {
 878             return datastoreContext;
 879         }
 880
 881         public SchemaContext getSchemaContext() {
 882             return schemaContext;
 883         }
 884
 885         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
 886             return restoreFromSnapshot;
 887         }
 888
 889         public TipProducingDataTree getDataTree() {
 890             return dataTree;
 891         }
 892
 893         public TreeType getTreeType() {
 894             switch (datastoreContext.getLogicalStoreType()) {
 895                 case CONFIGURATION:
 896                     return TreeType.CONFIGURATION;
 897                 case OPERATIONAL:
 898                     return TreeType.OPERATIONAL;
 899                 default:
 900                     throw new IllegalStateException("Unhandled logical store type "
 901                             + datastoreContext.getLogicalStoreType());
 902             }
 903         }
 904
 905         protected void verify() {
 906             Preconditions.checkNotNull(id, "id should not be null");
 907             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
 908             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
 909             Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
 910         }
 911
 912         public Props props() {
 913             sealed = true;
 914             verify();
 915             return Props.create(shardClass, this);
 916         }
 917     }
 918
 919     public static class Builder extends AbstractBuilder<Builder, Shard> {
 920         private Builder() {
 921             super(Shard.class);
 922         }
 923     }
 924
 925     Ticker ticker() {
 926         return Ticker.systemTicker();
 927     }
 928 }