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 long now = ticker().read();
 268                 final RequestEnvelope envelope = (RequestEnvelope)message;
 269
 270                 try {
 271                     final RequestSuccess<?, ?> success = handleRequest(envelope, now);
 272                     if (success != null) {
 273                         envelope.sendSuccess(success, ticker().read() - now);
 274                     }
 275                 } catch (RequestException e) {
 276                     LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
 277                     envelope.sendFailure(e, ticker().read() - now);
 278                 } catch (Exception e) {
 279                     LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
 280                     envelope.sendFailure(new RuntimeRequestException("Request failed to process", e),
 281                         ticker().read() - now);
 282                 }
 283             } else if (message instanceof ConnectClientRequest) {
 284                 handleConnectClient((ConnectClientRequest)message);
 285             } else if (CreateTransaction.isSerializedType(message)) {
 286                 handleCreateTransaction(message);
 287             } else if (message instanceof BatchedModifications) {
 288                 handleBatchedModifications((BatchedModifications)message);
 289             } else if (message instanceof ForwardedReadyTransaction) {
 290                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 291             } else if (message instanceof ReadyLocalTransaction) {
 292                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 293             } else if (CanCommitTransaction.isSerializedType(message)) {
 294                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 295             } else if (CommitTransaction.isSerializedType(message)) {
 296                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 297             } else if (AbortTransaction.isSerializedType(message)) {
 298                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 299             } else if (CloseTransactionChain.isSerializedType(message)) {
 300                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 301             } else if (message instanceof RegisterChangeListener) {
 302                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 303             } else if (message instanceof RegisterDataTreeChangeListener) {
 304                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 305             } else if (message instanceof UpdateSchemaContext) {
 306                 updateSchemaContext((UpdateSchemaContext) message);
 307             } else if (message instanceof PeerAddressResolved) {
 308                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 309                 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
 310             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 311                 store.checkForExpiredTransactions(transactionCommitTimeout);
 312                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 313             } else if (message instanceof DatastoreContext) {
 314                 onDatastoreContext((DatastoreContext)message);
 315             } else if (message instanceof RegisterRoleChangeListener) {
 316                 roleChangeNotifier.get().forward(message, context());
 317             } else if (message instanceof FollowerInitialSyncUpStatus) {
 318                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 319                 context().parent().tell(message, self());
 320             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 321                 sender().tell(getShardMBean(), self());
 322             } else if (message instanceof GetShardDataTree) {
 323                 sender().tell(store.getDataTree(), self());
 324             } else if (message instanceof ServerRemoved) {
 325                 context().parent().forward(message, context());
 326             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 327                 messageRetrySupport.onTimerMessage(message);
 328             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 329                 store.processCohortRegistryCommand(getSender(),
 330                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 331             } else {
 332                 super.handleNonRaftCommand(message);
 333             }
 334         }
 335     }
 336
 337     // Acquire our frontend tracking handle and verify generation matches
 338     private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
 339         final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
 340         if (existing != null) {
 341             final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
 342             if (cmp == 0) {
 343                 return existing;
 344             }
 345             if (cmp > 0) {
 346                 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
 347                 throw new RetiredGenerationException(existing.getIdentifier().getGeneration());
 348             }
 349
 350             LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
 351             existing.retire();
 352             knownFrontends.remove(clientId.getFrontendId());
 353         } else {
 354             LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
 355         }
 356
 357         final LeaderFrontendState ret = new LeaderFrontendState(persistenceId(), clientId, store);
 358         knownFrontends.put(clientId.getFrontendId(), ret);
 359         LOG.debug("{}: created state {} for client {}", persistenceId(), ret, clientId);
 360         return ret;
 361     }
 362
 363     private static @Nonnull ABIVersion selectVersion(final ConnectClientRequest message) {
 364         final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
 365         for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
 366             if (clientRange.contains(v)) {
 367                 return v;
 368             }
 369         }
 370
 371         throw new IllegalArgumentException(String.format(
 372             "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
 373             clientRange));
 374     }
 375
 376     @SuppressWarnings("checkstyle:IllegalCatch")
 377     private void handleConnectClient(final ConnectClientRequest message) {
 378         try {
 379             if (!isLeader() || !isLeaderActive()) {
 380                 LOG.debug("{}: not currently leader, rejecting request {}", persistenceId(), message);
 381                 throw new NotLeaderException(getSelf());
 382             }
 383
 384             final ABIVersion selectedVersion = selectVersion(message);
 385             final LeaderFrontendState frontend = getFrontend(message.getTarget());
 386             frontend.reconnect();
 387             message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
 388                 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
 389                 ActorRef.noSender());
 390         } catch (RequestException | RuntimeException e) {
 391             message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
 392         }
 393     }
 394
 395     private @Nullable RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope, final long now)
 396             throws RequestException {
 397         // We are not the leader, hence we want to fail-fast.
 398         if (!isLeader() || !isLeaderActive()) {
 399             LOG.debug("{}: not currently leader, rejecting request {}", persistenceId(), envelope);
 400             throw new NotLeaderException(getSelf());
 401         }
 402
 403         final Request<?, ?> request = envelope.getMessage();
 404         if (request instanceof TransactionRequest) {
 405             final TransactionRequest<?> txReq = (TransactionRequest<?>)request;
 406             final ClientIdentifier clientId = txReq.getTarget().getHistoryId().getClientId();
 407             return getFrontend(clientId).handleTransactionRequest(txReq, envelope, now);
 408         } else if (request instanceof LocalHistoryRequest) {
 409             final LocalHistoryRequest<?> lhReq = (LocalHistoryRequest<?>)request;
 410             final ClientIdentifier clientId = lhReq.getTarget().getClientId();
 411             return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope, now);
 412         } else {
 413             LOG.debug("{}: rejecting unsupported request {}", persistenceId(), request);
 414             throw new UnsupportedRequestException(request);
 415         }
 416     }
 417
 418     private boolean hasLeader() {
 419         return getLeaderId() != null;
 420     }
 421
 422     public int getPendingTxCommitQueueSize() {
 423         return store.getQueueSize();
 424     }
 425
 426     public int getCohortCacheSize() {
 427         return commitCoordinator.getCohortCacheSize();
 428     }
 429
 430     @Override
 431     protected Optional<ActorRef> getRoleChangeNotifier() {
 432         return roleChangeNotifier;
 433     }
 434
 435     @Override
 436     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 437             final short leaderPayloadVersion) {
 438         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 439                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 440     }
 441
 442     protected void onDatastoreContext(final DatastoreContext context) {
 443         datastoreContext = context;
 444
 445         setTransactionCommitTimeout();
 446
 447         setPersistence(datastoreContext.isPersistent());
 448
 449         updateConfigParams(datastoreContext.getShardRaftConfig());
 450     }
 451
 452     boolean canSkipPayload() {
 453         // If we do not have any followers and we are not using persistence we can apply modification to the state
 454         // immediately
 455         return !hasFollowers() && !persistence().isRecoveryApplicable();
 456     }
 457
 458     // applyState() will be invoked once consensus is reached on the payload
 459     void persistPayload(final TransactionIdentifier transactionId, final Payload payload) {
 460         // We are faking the sender
 461         persistData(self(), transactionId, payload);
 462     }
 463
 464     private void handleCommitTransaction(final CommitTransaction commit) {
 465         if (isLeader()) {
 466             commitCoordinator.handleCommit(commit.getTransactionId(), getSender(), this);
 467         } else {
 468             ActorSelection leader = getLeader();
 469             if (leader == null) {
 470                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 471                         "Could not commit transaction " + commit.getTransactionId());
 472             } else {
 473                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 474                 leader.forward(commit, getContext());
 475             }
 476         }
 477     }
 478
 479     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 480         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionId());
 481
 482         if (isLeader()) {
 483             commitCoordinator.handleCanCommit(canCommit.getTransactionId(), getSender(), this);
 484         } else {
 485             ActorSelection leader = getLeader();
 486             if (leader == null) {
 487                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 488                         "Could not canCommit transaction " + canCommit.getTransactionId());
 489             } else {
 490                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 491                 leader.forward(canCommit, getContext());
 492             }
 493         }
 494     }
 495
 496     @SuppressWarnings("checkstyle:IllegalCatch")
 497     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 498         try {
 499             commitCoordinator.handleBatchedModifications(batched, sender, this);
 500         } catch (Exception e) {
 501             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 502                     batched.getTransactionId(), e);
 503             sender.tell(new Failure(e), getSelf());
 504         }
 505     }
 506
 507     private void handleBatchedModifications(final BatchedModifications batched) {
 508         // This message is sent to prepare the modifications transaction directly on the Shard as an
 509         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 510         // BatchedModifications message, the caller sets the ready flag in the message indicating
 511         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 512         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 513         // ReadyTransaction message.
 514
 515         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 516         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 517         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 518         // window where it could have a stale leader during leadership transitions.
 519         //
 520         boolean isLeaderActive = isLeaderActive();
 521         if (isLeader() && isLeaderActive) {
 522             handleBatchedModificationsLocal(batched, getSender());
 523         } else {
 524             ActorSelection leader = getLeader();
 525             if (!isLeaderActive || leader == null) {
 526                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 527                         "Could not commit transaction " + batched.getTransactionId());
 528             } else {
 529                 // If this is not the first batch and leadership changed in between batched messages,
 530                 // we need to reconstruct previous BatchedModifications from the transaction
 531                 // DataTreeModification, honoring the max batched modification count, and forward all the
 532                 // previous BatchedModifications to the new leader.
 533                 Collection<BatchedModifications> newModifications = commitCoordinator
 534                         .createForwardedBatchedModifications(batched,
 535                                 datastoreContext.getShardBatchedModificationCount());
 536
 537                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 538                         newModifications.size(), leader);
 539
 540                 for (BatchedModifications bm : newModifications) {
 541                     leader.forward(bm, getContext());
 542                 }
 543             }
 544         }
 545     }
 546
 547     private boolean failIfIsolatedLeader(final ActorRef sender) {
 548         if (isIsolatedLeader()) {
 549             sender.tell(new Failure(new NoShardLeaderException(String.format(
 550                     "Shard %s was the leader but has lost contact with all of its followers. Either all"
 551                     + " other follower nodes are down or this node is isolated by a network partition.",
 552                     persistenceId()))), getSelf());
 553             return true;
 554         }
 555
 556         return false;
 557     }
 558
 559     protected boolean isIsolatedLeader() {
 560         return getRaftState() == RaftState.IsolatedLeader;
 561     }
 562
 563     @SuppressWarnings("checkstyle:IllegalCatch")
 564     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 565         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionId());
 566
 567         boolean isLeaderActive = isLeaderActive();
 568         if (isLeader() && isLeaderActive) {
 569             try {
 570                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 571             } catch (Exception e) {
 572                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 573                         message.getTransactionId(), e);
 574                 getSender().tell(new Failure(e), getSelf());
 575             }
 576         } else {
 577             ActorSelection leader = getLeader();
 578             if (!isLeaderActive || leader == null) {
 579                 messageRetrySupport.addMessageToRetry(message, getSender(),
 580                         "Could not commit transaction " + message.getTransactionId());
 581             } else {
 582                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 583                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 584                 leader.forward(message, getContext());
 585             }
 586         }
 587     }
 588
 589     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 590         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
 591
 592         boolean isLeaderActive = isLeaderActive();
 593         if (isLeader() && isLeaderActive) {
 594             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 595         } else {
 596             ActorSelection leader = getLeader();
 597             if (!isLeaderActive || leader == null) {
 598                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 599                         "Could not commit transaction " + forwardedReady.getTransactionId());
 600             } else {
 601                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 602
 603                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
 604                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 605                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 606                 leader.forward(readyLocal, getContext());
 607             }
 608         }
 609     }
 610
 611     private void handleAbortTransaction(final AbortTransaction abort) {
 612         doAbortTransaction(abort.getTransactionId(), getSender());
 613     }
 614
 615     void doAbortTransaction(final TransactionIdentifier transactionID, final ActorRef sender) {
 616         commitCoordinator.handleAbort(transactionID, sender, this);
 617     }
 618
 619     private void handleCreateTransaction(final Object message) {
 620         if (isLeader()) {
 621             createTransaction(CreateTransaction.fromSerializable(message));
 622         } else if (getLeader() != null) {
 623             getLeader().forward(message, getContext());
 624         } else {
 625             getSender().tell(new Failure(new NoShardLeaderException(
 626                     "Could not create a shard transaction", persistenceId())), getSelf());
 627         }
 628     }
 629
 630     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 631         store.closeTransactionChain(closeTransactionChain.getIdentifier());
 632     }
 633
 634     @SuppressWarnings("checkstyle:IllegalCatch")
 635     private void createTransaction(final CreateTransaction createTransaction) {
 636         try {
 637             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 638                     && failIfIsolatedLeader(getSender())) {
 639                 return;
 640             }
 641
 642             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 643                 createTransaction.getTransactionId());
 644
 645             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 646                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 647         } catch (Exception e) {
 648             getSender().tell(new Failure(e), getSelf());
 649         }
 650     }
 651
 652     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 653         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 654         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 655             transactionId);
 656     }
 657
 658     private void updateSchemaContext(final UpdateSchemaContext message) {
 659         updateSchemaContext(message.getSchemaContext());
 660     }
 661
 662     @VisibleForTesting
 663     void updateSchemaContext(final SchemaContext schemaContext) {
 664         store.updateSchemaContext(schemaContext);
 665     }
 666
 667     private boolean isMetricsCaptureEnabled() {
 668         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 669         return config.isMetricCaptureEnabled();
 670     }
 671
 672     @Override
 673     @VisibleForTesting
 674     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 675         return snapshotCohort;
 676     }
 677
 678     @Override
 679     @Nonnull
 680     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 681         return new ShardRecoveryCoordinator(store,
 682             restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 683     }
 684
 685     @Override
 686     protected void onRecoveryComplete() {
 687         restoreFromSnapshot = null;
 688
 689         //notify shard manager
 690         getContext().parent().tell(new ActorInitialized(), getSelf());
 691
 692         // Being paranoid here - this method should only be called once but just in case...
 693         if (txCommitTimeoutCheckSchedule == null) {
 694             // Schedule a message to be periodically sent to check if the current in-progress
 695             // transaction should be expired and aborted.
 696             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 697             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 698                     period, period, getSelf(),
 699                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 700         }
 701     }
 702
 703     @Override
 704     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 705         if (data instanceof Payload) {
 706             try {
 707                 store.applyReplicatedPayload(identifier, (Payload)data);
 708             } catch (DataValidationFailedException | IOException e) {
 709                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 710             }
 711         } else {
 712             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 713         }
 714     }
 715
 716     @Override
 717     protected void onStateChanged() {
 718         boolean isLeader = isLeader();
 719         boolean hasLeader = hasLeader();
 720         changeSupport.onLeadershipChange(isLeader, hasLeader);
 721         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 722
 723         // If this actor is no longer the leader close all the transaction chains
 724         if (!isLeader) {
 725             if (LOG.isDebugEnabled()) {
 726                 LOG.debug(
 727                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 728                     persistenceId(), getId());
 729             }
 730
 731             store.closeAllTransactionChains();
 732         }
 733
 734         if (hasLeader && !isIsolatedLeader()) {
 735             messageRetrySupport.retryMessages();
 736         }
 737     }
 738
 739     @Override
 740     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 741         shardMBean.incrementLeadershipChangeCount();
 742
 743         boolean hasLeader = hasLeader();
 744         if (hasLeader && !isLeader()) {
 745             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 746             // them to transaction messages and send to the new leader.
 747             ActorSelection leader = getLeader();
 748             if (leader != null) {
 749                 Collection<?> messagesToForward = convertPendingTransactionsToMessages();
 750
 751                 if (!messagesToForward.isEmpty()) {
 752                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 753                             messagesToForward.size(), leader);
 754
 755                     for (Object message : messagesToForward) {
 756                         leader.tell(message, self());
 757                     }
 758                 }
 759             } else {
 760                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
 761                         + "change and the leader address isn't available.", this);
 762             }
 763         }
 764
 765         if (hasLeader && !isIsolatedLeader()) {
 766             messageRetrySupport.retryMessages();
 767         }
 768     }
 769
 770     /**
 771      * Clears all pending transactions and converts them to messages to be forwarded to a new leader.
 772      *
 773      * @return the converted messages
 774      */
 775     public Collection<?> convertPendingTransactionsToMessages() {
 776         return commitCoordinator.convertPendingTransactionsToMessages(
 777                 datastoreContext.getShardBatchedModificationCount());
 778     }
 779
 780     @Override
 781     protected void pauseLeader(final Runnable operation) {
 782         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 783         store.setRunOnPendingTransactionsComplete(operation);
 784     }
 785
 786     @Override
 787     public String persistenceId() {
 788         return this.name;
 789     }
 790
 791     @VisibleForTesting
 792     ShardCommitCoordinator getCommitCoordinator() {
 793         return commitCoordinator;
 794     }
 795
 796     public DatastoreContext getDatastoreContext() {
 797         return datastoreContext;
 798     }
 799
 800     @VisibleForTesting
 801     public ShardDataTree getDataStore() {
 802         return store;
 803     }
 804
 805     @VisibleForTesting
 806     ShardStats getShardMBean() {
 807         return shardMBean;
 808     }
 809
 810     public static Builder builder() {
 811         return new Builder();
 812     }
 813
 814     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 815         private final Class<S> shardClass;
 816         private ShardIdentifier id;
 817         private Map<String, String> peerAddresses = Collections.emptyMap();
 818         private DatastoreContext datastoreContext;
 819         private SchemaContext schemaContext;
 820         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 821         private TipProducingDataTree dataTree;
 822         private volatile boolean sealed;
 823
 824         protected AbstractBuilder(final 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(final ShardIdentifier newId) {
 838             checkSealed();
 839             this.id = newId;
 840             return self();
 841         }
 842
 843         public T peerAddresses(final Map<String, String> newPeerAddresses) {
 844             checkSealed();
 845             this.peerAddresses = newPeerAddresses;
 846             return self();
 847         }
 848
 849         public T datastoreContext(final DatastoreContext newDatastoreContext) {
 850             checkSealed();
 851             this.datastoreContext = newDatastoreContext;
 852             return self();
 853         }
 854
 855         public T schemaContext(final SchemaContext newSchemaContext) {
 856             checkSealed();
 857             this.schemaContext = newSchemaContext;
 858             return self();
 859         }
 860
 861         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
 862             checkSealed();
 863             this.restoreFromSnapshot = newRestoreFromSnapshot;
 864             return self();
 865         }
 866
 867         public T dataTree(final TipProducingDataTree newDataTree) {
 868             checkSealed();
 869             this.dataTree = newDataTree;
 870             return self();
 871         }
 872
 873         public ShardIdentifier getId() {
 874             return id;
 875         }
 876
 877         public Map<String, String> getPeerAddresses() {
 878             return peerAddresses;
 879         }
 880
 881         public DatastoreContext getDatastoreContext() {
 882             return datastoreContext;
 883         }
 884
 885         public SchemaContext getSchemaContext() {
 886             return schemaContext;
 887         }
 888
 889         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
 890             return restoreFromSnapshot;
 891         }
 892
 893         public TipProducingDataTree getDataTree() {
 894             return dataTree;
 895         }
 896
 897         public TreeType getTreeType() {
 898             switch (datastoreContext.getLogicalStoreType()) {
 899                 case CONFIGURATION:
 900                     return TreeType.CONFIGURATION;
 901                 case OPERATIONAL:
 902                     return TreeType.OPERATIONAL;
 903                 default:
 904                     throw new IllegalStateException("Unhandled logical store type "
 905                             + datastoreContext.getLogicalStoreType());
 906             }
 907         }
 908
 909         protected void verify() {
 910             Preconditions.checkNotNull(id, "id should not be null");
 911             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
 912             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
 913             Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
 914         }
 915
 916         public Props props() {
 917             sealed = true;
 918             verify();
 919             return Props.create(shardClass, this);
 920         }
 921     }
 922
 923     public static class Builder extends AbstractBuilder<Builder, Shard> {
 924         private Builder() {
 925             super(Shard.class);
 926         }
 927     }
 928
 929     Ticker ticker() {
 930         return Ticker.systemTicker();
 931     }
 932 }