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;
  16 import akka.actor.Status.Failure;
  17 import akka.serialization.Serialization;
  18 import com.google.common.annotations.VisibleForTesting;
  19 import com.google.common.base.Optional;
  20 import com.google.common.base.Preconditions;
  21 import com.google.common.base.Ticker;
  22 import com.google.common.base.Verify;
  23 import com.google.common.collect.ImmutableList;
  24 import com.google.common.collect.ImmutableMap;
  25 import com.google.common.collect.Range;
  26 import java.io.IOException;
  27 import java.util.Arrays;
  28 import java.util.Collection;
  29 import java.util.Collections;
  30 import java.util.Map;
  31 import java.util.concurrent.TimeUnit;
  32 import javax.annotation.Nonnull;
  33 import javax.annotation.Nullable;
  34 import org.opendaylight.controller.cluster.access.ABIVersion;
  35 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  36 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  37 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
  38 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
  39 import org.opendaylight.controller.cluster.access.commands.OutOfSequenceEnvelopeException;
  40 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  41 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  42 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
  43 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  44 import org.opendaylight.controller.cluster.access.concepts.Request;
  45 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  46 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  47 import org.opendaylight.controller.cluster.access.concepts.RequestSuccess;
  48 import org.opendaylight.controller.cluster.access.concepts.RetiredGenerationException;
  49 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
  50 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  51 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  52 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  53 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  54 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
  55 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  56 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  57 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  58 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  59 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  60 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  61 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  62 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  63 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  64 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  65 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  66 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  67 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  68 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  69 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  70 import org.opendaylight.controller.cluster.datastore.messages.MakeLeaderLocal;
  71 import org.opendaylight.controller.cluster.datastore.messages.OnDemandShardState;
  72 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  73 import org.opendaylight.controller.cluster.datastore.messages.PersistAbortTransactionPayload;
  74 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  75 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  76 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  77 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  78 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  79 import org.opendaylight.controller.cluster.datastore.persisted.AbortTransactionPayload;
  80 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot;
  81 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot.ShardSnapshot;
  82 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  83 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  84 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  85 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  86 import org.opendaylight.controller.cluster.raft.LeadershipTransferFailedException;
  87 import org.opendaylight.controller.cluster.raft.RaftActor;
  88 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  89 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
  90 import org.opendaylight.controller.cluster.raft.RaftState;
  91 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  92 import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
  93 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  94 import org.opendaylight.controller.cluster.raft.messages.RequestLeadership;
  95 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
  96 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  97 import org.opendaylight.yangtools.concepts.Identifier;
  98 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  99 import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree;
 100 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
 101 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 102 import org.opendaylight.yangtools.yang.model.api.SchemaContextProvider;
 103 import scala.concurrent.duration.Duration;
 104 import scala.concurrent.duration.FiniteDuration;
 105
 106 /**
 107  * A Shard represents a portion of the logical data tree.
 108  *
 109  * <p>
 110  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
 111  */
 112 public class Shard extends RaftActor {
 113
 114     @VisibleForTesting
 115     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
 116         @Override
 117         public String toString() {
 118             return "txCommitTimeoutCheck";
 119         }
 120     };
 121
 122     @VisibleForTesting
 123     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
 124         @Override
 125         public String toString() {
 126             return "getShardMBeanMessage";
 127         }
 128     };
 129
 130     static final Object RESUME_NEXT_PENDING_TRANSACTION = new Object() {
 131         @Override
 132         public String toString() {
 133             return "resumeNextPendingTransaction";
 134         }
 135     };
 136
 137     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
 138     public static final String DEFAULT_NAME = "default";
 139
 140     private static final Collection<ABIVersion> SUPPORTED_ABIVERSIONS;
 141
 142     static {
 143         final ABIVersion[] values = ABIVersion.values();
 144         final ABIVersion[] real = Arrays.copyOfRange(values, 1, values.length - 1);
 145         SUPPORTED_ABIVERSIONS = ImmutableList.copyOf(real).reverse();
 146     }
 147
 148     // FIXME: make this a dynamic property based on mailbox size and maximum number of clients
 149     private static final int CLIENT_MAX_MESSAGES = 1000;
 150
 151     // The state of this Shard
 152     private final ShardDataTree store;
 153
 154     /// The name of this shard
 155     private final String name;
 156
 157     private final ShardStats shardMBean;
 158
 159     private DatastoreContext datastoreContext;
 160
 161     private final ShardCommitCoordinator commitCoordinator;
 162
 163     private long transactionCommitTimeout;
 164
 165     private Cancellable txCommitTimeoutCheckSchedule;
 166
 167     private final Optional<ActorRef> roleChangeNotifier;
 168
 169     private final MessageTracker appendEntriesReplyTracker;
 170
 171     private final ShardTransactionActorFactory transactionActorFactory;
 172
 173     private final ShardSnapshotCohort snapshotCohort;
 174
 175     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 176     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 177
 178
 179     private ShardSnapshot restoreFromSnapshot;
 180
 181     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 182
 183     private final FrontendMetadata frontendMetadata;
 184     private Map<FrontendIdentifier, LeaderFrontendState> knownFrontends = ImmutableMap.of();
 185     private boolean paused;
 186
 187     protected Shard(final AbstractBuilder<?, ?> builder) {
 188         super(builder.getId().toString(), builder.getPeerAddresses(),
 189                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 190
 191         this.name = builder.getId().toString();
 192         this.datastoreContext = builder.getDatastoreContext();
 193         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 194         this.frontendMetadata = new FrontendMetadata(name);
 195
 196         setPersistence(datastoreContext.isPersistent());
 197
 198         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 199
 200         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 201                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher", name);
 202         ShardDataChangeListenerPublisherActorProxy dataChangeListenerPublisher =
 203                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher", name);
 204         if (builder.getDataTree() != null) {
 205             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 206                     treeChangeListenerPublisher, dataChangeListenerPublisher, name, frontendMetadata);
 207         } else {
 208             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 209                     builder.getDatastoreContext().getStoreRoot(), treeChangeListenerPublisher,
 210                     dataChangeListenerPublisher, name, frontendMetadata);
 211         }
 212
 213         shardMBean = ShardMBeanFactory.getShardStatsMBean(name, datastoreContext.getDataStoreMXBeanType(), this);
 214
 215         if (isMetricsCaptureEnabled()) {
 216             getContext().become(new MeteringBehavior(this));
 217         }
 218
 219         commitCoordinator = new ShardCommitCoordinator(store, LOG, this.name);
 220
 221         setTransactionCommitTimeout();
 222
 223         // create a notifier actor for each cluster member
 224         roleChangeNotifier = createRoleChangeNotifier(name);
 225
 226         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 227                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 228
 229         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 230             new Dispatchers(context().system().dispatchers()).getDispatcherPath(Dispatchers.DispatcherType.Transaction),
 231                 self(), getContext(), shardMBean, builder.getId().getShardName());
 232
 233         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 234             this.name);
 235
 236         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 237     }
 238
 239     private void setTransactionCommitTimeout() {
 240         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 241                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 242     }
 243
 244     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 245         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 246             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 247         return Optional.of(shardRoleChangeNotifier);
 248     }
 249
 250     @Override
 251     public void postStop() {
 252         LOG.info("Stopping Shard {}", persistenceId());
 253
 254         super.postStop();
 255
 256         messageRetrySupport.close();
 257
 258         if (txCommitTimeoutCheckSchedule != null) {
 259             txCommitTimeoutCheckSchedule.cancel();
 260         }
 261
 262         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 263
 264         shardMBean.unregisterMBean();
 265     }
 266
 267     @Override
 268     protected void handleRecover(final Object message) {
 269         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 270             getSender());
 271
 272         super.handleRecover(message);
 273         if (LOG.isTraceEnabled()) {
 274             appendEntriesReplyTracker.begin();
 275         }
 276     }
 277
 278     @SuppressWarnings("checkstyle:IllegalCatch")
 279     @Override
 280     protected void handleNonRaftCommand(final Object message) {
 281         try (MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 282             final Optional<Error> maybeError = context.error();
 283             if (maybeError.isPresent()) {
 284                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 285                     maybeError.get());
 286             }
 287
 288             store.resetTransactionBatch();
 289
 290             if (message instanceof RequestEnvelope) {
 291                 final long now = ticker().read();
 292                 final RequestEnvelope envelope = (RequestEnvelope)message;
 293
 294                 try {
 295                     final RequestSuccess<?, ?> success = handleRequest(envelope, now);
 296                     if (success != null) {
 297                         envelope.sendSuccess(success, ticker().read() - now);
 298                     }
 299                 } catch (RequestException e) {
 300                     LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
 301                     envelope.sendFailure(e, ticker().read() - now);
 302                 } catch (Exception e) {
 303                     LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
 304                     envelope.sendFailure(new RuntimeRequestException("Request failed to process", e),
 305                         ticker().read() - now);
 306                 }
 307             } else if (message instanceof ConnectClientRequest) {
 308                 handleConnectClient((ConnectClientRequest)message);
 309             } else if (CreateTransaction.isSerializedType(message)) {
 310                 handleCreateTransaction(message);
 311             } else if (message instanceof BatchedModifications) {
 312                 handleBatchedModifications((BatchedModifications)message);
 313             } else if (message instanceof ForwardedReadyTransaction) {
 314                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 315             } else if (message instanceof ReadyLocalTransaction) {
 316                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 317             } else if (CanCommitTransaction.isSerializedType(message)) {
 318                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 319             } else if (CommitTransaction.isSerializedType(message)) {
 320                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 321             } else if (AbortTransaction.isSerializedType(message)) {
 322                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 323             } else if (CloseTransactionChain.isSerializedType(message)) {
 324                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 325             } else if (message instanceof RegisterChangeListener) {
 326                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 327             } else if (message instanceof RegisterDataTreeChangeListener) {
 328                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 329             } else if (message instanceof UpdateSchemaContext) {
 330                 updateSchemaContext((UpdateSchemaContext) message);
 331             } else if (message instanceof PeerAddressResolved) {
 332                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 333                 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
 334             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 335                 store.checkForExpiredTransactions(transactionCommitTimeout);
 336                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 337             } else if (message instanceof DatastoreContext) {
 338                 onDatastoreContext((DatastoreContext)message);
 339             } else if (message instanceof RegisterRoleChangeListener) {
 340                 roleChangeNotifier.get().forward(message, context());
 341             } else if (message instanceof FollowerInitialSyncUpStatus) {
 342                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 343                 context().parent().tell(message, self());
 344             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 345                 sender().tell(getShardMBean(), self());
 346             } else if (message instanceof GetShardDataTree) {
 347                 sender().tell(store.getDataTree(), self());
 348             } else if (message instanceof ServerRemoved) {
 349                 context().parent().forward(message, context());
 350             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 351                 messageRetrySupport.onTimerMessage(message);
 352             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 353                 store.processCohortRegistryCommand(getSender(),
 354                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 355             } else if (message instanceof PersistAbortTransactionPayload) {
 356                 final TransactionIdentifier txId = ((PersistAbortTransactionPayload) message).getTransactionId();
 357                 persistPayload(txId, AbortTransactionPayload.create(txId), true);
 358             } else if (message instanceof MakeLeaderLocal) {
 359                 onMakeLeaderLocal();
 360             } else if (RESUME_NEXT_PENDING_TRANSACTION.equals(message)) {
 361                 store.resumeNextPendingTransaction();
 362             } else {
 363                 super.handleNonRaftCommand(message);
 364             }
 365         }
 366     }
 367
 368     private void onMakeLeaderLocal() {
 369         LOG.debug("{}: onMakeLeaderLocal received", persistenceId());
 370         if (isLeader()) {
 371             getSender().tell(new Status.Success(null), getSelf());
 372             return;
 373         }
 374
 375         final ActorSelection leader = getLeader();
 376
 377         if (leader == null) {
 378             // Leader is not present. The cluster is most likely trying to
 379             // elect a leader and we should let that run its normal course
 380
 381             // TODO we can wait for the election to complete and retry the
 382             // request. We can also let the caller retry by sending a flag
 383             // in the response indicating the request is "reTryable".
 384             getSender().tell(new Failure(
 385                     new LeadershipTransferFailedException("We cannot initiate leadership transfer to local node. "
 386                             + "Currently there is no leader for " + persistenceId())),
 387                     getSelf());
 388             return;
 389         }
 390
 391         leader.tell(new RequestLeadership(getId(), getSender()), getSelf());
 392     }
 393
 394     // Acquire our frontend tracking handle and verify generation matches
 395     @Nullable
 396     private LeaderFrontendState findFrontend(final ClientIdentifier clientId) throws RequestException {
 397         final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
 398         if (existing != null) {
 399             final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
 400             if (cmp == 0) {
 401                 existing.touch();
 402                 return existing;
 403             }
 404             if (cmp > 0) {
 405                 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
 406                 throw new RetiredGenerationException(existing.getIdentifier().getGeneration());
 407             }
 408
 409             LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
 410             existing.retire();
 411             knownFrontends.remove(clientId.getFrontendId());
 412         } else {
 413             LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
 414         }
 415
 416         return null;
 417     }
 418
 419     private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
 420         final LeaderFrontendState ret = findFrontend(clientId);
 421         if (ret != null) {
 422             return ret;
 423         }
 424
 425         // TODO: a dedicated exception would be better, but this is technically true, too
 426         throw new OutOfSequenceEnvelopeException(0);
 427     }
 428
 429     private static @Nonnull ABIVersion selectVersion(final ConnectClientRequest message) {
 430         final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
 431         for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
 432             if (clientRange.contains(v)) {
 433                 return v;
 434             }
 435         }
 436
 437         throw new IllegalArgumentException(String.format(
 438             "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
 439             clientRange));
 440     }
 441
 442     @SuppressWarnings("checkstyle:IllegalCatch")
 443     private void handleConnectClient(final ConnectClientRequest message) {
 444         try {
 445             final ClientIdentifier clientId = message.getTarget();
 446             final LeaderFrontendState existing = findFrontend(clientId);
 447             if (existing != null) {
 448                 existing.touch();
 449             }
 450
 451             if (!isLeader() || !isLeaderActive()) {
 452                 LOG.info("{}: not currently leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 453                                 + "isLeadershipTransferInProgress: {}.",
 454                         persistenceId(), message, isLeader(), isLeaderActive(), isLeadershipTransferInProgress());
 455                 throw new NotLeaderException(getSelf());
 456             }
 457
 458             final ABIVersion selectedVersion = selectVersion(message);
 459             final LeaderFrontendState frontend;
 460             if (existing == null) {
 461                 frontend = new LeaderFrontendState(persistenceId(), clientId, store);
 462                 knownFrontends.put(clientId.getFrontendId(), frontend);
 463                 LOG.debug("{}: created state {} for client {}", persistenceId(), frontend, clientId);
 464             } else {
 465                 frontend = existing;
 466             }
 467
 468             frontend.reconnect();
 469             message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
 470                 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
 471                 ActorRef.noSender());
 472         } catch (RequestException | RuntimeException e) {
 473             message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
 474         }
 475     }
 476
 477     private @Nullable RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope, final long now)
 478             throws RequestException {
 479         // We are not the leader, hence we want to fail-fast.
 480         if (!isLeader() || paused || !isLeaderActive()) {
 481             LOG.debug("{}: not currently active leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 482                             + "isLeadershipTransferInProgress: {}, paused: {}",
 483                     persistenceId(), envelope, isLeader(), isLeaderActive(), isLeadershipTransferInProgress(), paused);
 484             throw new NotLeaderException(getSelf());
 485         }
 486
 487         final Request<?, ?> request = envelope.getMessage();
 488         if (request instanceof TransactionRequest) {
 489             final TransactionRequest<?> txReq = (TransactionRequest<?>)request;
 490             final ClientIdentifier clientId = txReq.getTarget().getHistoryId().getClientId();
 491             return getFrontend(clientId).handleTransactionRequest(txReq, envelope, now);
 492         } else if (request instanceof LocalHistoryRequest) {
 493             final LocalHistoryRequest<?> lhReq = (LocalHistoryRequest<?>)request;
 494             final ClientIdentifier clientId = lhReq.getTarget().getClientId();
 495             return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope, now);
 496         } else {
 497             LOG.warn("{}: rejecting unsupported request {}", persistenceId(), request);
 498             throw new UnsupportedRequestException(request);
 499         }
 500     }
 501
 502     private boolean hasLeader() {
 503         return getLeaderId() != null;
 504     }
 505
 506     public int getPendingTxCommitQueueSize() {
 507         return store.getQueueSize();
 508     }
 509
 510     public int getCohortCacheSize() {
 511         return commitCoordinator.getCohortCacheSize();
 512     }
 513
 514     @Override
 515     protected Optional<ActorRef> getRoleChangeNotifier() {
 516         return roleChangeNotifier;
 517     }
 518
 519     @Override
 520     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 521             final short leaderPayloadVersion) {
 522         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 523                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 524     }
 525
 526     protected void onDatastoreContext(final DatastoreContext context) {
 527         datastoreContext = context;
 528
 529         setTransactionCommitTimeout();
 530
 531         setPersistence(datastoreContext.isPersistent());
 532
 533         updateConfigParams(datastoreContext.getShardRaftConfig());
 534     }
 535
 536     // applyState() will be invoked once consensus is reached on the payload
 537     void persistPayload(final Identifier id, final Payload payload, final boolean batchHint) {
 538         boolean canSkipPayload = !hasFollowers() && !persistence().isRecoveryApplicable();
 539         if (canSkipPayload) {
 540             applyState(self(), id, payload);
 541         } else {
 542             // We are faking the sender
 543             persistData(self(), id, payload, batchHint);
 544         }
 545     }
 546
 547     private void handleCommitTransaction(final CommitTransaction commit) {
 548         if (isLeader()) {
 549             commitCoordinator.handleCommit(commit.getTransactionId(), getSender(), this);
 550         } else {
 551             ActorSelection leader = getLeader();
 552             if (leader == null) {
 553                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 554                         "Could not commit transaction " + commit.getTransactionId());
 555             } else {
 556                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 557                 leader.forward(commit, getContext());
 558             }
 559         }
 560     }
 561
 562     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 563         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionId());
 564
 565         if (isLeader()) {
 566             commitCoordinator.handleCanCommit(canCommit.getTransactionId(), getSender(), this);
 567         } else {
 568             ActorSelection leader = getLeader();
 569             if (leader == null) {
 570                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 571                         "Could not canCommit transaction " + canCommit.getTransactionId());
 572             } else {
 573                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 574                 leader.forward(canCommit, getContext());
 575             }
 576         }
 577     }
 578
 579     @SuppressWarnings("checkstyle:IllegalCatch")
 580     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 581         try {
 582             commitCoordinator.handleBatchedModifications(batched, sender, this);
 583         } catch (Exception e) {
 584             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 585                     batched.getTransactionId(), e);
 586             sender.tell(new Failure(e), getSelf());
 587         }
 588     }
 589
 590     private void handleBatchedModifications(final BatchedModifications batched) {
 591         // This message is sent to prepare the modifications transaction directly on the Shard as an
 592         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 593         // BatchedModifications message, the caller sets the ready flag in the message indicating
 594         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 595         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 596         // ReadyTransaction message.
 597
 598         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 599         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 600         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 601         // window where it could have a stale leader during leadership transitions.
 602         //
 603         boolean isLeaderActive = isLeaderActive();
 604         if (isLeader() && isLeaderActive) {
 605             handleBatchedModificationsLocal(batched, getSender());
 606         } else {
 607             ActorSelection leader = getLeader();
 608             if (!isLeaderActive || leader == null) {
 609                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 610                         "Could not commit transaction " + batched.getTransactionId());
 611             } else {
 612                 // If this is not the first batch and leadership changed in between batched messages,
 613                 // we need to reconstruct previous BatchedModifications from the transaction
 614                 // DataTreeModification, honoring the max batched modification count, and forward all the
 615                 // previous BatchedModifications to the new leader.
 616                 Collection<BatchedModifications> newModifications = commitCoordinator
 617                         .createForwardedBatchedModifications(batched,
 618                                 datastoreContext.getShardBatchedModificationCount());
 619
 620                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 621                         newModifications.size(), leader);
 622
 623                 for (BatchedModifications bm : newModifications) {
 624                     leader.forward(bm, getContext());
 625                 }
 626             }
 627         }
 628     }
 629
 630     private boolean failIfIsolatedLeader(final ActorRef sender) {
 631         if (isIsolatedLeader()) {
 632             sender.tell(new Failure(new NoShardLeaderException(String.format(
 633                     "Shard %s was the leader but has lost contact with all of its followers. Either all"
 634                     + " other follower nodes are down or this node is isolated by a network partition.",
 635                     persistenceId()))), getSelf());
 636             return true;
 637         }
 638
 639         return false;
 640     }
 641
 642     protected boolean isIsolatedLeader() {
 643         return getRaftState() == RaftState.IsolatedLeader;
 644     }
 645
 646     @SuppressWarnings("checkstyle:IllegalCatch")
 647     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 648         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionId());
 649
 650         boolean isLeaderActive = isLeaderActive();
 651         if (isLeader() && isLeaderActive) {
 652             try {
 653                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 654             } catch (Exception e) {
 655                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 656                         message.getTransactionId(), e);
 657                 getSender().tell(new Failure(e), getSelf());
 658             }
 659         } else {
 660             ActorSelection leader = getLeader();
 661             if (!isLeaderActive || leader == null) {
 662                 messageRetrySupport.addMessageToRetry(message, getSender(),
 663                         "Could not commit transaction " + message.getTransactionId());
 664             } else {
 665                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 666                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 667                 leader.forward(message, getContext());
 668             }
 669         }
 670     }
 671
 672     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 673         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
 674
 675         boolean isLeaderActive = isLeaderActive();
 676         if (isLeader() && isLeaderActive) {
 677             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 678         } else {
 679             ActorSelection leader = getLeader();
 680             if (!isLeaderActive || leader == null) {
 681                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 682                         "Could not commit transaction " + forwardedReady.getTransactionId());
 683             } else {
 684                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 685
 686                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
 687                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 688                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 689                 leader.forward(readyLocal, getContext());
 690             }
 691         }
 692     }
 693
 694     private void handleAbortTransaction(final AbortTransaction abort) {
 695         doAbortTransaction(abort.getTransactionId(), getSender());
 696     }
 697
 698     void doAbortTransaction(final Identifier transactionID, final ActorRef sender) {
 699         commitCoordinator.handleAbort(transactionID, sender, this);
 700     }
 701
 702     private void handleCreateTransaction(final Object message) {
 703         if (isLeader()) {
 704             createTransaction(CreateTransaction.fromSerializable(message));
 705         } else if (getLeader() != null) {
 706             getLeader().forward(message, getContext());
 707         } else {
 708             getSender().tell(new Failure(new NoShardLeaderException(
 709                     "Could not create a shard transaction", persistenceId())), getSelf());
 710         }
 711     }
 712
 713     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 714         final LocalHistoryIdentifier id = closeTransactionChain.getIdentifier();
 715         store.closeTransactionChain(id, null);
 716         store.purgeTransactionChain(id, null);
 717     }
 718
 719     @SuppressWarnings("checkstyle:IllegalCatch")
 720     private void createTransaction(final CreateTransaction createTransaction) {
 721         try {
 722             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 723                     && failIfIsolatedLeader(getSender())) {
 724                 return;
 725             }
 726
 727             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 728                 createTransaction.getTransactionId());
 729
 730             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 731                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 732         } catch (Exception e) {
 733             getSender().tell(new Failure(e), getSelf());
 734         }
 735     }
 736
 737     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 738         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 739         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 740             transactionId);
 741     }
 742
 743     private void updateSchemaContext(final UpdateSchemaContext message) {
 744         updateSchemaContext(message.getSchemaContext());
 745     }
 746
 747     @VisibleForTesting
 748     void updateSchemaContext(final SchemaContext schemaContext) {
 749         store.updateSchemaContext(schemaContext);
 750     }
 751
 752     private boolean isMetricsCaptureEnabled() {
 753         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 754         return config.isMetricCaptureEnabled();
 755     }
 756
 757     @Override
 758     @VisibleForTesting
 759     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 760         return snapshotCohort;
 761     }
 762
 763     @Override
 764     @Nonnull
 765     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 766         return new ShardRecoveryCoordinator(store,
 767             restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 768     }
 769
 770     @Override
 771     protected void onRecoveryComplete() {
 772         restoreFromSnapshot = null;
 773
 774         //notify shard manager
 775         getContext().parent().tell(new ActorInitialized(), getSelf());
 776
 777         // Being paranoid here - this method should only be called once but just in case...
 778         if (txCommitTimeoutCheckSchedule == null) {
 779             // Schedule a message to be periodically sent to check if the current in-progress
 780             // transaction should be expired and aborted.
 781             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 782             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 783                     period, period, getSelf(),
 784                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 785         }
 786     }
 787
 788     @Override
 789     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 790         if (data instanceof Payload) {
 791             try {
 792                 store.applyReplicatedPayload(identifier, (Payload)data);
 793             } catch (DataValidationFailedException | IOException e) {
 794                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 795             }
 796         } else {
 797             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 798         }
 799     }
 800
 801     @Override
 802     protected void onStateChanged() {
 803         boolean isLeader = isLeader();
 804         boolean hasLeader = hasLeader();
 805         changeSupport.onLeadershipChange(isLeader, hasLeader);
 806         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 807
 808         // If this actor is no longer the leader close all the transaction chains
 809         if (!isLeader) {
 810             if (LOG.isDebugEnabled()) {
 811                 LOG.debug(
 812                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 813                     persistenceId(), getId());
 814             }
 815
 816             paused = false;
 817             store.purgeLeaderState();
 818         }
 819
 820         if (hasLeader && !isIsolatedLeader()) {
 821             messageRetrySupport.retryMessages();
 822         }
 823     }
 824
 825     @Override
 826     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 827         shardMBean.incrementLeadershipChangeCount();
 828         paused = false;
 829
 830         if (!isLeader()) {
 831             if (!knownFrontends.isEmpty()) {
 832                 LOG.debug("{}: removing frontend state for {}", persistenceId(), knownFrontends.keySet());
 833                 knownFrontends = ImmutableMap.of();
 834             }
 835
 836             if (!hasLeader()) {
 837                 // No leader anywhere, nothing else to do
 838                 return;
 839             }
 840
 841             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 842             // them to transaction messages and send to the new leader.
 843             ActorSelection leader = getLeader();
 844             if (leader != null) {
 845                 Collection<?> messagesToForward = convertPendingTransactionsToMessages();
 846
 847                 if (!messagesToForward.isEmpty()) {
 848                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 849                             messagesToForward.size(), leader);
 850
 851                     for (Object message : messagesToForward) {
 852                         leader.tell(message, self());
 853                     }
 854                 }
 855             } else {
 856                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
 857                         + "change and the leader address isn't available.", this);
 858             }
 859         } else {
 860             // We have become the leader, we need to reconstruct frontend state
 861             knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
 862             LOG.debug("{}: became leader with frontend state for {}", persistenceId(), knownFrontends.keySet());
 863         }
 864
 865         if (!isIsolatedLeader()) {
 866             messageRetrySupport.retryMessages();
 867         }
 868     }
 869
 870     /**
 871      * Clears all pending transactions and converts them to messages to be forwarded to a new leader.
 872      *
 873      * @return the converted messages
 874      */
 875     public Collection<?> convertPendingTransactionsToMessages() {
 876         return commitCoordinator.convertPendingTransactionsToMessages(
 877                 datastoreContext.getShardBatchedModificationCount());
 878     }
 879
 880     @Override
 881     protected void pauseLeader(final Runnable operation) {
 882         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 883         paused = true;
 884
 885         // Tell-based protocol can replay transaction state, so it is safe to blow it up when we are paused.
 886         knownFrontends.values().forEach(LeaderFrontendState::retire);
 887         knownFrontends = ImmutableMap.of();
 888
 889         store.setRunOnPendingTransactionsComplete(operation);
 890     }
 891
 892     @Override
 893     protected void unpauseLeader() {
 894         LOG.debug("{}: In unpauseLeader", persistenceId());
 895         paused = false;
 896
 897         store.setRunOnPendingTransactionsComplete(null);
 898
 899         // Restore tell-based protocol state as if we were becoming the leader
 900         knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
 901     }
 902
 903     @Override
 904     protected OnDemandRaftState.AbstractBuilder<?> newOnDemandRaftStateBuilder() {
 905         return OnDemandShardState.newBuilder().treeChangeListenerActors(treeChangeSupport.getListenerActors())
 906                 .dataChangeListenerActors(changeSupport.getListenerActors())
 907                 .commitCohortActors(store.getCohortActors());
 908     }
 909
 910     @Override
 911     public String persistenceId() {
 912         return this.name;
 913     }
 914
 915     @VisibleForTesting
 916     ShardCommitCoordinator getCommitCoordinator() {
 917         return commitCoordinator;
 918     }
 919
 920     public DatastoreContext getDatastoreContext() {
 921         return datastoreContext;
 922     }
 923
 924     @VisibleForTesting
 925     public ShardDataTree getDataStore() {
 926         return store;
 927     }
 928
 929     @VisibleForTesting
 930     ShardStats getShardMBean() {
 931         return shardMBean;
 932     }
 933
 934     public static Builder builder() {
 935         return new Builder();
 936     }
 937
 938     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 939         private final Class<S> shardClass;
 940         private ShardIdentifier id;
 941         private Map<String, String> peerAddresses = Collections.emptyMap();
 942         private DatastoreContext datastoreContext;
 943         private SchemaContextProvider schemaContextProvider;
 944         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 945         private TipProducingDataTree dataTree;
 946         private volatile boolean sealed;
 947
 948         protected AbstractBuilder(final Class<S> shardClass) {
 949             this.shardClass = shardClass;
 950         }
 951
 952         protected void checkSealed() {
 953             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 954         }
 955
 956         @SuppressWarnings("unchecked")
 957         private T self() {
 958             return (T) this;
 959         }
 960
 961         public T id(final ShardIdentifier newId) {
 962             checkSealed();
 963             this.id = newId;
 964             return self();
 965         }
 966
 967         public T peerAddresses(final Map<String, String> newPeerAddresses) {
 968             checkSealed();
 969             this.peerAddresses = newPeerAddresses;
 970             return self();
 971         }
 972
 973         public T datastoreContext(final DatastoreContext newDatastoreContext) {
 974             checkSealed();
 975             this.datastoreContext = newDatastoreContext;
 976             return self();
 977         }
 978
 979         public T schemaContextProvider(final SchemaContextProvider schemaContextProvider) {
 980             checkSealed();
 981             this.schemaContextProvider = Preconditions.checkNotNull(schemaContextProvider);
 982             return self();
 983         }
 984
 985         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
 986             checkSealed();
 987             this.restoreFromSnapshot = newRestoreFromSnapshot;
 988             return self();
 989         }
 990
 991         public T dataTree(final TipProducingDataTree newDataTree) {
 992             checkSealed();
 993             this.dataTree = newDataTree;
 994             return self();
 995         }
 996
 997         public ShardIdentifier getId() {
 998             return id;
 999         }
1000
1001         public Map<String, String> getPeerAddresses() {
1002             return peerAddresses;
1003         }
1004
1005         public DatastoreContext getDatastoreContext() {
1006             return datastoreContext;
1007         }
1008
1009         public SchemaContext getSchemaContext() {
1010             return Verify.verifyNotNull(schemaContextProvider.getSchemaContext());
1011         }
1012
1013         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
1014             return restoreFromSnapshot;
1015         }
1016
1017         public TipProducingDataTree getDataTree() {
1018             return dataTree;
1019         }
1020
1021         public TreeType getTreeType() {
1022             switch (datastoreContext.getLogicalStoreType()) {
1023                 case CONFIGURATION:
1024                     return TreeType.CONFIGURATION;
1025                 case OPERATIONAL:
1026                     return TreeType.OPERATIONAL;
1027                 default:
1028                     throw new IllegalStateException("Unhandled logical store type "
1029                             + datastoreContext.getLogicalStoreType());
1030             }
1031         }
1032
1033         protected void verify() {
1034             Preconditions.checkNotNull(id, "id should not be null");
1035             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
1036             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
1037             Preconditions.checkNotNull(schemaContextProvider, "schemaContextProvider should not be null");
1038         }
1039
1040         public Props props() {
1041             sealed = true;
1042             verify();
1043             return Props.create(shardClass, this);
1044         }
1045     }
1046
1047     public static class Builder extends AbstractBuilder<Builder, Shard> {
1048         private Builder() {
1049             super(Shard.class);
1050         }
1051     }
1052
1053     Ticker ticker() {
1054         return Ticker.systemTicker();
1055     }
1056
1057     void scheduleNextPendingTransaction() {
1058         self().tell(RESUME_NEXT_PENDING_TRANSACTION, ActorRef.noSender());
1059     }
1060 }