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.TransactionRequest;
  40 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  41 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
  42 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  43 import org.opendaylight.controller.cluster.access.concepts.Request;
  44 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  45 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  46 import org.opendaylight.controller.cluster.access.concepts.RequestSuccess;
  47 import org.opendaylight.controller.cluster.access.concepts.RetiredGenerationException;
  48 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
  49 import org.opendaylight.controller.cluster.access.concepts.SliceableMessage;
  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.Dispatchers;
  54 import org.opendaylight.controller.cluster.common.actor.Dispatchers.DispatcherType;
  55 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  56 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
  57 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  58 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  59 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  60 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  61 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  62 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  63 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  64 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  65 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  66 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  67 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  68 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  69 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  70 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  71 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  72 import org.opendaylight.controller.cluster.datastore.messages.MakeLeaderLocal;
  73 import org.opendaylight.controller.cluster.datastore.messages.OnDemandShardState;
  74 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  75 import org.opendaylight.controller.cluster.datastore.messages.PersistAbortTransactionPayload;
  76 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  77 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  78 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  79 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  80 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  81 import org.opendaylight.controller.cluster.datastore.persisted.AbortTransactionPayload;
  82 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot;
  83 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot.ShardSnapshot;
  84 import org.opendaylight.controller.cluster.messaging.MessageSlicer;
  85 import org.opendaylight.controller.cluster.messaging.SliceOptions;
  86 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  87 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  88 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  89 import org.opendaylight.controller.cluster.raft.LeadershipTransferFailedException;
  90 import org.opendaylight.controller.cluster.raft.RaftActor;
  91 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  92 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
  93 import org.opendaylight.controller.cluster.raft.RaftState;
  94 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  95 import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
  96 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  97 import org.opendaylight.controller.cluster.raft.messages.RequestLeadership;
  98 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
  99 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
 100 import org.opendaylight.yangtools.concepts.Identifier;
 101 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
 102 import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree;
 103 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
 104 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 105 import org.opendaylight.yangtools.yang.model.api.SchemaContextProvider;
 106 import scala.concurrent.duration.Duration;
 107 import scala.concurrent.duration.FiniteDuration;
 108
 109 /**
 110  * A Shard represents a portion of the logical data tree.
 111  *
 112  * <p>
 113  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
 114  */
 115 public class Shard extends RaftActor {
 116
 117     @VisibleForTesting
 118     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
 119         @Override
 120         public String toString() {
 121             return "txCommitTimeoutCheck";
 122         }
 123     };
 124
 125     @VisibleForTesting
 126     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
 127         @Override
 128         public String toString() {
 129             return "getShardMBeanMessage";
 130         }
 131     };
 132
 133     static final Object RESUME_NEXT_PENDING_TRANSACTION = new Object() {
 134         @Override
 135         public String toString() {
 136             return "resumeNextPendingTransaction";
 137         }
 138     };
 139
 140     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
 141     public static final String DEFAULT_NAME = "default";
 142
 143     private static final Collection<ABIVersion> SUPPORTED_ABIVERSIONS;
 144
 145     static {
 146         final ABIVersion[] values = ABIVersion.values();
 147         final ABIVersion[] real = Arrays.copyOfRange(values, 1, values.length - 1);
 148         SUPPORTED_ABIVERSIONS = ImmutableList.copyOf(real).reverse();
 149     }
 150
 151     // FIXME: make this a dynamic property based on mailbox size and maximum number of clients
 152     private static final int CLIENT_MAX_MESSAGES = 1000;
 153
 154     // The state of this Shard
 155     private final ShardDataTree store;
 156
 157     /// The name of this shard
 158     private final String name;
 159
 160     private final ShardStats shardMBean;
 161
 162     private DatastoreContext datastoreContext;
 163
 164     private final ShardCommitCoordinator commitCoordinator;
 165
 166     private long transactionCommitTimeout;
 167
 168     private Cancellable txCommitTimeoutCheckSchedule;
 169
 170     private final Optional<ActorRef> roleChangeNotifier;
 171
 172     private final MessageTracker appendEntriesReplyTracker;
 173
 174     private final ShardTransactionActorFactory transactionActorFactory;
 175
 176     private final ShardSnapshotCohort snapshotCohort;
 177
 178     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 179     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 180
 181
 182     private ShardSnapshot restoreFromSnapshot;
 183
 184     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 185
 186     private final FrontendMetadata frontendMetadata;
 187     private Map<FrontendIdentifier, LeaderFrontendState> knownFrontends = ImmutableMap.of();
 188     private boolean paused;
 189
 190     private final MessageSlicer responseMessageSlicer;
 191     private final Dispatchers dispatchers;
 192
 193     protected Shard(final AbstractBuilder<?, ?> builder) {
 194         super(builder.getId().toString(), builder.getPeerAddresses(),
 195                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 196
 197         this.name = builder.getId().toString();
 198         this.datastoreContext = builder.getDatastoreContext();
 199         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 200         this.frontendMetadata = new FrontendMetadata(name);
 201
 202         setPersistence(datastoreContext.isPersistent());
 203
 204         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 205
 206         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 207                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher", name);
 208         ShardDataChangeListenerPublisherActorProxy dataChangeListenerPublisher =
 209                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher", name);
 210         if (builder.getDataTree() != null) {
 211             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 212                     treeChangeListenerPublisher, dataChangeListenerPublisher, name, frontendMetadata);
 213         } else {
 214             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 215                     builder.getDatastoreContext().getStoreRoot(), treeChangeListenerPublisher,
 216                     dataChangeListenerPublisher, name, frontendMetadata);
 217         }
 218
 219         shardMBean = ShardMBeanFactory.getShardStatsMBean(name, datastoreContext.getDataStoreMXBeanType(), this);
 220
 221         if (isMetricsCaptureEnabled()) {
 222             getContext().become(new MeteringBehavior(this));
 223         }
 224
 225         commitCoordinator = new ShardCommitCoordinator(store, LOG, this.name);
 226
 227         setTransactionCommitTimeout();
 228
 229         // create a notifier actor for each cluster member
 230         roleChangeNotifier = createRoleChangeNotifier(name);
 231
 232         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 233                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 234
 235         dispatchers = new Dispatchers(context().system().dispatchers());
 236         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 237             dispatchers.getDispatcherPath(Dispatchers.DispatcherType.Transaction),
 238                 self(), getContext(), shardMBean, builder.getId().getShardName());
 239
 240         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 241             this.name);
 242
 243         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 244
 245         responseMessageSlicer = MessageSlicer.builder().logContext(this.name)
 246                 .messageSliceSize(datastoreContext.getMaximumMessageSliceSize())
 247                 .fileBackedStreamFactory(getRaftActorContext().getFileBackedOutputStreamFactory())
 248                 .expireStateAfterInactivity(2, TimeUnit.MINUTES).build();
 249     }
 250
 251     private void setTransactionCommitTimeout() {
 252         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 253                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 254     }
 255
 256     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 257         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 258             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 259         return Optional.of(shardRoleChangeNotifier);
 260     }
 261
 262     @Override
 263     public void postStop() {
 264         LOG.info("Stopping Shard {}", persistenceId());
 265
 266         super.postStop();
 267
 268         messageRetrySupport.close();
 269
 270         if (txCommitTimeoutCheckSchedule != null) {
 271             txCommitTimeoutCheckSchedule.cancel();
 272         }
 273
 274         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 275
 276         shardMBean.unregisterMBean();
 277     }
 278
 279     @Override
 280     protected void handleRecover(final Object message) {
 281         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 282             getSender());
 283
 284         super.handleRecover(message);
 285         if (LOG.isTraceEnabled()) {
 286             appendEntriesReplyTracker.begin();
 287         }
 288     }
 289
 290     @Override
 291     protected void handleNonRaftCommand(final Object message) {
 292         try (MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 293             final Optional<Error> maybeError = context.error();
 294             if (maybeError.isPresent()) {
 295                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 296                     maybeError.get());
 297             }
 298
 299             store.resetTransactionBatch();
 300
 301             if (message instanceof RequestEnvelope) {
 302                 handleRequestEnvelope((RequestEnvelope)message);
 303             } else if (message instanceof ConnectClientRequest) {
 304                 handleConnectClient((ConnectClientRequest)message);
 305             } else if (CreateTransaction.isSerializedType(message)) {
 306                 handleCreateTransaction(message);
 307             } else if (message instanceof BatchedModifications) {
 308                 handleBatchedModifications((BatchedModifications)message);
 309             } else if (message instanceof ForwardedReadyTransaction) {
 310                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 311             } else if (message instanceof ReadyLocalTransaction) {
 312                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 313             } else if (CanCommitTransaction.isSerializedType(message)) {
 314                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 315             } else if (CommitTransaction.isSerializedType(message)) {
 316                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 317             } else if (AbortTransaction.isSerializedType(message)) {
 318                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 319             } else if (CloseTransactionChain.isSerializedType(message)) {
 320                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 321             } else if (message instanceof RegisterChangeListener) {
 322                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 323             } else if (message instanceof RegisterDataTreeChangeListener) {
 324                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 325             } else if (message instanceof UpdateSchemaContext) {
 326                 updateSchemaContext((UpdateSchemaContext) message);
 327             } else if (message instanceof PeerAddressResolved) {
 328                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 329                 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
 330             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 331                 store.checkForExpiredTransactions(transactionCommitTimeout);
 332                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 333             } else if (message instanceof DatastoreContext) {
 334                 onDatastoreContext((DatastoreContext)message);
 335             } else if (message instanceof RegisterRoleChangeListener) {
 336                 roleChangeNotifier.get().forward(message, context());
 337             } else if (message instanceof FollowerInitialSyncUpStatus) {
 338                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 339                 context().parent().tell(message, self());
 340             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 341                 sender().tell(getShardMBean(), self());
 342             } else if (message instanceof GetShardDataTree) {
 343                 sender().tell(store.getDataTree(), self());
 344             } else if (message instanceof ServerRemoved) {
 345                 context().parent().forward(message, context());
 346             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 347                 messageRetrySupport.onTimerMessage(message);
 348             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 349                 store.processCohortRegistryCommand(getSender(),
 350                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 351             } else if (message instanceof PersistAbortTransactionPayload) {
 352                 final TransactionIdentifier txId = ((PersistAbortTransactionPayload) message).getTransactionId();
 353                 persistPayload(txId, AbortTransactionPayload.create(txId), true);
 354             } else if (message instanceof MakeLeaderLocal) {
 355                 onMakeLeaderLocal();
 356             } else if (RESUME_NEXT_PENDING_TRANSACTION.equals(message)) {
 357                 store.resumeNextPendingTransaction();
 358             } else if (!responseMessageSlicer.handleMessage(message)) {
 359                 super.handleNonRaftCommand(message);
 360             }
 361         }
 362     }
 363
 364     @SuppressWarnings("checkstyle:IllegalCatch")
 365     private void handleRequestEnvelope(final RequestEnvelope envelope) {
 366         final long now = ticker().read();
 367         try {
 368             final RequestSuccess<?, ?> success = handleRequest(envelope, now);
 369             if (success != null) {
 370                 final long executionTimeNanos = ticker().read() - now;
 371                 if (success instanceof SliceableMessage) {
 372                     dispatchers.getDispatcher(DispatcherType.Serialization).execute(() ->
 373                         responseMessageSlicer.slice(SliceOptions.builder().identifier(success.getTarget())
 374                             .message(envelope.newSuccessEnvelope(success, executionTimeNanos))
 375                             .sendTo(envelope.getMessage().getReplyTo()).replyTo(self())
 376                             .onFailureCallback(t -> {
 377                                 LOG.warn("Error slicing response {}", success, t);
 378                             }).build()));
 379                 } else {
 380                     envelope.sendSuccess(success, executionTimeNanos);
 381                 }
 382             }
 383         } catch (RequestException e) {
 384             LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
 385             envelope.sendFailure(e, ticker().read() - now);
 386         } catch (Exception e) {
 387             LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
 388             envelope.sendFailure(new RuntimeRequestException("Request failed to process", e),
 389                 ticker().read() - now);
 390         }
 391     }
 392
 393     private void onMakeLeaderLocal() {
 394         LOG.debug("{}: onMakeLeaderLocal received", persistenceId());
 395         if (isLeader()) {
 396             getSender().tell(new Status.Success(null), getSelf());
 397             return;
 398         }
 399
 400         final ActorSelection leader = getLeader();
 401
 402         if (leader == null) {
 403             // Leader is not present. The cluster is most likely trying to
 404             // elect a leader and we should let that run its normal course
 405
 406             // TODO we can wait for the election to complete and retry the
 407             // request. We can also let the caller retry by sending a flag
 408             // in the response indicating the request is "reTryable".
 409             getSender().tell(new Failure(
 410                     new LeadershipTransferFailedException("We cannot initiate leadership transfer to local node. "
 411                             + "Currently there is no leader for " + persistenceId())),
 412                     getSelf());
 413             return;
 414         }
 415
 416         leader.tell(new RequestLeadership(getId(), getSender()), getSelf());
 417     }
 418
 419     // Acquire our frontend tracking handle and verify generation matches
 420     private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
 421         final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
 422         if (existing != null) {
 423             final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
 424             if (cmp == 0) {
 425                 return existing;
 426             }
 427             if (cmp > 0) {
 428                 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
 429                 throw new RetiredGenerationException(existing.getIdentifier().getGeneration());
 430             }
 431
 432             LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
 433             existing.retire();
 434             knownFrontends.remove(clientId.getFrontendId());
 435         } else {
 436             LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
 437         }
 438
 439         final LeaderFrontendState ret = new LeaderFrontendState(persistenceId(), clientId, store);
 440         knownFrontends.put(clientId.getFrontendId(), ret);
 441         LOG.debug("{}: created state {} for client {}", persistenceId(), ret, clientId);
 442         return ret;
 443     }
 444
 445     private static @Nonnull ABIVersion selectVersion(final ConnectClientRequest message) {
 446         final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
 447         for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
 448             if (clientRange.contains(v)) {
 449                 return v;
 450             }
 451         }
 452
 453         throw new IllegalArgumentException(String.format(
 454             "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
 455             clientRange));
 456     }
 457
 458     @SuppressWarnings("checkstyle:IllegalCatch")
 459     private void handleConnectClient(final ConnectClientRequest message) {
 460         try {
 461             if (!isLeader() || !isLeaderActive()) {
 462                 LOG.info("{}: not currently leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 463                                 + "isLeadershipTransferInProgress: {}.",
 464                         persistenceId(), message, isLeader(), isLeaderActive(), isLeadershipTransferInProgress());
 465                 throw new NotLeaderException(getSelf());
 466             }
 467
 468             final ABIVersion selectedVersion = selectVersion(message);
 469             final LeaderFrontendState frontend = getFrontend(message.getTarget());
 470             frontend.reconnect();
 471             message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
 472                 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
 473                 ActorRef.noSender());
 474         } catch (RequestException | RuntimeException e) {
 475             message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
 476         }
 477     }
 478
 479     private @Nullable RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope, final long now)
 480             throws RequestException {
 481         // We are not the leader, hence we want to fail-fast.
 482         if (!isLeader() || paused || !isLeaderActive()) {
 483             LOG.debug("{}: not currently active leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 484                             + "isLeadershipTransferInProgress: {}, paused: {}",
 485                     persistenceId(), envelope, isLeader(), isLeaderActive(), isLeadershipTransferInProgress(), paused);
 486             throw new NotLeaderException(getSelf());
 487         }
 488
 489         final Request<?, ?> request = envelope.getMessage();
 490         if (request instanceof TransactionRequest) {
 491             final TransactionRequest<?> txReq = (TransactionRequest<?>)request;
 492             final ClientIdentifier clientId = txReq.getTarget().getHistoryId().getClientId();
 493             return getFrontend(clientId).handleTransactionRequest(txReq, envelope, now);
 494         } else if (request instanceof LocalHistoryRequest) {
 495             final LocalHistoryRequest<?> lhReq = (LocalHistoryRequest<?>)request;
 496             final ClientIdentifier clientId = lhReq.getTarget().getClientId();
 497             return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope, now);
 498         } else {
 499             LOG.warn("{}: rejecting unsupported request {}", persistenceId(), request);
 500             throw new UnsupportedRequestException(request);
 501         }
 502     }
 503
 504     private boolean hasLeader() {
 505         return getLeaderId() != null;
 506     }
 507
 508     public int getPendingTxCommitQueueSize() {
 509         return store.getQueueSize();
 510     }
 511
 512     public int getCohortCacheSize() {
 513         return commitCoordinator.getCohortCacheSize();
 514     }
 515
 516     @Override
 517     protected Optional<ActorRef> getRoleChangeNotifier() {
 518         return roleChangeNotifier;
 519     }
 520
 521     @Override
 522     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 523             final short leaderPayloadVersion) {
 524         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 525                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 526     }
 527
 528     protected void onDatastoreContext(final DatastoreContext context) {
 529         datastoreContext = context;
 530
 531         setTransactionCommitTimeout();
 532
 533         setPersistence(datastoreContext.isPersistent());
 534
 535         updateConfigParams(datastoreContext.getShardRaftConfig());
 536     }
 537
 538     // applyState() will be invoked once consensus is reached on the payload
 539     void persistPayload(final Identifier id, final Payload payload, final boolean batchHint) {
 540         boolean canSkipPayload = !hasFollowers() && !persistence().isRecoveryApplicable();
 541         if (canSkipPayload) {
 542             applyState(self(), id, payload);
 543         } else {
 544             // We are faking the sender
 545             persistData(self(), id, payload, batchHint);
 546         }
 547     }
 548
 549     private void handleCommitTransaction(final CommitTransaction commit) {
 550         if (isLeader()) {
 551             commitCoordinator.handleCommit(commit.getTransactionId(), getSender(), this);
 552         } else {
 553             ActorSelection leader = getLeader();
 554             if (leader == null) {
 555                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 556                         "Could not commit transaction " + commit.getTransactionId());
 557             } else {
 558                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 559                 leader.forward(commit, getContext());
 560             }
 561         }
 562     }
 563
 564     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 565         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionId());
 566
 567         if (isLeader()) {
 568             commitCoordinator.handleCanCommit(canCommit.getTransactionId(), getSender(), this);
 569         } else {
 570             ActorSelection leader = getLeader();
 571             if (leader == null) {
 572                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 573                         "Could not canCommit transaction " + canCommit.getTransactionId());
 574             } else {
 575                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 576                 leader.forward(canCommit, getContext());
 577             }
 578         }
 579     }
 580
 581     @SuppressWarnings("checkstyle:IllegalCatch")
 582     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 583         try {
 584             commitCoordinator.handleBatchedModifications(batched, sender, this);
 585         } catch (Exception e) {
 586             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 587                     batched.getTransactionId(), e);
 588             sender.tell(new Failure(e), getSelf());
 589         }
 590     }
 591
 592     private void handleBatchedModifications(final BatchedModifications batched) {
 593         // This message is sent to prepare the modifications transaction directly on the Shard as an
 594         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 595         // BatchedModifications message, the caller sets the ready flag in the message indicating
 596         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 597         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 598         // ReadyTransaction message.
 599
 600         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 601         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 602         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 603         // window where it could have a stale leader during leadership transitions.
 604         //
 605         boolean isLeaderActive = isLeaderActive();
 606         if (isLeader() && isLeaderActive) {
 607             handleBatchedModificationsLocal(batched, getSender());
 608         } else {
 609             ActorSelection leader = getLeader();
 610             if (!isLeaderActive || leader == null) {
 611                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 612                         "Could not commit transaction " + batched.getTransactionId());
 613             } else {
 614                 // If this is not the first batch and leadership changed in between batched messages,
 615                 // we need to reconstruct previous BatchedModifications from the transaction
 616                 // DataTreeModification, honoring the max batched modification count, and forward all the
 617                 // previous BatchedModifications to the new leader.
 618                 Collection<BatchedModifications> newModifications = commitCoordinator
 619                         .createForwardedBatchedModifications(batched,
 620                                 datastoreContext.getShardBatchedModificationCount());
 621
 622                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 623                         newModifications.size(), leader);
 624
 625                 for (BatchedModifications bm : newModifications) {
 626                     leader.forward(bm, getContext());
 627                 }
 628             }
 629         }
 630     }
 631
 632     private boolean failIfIsolatedLeader(final ActorRef sender) {
 633         if (isIsolatedLeader()) {
 634             sender.tell(new Failure(new NoShardLeaderException(String.format(
 635                     "Shard %s was the leader but has lost contact with all of its followers. Either all"
 636                     + " other follower nodes are down or this node is isolated by a network partition.",
 637                     persistenceId()))), getSelf());
 638             return true;
 639         }
 640
 641         return false;
 642     }
 643
 644     protected boolean isIsolatedLeader() {
 645         return getRaftState() == RaftState.IsolatedLeader;
 646     }
 647
 648     @SuppressWarnings("checkstyle:IllegalCatch")
 649     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 650         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionId());
 651
 652         boolean isLeaderActive = isLeaderActive();
 653         if (isLeader() && isLeaderActive) {
 654             try {
 655                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 656             } catch (Exception e) {
 657                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 658                         message.getTransactionId(), e);
 659                 getSender().tell(new Failure(e), getSelf());
 660             }
 661         } else {
 662             ActorSelection leader = getLeader();
 663             if (!isLeaderActive || leader == null) {
 664                 messageRetrySupport.addMessageToRetry(message, getSender(),
 665                         "Could not commit transaction " + message.getTransactionId());
 666             } else {
 667                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 668                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 669                 leader.forward(message, getContext());
 670             }
 671         }
 672     }
 673
 674     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 675         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
 676
 677         boolean isLeaderActive = isLeaderActive();
 678         if (isLeader() && isLeaderActive) {
 679             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 680         } else {
 681             ActorSelection leader = getLeader();
 682             if (!isLeaderActive || leader == null) {
 683                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 684                         "Could not commit transaction " + forwardedReady.getTransactionId());
 685             } else {
 686                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 687
 688                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
 689                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 690                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 691                 leader.forward(readyLocal, getContext());
 692             }
 693         }
 694     }
 695
 696     private void handleAbortTransaction(final AbortTransaction abort) {
 697         doAbortTransaction(abort.getTransactionId(), getSender());
 698     }
 699
 700     void doAbortTransaction(final Identifier transactionID, final ActorRef sender) {
 701         commitCoordinator.handleAbort(transactionID, sender, this);
 702     }
 703
 704     private void handleCreateTransaction(final Object message) {
 705         if (isLeader()) {
 706             createTransaction(CreateTransaction.fromSerializable(message));
 707         } else if (getLeader() != null) {
 708             getLeader().forward(message, getContext());
 709         } else {
 710             getSender().tell(new Failure(new NoShardLeaderException(
 711                     "Could not create a shard transaction", persistenceId())), getSelf());
 712         }
 713     }
 714
 715     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 716         final LocalHistoryIdentifier id = closeTransactionChain.getIdentifier();
 717         store.closeTransactionChain(id, null);
 718         store.purgeTransactionChain(id, null);
 719     }
 720
 721     @SuppressWarnings("checkstyle:IllegalCatch")
 722     private void createTransaction(final CreateTransaction createTransaction) {
 723         try {
 724             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 725                     && failIfIsolatedLeader(getSender())) {
 726                 return;
 727             }
 728
 729             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 730                 createTransaction.getTransactionId());
 731
 732             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 733                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 734         } catch (Exception e) {
 735             getSender().tell(new Failure(e), getSelf());
 736         }
 737     }
 738
 739     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 740         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 741         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 742             transactionId);
 743     }
 744
 745     private void updateSchemaContext(final UpdateSchemaContext message) {
 746         updateSchemaContext(message.getSchemaContext());
 747     }
 748
 749     @VisibleForTesting
 750     void updateSchemaContext(final SchemaContext schemaContext) {
 751         store.updateSchemaContext(schemaContext);
 752     }
 753
 754     private boolean isMetricsCaptureEnabled() {
 755         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 756         return config.isMetricCaptureEnabled();
 757     }
 758
 759     @Override
 760     @VisibleForTesting
 761     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 762         return snapshotCohort;
 763     }
 764
 765     @Override
 766     @Nonnull
 767     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 768         return new ShardRecoveryCoordinator(store,
 769             restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 770     }
 771
 772     @Override
 773     protected void onRecoveryComplete() {
 774         restoreFromSnapshot = null;
 775
 776         //notify shard manager
 777         getContext().parent().tell(new ActorInitialized(), getSelf());
 778
 779         // Being paranoid here - this method should only be called once but just in case...
 780         if (txCommitTimeoutCheckSchedule == null) {
 781             // Schedule a message to be periodically sent to check if the current in-progress
 782             // transaction should be expired and aborted.
 783             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 784             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 785                     period, period, getSelf(),
 786                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 787         }
 788     }
 789
 790     @Override
 791     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 792         if (data instanceof Payload) {
 793             try {
 794                 store.applyReplicatedPayload(identifier, (Payload)data);
 795             } catch (DataValidationFailedException | IOException e) {
 796                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 797             }
 798         } else {
 799             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 800         }
 801     }
 802
 803     @Override
 804     protected void onStateChanged() {
 805         boolean isLeader = isLeader();
 806         boolean hasLeader = hasLeader();
 807         changeSupport.onLeadershipChange(isLeader, hasLeader);
 808         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 809
 810         // If this actor is no longer the leader close all the transaction chains
 811         if (!isLeader) {
 812             if (LOG.isDebugEnabled()) {
 813                 LOG.debug(
 814                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 815                     persistenceId(), getId());
 816             }
 817
 818             paused = false;
 819             store.purgeLeaderState();
 820         }
 821
 822         if (hasLeader && !isIsolatedLeader()) {
 823             messageRetrySupport.retryMessages();
 824         }
 825     }
 826
 827     @Override
 828     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 829         shardMBean.incrementLeadershipChangeCount();
 830         paused = false;
 831
 832         if (!isLeader()) {
 833             if (!knownFrontends.isEmpty()) {
 834                 LOG.debug("{}: removing frontend state for {}", persistenceId(), knownFrontends.keySet());
 835                 knownFrontends = ImmutableMap.of();
 836             }
 837
 838             if (!hasLeader()) {
 839                 // No leader anywhere, nothing else to do
 840                 return;
 841             }
 842
 843             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 844             // them to transaction messages and send to the new leader.
 845             ActorSelection leader = getLeader();
 846             if (leader != null) {
 847                 Collection<?> messagesToForward = convertPendingTransactionsToMessages();
 848
 849                 if (!messagesToForward.isEmpty()) {
 850                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 851                             messagesToForward.size(), leader);
 852
 853                     for (Object message : messagesToForward) {
 854                         leader.tell(message, self());
 855                     }
 856                 }
 857             } else {
 858                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
 859                         + "change and the leader address isn't available.", this);
 860             }
 861         } else {
 862             // We have become the leader, we need to reconstruct frontend state
 863             knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
 864             LOG.debug("{}: became leader with frontend state for {}", persistenceId(), knownFrontends.keySet());
 865         }
 866
 867         if (!isIsolatedLeader()) {
 868             messageRetrySupport.retryMessages();
 869         }
 870     }
 871
 872     /**
 873      * Clears all pending transactions and converts them to messages to be forwarded to a new leader.
 874      *
 875      * @return the converted messages
 876      */
 877     public Collection<?> convertPendingTransactionsToMessages() {
 878         return commitCoordinator.convertPendingTransactionsToMessages(
 879                 datastoreContext.getShardBatchedModificationCount());
 880     }
 881
 882     @Override
 883     protected void pauseLeader(final Runnable operation) {
 884         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 885         paused = true;
 886
 887         // Tell-based protocol can replay transaction state, so it is safe to blow it up when we are paused.
 888         knownFrontends.values().forEach(LeaderFrontendState::retire);
 889         knownFrontends = ImmutableMap.of();
 890
 891         store.setRunOnPendingTransactionsComplete(operation);
 892     }
 893
 894     @Override
 895     protected void unpauseLeader() {
 896         LOG.debug("{}: In unpauseLeader", persistenceId());
 897         paused = false;
 898
 899         store.setRunOnPendingTransactionsComplete(null);
 900
 901         // Restore tell-based protocol state as if we were becoming the leader
 902         knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
 903     }
 904
 905     @Override
 906     protected OnDemandRaftState.AbstractBuilder<?> newOnDemandRaftStateBuilder() {
 907         return OnDemandShardState.newBuilder().treeChangeListenerActors(treeChangeSupport.getListenerActors())
 908                 .dataChangeListenerActors(changeSupport.getListenerActors())
 909                 .commitCohortActors(store.getCohortActors());
 910     }
 911
 912     @Override
 913     public String persistenceId() {
 914         return this.name;
 915     }
 916
 917     @VisibleForTesting
 918     ShardCommitCoordinator getCommitCoordinator() {
 919         return commitCoordinator;
 920     }
 921
 922     public DatastoreContext getDatastoreContext() {
 923         return datastoreContext;
 924     }
 925
 926     @VisibleForTesting
 927     public ShardDataTree getDataStore() {
 928         return store;
 929     }
 930
 931     @VisibleForTesting
 932     ShardStats getShardMBean() {
 933         return shardMBean;
 934     }
 935
 936     public static Builder builder() {
 937         return new Builder();
 938     }
 939
 940     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 941         private final Class<S> shardClass;
 942         private ShardIdentifier id;
 943         private Map<String, String> peerAddresses = Collections.emptyMap();
 944         private DatastoreContext datastoreContext;
 945         private SchemaContextProvider schemaContextProvider;
 946         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 947         private TipProducingDataTree dataTree;
 948         private volatile boolean sealed;
 949
 950         protected AbstractBuilder(final Class<S> shardClass) {
 951             this.shardClass = shardClass;
 952         }
 953
 954         protected void checkSealed() {
 955             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 956         }
 957
 958         @SuppressWarnings("unchecked")
 959         private T self() {
 960             return (T) this;
 961         }
 962
 963         public T id(final ShardIdentifier newId) {
 964             checkSealed();
 965             this.id = newId;
 966             return self();
 967         }
 968
 969         public T peerAddresses(final Map<String, String> newPeerAddresses) {
 970             checkSealed();
 971             this.peerAddresses = newPeerAddresses;
 972             return self();
 973         }
 974
 975         public T datastoreContext(final DatastoreContext newDatastoreContext) {
 976             checkSealed();
 977             this.datastoreContext = newDatastoreContext;
 978             return self();
 979         }
 980
 981         public T schemaContextProvider(final SchemaContextProvider schemaContextProvider) {
 982             checkSealed();
 983             this.schemaContextProvider = Preconditions.checkNotNull(schemaContextProvider);
 984             return self();
 985         }
 986
 987         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
 988             checkSealed();
 989             this.restoreFromSnapshot = newRestoreFromSnapshot;
 990             return self();
 991         }
 992
 993         public T dataTree(final TipProducingDataTree newDataTree) {
 994             checkSealed();
 995             this.dataTree = newDataTree;
 996             return self();
 997         }
 998
 999         public ShardIdentifier getId() {
1000             return id;
1001         }
1002
1003         public Map<String, String> getPeerAddresses() {
1004             return peerAddresses;
1005         }
1006
1007         public DatastoreContext getDatastoreContext() {
1008             return datastoreContext;
1009         }
1010
1011         public SchemaContext getSchemaContext() {
1012             return Verify.verifyNotNull(schemaContextProvider.getSchemaContext());
1013         }
1014
1015         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
1016             return restoreFromSnapshot;
1017         }
1018
1019         public TipProducingDataTree getDataTree() {
1020             return dataTree;
1021         }
1022
1023         public TreeType getTreeType() {
1024             switch (datastoreContext.getLogicalStoreType()) {
1025                 case CONFIGURATION:
1026                     return TreeType.CONFIGURATION;
1027                 case OPERATIONAL:
1028                     return TreeType.OPERATIONAL;
1029                 default:
1030                     throw new IllegalStateException("Unhandled logical store type "
1031                             + datastoreContext.getLogicalStoreType());
1032             }
1033         }
1034
1035         protected void verify() {
1036             Preconditions.checkNotNull(id, "id should not be null");
1037             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
1038             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
1039             Preconditions.checkNotNull(schemaContextProvider, "schemaContextProvider should not be null");
1040         }
1041
1042         public Props props() {
1043             sealed = true;
1044             verify();
1045             return Props.create(shardClass, this);
1046         }
1047     }
1048
1049     public static class Builder extends AbstractBuilder<Builder, Shard> {
1050         private Builder() {
1051             super(Shard.class);
1052         }
1053     }
1054
1055     Ticker ticker() {
1056         return Ticker.systemTicker();
1057     }
1058
1059     void scheduleNextPendingTransaction() {
1060         self().tell(RESUME_NEXT_PENDING_TRANSACTION, ActorRef.noSender());
1061     }
1062 }