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 package org.opendaylight.controller.cluster.datastore;
   9
  10 import static com.google.common.base.Preconditions.checkState;
  11 import static com.google.common.base.Verify.verify;
  12 import static com.google.common.base.Verify.verifyNotNull;
  13 import static java.util.Objects.requireNonNull;
  14
  15 import akka.actor.ActorRef;
  16 import akka.actor.ActorSelection;
  17 import akka.actor.Cancellable;
  18 import akka.actor.ExtendedActorSystem;
  19 import akka.actor.PoisonPill;
  20 import akka.actor.Props;
  21 import akka.actor.Status;
  22 import akka.actor.Status.Failure;
  23 import akka.persistence.RecoveryCompleted;
  24 import akka.persistence.SnapshotOffer;
  25 import akka.serialization.JavaSerializer;
  26 import akka.serialization.Serialization;
  27 import com.google.common.annotations.VisibleForTesting;
  28 import com.google.common.base.Ticker;
  29 import com.google.common.collect.ImmutableList;
  30 import com.google.common.collect.ImmutableMap;
  31 import com.google.common.collect.ImmutableSet;
  32 import com.google.common.collect.Range;
  33 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  34 import java.io.IOException;
  35 import java.util.Arrays;
  36 import java.util.Collection;
  37 import java.util.Collections;
  38 import java.util.HashMap;
  39 import java.util.Map;
  40 import java.util.Optional;
  41 import java.util.OptionalLong;
  42 import java.util.concurrent.TimeUnit;
  43 import java.util.function.Supplier;
  44 import org.eclipse.jdt.annotation.NonNull;
  45 import org.eclipse.jdt.annotation.Nullable;
  46 import org.opendaylight.controller.cluster.access.ABIVersion;
  47 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  48 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  49 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
  50 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
  51 import org.opendaylight.controller.cluster.access.commands.OutOfSequenceEnvelopeException;
  52 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  53 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  54 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
  55 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  56 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  57 import org.opendaylight.controller.cluster.access.concepts.RequestSuccess;
  58 import org.opendaylight.controller.cluster.access.concepts.RetiredGenerationException;
  59 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
  60 import org.opendaylight.controller.cluster.access.concepts.SliceableMessage;
  61 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  62 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  63 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  64 import org.opendaylight.controller.cluster.common.actor.Dispatchers;
  65 import org.opendaylight.controller.cluster.common.actor.Dispatchers.DispatcherType;
  66 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  67 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  68 import org.opendaylight.controller.cluster.datastore.actors.JsonExportActor;
  69 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  70 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  71 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  72 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  73 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  74 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  75 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  76 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  77 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  78 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  79 import org.opendaylight.controller.cluster.datastore.messages.DataTreeChangedReply;
  80 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  81 import org.opendaylight.controller.cluster.datastore.messages.GetKnownClients;
  82 import org.opendaylight.controller.cluster.datastore.messages.GetKnownClientsReply;
  83 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  84 import org.opendaylight.controller.cluster.datastore.messages.MakeLeaderLocal;
  85 import org.opendaylight.controller.cluster.datastore.messages.OnDemandShardState;
  86 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  87 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  88 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  89 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  90 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  91 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot;
  92 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot.ShardSnapshot;
  93 import org.opendaylight.controller.cluster.datastore.persisted.DisableTrackingPayload;
  94 import org.opendaylight.controller.cluster.messaging.MessageAssembler;
  95 import org.opendaylight.controller.cluster.messaging.MessageSlicer;
  96 import org.opendaylight.controller.cluster.messaging.SliceOptions;
  97 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  98 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  99 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
 100 import org.opendaylight.controller.cluster.raft.LeadershipTransferFailedException;
 101 import org.opendaylight.controller.cluster.raft.RaftActor;
 102 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
 103 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
 104 import org.opendaylight.controller.cluster.raft.RaftState;
 105 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
 106 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
 107 import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
 108 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
 109 import org.opendaylight.controller.cluster.raft.messages.Payload;
 110 import org.opendaylight.controller.cluster.raft.messages.RequestLeadership;
 111 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
 112 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.config.distributed.datastore.provider.rev231229.DataStoreProperties.ExportOnRecovery;
 113 import org.opendaylight.yangtools.concepts.Identifier;
 114 import org.opendaylight.yangtools.yang.data.tree.api.DataTree;
 115 import org.opendaylight.yangtools.yang.data.tree.api.DataValidationFailedException;
 116 import org.opendaylight.yangtools.yang.data.tree.api.TreeType;
 117 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
 118 import scala.concurrent.duration.FiniteDuration;
 119
 120 /**
 121  * A Shard represents a portion of the logical data tree.
 122  *
 123  * <p>
 124  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
 125  */
 126 // FIXME: non-final for testing?
 127 public class Shard extends RaftActor {
 128
 129     @VisibleForTesting
 130     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
 131         @Override
 132         public String toString() {
 133             return "txCommitTimeoutCheck";
 134         }
 135     };
 136
 137     @VisibleForTesting
 138     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
 139         @Override
 140         public String toString() {
 141             return "getShardMBeanMessage";
 142         }
 143     };
 144
 145     static final Object RESUME_NEXT_PENDING_TRANSACTION = new Object() {
 146         @Override
 147         public String toString() {
 148             return "resumeNextPendingTransaction";
 149         }
 150     };
 151
 152     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
 153     public static final String DEFAULT_NAME = "default";
 154
 155     private static final Collection<ABIVersion> SUPPORTED_ABIVERSIONS;
 156
 157     // Make sure to keep this in sync with the journal configuration in factory-akka.conf
 158     public static final String NON_PERSISTENT_JOURNAL_ID = "akka.persistence.non-persistent.journal";
 159
 160     static {
 161         final ABIVersion[] values = ABIVersion.values();
 162         final ABIVersion[] real = Arrays.copyOfRange(values, 1, values.length - 1);
 163         SUPPORTED_ABIVERSIONS = ImmutableList.copyOf(real).reverse();
 164     }
 165
 166     // FIXME: make this a dynamic property based on mailbox size and maximum number of clients
 167     private static final int CLIENT_MAX_MESSAGES = 1000;
 168
 169     // The state of this Shard
 170     private final ShardDataTree store;
 171
 172     /// The name of this shard
 173     private final String name;
 174
 175     private final String shardName;
 176
 177     private final ShardStats shardMBean;
 178
 179     private final ShardDataTreeListenerInfoMXBeanImpl listenerInfoMXBean;
 180
 181     private DatastoreContext datastoreContext;
 182
 183     @Deprecated(since = "9.0.0", forRemoval = true)
 184     private final ShardCommitCoordinator commitCoordinator;
 185
 186     private long transactionCommitTimeout;
 187
 188     private Cancellable txCommitTimeoutCheckSchedule;
 189
 190     private final Optional<ActorRef> roleChangeNotifier;
 191
 192     private final MessageTracker appendEntriesReplyTracker;
 193
 194     @Deprecated(since = "9.0.0", forRemoval = true)
 195     private final ShardTransactionActorFactory transactionActorFactory;
 196
 197     private final ShardSnapshotCohort snapshotCohort;
 198
 199     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 200
 201     private ShardSnapshot restoreFromSnapshot;
 202
 203     @Deprecated(since = "9.0.0", forRemoval = true)
 204     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 205
 206     @VisibleForTesting
 207     final FrontendMetadata frontendMetadata;
 208
 209     private Map<FrontendIdentifier, LeaderFrontendState> knownFrontends = ImmutableMap.of();
 210     private boolean paused;
 211
 212     private final MessageSlicer responseMessageSlicer;
 213     private final Dispatchers dispatchers;
 214
 215     private final MessageAssembler requestMessageAssembler;
 216
 217     private final ExportOnRecovery exportOnRecovery;
 218
 219     private final ActorRef exportActor;
 220
 221     @SuppressFBWarnings(value = "MC_OVERRIDABLE_METHOD_CALL_IN_CONSTRUCTOR", justification = "Akka class design")
 222     Shard(final AbstractBuilder<?, ?> builder) {
 223         super(builder.getId().toString(), builder.getPeerAddresses(),
 224                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 225
 226         name = builder.getId().toString();
 227         shardName = builder.getId().getShardName();
 228         datastoreContext = builder.getDatastoreContext();
 229         restoreFromSnapshot = builder.getRestoreFromSnapshot();
 230         frontendMetadata = new FrontendMetadata(name);
 231         exportOnRecovery = datastoreContext.getExportOnRecovery();
 232
 233         exportActor = switch (exportOnRecovery) {
 234             case Json -> getContext().actorOf(JsonExportActor.props(builder.getSchemaContext(),
 235                 datastoreContext.getRecoveryExportBaseDir()));
 236             case Off -> null;
 237         };
 238
 239         setPersistence(datastoreContext.isPersistent());
 240
 241         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 242
 243         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 244                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher", name);
 245         if (builder.getDataTree() != null) {
 246             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 247                     treeChangeListenerPublisher, name,
 248                     frontendMetadata);
 249         } else {
 250             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 251                     builder.getDatastoreContext().getStoreRoot(), treeChangeListenerPublisher, name,
 252                     frontendMetadata);
 253         }
 254
 255         shardMBean = ShardStats.create(name, datastoreContext.getDataStoreMXBeanType(), this);
 256
 257         if (isMetricsCaptureEnabled()) {
 258             getContext().become(new MeteringBehavior(this));
 259         }
 260
 261         commitCoordinator = new ShardCommitCoordinator(store, LOG, name);
 262
 263         setTransactionCommitTimeout();
 264
 265         // create a notifier actor for each cluster member
 266         roleChangeNotifier = createRoleChangeNotifier(name);
 267
 268         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 269                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 270
 271         dispatchers = new Dispatchers(context().system().dispatchers());
 272         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 273             dispatchers.getDispatcherPath(Dispatchers.DispatcherType.Transaction),
 274                 self(), getContext(), shardMBean, builder.getId().getShardName());
 275
 276         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 277             name, datastoreContext);
 278
 279         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 280
 281         responseMessageSlicer = MessageSlicer.builder().logContext(name)
 282                 .messageSliceSize(datastoreContext.getMaximumMessageSliceSize())
 283                 .fileBackedStreamFactory(getRaftActorContext().getFileBackedOutputStreamFactory())
 284                 .expireStateAfterInactivity(2, TimeUnit.MINUTES).build();
 285
 286         requestMessageAssembler = MessageAssembler.builder().logContext(name)
 287                 .fileBackedStreamFactory(getRaftActorContext().getFileBackedOutputStreamFactory())
 288                 .assembledMessageCallback((message, sender) -> self().tell(message, sender))
 289                 .expireStateAfterInactivity(datastoreContext.getRequestTimeout(), TimeUnit.NANOSECONDS).build();
 290
 291         listenerInfoMXBean = new ShardDataTreeListenerInfoMXBeanImpl(name, datastoreContext.getDataStoreMXBeanType(),
 292                 self());
 293         listenerInfoMXBean.register();
 294     }
 295
 296     private void setTransactionCommitTimeout() {
 297         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 298                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 299     }
 300
 301     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 302         ActorRef shardRoleChangeNotifier = getContext().actorOf(
 303             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 304         return Optional.of(shardRoleChangeNotifier);
 305     }
 306
 307     @Override
 308     public final void postStop() throws Exception {
 309         LOG.info("Stopping Shard {}", persistenceId());
 310
 311         super.postStop();
 312
 313         messageRetrySupport.close();
 314
 315         if (txCommitTimeoutCheckSchedule != null) {
 316             txCommitTimeoutCheckSchedule.cancel();
 317         }
 318
 319         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 320
 321         shardMBean.unregisterMBean();
 322         listenerInfoMXBean.unregister();
 323     }
 324
 325     @Override
 326     protected final void handleRecover(final Object message) {
 327         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 328             getSender());
 329
 330         super.handleRecover(message);
 331
 332         switch (exportOnRecovery) {
 333             case Json:
 334                 if (message instanceof SnapshotOffer) {
 335                     exportActor.tell(new JsonExportActor.ExportSnapshot(store.readCurrentData().orElseThrow(), name),
 336                             ActorRef.noSender());
 337                 } else if (message instanceof ReplicatedLogEntry replicatedLogEntry) {
 338                     exportActor.tell(new JsonExportActor.ExportJournal(replicatedLogEntry), ActorRef.noSender());
 339                 } else if (message instanceof RecoveryCompleted) {
 340                     exportActor.tell(new JsonExportActor.FinishExport(name), ActorRef.noSender());
 341                     exportActor.tell(PoisonPill.getInstance(), ActorRef.noSender());
 342                 }
 343                 break;
 344             case Off:
 345             default:
 346                 break;
 347         }
 348
 349         if (LOG.isTraceEnabled()) {
 350             appendEntriesReplyTracker.begin();
 351         }
 352     }
 353
 354     @Override
 355     // non-final for TestShard
 356     protected void handleNonRaftCommand(final Object message) {
 357         try (var context = appendEntriesReplyTracker.received(message)) {
 358             final var maybeError = context.error();
 359             if (maybeError.isPresent()) {
 360                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 361                     maybeError.orElseThrow());
 362             }
 363
 364             store.resetTransactionBatch();
 365
 366             if (message instanceof RequestEnvelope request) {
 367                 handleRequestEnvelope(request);
 368             } else if (MessageAssembler.isHandledMessage(message)) {
 369                 handleRequestAssemblerMessage(message);
 370             } else if (message instanceof ConnectClientRequest request) {
 371                 handleConnectClient(request);
 372             } else if (message instanceof DataTreeChangedReply) {
 373                 // Ignore reply
 374             } else if (message instanceof RegisterDataTreeChangeListener request) {
 375                 treeChangeSupport.onMessage(request, isLeader(), hasLeader());
 376             } else if (message instanceof UpdateSchemaContext request) {
 377                 updateSchemaContext(request);
 378             } else if (message instanceof PeerAddressResolved resolved) {
 379                 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
 380             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 381                 commitTimeoutCheck();
 382             } else if (message instanceof DatastoreContext request) {
 383                 onDatastoreContext(request);
 384             } else if (message instanceof RegisterRoleChangeListener) {
 385                 roleChangeNotifier.orElseThrow().forward(message, context());
 386             } else if (message instanceof FollowerInitialSyncUpStatus request) {
 387                 shardMBean.setFollowerInitialSyncStatus(request.isInitialSyncDone());
 388                 context().parent().tell(message, self());
 389             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 390                 sender().tell(getShardMBean(), self());
 391             } else if (message instanceof GetShardDataTree) {
 392                 sender().tell(store.getDataTree(), self());
 393             } else if (message instanceof ServerRemoved) {
 394                 context().parent().forward(message, context());
 395             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand request) {
 396                 store.processCohortRegistryCommand(getSender(), request);
 397             } else if (message instanceof MakeLeaderLocal) {
 398                 onMakeLeaderLocal();
 399             } else if (RESUME_NEXT_PENDING_TRANSACTION.equals(message)) {
 400                 store.resumeNextPendingTransaction();
 401             } else if (GetKnownClients.INSTANCE.equals(message)) {
 402                 handleGetKnownClients();
 403             } else if (!responseMessageSlicer.handleMessage(message)) {
 404                 // Ask-based protocol messages
 405                 if (CreateTransaction.isSerializedType(message)) {
 406                     handleCreateTransaction(message);
 407                 } else if (message instanceof BatchedModifications request) {
 408                     handleBatchedModifications(request);
 409                 } else if (message instanceof ForwardedReadyTransaction request) {
 410                     handleForwardedReadyTransaction(request);
 411                 } else if (message instanceof ReadyLocalTransaction request) {
 412                     handleReadyLocalTransaction(request);
 413                 } else if (CanCommitTransaction.isSerializedType(message)) {
 414                     handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 415                 } else if (CommitTransaction.isSerializedType(message)) {
 416                     handleCommitTransaction(CommitTransaction.fromSerializable(message));
 417                 } else if (AbortTransaction.isSerializedType(message)) {
 418                     handleAbortTransaction(AbortTransaction.fromSerializable(message));
 419                 } else if (CloseTransactionChain.isSerializedType(message)) {
 420                     closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 421                 } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 422                     messageRetrySupport.onTimerMessage(message);
 423                 } else {
 424                     super.handleNonRaftCommand(message);
 425                 }
 426             }
 427         }
 428     }
 429
 430     private void handleRequestAssemblerMessage(final Object message) {
 431         dispatchers.getDispatcher(DispatcherType.Serialization).execute(() -> {
 432             JavaSerializer.currentSystem().value_$eq((ExtendedActorSystem) context().system());
 433             requestMessageAssembler.handleMessage(message, self());
 434         });
 435     }
 436
 437     @SuppressWarnings("checkstyle:IllegalCatch")
 438     private void handleRequestEnvelope(final RequestEnvelope envelope) {
 439         final long now = ticker().read();
 440         try {
 441             final RequestSuccess<?, ?> success = handleRequest(envelope, now);
 442             if (success != null) {
 443                 final long executionTimeNanos = ticker().read() - now;
 444                 if (success instanceof SliceableMessage) {
 445                     dispatchers.getDispatcher(DispatcherType.Serialization).execute(() ->
 446                         responseMessageSlicer.slice(SliceOptions.builder().identifier(success.getTarget())
 447                             .message(envelope.newSuccessEnvelope(success, executionTimeNanos))
 448                             .sendTo(envelope.getMessage().getReplyTo()).replyTo(self())
 449                             .onFailureCallback(t -> LOG.warn("Error slicing response {}", success, t)).build()));
 450                 } else {
 451                     envelope.sendSuccess(success, executionTimeNanos);
 452                 }
 453             }
 454         } catch (RequestException e) {
 455             LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
 456             envelope.sendFailure(e, ticker().read() - now);
 457         } catch (Exception e) {
 458             LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
 459             envelope.sendFailure(new RuntimeRequestException("Request failed to process", e),
 460                 ticker().read() - now);
 461         }
 462     }
 463
 464     private void commitTimeoutCheck() {
 465         store.checkForExpiredTransactions(transactionCommitTimeout, this::updateAccess);
 466         commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 467         requestMessageAssembler.checkExpiredAssembledMessageState();
 468     }
 469
 470     private OptionalLong updateAccess(final SimpleShardDataTreeCohort cohort) {
 471         final FrontendIdentifier frontend = cohort.transactionId().getHistoryId().getClientId().getFrontendId();
 472         final LeaderFrontendState state = knownFrontends.get(frontend);
 473         if (state == null) {
 474             // Not tell-based protocol, do nothing
 475             return OptionalLong.empty();
 476         }
 477
 478         if (isIsolatedLeader()) {
 479             // We are isolated and no new request can come through until we emerge from it. We are still updating
 480             // liveness of frontend when we see it attempting to communicate. Use the last access timer.
 481             return OptionalLong.of(state.getLastSeenTicks());
 482         }
 483
 484         // If this frontend has freshly connected, give it some time to catch up before killing its transactions.
 485         return OptionalLong.of(state.getLastConnectTicks());
 486     }
 487
 488     private void disableTracking(final DisableTrackingPayload payload) {
 489         final ClientIdentifier clientId = payload.getIdentifier();
 490         LOG.debug("{}: disabling tracking of {}", persistenceId(), clientId);
 491         frontendMetadata.disableTracking(clientId);
 492
 493         if (isLeader()) {
 494             final FrontendIdentifier frontendId = clientId.getFrontendId();
 495             final LeaderFrontendState frontend = knownFrontends.get(frontendId);
 496             if (frontend != null) {
 497                 if (clientId.equals(frontend.getIdentifier())) {
 498                     if (!(frontend instanceof LeaderFrontendState.Disabled)) {
 499                         verify(knownFrontends.replace(frontendId, frontend,
 500                             new LeaderFrontendState.Disabled(persistenceId(), clientId, store)));
 501                         LOG.debug("{}: leader state for {} disabled", persistenceId(), clientId);
 502                     } else {
 503                         LOG.debug("{}: leader state {} is already disabled", persistenceId(), frontend);
 504                     }
 505                 } else {
 506                     LOG.debug("{}: leader state {} does not match {}", persistenceId(), frontend, clientId);
 507                 }
 508             } else {
 509                 LOG.debug("{}: leader state for {} not found", persistenceId(), clientId);
 510                 knownFrontends.put(frontendId, new LeaderFrontendState.Disabled(persistenceId(), clientId,
 511                     getDataStore()));
 512             }
 513         }
 514     }
 515
 516     private void onMakeLeaderLocal() {
 517         LOG.debug("{}: onMakeLeaderLocal received", persistenceId());
 518         if (isLeader()) {
 519             getSender().tell(new Status.Success(null), getSelf());
 520             return;
 521         }
 522
 523         final ActorSelection leader = getLeader();
 524
 525         if (leader == null) {
 526             // Leader is not present. The cluster is most likely trying to
 527             // elect a leader and we should let that run its normal course
 528
 529             // TODO we can wait for the election to complete and retry the
 530             // request. We can also let the caller retry by sending a flag
 531             // in the response indicating the request is "reTryable".
 532             getSender().tell(new Failure(
 533                     new LeadershipTransferFailedException("We cannot initiate leadership transfer to local node. "
 534                             + "Currently there is no leader for " + persistenceId())),
 535                     getSelf());
 536             return;
 537         }
 538
 539         leader.tell(new RequestLeadership(getId(), getSender()), getSelf());
 540     }
 541
 542     // Acquire our frontend tracking handle and verify generation matches
 543     private @Nullable LeaderFrontendState findFrontend(final ClientIdentifier clientId) throws RequestException {
 544         final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
 545         if (existing != null) {
 546             final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
 547             if (cmp == 0) {
 548                 existing.touch();
 549                 return existing;
 550             }
 551             if (cmp > 0) {
 552                 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
 553                 throw new RetiredGenerationException(clientId.getGeneration(),
 554                     existing.getIdentifier().getGeneration());
 555             }
 556
 557             LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
 558             existing.retire();
 559             knownFrontends.remove(clientId.getFrontendId());
 560         } else {
 561             LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
 562         }
 563
 564         return null;
 565     }
 566
 567     private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
 568         final LeaderFrontendState ret = findFrontend(clientId);
 569         if (ret != null) {
 570             return ret;
 571         }
 572
 573         // TODO: a dedicated exception would be better, but this is technically true, too
 574         throw new OutOfSequenceEnvelopeException(0);
 575     }
 576
 577     private static @NonNull ABIVersion selectVersion(final ConnectClientRequest message) {
 578         final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
 579         for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
 580             if (clientRange.contains(v)) {
 581                 return v;
 582             }
 583         }
 584
 585         throw new IllegalArgumentException(String.format(
 586             "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
 587             clientRange));
 588     }
 589
 590     @SuppressWarnings("checkstyle:IllegalCatch")
 591     private void handleConnectClient(final ConnectClientRequest message) {
 592         try {
 593             final ClientIdentifier clientId = message.getTarget();
 594             final LeaderFrontendState existing = findFrontend(clientId);
 595             if (existing != null) {
 596                 existing.touch();
 597             }
 598
 599             if (!isLeader() || !isLeaderActive()) {
 600                 LOG.info("{}: not currently leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 601                                 + "isLeadershipTransferInProgress: {}.",
 602                         persistenceId(), message, isLeader(), isLeaderActive(), isLeadershipTransferInProgress());
 603                 throw new NotLeaderException(getSelf());
 604             }
 605
 606             final ABIVersion selectedVersion = selectVersion(message);
 607             final LeaderFrontendState frontend;
 608             if (existing == null) {
 609                 frontend = new LeaderFrontendState.Enabled(persistenceId(), clientId, store);
 610                 knownFrontends.put(clientId.getFrontendId(), frontend);
 611                 LOG.debug("{}: created state {} for client {}", persistenceId(), frontend, clientId);
 612             } else {
 613                 frontend = existing;
 614             }
 615
 616             frontend.reconnect();
 617             message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
 618                 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
 619                 ActorRef.noSender());
 620         } catch (RequestException | RuntimeException e) {
 621             message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
 622         }
 623     }
 624
 625     private @Nullable RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope, final long now)
 626             throws RequestException {
 627         // We are not the leader, hence we want to fail-fast.
 628         if (!isLeader() || paused || !isLeaderActive()) {
 629             LOG.debug("{}: not currently active leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 630                             + "isLeadershipTransferInProgress: {}, paused: {}",
 631                     persistenceId(), envelope, isLeader(), isLeaderActive(), isLeadershipTransferInProgress(), paused);
 632             throw new NotLeaderException(getSelf());
 633         }
 634
 635         final var request = envelope.getMessage();
 636         if (request instanceof TransactionRequest<?> txReq) {
 637             final var clientId = txReq.getTarget().getHistoryId().getClientId();
 638             return getFrontend(clientId).handleTransactionRequest(txReq, envelope, now);
 639         } else if (request instanceof LocalHistoryRequest<?> lhReq) {
 640             final var clientId = lhReq.getTarget().getClientId();
 641             return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope, now);
 642         } else {
 643             LOG.warn("{}: rejecting unsupported request {}", persistenceId(), request);
 644             throw new UnsupportedRequestException(request);
 645         }
 646     }
 647
 648     private void handleGetKnownClients() {
 649         final ImmutableSet<ClientIdentifier> clients;
 650         if (isLeader()) {
 651             clients = knownFrontends.values().stream()
 652                     .map(LeaderFrontendState::getIdentifier)
 653                     .collect(ImmutableSet.toImmutableSet());
 654         } else {
 655             clients = frontendMetadata.getClients();
 656         }
 657         sender().tell(new GetKnownClientsReply(clients), self());
 658     }
 659
 660     private boolean hasLeader() {
 661         return getLeaderId() != null;
 662     }
 663
 664     final int getPendingTxCommitQueueSize() {
 665         return store.getQueueSize();
 666     }
 667
 668     final int getCohortCacheSize() {
 669         return commitCoordinator.getCohortCacheSize();
 670     }
 671
 672     @Override
 673     protected final Optional<ActorRef> getRoleChangeNotifier() {
 674         return roleChangeNotifier;
 675     }
 676
 677     final String getShardName() {
 678         return shardName;
 679     }
 680
 681     @Override
 682     protected final LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 683             final short leaderPayloadVersion) {
 684         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 685                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 686     }
 687
 688     private void onDatastoreContext(final DatastoreContext context) {
 689         datastoreContext = verifyNotNull(context);
 690
 691         setTransactionCommitTimeout();
 692
 693         setPersistence(datastoreContext.isPersistent());
 694
 695         updateConfigParams(datastoreContext.getShardRaftConfig());
 696     }
 697
 698     // applyState() will be invoked once consensus is reached on the payload
 699     // non-final for mocking
 700     void persistPayload(final Identifier id, final Payload payload, final boolean batchHint) {
 701         final boolean canSkipPayload = !hasFollowers() && !persistence().isRecoveryApplicable();
 702         if (canSkipPayload) {
 703             applyState(self(), id, payload);
 704         } else {
 705             // We are faking the sender
 706             persistData(self(), id, payload, batchHint);
 707         }
 708     }
 709
 710     @Deprecated(since = "9.0.0", forRemoval = true)
 711     private void handleCommitTransaction(final CommitTransaction commit) {
 712         final var txId = commit.getTransactionId();
 713         if (isLeader()) {
 714             askProtocolEncountered(txId);
 715             commitCoordinator.handleCommit(txId, getSender(), this);
 716         } else {
 717             final var leader = getLeader();
 718             if (leader == null) {
 719                 messageRetrySupport.addMessageToRetry(commit, getSender(), "Could not commit transaction " + txId);
 720             } else {
 721                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 722                 leader.forward(commit, getContext());
 723             }
 724         }
 725     }
 726
 727     @Deprecated(since = "9.0.0", forRemoval = true)
 728     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 729         final var txId = canCommit.getTransactionId();
 730         LOG.debug("{}: Can committing transaction {}", persistenceId(), txId);
 731
 732         if (isLeader()) {
 733             askProtocolEncountered(txId);
 734             commitCoordinator.handleCanCommit(txId, getSender(), this);
 735         } else {
 736             final var leader = getLeader();
 737             if (leader == null) {
 738                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 739                         "Could not canCommit transaction " + txId);
 740             } else {
 741                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 742                 leader.forward(canCommit, getContext());
 743             }
 744         }
 745     }
 746
 747     @SuppressWarnings("checkstyle:IllegalCatch")
 748     @Deprecated(since = "9.0.0", forRemoval = true)
 749     private void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 750         askProtocolEncountered(batched.getTransactionId());
 751
 752         try {
 753             commitCoordinator.handleBatchedModifications(batched, sender, this);
 754         } catch (Exception e) {
 755             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 756                     batched.getTransactionId(), e);
 757             sender.tell(new Failure(e), getSelf());
 758         }
 759     }
 760
 761     @Deprecated(since = "9.0.0", forRemoval = true)
 762     private void handleBatchedModifications(final BatchedModifications batched) {
 763         // This message is sent to prepare the modifications transaction directly on the Shard as an
 764         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 765         // BatchedModifications message, the caller sets the ready flag in the message indicating
 766         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 767         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 768         // ReadyTransaction message.
 769
 770         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 771         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 772         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 773         // window where it could have a stale leader during leadership transitions.
 774         //
 775         boolean isLeaderActive = isLeaderActive();
 776         if (isLeader() && isLeaderActive) {
 777             handleBatchedModificationsLocal(batched, getSender());
 778         } else {
 779             final var leader = getLeader();
 780             if (!isLeaderActive || leader == null) {
 781                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 782                         "Could not process BatchedModifications " + batched.getTransactionId());
 783             } else {
 784                 // If this is not the first batch and leadership changed in between batched messages,
 785                 // we need to reconstruct previous BatchedModifications from the transaction
 786                 // DataTreeModification, honoring the max batched modification count, and forward all the
 787                 // previous BatchedModifications to the new leader.
 788                 final var newModifications = commitCoordinator.createForwardedBatchedModifications(batched,
 789                     datastoreContext.getShardBatchedModificationCount());
 790
 791                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 792                         newModifications.size(), leader);
 793
 794                 for (BatchedModifications bm : newModifications) {
 795                     leader.forward(bm, getContext());
 796                 }
 797             }
 798         }
 799     }
 800
 801     private boolean failIfIsolatedLeader(final ActorRef sender) {
 802         if (isIsolatedLeader()) {
 803             sender.tell(new Failure(new NoShardLeaderException(String.format(
 804                     "Shard %s was the leader but has lost contact with all of its followers. Either all"
 805                     + " other follower nodes are down or this node is isolated by a network partition.",
 806                     persistenceId()))), getSelf());
 807             return true;
 808         }
 809
 810         return false;
 811     }
 812
 813     protected boolean isIsolatedLeader() {
 814         return getRaftState() == RaftState.IsolatedLeader;
 815     }
 816
 817     @SuppressWarnings("checkstyle:IllegalCatch")
 818     @Deprecated(since = "9.0.0", forRemoval = true)
 819    private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 820         final var txId = message.getTransactionId();
 821         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), txId);
 822
 823         final var isLeaderActive = isLeaderActive();
 824         if (isLeader() && isLeaderActive) {
 825             askProtocolEncountered(txId);
 826             try {
 827                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 828             } catch (Exception e) {
 829                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(), txId, e);
 830                 getSender().tell(new Failure(e), getSelf());
 831             }
 832         } else {
 833             final var leader = getLeader();
 834             if (!isLeaderActive || leader == null) {
 835                 messageRetrySupport.addMessageToRetry(message, getSender(),
 836                         "Could not process ready local transaction " + txId);
 837             } else {
 838                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 839                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 840                 leader.forward(message, getContext());
 841             }
 842         }
 843     }
 844
 845     @Deprecated(since = "9.0.0", forRemoval = true)
 846     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 847         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
 848
 849         final var isLeaderActive = isLeaderActive();
 850         if (isLeader() && isLeaderActive) {
 851             askProtocolEncountered(forwardedReady.getTransactionId());
 852             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 853         } else {
 854             final var leader = getLeader();
 855             if (!isLeaderActive || leader == null) {
 856                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 857                         "Could not process forwarded ready transaction " + forwardedReady.getTransactionId());
 858             } else {
 859                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 860
 861                 final var readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
 862                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit(),
 863                         forwardedReady.getParticipatingShardNames());
 864                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 865                 leader.forward(readyLocal, getContext());
 866             }
 867         }
 868     }
 869
 870     @Deprecated(since = "9.0.0", forRemoval = true)
 871     private void handleAbortTransaction(final AbortTransaction abort) {
 872         final var transactionId = abort.getTransactionId();
 873         askProtocolEncountered(transactionId);
 874         doAbortTransaction(transactionId, getSender());
 875     }
 876
 877     final void doAbortTransaction(final Identifier transactionID, final ActorRef sender) {
 878         commitCoordinator.handleAbort(transactionID, sender, this);
 879     }
 880
 881     @Deprecated(since = "9.0.0", forRemoval = true)
 882     private void handleCreateTransaction(final Object message) {
 883         if (isLeader()) {
 884             createTransaction(CreateTransaction.fromSerializable(message));
 885         } else if (getLeader() != null) {
 886             getLeader().forward(message, getContext());
 887         } else {
 888             getSender().tell(new Failure(new NoShardLeaderException(
 889                     "Could not create a shard transaction", persistenceId())), getSelf());
 890         }
 891     }
 892
 893     @Deprecated(since = "9.0.0", forRemoval = true)
 894     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 895         if (isLeader()) {
 896             final var id = closeTransactionChain.getIdentifier();
 897             askProtocolEncountered(id.getClientId());
 898             store.closeTransactionChain(id);
 899         } else if (getLeader() != null) {
 900             getLeader().forward(closeTransactionChain, getContext());
 901         } else {
 902             LOG.warn("{}: Could not close transaction {}", persistenceId(), closeTransactionChain.getIdentifier());
 903         }
 904     }
 905
 906     @Deprecated(since = "9.0.0", forRemoval = true)
 907     @SuppressWarnings("checkstyle:IllegalCatch")
 908     private void createTransaction(final CreateTransaction createTransaction) {
 909         askProtocolEncountered(createTransaction.getTransactionId());
 910
 911         try {
 912             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 913                     && failIfIsolatedLeader(getSender())) {
 914                 return;
 915             }
 916
 917             final var transactionActor = createTransaction(createTransaction.getTransactionType(),
 918                 createTransaction.getTransactionId());
 919
 920             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 921                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 922         } catch (Exception e) {
 923             getSender().tell(new Failure(e), getSelf());
 924         }
 925     }
 926
 927     @Deprecated(since = "9.0.0", forRemoval = true)
 928     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 929         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 930         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 931             transactionId);
 932     }
 933
 934     // Called on leader only
 935     @Deprecated(since = "9.0.0", forRemoval = true)
 936     private void askProtocolEncountered(final TransactionIdentifier transactionId) {
 937         askProtocolEncountered(transactionId.getHistoryId().getClientId());
 938     }
 939
 940     // Called on leader only
 941     @Deprecated(since = "9.0.0", forRemoval = true)
 942     private void askProtocolEncountered(final ClientIdentifier clientId) {
 943         final var frontend = clientId.getFrontendId();
 944         final var state = knownFrontends.get(frontend);
 945         if (!(state instanceof LeaderFrontendState.Disabled)) {
 946             LOG.debug("{}: encountered ask-based client {}, disabling transaction tracking", persistenceId(), clientId);
 947             if (knownFrontends.isEmpty()) {
 948                 knownFrontends = new HashMap<>();
 949             }
 950             knownFrontends.put(frontend, new LeaderFrontendState.Disabled(persistenceId(), clientId, getDataStore()));
 951
 952             persistPayload(clientId, DisableTrackingPayload.create(clientId,
 953                 datastoreContext.getInitialPayloadSerializedBufferCapacity()), false);
 954         }
 955     }
 956
 957     private void updateSchemaContext(final UpdateSchemaContext message) {
 958         updateSchemaContext(message.modelContext());
 959     }
 960
 961     @VisibleForTesting
 962     void updateSchemaContext(final @NonNull EffectiveModelContext schemaContext) {
 963         store.updateSchemaContext(schemaContext);
 964     }
 965
 966     private boolean isMetricsCaptureEnabled() {
 967         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 968         return config.isMetricCaptureEnabled();
 969     }
 970
 971     @Override
 972     protected final RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 973         return snapshotCohort;
 974     }
 975
 976     @Override
 977     protected final RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 978         if (restoreFromSnapshot == null) {
 979             return ShardRecoveryCoordinator.create(store, persistenceId(), LOG);
 980         }
 981
 982         return ShardRecoveryCoordinator.forSnapshot(store, persistenceId(), LOG, restoreFromSnapshot.getSnapshot());
 983     }
 984
 985     @Override
 986     // non-final for testing
 987     protected void onRecoveryComplete() {
 988         restoreFromSnapshot = null;
 989
 990         //notify shard manager
 991         getContext().parent().tell(new ActorInitialized(getSelf()), ActorRef.noSender());
 992
 993         // Being paranoid here - this method should only be called once but just in case...
 994         if (txCommitTimeoutCheckSchedule == null) {
 995             // Schedule a message to be periodically sent to check if the current in-progress
 996             // transaction should be expired and aborted.
 997             final var period = FiniteDuration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 998             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 999                     period, period, getSelf(),
1000                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
1001         }
1002     }
1003
1004     @Override
1005     protected final void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
1006         if (data instanceof Payload payload) {
1007             if (payload instanceof DisableTrackingPayload disableTracking) {
1008                 disableTracking(disableTracking);
1009                 return;
1010             }
1011
1012             try {
1013                 store.applyReplicatedPayload(identifier, payload);
1014             } catch (DataValidationFailedException | IOException e) {
1015                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
1016             }
1017         } else {
1018             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
1019         }
1020     }
1021
1022     @Override
1023     protected final void onStateChanged() {
1024         boolean isLeader = isLeader();
1025         boolean hasLeader = hasLeader();
1026         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
1027
1028         // If this actor is no longer the leader close all the transaction chains
1029         if (!isLeader) {
1030             if (LOG.isDebugEnabled()) {
1031                 LOG.debug(
1032                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
1033                     persistenceId(), getId());
1034             }
1035
1036             paused = false;
1037             store.purgeLeaderState();
1038         }
1039
1040         if (hasLeader && !isIsolatedLeader()) {
1041             messageRetrySupport.retryMessages();
1042         }
1043     }
1044
1045     @Override
1046     protected final void onLeaderChanged(final String oldLeader, final String newLeader) {
1047         shardMBean.incrementLeadershipChangeCount();
1048         paused = false;
1049
1050         if (!isLeader()) {
1051             if (!knownFrontends.isEmpty()) {
1052                 LOG.debug("{}: removing frontend state for {}", persistenceId(), knownFrontends.keySet());
1053                 knownFrontends = ImmutableMap.of();
1054             }
1055
1056             requestMessageAssembler.close();
1057
1058             if (!hasLeader()) {
1059                 // No leader anywhere, nothing else to do
1060                 return;
1061             }
1062
1063             // Another leader was elected. If we were the previous leader and had pending transactions, convert
1064             // them to transaction messages and send to the new leader.
1065             ActorSelection leader = getLeader();
1066             if (leader != null) {
1067                 // Clears all pending transactions and converts them to messages to be forwarded to a new leader.
1068                 Collection<?> messagesToForward = commitCoordinator.convertPendingTransactionsToMessages(
1069                     datastoreContext.getShardBatchedModificationCount());
1070
1071                 if (!messagesToForward.isEmpty()) {
1072                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
1073                             messagesToForward.size(), leader);
1074
1075                     for (Object message : messagesToForward) {
1076                         LOG.debug("{}: Forwarding pending transaction message {}", persistenceId(), message);
1077
1078                         leader.tell(message, self());
1079                     }
1080                 }
1081             } else {
1082                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
1083                         + "change and the leader address isn't available.", this);
1084             }
1085         } else {
1086             // We have become the leader, we need to reconstruct frontend state
1087             knownFrontends = verifyNotNull(frontendMetadata.toLeaderState(this));
1088             LOG.debug("{}: became leader with frontend state for {}", persistenceId(), knownFrontends.keySet());
1089         }
1090
1091         if (!isIsolatedLeader()) {
1092             messageRetrySupport.retryMessages();
1093         }
1094     }
1095
1096     @Override
1097     protected final void pauseLeader(final Runnable operation) {
1098         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
1099         paused = true;
1100
1101         // Tell-based protocol can replay transaction state, so it is safe to blow it up when we are paused.
1102         knownFrontends.values().forEach(LeaderFrontendState::retire);
1103         knownFrontends = ImmutableMap.of();
1104
1105         store.setRunOnPendingTransactionsComplete(operation);
1106     }
1107
1108     @Override
1109     protected final void unpauseLeader() {
1110         LOG.debug("{}: In unpauseLeader", persistenceId());
1111         paused = false;
1112
1113         store.setRunOnPendingTransactionsComplete(null);
1114
1115         // Restore tell-based protocol state as if we were becoming the leader
1116         knownFrontends = verifyNotNull(frontendMetadata.toLeaderState(this));
1117     }
1118
1119     @Override
1120     protected final OnDemandRaftState.AbstractBuilder<?, ?> newOnDemandRaftStateBuilder() {
1121         return OnDemandShardState.newBuilder()
1122             .treeChangeListenerActors(treeChangeSupport.getListenerActors())
1123             .commitCohortActors(store.getCohortActors());
1124     }
1125
1126     @Override
1127     public final String persistenceId() {
1128         return name;
1129     }
1130
1131     @Override
1132     public final String journalPluginId() {
1133         // This method may be invoked from super constructor (wonderful), hence we also need to handle the case of
1134         // the field being uninitialized because our constructor is not finished.
1135         if (datastoreContext != null && !datastoreContext.isPersistent()) {
1136             return NON_PERSISTENT_JOURNAL_ID;
1137         }
1138         return super.journalPluginId();
1139     }
1140
1141     @VisibleForTesting
1142     final ShardCommitCoordinator getCommitCoordinator() {
1143         return commitCoordinator;
1144     }
1145
1146     // non-final for mocking
1147     DatastoreContext getDatastoreContext() {
1148         return datastoreContext;
1149     }
1150
1151     @VisibleForTesting
1152     final ShardDataTree getDataStore() {
1153         return store;
1154     }
1155
1156     @VisibleForTesting
1157     // non-final for mocking
1158     ShardStats getShardMBean() {
1159         return shardMBean;
1160     }
1161
1162     public static Builder builder() {
1163         return new Builder();
1164     }
1165
1166     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
1167         private final Class<? extends S> shardClass;
1168         private ShardIdentifier id;
1169         private Map<String, String> peerAddresses = Collections.emptyMap();
1170         private DatastoreContext datastoreContext;
1171         private Supplier<@NonNull EffectiveModelContext> schemaContextProvider;
1172         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
1173         private DataTree dataTree;
1174
1175         private volatile boolean sealed;
1176
1177         AbstractBuilder(final Class<? extends S> shardClass) {
1178             this.shardClass = shardClass;
1179         }
1180
1181         final void checkSealed() {
1182             checkState(!sealed, "Builder is already sealed - further modifications are not allowed");
1183         }
1184
1185         @SuppressWarnings("unchecked")
1186         private T self() {
1187             return (T) this;
1188         }
1189
1190         public T id(final ShardIdentifier newId) {
1191             checkSealed();
1192             id = newId;
1193             return self();
1194         }
1195
1196         public T peerAddresses(final Map<String, String> newPeerAddresses) {
1197             checkSealed();
1198             peerAddresses = newPeerAddresses;
1199             return self();
1200         }
1201
1202         public T datastoreContext(final DatastoreContext newDatastoreContext) {
1203             checkSealed();
1204             datastoreContext = newDatastoreContext;
1205             return self();
1206         }
1207
1208         public T schemaContextProvider(final Supplier<@NonNull EffectiveModelContext> newSchemaContextProvider) {
1209             checkSealed();
1210             schemaContextProvider = requireNonNull(newSchemaContextProvider);
1211             return self();
1212         }
1213
1214         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
1215             checkSealed();
1216             restoreFromSnapshot = newRestoreFromSnapshot;
1217             return self();
1218         }
1219
1220         public T dataTree(final DataTree newDataTree) {
1221             checkSealed();
1222             dataTree = newDataTree;
1223             return self();
1224         }
1225
1226         public ShardIdentifier getId() {
1227             return id;
1228         }
1229
1230         public Map<String, String> getPeerAddresses() {
1231             return peerAddresses;
1232         }
1233
1234         public DatastoreContext getDatastoreContext() {
1235             return datastoreContext;
1236         }
1237
1238         public EffectiveModelContext getSchemaContext() {
1239             return verifyNotNull(schemaContextProvider.get());
1240         }
1241
1242         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
1243             return restoreFromSnapshot;
1244         }
1245
1246         public DataTree getDataTree() {
1247             return dataTree;
1248         }
1249
1250         public TreeType getTreeType() {
1251             return switch (datastoreContext.getLogicalStoreType()) {
1252                 case CONFIGURATION -> TreeType.CONFIGURATION;
1253                 case OPERATIONAL -> TreeType.OPERATIONAL;
1254             };
1255         }
1256
1257         protected void verify() {
1258             requireNonNull(id, "id should not be null");
1259             requireNonNull(peerAddresses, "peerAddresses should not be null");
1260             requireNonNull(datastoreContext, "dataStoreContext should not be null");
1261             requireNonNull(schemaContextProvider, "schemaContextProvider should not be null");
1262         }
1263
1264         public Props props() {
1265             sealed = true;
1266             verify();
1267             return Props.create(shardClass, this);
1268         }
1269     }
1270
1271     public static class Builder extends AbstractBuilder<Builder, Shard> {
1272         Builder() {
1273             this(Shard.class);
1274         }
1275
1276         Builder(final Class<? extends Shard> shardClass) {
1277             super(shardClass);
1278         }
1279     }
1280
1281     Ticker ticker() {
1282         return Ticker.systemTicker();
1283     }
1284
1285     void scheduleNextPendingTransaction() {
1286         self().tell(RESUME_NEXT_PENDING_TRANSACTION, ActorRef.noSender());
1287     }
1288 }