opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/Shard.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.controller.cluster.datastore;
  10
  11 import akka.actor.ActorRef;
  12 import akka.actor.ActorSelection;
  13 import akka.actor.Cancellable;
  14 import akka.actor.Props;
  15 import akka.actor.Status;
  16 import akka.actor.Status.Failure;
  17 import akka.serialization.Serialization;
  18 import com.google.common.annotations.VisibleForTesting;
  19 import com.google.common.base.Optional;
  20 import com.google.common.base.Preconditions;
  21 import com.google.common.base.Ticker;
  22 import com.google.common.base.Verify;
  23 import com.google.common.collect.ImmutableList;
  24 import com.google.common.collect.ImmutableMap;
  25 import com.google.common.collect.Range;
  26 import java.io.IOException;
  27 import java.util.Arrays;
  28 import java.util.Collection;
  29 import java.util.Collections;
  30 import java.util.Map;
  31 import java.util.concurrent.TimeUnit;
  32 import javax.annotation.Nonnull;
  33 import javax.annotation.Nullable;
  34 import org.opendaylight.controller.cluster.access.ABIVersion;
  35 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  36 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  37 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
  38 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
  39 import org.opendaylight.controller.cluster.access.commands.OutOfSequenceEnvelopeException;
  40 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  41 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  42 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
  43 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  44 import org.opendaylight.controller.cluster.access.concepts.Request;
  45 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  46 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  47 import org.opendaylight.controller.cluster.access.concepts.RequestSuccess;
  48 import org.opendaylight.controller.cluster.access.concepts.RetiredGenerationException;
  49 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
  50 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  51 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  52 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
  53 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
  54 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
  55 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
  56 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  57 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  58 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
  59 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
  60 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  61 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  62 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  63 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  64 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
  65 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  66 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  67 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  68 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  69 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
  70 import org.opendaylight.controller.cluster.datastore.messages.MakeLeaderLocal;
  71 import org.opendaylight.controller.cluster.datastore.messages.OnDemandShardState;
  72 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  73 import org.opendaylight.controller.cluster.datastore.messages.PersistAbortTransactionPayload;
  74 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  75 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  76 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  77 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  78 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  79 import org.opendaylight.controller.cluster.datastore.persisted.AbortTransactionPayload;
  80 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot;
  81 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot.ShardSnapshot;
  82 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  83 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  84 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  85 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
  86 import org.opendaylight.controller.cluster.raft.LeadershipTransferFailedException;
  87 import org.opendaylight.controller.cluster.raft.RaftActor;
  88 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
  89 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
  90 import org.opendaylight.controller.cluster.raft.RaftState;
  91 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  92 import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
  93 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  94 import org.opendaylight.controller.cluster.raft.messages.RequestLeadership;
  95 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
  96 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  97 import org.opendaylight.yangtools.concepts.Identifier;
  98 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  99 import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree;
 100 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
 101 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 102 import org.opendaylight.yangtools.yang.model.api.SchemaContextProvider;
 103 import scala.concurrent.duration.Duration;
 104 import scala.concurrent.duration.FiniteDuration;
 105
 106 /**
 107  * A Shard represents a portion of the logical data tree.
 108  *
 109  * <p>
 110  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
 111  */
 112 public class Shard extends RaftActor {
 113
 114     @VisibleForTesting
 115     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
 116         @Override
 117         public String toString() {
 118             return "txCommitTimeoutCheck";
 119         }
 120     };
 121
 122     @VisibleForTesting
 123     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
 124         @Override
 125         public String toString() {
 126             return "getShardMBeanMessage";
 127         }
 128     };
 129
 130     static final Object RESUME_NEXT_PENDING_TRANSACTION = new Object() {
 131         @Override
 132         public String toString() {
 133             return "resumeNextPendingTransaction";
 134         }
 135     };
 136
 137     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
 138     public static final String DEFAULT_NAME = "default";
 139
 140     private static final Collection<ABIVersion> SUPPORTED_ABIVERSIONS;
 141
 142     static {
 143         final ABIVersion[] values = ABIVersion.values();
 144         final ABIVersion[] real = Arrays.copyOfRange(values, 1, values.length - 1);
 145         SUPPORTED_ABIVERSIONS = ImmutableList.copyOf(real).reverse();
 146     }
 147
 148     // FIXME: make this a dynamic property based on mailbox size and maximum number of clients
 149     private static final int CLIENT_MAX_MESSAGES = 1000;
 150
 151     // The state of this Shard
 152     private final ShardDataTree store;
 153
 154     /// The name of this shard
 155     private final String name;
 156
 157     private final ShardStats shardMBean;
 158
 159     private DatastoreContext datastoreContext;
 160
 161     private final ShardCommitCoordinator commitCoordinator;
 162
 163     private long transactionCommitTimeout;
 164
 165     private Cancellable txCommitTimeoutCheckSchedule;
 166
 167     private final Optional<ActorRef> roleChangeNotifier;
 168
 169     private final MessageTracker appendEntriesReplyTracker;
 170
 171     private final ShardTransactionActorFactory transactionActorFactory;
 172
 173     private final ShardSnapshotCohort snapshotCohort;
 174
 175     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
 176     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
 177
 178
 179     private ShardSnapshot restoreFromSnapshot;
 180
 181     private final ShardTransactionMessageRetrySupport messageRetrySupport;
 182
 183     private final FrontendMetadata frontendMetadata;
 184     private Map<FrontendIdentifier, LeaderFrontendState> knownFrontends = ImmutableMap.of();
 185     private boolean paused;
 186
 187     protected Shard(final AbstractBuilder<?, ?> builder) {
 188         super(builder.getId().toString(), builder.getPeerAddresses(),
 189                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
 190
 191         this.name = builder.getId().toString();
 192         this.datastoreContext = builder.getDatastoreContext();
 193         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 194         this.frontendMetadata = new FrontendMetadata(name);
 195
 196         setPersistence(datastoreContext.isPersistent());
 197
 198         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
 199
 200         ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
 201                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher", name);
 202         ShardDataChangeListenerPublisherActorProxy dataChangeListenerPublisher =
 203                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher", name);
 204         if (builder.getDataTree() != null) {
 205             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
 206                     treeChangeListenerPublisher, dataChangeListenerPublisher, name, frontendMetadata);
 207         } else {
 208             store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
 209                     builder.getDatastoreContext().getStoreRoot(), treeChangeListenerPublisher,
 210                     dataChangeListenerPublisher, name, frontendMetadata);
 211         }
 212
 213         shardMBean = ShardMBeanFactory.getShardStatsMBean(name, datastoreContext.getDataStoreMXBeanType(), this);
 214
 215         if (isMetricsCaptureEnabled()) {
 216             getContext().become(new MeteringBehavior(this));
 217         }
 218
 219         commitCoordinator = new ShardCommitCoordinator(store, LOG, this.name);
 220
 221         setTransactionCommitTimeout();
 222
 223         // create a notifier actor for each cluster member
 224         roleChangeNotifier = createRoleChangeNotifier(name);
 225
 226         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
 227                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
 228
 229         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
 230             new Dispatchers(context().system().dispatchers()).getDispatcherPath(Dispatchers.DispatcherType.Transaction),
 231                 self(), getContext(), shardMBean, builder.getId().getShardName());
 232
 233         snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
 234             this.name);
 235
 236         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
 237     }
 238
 239     private void setTransactionCommitTimeout() {
 240         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
 241                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
 242     }
 243
 244     private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
 245         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
 246             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
 247         return Optional.of(shardRoleChangeNotifier);
 248     }
 249
 250     @Override
 251     public void postStop() {
 252         LOG.info("Stopping Shard {}", persistenceId());
 253
 254         super.postStop();
 255
 256         messageRetrySupport.close();
 257
 258         if (txCommitTimeoutCheckSchedule != null) {
 259             txCommitTimeoutCheckSchedule.cancel();
 260         }
 261
 262         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
 263
 264         shardMBean.unregisterMBean();
 265     }
 266
 267     @Override
 268     protected void handleRecover(final Object message) {
 269         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
 270             getSender());
 271
 272         super.handleRecover(message);
 273         if (LOG.isTraceEnabled()) {
 274             appendEntriesReplyTracker.begin();
 275         }
 276     }
 277
 278     @SuppressWarnings("checkstyle:IllegalCatch")
 279     @Override
 280     protected void handleNonRaftCommand(final Object message) {
 281         try (MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
 282             final Optional<Error> maybeError = context.error();
 283             if (maybeError.isPresent()) {
 284                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
 285                     maybeError.get());
 286             }
 287
 288             store.resetTransactionBatch();
 289
 290             if (message instanceof RequestEnvelope) {
 291                 final long now = ticker().read();
 292                 final RequestEnvelope envelope = (RequestEnvelope)message;
 293
 294                 try {
 295                     final RequestSuccess<?, ?> success = handleRequest(envelope, now);
 296                     if (success != null) {
 297                         envelope.sendSuccess(success, ticker().read() - now);
 298                     }
 299                 } catch (RequestException e) {
 300                     LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
 301                     envelope.sendFailure(e, ticker().read() - now);
 302                 } catch (Exception e) {
 303                     LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
 304                     envelope.sendFailure(new RuntimeRequestException("Request failed to process", e),
 305                         ticker().read() - now);
 306                 }
 307             } else if (message instanceof ConnectClientRequest) {
 308                 handleConnectClient((ConnectClientRequest)message);
 309             } else if (CreateTransaction.isSerializedType(message)) {
 310                 handleCreateTransaction(message);
 311             } else if (message instanceof BatchedModifications) {
 312                 handleBatchedModifications((BatchedModifications)message);
 313             } else if (message instanceof ForwardedReadyTransaction) {
 314                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
 315             } else if (message instanceof ReadyLocalTransaction) {
 316                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
 317             } else if (CanCommitTransaction.isSerializedType(message)) {
 318                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
 319             } else if (CommitTransaction.isSerializedType(message)) {
 320                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
 321             } else if (AbortTransaction.isSerializedType(message)) {
 322                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
 323             } else if (CloseTransactionChain.isSerializedType(message)) {
 324                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
 325             } else if (message instanceof RegisterChangeListener) {
 326                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
 327             } else if (message instanceof RegisterDataTreeChangeListener) {
 328                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
 329             } else if (message instanceof UpdateSchemaContext) {
 330                 updateSchemaContext((UpdateSchemaContext) message);
 331             } else if (message instanceof PeerAddressResolved) {
 332                 PeerAddressResolved resolved = (PeerAddressResolved) message;
 333                 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
 334             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
 335                 commitTimeoutCheck();
 336             } else if (message instanceof DatastoreContext) {
 337                 onDatastoreContext((DatastoreContext)message);
 338             } else if (message instanceof RegisterRoleChangeListener) {
 339                 roleChangeNotifier.get().forward(message, context());
 340             } else if (message instanceof FollowerInitialSyncUpStatus) {
 341                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
 342                 context().parent().tell(message, self());
 343             } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
 344                 sender().tell(getShardMBean(), self());
 345             } else if (message instanceof GetShardDataTree) {
 346                 sender().tell(store.getDataTree(), self());
 347             } else if (message instanceof ServerRemoved) {
 348                 context().parent().forward(message, context());
 349             } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
 350                 messageRetrySupport.onTimerMessage(message);
 351             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
 352                 store.processCohortRegistryCommand(getSender(),
 353                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
 354             } else if (message instanceof PersistAbortTransactionPayload) {
 355                 final TransactionIdentifier txId = ((PersistAbortTransactionPayload) message).getTransactionId();
 356                 persistPayload(txId, AbortTransactionPayload.create(txId), true);
 357             } else if (message instanceof MakeLeaderLocal) {
 358                 onMakeLeaderLocal();
 359             } else if (RESUME_NEXT_PENDING_TRANSACTION.equals(message)) {
 360                 store.resumeNextPendingTransaction();
 361             } else {
 362                 super.handleNonRaftCommand(message);
 363             }
 364         }
 365     }
 366
 367     private void commitTimeoutCheck() {
 368         store.checkForExpiredTransactions(transactionCommitTimeout, this::updateAccess);
 369         commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
 370     }
 371
 372     private Optional<Long> updateAccess(final SimpleShardDataTreeCohort cohort) {
 373         final FrontendIdentifier frontend = cohort.getIdentifier().getHistoryId().getClientId().getFrontendId();
 374         // If this frontend has freshly connected, give it some time to catch up before killing its transactions.
 375         final LeaderFrontendState state = knownFrontends.get(frontend);
 376         return state == null ? Optional.absent() : Optional.of(state.getLastConnectTicks());
 377     }
 378
 379     private void onMakeLeaderLocal() {
 380         LOG.debug("{}: onMakeLeaderLocal received", persistenceId());
 381         if (isLeader()) {
 382             getSender().tell(new Status.Success(null), getSelf());
 383             return;
 384         }
 385
 386         final ActorSelection leader = getLeader();
 387
 388         if (leader == null) {
 389             // Leader is not present. The cluster is most likely trying to
 390             // elect a leader and we should let that run its normal course
 391
 392             // TODO we can wait for the election to complete and retry the
 393             // request. We can also let the caller retry by sending a flag
 394             // in the response indicating the request is "reTryable".
 395             getSender().tell(new Failure(
 396                     new LeadershipTransferFailedException("We cannot initiate leadership transfer to local node. "
 397                             + "Currently there is no leader for " + persistenceId())),
 398                     getSelf());
 399             return;
 400         }
 401
 402         leader.tell(new RequestLeadership(getId(), getSender()), getSelf());
 403     }
 404
 405     // Acquire our frontend tracking handle and verify generation matches
 406     @Nullable
 407     private LeaderFrontendState findFrontend(final ClientIdentifier clientId) throws RequestException {
 408         final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
 409         if (existing != null) {
 410             final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
 411             if (cmp == 0) {
 412                 existing.touch();
 413                 return existing;
 414             }
 415             if (cmp > 0) {
 416                 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
 417                 throw new RetiredGenerationException(existing.getIdentifier().getGeneration());
 418             }
 419
 420             LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
 421             existing.retire();
 422             knownFrontends.remove(clientId.getFrontendId());
 423         } else {
 424             LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
 425         }
 426
 427         return null;
 428     }
 429
 430     private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
 431         final LeaderFrontendState ret = findFrontend(clientId);
 432         if (ret != null) {
 433             return ret;
 434         }
 435
 436         // TODO: a dedicated exception would be better, but this is technically true, too
 437         throw new OutOfSequenceEnvelopeException(0);
 438     }
 439
 440     private static @Nonnull ABIVersion selectVersion(final ConnectClientRequest message) {
 441         final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
 442         for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
 443             if (clientRange.contains(v)) {
 444                 return v;
 445             }
 446         }
 447
 448         throw new IllegalArgumentException(String.format(
 449             "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
 450             clientRange));
 451     }
 452
 453     @SuppressWarnings("checkstyle:IllegalCatch")
 454     private void handleConnectClient(final ConnectClientRequest message) {
 455         try {
 456             final ClientIdentifier clientId = message.getTarget();
 457             final LeaderFrontendState existing = findFrontend(clientId);
 458             if (existing != null) {
 459                 existing.touch();
 460             }
 461
 462             if (!isLeader() || !isLeaderActive()) {
 463                 LOG.info("{}: not currently leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 464                                 + "isLeadershipTransferInProgress: {}.",
 465                         persistenceId(), message, isLeader(), isLeaderActive(), isLeadershipTransferInProgress());
 466                 throw new NotLeaderException(getSelf());
 467             }
 468
 469             final ABIVersion selectedVersion = selectVersion(message);
 470             final LeaderFrontendState frontend;
 471             if (existing == null) {
 472                 frontend = new LeaderFrontendState(persistenceId(), clientId, store);
 473                 knownFrontends.put(clientId.getFrontendId(), frontend);
 474                 LOG.debug("{}: created state {} for client {}", persistenceId(), frontend, clientId);
 475             } else {
 476                 frontend = existing;
 477             }
 478
 479             frontend.reconnect();
 480             message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
 481                 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
 482                 ActorRef.noSender());
 483         } catch (RequestException | RuntimeException e) {
 484             message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
 485         }
 486     }
 487
 488     private @Nullable RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope, final long now)
 489             throws RequestException {
 490         // We are not the leader, hence we want to fail-fast.
 491         if (!isLeader() || paused || !isLeaderActive()) {
 492             LOG.debug("{}: not currently active leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
 493                             + "isLeadershipTransferInProgress: {}, paused: {}",
 494                     persistenceId(), envelope, isLeader(), isLeaderActive(), isLeadershipTransferInProgress(), paused);
 495             throw new NotLeaderException(getSelf());
 496         }
 497
 498         final Request<?, ?> request = envelope.getMessage();
 499         if (request instanceof TransactionRequest) {
 500             final TransactionRequest<?> txReq = (TransactionRequest<?>)request;
 501             final ClientIdentifier clientId = txReq.getTarget().getHistoryId().getClientId();
 502             return getFrontend(clientId).handleTransactionRequest(txReq, envelope, now);
 503         } else if (request instanceof LocalHistoryRequest) {
 504             final LocalHistoryRequest<?> lhReq = (LocalHistoryRequest<?>)request;
 505             final ClientIdentifier clientId = lhReq.getTarget().getClientId();
 506             return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope, now);
 507         } else {
 508             LOG.warn("{}: rejecting unsupported request {}", persistenceId(), request);
 509             throw new UnsupportedRequestException(request);
 510         }
 511     }
 512
 513     private boolean hasLeader() {
 514         return getLeaderId() != null;
 515     }
 516
 517     public int getPendingTxCommitQueueSize() {
 518         return store.getQueueSize();
 519     }
 520
 521     public int getCohortCacheSize() {
 522         return commitCoordinator.getCohortCacheSize();
 523     }
 524
 525     @Override
 526     protected Optional<ActorRef> getRoleChangeNotifier() {
 527         return roleChangeNotifier;
 528     }
 529
 530     @Override
 531     protected LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
 532             final short leaderPayloadVersion) {
 533         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
 534                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
 535     }
 536
 537     protected void onDatastoreContext(final DatastoreContext context) {
 538         datastoreContext = context;
 539
 540         setTransactionCommitTimeout();
 541
 542         setPersistence(datastoreContext.isPersistent());
 543
 544         updateConfigParams(datastoreContext.getShardRaftConfig());
 545     }
 546
 547     // applyState() will be invoked once consensus is reached on the payload
 548     void persistPayload(final Identifier id, final Payload payload, final boolean batchHint) {
 549         boolean canSkipPayload = !hasFollowers() && !persistence().isRecoveryApplicable();
 550         if (canSkipPayload) {
 551             applyState(self(), id, payload);
 552         } else {
 553             // We are faking the sender
 554             persistData(self(), id, payload, batchHint);
 555         }
 556     }
 557
 558     private void handleCommitTransaction(final CommitTransaction commit) {
 559         if (isLeader()) {
 560             commitCoordinator.handleCommit(commit.getTransactionId(), getSender(), this);
 561         } else {
 562             ActorSelection leader = getLeader();
 563             if (leader == null) {
 564                 messageRetrySupport.addMessageToRetry(commit, getSender(),
 565                         "Could not commit transaction " + commit.getTransactionId());
 566             } else {
 567                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
 568                 leader.forward(commit, getContext());
 569             }
 570         }
 571     }
 572
 573     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
 574         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionId());
 575
 576         if (isLeader()) {
 577             commitCoordinator.handleCanCommit(canCommit.getTransactionId(), getSender(), this);
 578         } else {
 579             ActorSelection leader = getLeader();
 580             if (leader == null) {
 581                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
 582                         "Could not canCommit transaction " + canCommit.getTransactionId());
 583             } else {
 584                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
 585                 leader.forward(canCommit, getContext());
 586             }
 587         }
 588     }
 589
 590     @SuppressWarnings("checkstyle:IllegalCatch")
 591     protected void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
 592         try {
 593             commitCoordinator.handleBatchedModifications(batched, sender, this);
 594         } catch (Exception e) {
 595             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
 596                     batched.getTransactionId(), e);
 597             sender.tell(new Failure(e), getSelf());
 598         }
 599     }
 600
 601     private void handleBatchedModifications(final BatchedModifications batched) {
 602         // This message is sent to prepare the modifications transaction directly on the Shard as an
 603         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
 604         // BatchedModifications message, the caller sets the ready flag in the message indicating
 605         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
 606         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
 607         // ReadyTransaction message.
 608
 609         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
 610         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
 611         // the primary/leader shard. However with timing and caching on the front-end, there's a small
 612         // window where it could have a stale leader during leadership transitions.
 613         //
 614         boolean isLeaderActive = isLeaderActive();
 615         if (isLeader() && isLeaderActive) {
 616             handleBatchedModificationsLocal(batched, getSender());
 617         } else {
 618             ActorSelection leader = getLeader();
 619             if (!isLeaderActive || leader == null) {
 620                 messageRetrySupport.addMessageToRetry(batched, getSender(),
 621                         "Could not commit transaction " + batched.getTransactionId());
 622             } else {
 623                 // If this is not the first batch and leadership changed in between batched messages,
 624                 // we need to reconstruct previous BatchedModifications from the transaction
 625                 // DataTreeModification, honoring the max batched modification count, and forward all the
 626                 // previous BatchedModifications to the new leader.
 627                 Collection<BatchedModifications> newModifications = commitCoordinator
 628                         .createForwardedBatchedModifications(batched,
 629                                 datastoreContext.getShardBatchedModificationCount());
 630
 631                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
 632                         newModifications.size(), leader);
 633
 634                 for (BatchedModifications bm : newModifications) {
 635                     leader.forward(bm, getContext());
 636                 }
 637             }
 638         }
 639     }
 640
 641     private boolean failIfIsolatedLeader(final ActorRef sender) {
 642         if (isIsolatedLeader()) {
 643             sender.tell(new Failure(new NoShardLeaderException(String.format(
 644                     "Shard %s was the leader but has lost contact with all of its followers. Either all"
 645                     + " other follower nodes are down or this node is isolated by a network partition.",
 646                     persistenceId()))), getSelf());
 647             return true;
 648         }
 649
 650         return false;
 651     }
 652
 653     protected boolean isIsolatedLeader() {
 654         return getRaftState() == RaftState.IsolatedLeader;
 655     }
 656
 657     @SuppressWarnings("checkstyle:IllegalCatch")
 658     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
 659         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionId());
 660
 661         boolean isLeaderActive = isLeaderActive();
 662         if (isLeader() && isLeaderActive) {
 663             try {
 664                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
 665             } catch (Exception e) {
 666                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
 667                         message.getTransactionId(), e);
 668                 getSender().tell(new Failure(e), getSelf());
 669             }
 670         } else {
 671             ActorSelection leader = getLeader();
 672             if (!isLeaderActive || leader == null) {
 673                 messageRetrySupport.addMessageToRetry(message, getSender(),
 674                         "Could not commit transaction " + message.getTransactionId());
 675             } else {
 676                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
 677                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 678                 leader.forward(message, getContext());
 679             }
 680         }
 681     }
 682
 683     private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
 684         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
 685
 686         boolean isLeaderActive = isLeaderActive();
 687         if (isLeader() && isLeaderActive) {
 688             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
 689         } else {
 690             ActorSelection leader = getLeader();
 691             if (!isLeaderActive || leader == null) {
 692                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
 693                         "Could not commit transaction " + forwardedReady.getTransactionId());
 694             } else {
 695                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
 696
 697                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
 698                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
 699                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
 700                 leader.forward(readyLocal, getContext());
 701             }
 702         }
 703     }
 704
 705     private void handleAbortTransaction(final AbortTransaction abort) {
 706         doAbortTransaction(abort.getTransactionId(), getSender());
 707     }
 708
 709     void doAbortTransaction(final Identifier transactionID, final ActorRef sender) {
 710         commitCoordinator.handleAbort(transactionID, sender, this);
 711     }
 712
 713     private void handleCreateTransaction(final Object message) {
 714         if (isLeader()) {
 715             createTransaction(CreateTransaction.fromSerializable(message));
 716         } else if (getLeader() != null) {
 717             getLeader().forward(message, getContext());
 718         } else {
 719             getSender().tell(new Failure(new NoShardLeaderException(
 720                     "Could not create a shard transaction", persistenceId())), getSelf());
 721         }
 722     }
 723
 724     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
 725         final LocalHistoryIdentifier id = closeTransactionChain.getIdentifier();
 726         store.closeTransactionChain(id, null);
 727         store.purgeTransactionChain(id, null);
 728     }
 729
 730     @SuppressWarnings("checkstyle:IllegalCatch")
 731     private void createTransaction(final CreateTransaction createTransaction) {
 732         try {
 733             if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
 734                     && failIfIsolatedLeader(getSender())) {
 735                 return;
 736             }
 737
 738             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
 739                 createTransaction.getTransactionId());
 740
 741             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
 742                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
 743         } catch (Exception e) {
 744             getSender().tell(new Failure(e), getSelf());
 745         }
 746     }
 747
 748     private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
 749         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
 750         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
 751             transactionId);
 752     }
 753
 754     private void updateSchemaContext(final UpdateSchemaContext message) {
 755         updateSchemaContext(message.getSchemaContext());
 756     }
 757
 758     @VisibleForTesting
 759     void updateSchemaContext(final SchemaContext schemaContext) {
 760         store.updateSchemaContext(schemaContext);
 761     }
 762
 763     private boolean isMetricsCaptureEnabled() {
 764         CommonConfig config = new CommonConfig(getContext().system().settings().config());
 765         return config.isMetricCaptureEnabled();
 766     }
 767
 768     @Override
 769     @VisibleForTesting
 770     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
 771         return snapshotCohort;
 772     }
 773
 774     @Override
 775     @Nonnull
 776     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
 777         return new ShardRecoveryCoordinator(store,
 778             restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
 779     }
 780
 781     @Override
 782     protected void onRecoveryComplete() {
 783         restoreFromSnapshot = null;
 784
 785         //notify shard manager
 786         getContext().parent().tell(new ActorInitialized(), getSelf());
 787
 788         // Being paranoid here - this method should only be called once but just in case...
 789         if (txCommitTimeoutCheckSchedule == null) {
 790             // Schedule a message to be periodically sent to check if the current in-progress
 791             // transaction should be expired and aborted.
 792             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
 793             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
 794                     period, period, getSelf(),
 795                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
 796         }
 797     }
 798
 799     @Override
 800     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
 801         if (data instanceof Payload) {
 802             try {
 803                 store.applyReplicatedPayload(identifier, (Payload)data);
 804             } catch (DataValidationFailedException | IOException e) {
 805                 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
 806             }
 807         } else {
 808             LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
 809         }
 810     }
 811
 812     @Override
 813     protected void onStateChanged() {
 814         boolean isLeader = isLeader();
 815         boolean hasLeader = hasLeader();
 816         changeSupport.onLeadershipChange(isLeader, hasLeader);
 817         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
 818
 819         // If this actor is no longer the leader close all the transaction chains
 820         if (!isLeader) {
 821             if (LOG.isDebugEnabled()) {
 822                 LOG.debug(
 823                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
 824                     persistenceId(), getId());
 825             }
 826
 827             paused = false;
 828             store.purgeLeaderState();
 829         }
 830
 831         if (hasLeader && !isIsolatedLeader()) {
 832             messageRetrySupport.retryMessages();
 833         }
 834     }
 835
 836     @Override
 837     protected void onLeaderChanged(final String oldLeader, final String newLeader) {
 838         shardMBean.incrementLeadershipChangeCount();
 839         paused = false;
 840
 841         if (!isLeader()) {
 842             if (!knownFrontends.isEmpty()) {
 843                 LOG.debug("{}: removing frontend state for {}", persistenceId(), knownFrontends.keySet());
 844                 knownFrontends = ImmutableMap.of();
 845             }
 846
 847             if (!hasLeader()) {
 848                 // No leader anywhere, nothing else to do
 849                 return;
 850             }
 851
 852             // Another leader was elected. If we were the previous leader and had pending transactions, convert
 853             // them to transaction messages and send to the new leader.
 854             ActorSelection leader = getLeader();
 855             if (leader != null) {
 856                 Collection<?> messagesToForward = convertPendingTransactionsToMessages();
 857
 858                 if (!messagesToForward.isEmpty()) {
 859                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
 860                             messagesToForward.size(), leader);
 861
 862                     for (Object message : messagesToForward) {
 863                         leader.tell(message, self());
 864                     }
 865                 }
 866             } else {
 867                 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
 868                         + "change and the leader address isn't available.", this);
 869             }
 870         } else {
 871             // We have become the leader, we need to reconstruct frontend state
 872             knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
 873             LOG.debug("{}: became leader with frontend state for {}", persistenceId(), knownFrontends.keySet());
 874         }
 875
 876         if (!isIsolatedLeader()) {
 877             messageRetrySupport.retryMessages();
 878         }
 879     }
 880
 881     /**
 882      * Clears all pending transactions and converts them to messages to be forwarded to a new leader.
 883      *
 884      * @return the converted messages
 885      */
 886     public Collection<?> convertPendingTransactionsToMessages() {
 887         return commitCoordinator.convertPendingTransactionsToMessages(
 888                 datastoreContext.getShardBatchedModificationCount());
 889     }
 890
 891     @Override
 892     protected void pauseLeader(final Runnable operation) {
 893         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
 894         paused = true;
 895
 896         // Tell-based protocol can replay transaction state, so it is safe to blow it up when we are paused.
 897         knownFrontends.values().forEach(LeaderFrontendState::retire);
 898         knownFrontends = ImmutableMap.of();
 899
 900         store.setRunOnPendingTransactionsComplete(operation);
 901     }
 902
 903     @Override
 904     protected void unpauseLeader() {
 905         LOG.debug("{}: In unpauseLeader", persistenceId());
 906         paused = false;
 907
 908         store.setRunOnPendingTransactionsComplete(null);
 909
 910         // Restore tell-based protocol state as if we were becoming the leader
 911         knownFrontends = Verify.verifyNotNull(frontendMetadata.toLeaderState(this));
 912     }
 913
 914     @Override
 915     protected OnDemandRaftState.AbstractBuilder<?> newOnDemandRaftStateBuilder() {
 916         return OnDemandShardState.newBuilder().treeChangeListenerActors(treeChangeSupport.getListenerActors())
 917                 .dataChangeListenerActors(changeSupport.getListenerActors())
 918                 .commitCohortActors(store.getCohortActors());
 919     }
 920
 921     @Override
 922     public String persistenceId() {
 923         return this.name;
 924     }
 925
 926     @VisibleForTesting
 927     ShardCommitCoordinator getCommitCoordinator() {
 928         return commitCoordinator;
 929     }
 930
 931     public DatastoreContext getDatastoreContext() {
 932         return datastoreContext;
 933     }
 934
 935     @VisibleForTesting
 936     public ShardDataTree getDataStore() {
 937         return store;
 938     }
 939
 940     @VisibleForTesting
 941     ShardStats getShardMBean() {
 942         return shardMBean;
 943     }
 944
 945     public static Builder builder() {
 946         return new Builder();
 947     }
 948
 949     public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
 950         private final Class<S> shardClass;
 951         private ShardIdentifier id;
 952         private Map<String, String> peerAddresses = Collections.emptyMap();
 953         private DatastoreContext datastoreContext;
 954         private SchemaContextProvider schemaContextProvider;
 955         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
 956         private TipProducingDataTree dataTree;
 957         private volatile boolean sealed;
 958
 959         protected AbstractBuilder(final Class<S> shardClass) {
 960             this.shardClass = shardClass;
 961         }
 962
 963         protected void checkSealed() {
 964             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
 965         }
 966
 967         @SuppressWarnings("unchecked")
 968         private T self() {
 969             return (T) this;
 970         }
 971
 972         public T id(final ShardIdentifier newId) {
 973             checkSealed();
 974             this.id = newId;
 975             return self();
 976         }
 977
 978         public T peerAddresses(final Map<String, String> newPeerAddresses) {
 979             checkSealed();
 980             this.peerAddresses = newPeerAddresses;
 981             return self();
 982         }
 983
 984         public T datastoreContext(final DatastoreContext newDatastoreContext) {
 985             checkSealed();
 986             this.datastoreContext = newDatastoreContext;
 987             return self();
 988         }
 989
 990         public T schemaContextProvider(final SchemaContextProvider schemaContextProvider) {
 991             checkSealed();
 992             this.schemaContextProvider = Preconditions.checkNotNull(schemaContextProvider);
 993             return self();
 994         }
 995
 996         public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
 997             checkSealed();
 998             this.restoreFromSnapshot = newRestoreFromSnapshot;
 999             return self();
1000         }
1001
1002         public T dataTree(final TipProducingDataTree newDataTree) {
1003             checkSealed();
1004             this.dataTree = newDataTree;
1005             return self();
1006         }
1007
1008         public ShardIdentifier getId() {
1009             return id;
1010         }
1011
1012         public Map<String, String> getPeerAddresses() {
1013             return peerAddresses;
1014         }
1015
1016         public DatastoreContext getDatastoreContext() {
1017             return datastoreContext;
1018         }
1019
1020         public SchemaContext getSchemaContext() {
1021             return Verify.verifyNotNull(schemaContextProvider.getSchemaContext());
1022         }
1023
1024         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
1025             return restoreFromSnapshot;
1026         }
1027
1028         public TipProducingDataTree getDataTree() {
1029             return dataTree;
1030         }
1031
1032         public TreeType getTreeType() {
1033             switch (datastoreContext.getLogicalStoreType()) {
1034                 case CONFIGURATION:
1035                     return TreeType.CONFIGURATION;
1036                 case OPERATIONAL:
1037                     return TreeType.OPERATIONAL;
1038                 default:
1039                     throw new IllegalStateException("Unhandled logical store type "
1040                             + datastoreContext.getLogicalStoreType());
1041             }
1042         }
1043
1044         protected void verify() {
1045             Preconditions.checkNotNull(id, "id should not be null");
1046             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
1047             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
1048             Preconditions.checkNotNull(schemaContextProvider, "schemaContextProvider should not be null");
1049         }
1050
1051         public Props props() {
1052             sealed = true;
1053             verify();
1054             return Props.create(shardClass, this);
1055         }
1056     }
1057
1058     public static class Builder extends AbstractBuilder<Builder, Shard> {
1059         private Builder() {
1060             super(Shard.class);
1061         }
1062     }
1063
1064     Ticker ticker() {
1065         return Ticker.systemTicker();
1066     }
1067
1068     void scheduleNextPendingTransaction() {
1069         self().tell(RESUME_NEXT_PENDING_TRANSACTION, ActorRef.noSender());
1070     }
1071 }