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

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