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