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