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