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