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