opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardmanager/ShardManager.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.shardmanager;
  10
  11 import static akka.pattern.Patterns.ask;
  12 import akka.actor.ActorRef;
  13 import akka.actor.Address;
  14 import akka.actor.Cancellable;
  15 import akka.actor.OneForOneStrategy;
  16 import akka.actor.PoisonPill;
  17 import akka.actor.Props;
  18 import akka.actor.Status;
  19 import akka.actor.SupervisorStrategy;
  20 import akka.cluster.ClusterEvent;
  21 import akka.dispatch.Futures;
  22 import akka.dispatch.OnComplete;
  23 import akka.japi.Function;
  24 import akka.pattern.Patterns;
  25 import akka.persistence.RecoveryCompleted;
  26 import akka.persistence.SaveSnapshotFailure;
  27 import akka.persistence.SaveSnapshotSuccess;
  28 import akka.persistence.SnapshotOffer;
  29 import akka.persistence.SnapshotSelectionCriteria;
  30 import akka.serialization.Serialization;
  31 import akka.util.Timeout;
  32 import com.google.common.annotations.VisibleForTesting;
  33 import com.google.common.base.Objects;
  34 import com.google.common.base.Optional;
  35 import com.google.common.base.Preconditions;
  36 import com.google.common.base.Strings;
  37 import com.google.common.base.Supplier;
  38 import com.google.common.collect.Sets;
  39 import java.io.ByteArrayInputStream;
  40 import java.io.ObjectInputStream;
  41 import java.util.ArrayList;
  42 import java.util.Collection;
  43 import java.util.Collections;
  44 import java.util.HashMap;
  45 import java.util.HashSet;
  46 import java.util.Iterator;
  47 import java.util.List;
  48 import java.util.Map;
  49 import java.util.Set;
  50 import java.util.concurrent.CountDownLatch;
  51 import java.util.concurrent.TimeUnit;
  52 import java.util.concurrent.TimeoutException;
  53 import javax.annotation.Nonnull;
  54 import javax.annotation.Nullable;
  55 import org.apache.commons.lang3.SerializationUtils;
  56 import org.opendaylight.controller.cluster.common.actor.AbstractUntypedPersistentActorWithMetering;
  57 import org.opendaylight.controller.cluster.datastore.ClusterWrapper;
  58 import org.opendaylight.controller.cluster.datastore.DatastoreContext;
  59 import org.opendaylight.controller.cluster.datastore.DatastoreContextFactory;
  60 import org.opendaylight.controller.cluster.datastore.Shard;
  61 import org.opendaylight.controller.cluster.datastore.config.Configuration;
  62 import org.opendaylight.controller.cluster.datastore.config.ModuleShardConfiguration;
  63 import org.opendaylight.controller.cluster.datastore.exceptions.AlreadyExistsException;
  64 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  65 import org.opendaylight.controller.cluster.datastore.exceptions.NotInitializedException;
  66 import org.opendaylight.controller.cluster.datastore.exceptions.PrimaryNotFoundException;
  67 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  68 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shardmanager.ShardManagerInfoMBean;
  69 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
  70 import org.opendaylight.controller.cluster.datastore.messages.AddShardReplica;
  71 import org.opendaylight.controller.cluster.datastore.messages.CreateShard;
  72 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot;
  73 import org.opendaylight.controller.cluster.datastore.messages.FindLocalShard;
  74 import org.opendaylight.controller.cluster.datastore.messages.FindPrimary;
  75 import org.opendaylight.controller.cluster.datastore.messages.LocalPrimaryShardFound;
  76 import org.opendaylight.controller.cluster.datastore.messages.LocalShardFound;
  77 import org.opendaylight.controller.cluster.datastore.messages.LocalShardNotFound;
  78 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
  79 import org.opendaylight.controller.cluster.datastore.messages.PeerDown;
  80 import org.opendaylight.controller.cluster.datastore.messages.PeerUp;
  81 import org.opendaylight.controller.cluster.datastore.messages.RemoteFindPrimary;
  82 import org.opendaylight.controller.cluster.datastore.messages.RemotePrimaryShardFound;
  83 import org.opendaylight.controller.cluster.datastore.messages.RemoveShardReplica;
  84 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
  85 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
  86 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
  87 import org.opendaylight.controller.cluster.datastore.utils.PrimaryShardInfoFutureCache;
  88 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  89 import org.opendaylight.controller.cluster.notifications.RoleChangeNotification;
  90 import org.opendaylight.controller.cluster.raft.RaftState;
  91 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
  92 import org.opendaylight.controller.cluster.raft.base.messages.SwitchBehavior;
  93 import org.opendaylight.controller.cluster.raft.client.messages.GetSnapshot;
  94 import org.opendaylight.controller.cluster.raft.client.messages.Shutdown;
  95 import org.opendaylight.controller.cluster.raft.messages.AddServer;
  96 import org.opendaylight.controller.cluster.raft.messages.AddServerReply;
  97 import org.opendaylight.controller.cluster.raft.messages.RemoveServer;
  98 import org.opendaylight.controller.cluster.raft.messages.RemoveServerReply;
  99 import org.opendaylight.controller.cluster.raft.messages.ServerChangeStatus;
 100 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
 101 import org.opendaylight.controller.cluster.raft.policy.DisableElectionsRaftPolicy;
 102 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree;
 103 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 104 import org.slf4j.Logger;
 105 import org.slf4j.LoggerFactory;
 106 import scala.concurrent.ExecutionContext;
 107 import scala.concurrent.Future;
 108 import scala.concurrent.duration.Duration;
 109 import scala.concurrent.duration.FiniteDuration;
 110
 111 /**
 112  * The ShardManager has the following jobs,
 113  * <ul>
 114  * <li> Create all the local shard replicas that belong on this cluster member
 115  * <li> Find the address of the local shard
 116  * <li> Find the primary replica for any given shard
 117  * <li> Monitor the cluster members and store their addresses
 118  * <ul>
 119  */
 120 class ShardManager extends AbstractUntypedPersistentActorWithMetering {
 121
 122     private static final Logger LOG = LoggerFactory.getLogger(ShardManager.class);
 123
 124     // Stores a mapping between a shard name and it's corresponding information
 125     // Shard names look like inventory, topology etc and are as specified in
 126     // configuration
 127     private final Map<String, ShardInformation> localShards = new HashMap<>();
 128
 129     // The type of a ShardManager reflects the type of the datastore itself
 130     // A data store could be of type config/operational
 131     private final String type;
 132
 133     private final ClusterWrapper cluster;
 134
 135     private final Configuration configuration;
 136
 137     private final String shardDispatcherPath;
 138
 139     private final ShardManagerInfo mBean;
 140
 141     private DatastoreContextFactory datastoreContextFactory;
 142
 143     private final CountDownLatch waitTillReadyCountdownLatch;
 144
 145     private final PrimaryShardInfoFutureCache primaryShardInfoCache;
 146
 147     private final ShardPeerAddressResolver peerAddressResolver;
 148
 149     private SchemaContext schemaContext;
 150
 151     private DatastoreSnapshot restoreFromSnapshot;
 152
 153     private ShardManagerSnapshot currentSnapshot;
 154
 155     private final Set<String> shardReplicaOperationsInProgress = new HashSet<>();
 156
 157     private final String persistenceId;
 158
 159     ShardManager(AbstractShardManagerCreator<?> builder) {
 160         this.cluster = builder.getCluster();
 161         this.configuration = builder.getConfiguration();
 162         this.datastoreContextFactory = builder.getDdatastoreContextFactory();
 163         this.type = datastoreContextFactory.getBaseDatastoreContext().getDataStoreName();
 164         this.shardDispatcherPath =
 165                 new Dispatchers(context().system().dispatchers()).getDispatcherPath(Dispatchers.DispatcherType.Shard);
 166         this.waitTillReadyCountdownLatch = builder.getWaitTillReadyCountdownLatch();
 167         this.primaryShardInfoCache = builder.getPrimaryShardInfoCache();
 168         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
 169
 170         String possiblePersistenceId = datastoreContextFactory.getBaseDatastoreContext().getShardManagerPersistenceId();
 171         persistenceId = possiblePersistenceId != null ? possiblePersistenceId : "shard-manager-" + type;
 172
 173         peerAddressResolver = new ShardPeerAddressResolver(type, cluster.getCurrentMemberName());
 174
 175         // Subscribe this actor to cluster member events
 176         cluster.subscribeToMemberEvents(getSelf());
 177
 178         List<String> localShardActorNames = new ArrayList<>();
 179         mBean = ShardManagerInfo.createShardManagerMBean(cluster.getCurrentMemberName(),
 180                 "shard-manager-" + this.type,
 181                 datastoreContextFactory.getBaseDatastoreContext().getDataStoreMXBeanType(),
 182                 localShardActorNames);
 183         mBean.setShardManager(this);
 184     }
 185
 186     @Override
 187     public void postStop() {
 188         LOG.info("Stopping ShardManager {}", persistenceId());
 189
 190         mBean.unregisterMBean();
 191     }
 192
 193     @Override
 194     public void handleCommand(Object message) throws Exception {
 195         if (message  instanceof FindPrimary) {
 196             findPrimary((FindPrimary)message);
 197         } else if(message instanceof FindLocalShard){
 198             findLocalShard((FindLocalShard) message);
 199         } else if (message instanceof UpdateSchemaContext) {
 200             updateSchemaContext(message);
 201         } else if(message instanceof ActorInitialized) {
 202             onActorInitialized(message);
 203         } else if (message instanceof ClusterEvent.MemberUp){
 204             memberUp((ClusterEvent.MemberUp) message);
 205         } else if (message instanceof ClusterEvent.MemberExited){
 206             memberExited((ClusterEvent.MemberExited) message);
 207         } else if(message instanceof ClusterEvent.MemberRemoved) {
 208             memberRemoved((ClusterEvent.MemberRemoved) message);
 209         } else if(message instanceof ClusterEvent.UnreachableMember) {
 210             memberUnreachable((ClusterEvent.UnreachableMember)message);
 211         } else if(message instanceof ClusterEvent.ReachableMember) {
 212             memberReachable((ClusterEvent.ReachableMember) message);
 213         } else if(message instanceof DatastoreContextFactory) {
 214             onDatastoreContextFactory((DatastoreContextFactory)message);
 215         } else if(message instanceof RoleChangeNotification) {
 216             onRoleChangeNotification((RoleChangeNotification) message);
 217         } else if(message instanceof FollowerInitialSyncUpStatus){
 218             onFollowerInitialSyncStatus((FollowerInitialSyncUpStatus) message);
 219         } else if(message instanceof ShardNotInitializedTimeout) {
 220             onShardNotInitializedTimeout((ShardNotInitializedTimeout)message);
 221         } else if(message instanceof ShardLeaderStateChanged) {
 222             onLeaderStateChanged((ShardLeaderStateChanged) message);
 223         } else if(message instanceof SwitchShardBehavior){
 224             onSwitchShardBehavior((SwitchShardBehavior) message);
 225         } else if(message instanceof CreateShard) {
 226             onCreateShard((CreateShard)message);
 227         } else if(message instanceof AddShardReplica){
 228             onAddShardReplica((AddShardReplica)message);
 229         } else if(message instanceof ForwardedAddServerReply) {
 230             ForwardedAddServerReply msg = (ForwardedAddServerReply)message;
 231             onAddServerReply(msg.shardInfo, msg.addServerReply, getSender(), msg.leaderPath,
 232                     msg.removeShardOnFailure);
 233         } else if(message instanceof ForwardedAddServerFailure) {
 234             ForwardedAddServerFailure msg = (ForwardedAddServerFailure)message;
 235             onAddServerFailure(msg.shardName, msg.failureMessage, msg.failure, getSender(), msg.removeShardOnFailure);
 236         } else if(message instanceof PrimaryShardFoundForContext) {
 237             PrimaryShardFoundForContext primaryShardFoundContext = (PrimaryShardFoundForContext)message;
 238             onPrimaryShardFoundContext(primaryShardFoundContext);
 239         } else if(message instanceof RemoveShardReplica) {
 240             onRemoveShardReplica((RemoveShardReplica) message);
 241         } else if(message instanceof WrappedShardResponse){
 242             onWrappedShardResponse((WrappedShardResponse) message);
 243         } else if(message instanceof GetSnapshot) {
 244             onGetSnapshot();
 245         } else if(message instanceof ServerRemoved){
 246             onShardReplicaRemoved((ServerRemoved) message);
 247         } else if(message instanceof SaveSnapshotSuccess) {
 248             onSaveSnapshotSuccess((SaveSnapshotSuccess)message);
 249         } else if(message instanceof SaveSnapshotFailure) {
 250             LOG.error("{}: SaveSnapshotFailure received for saving snapshot of shards",
 251                     persistenceId(), ((SaveSnapshotFailure) message).cause());
 252         } else if(message instanceof Shutdown) {
 253             onShutDown();
 254         } else {
 255             unknownMessage(message);
 256         }
 257     }
 258
 259     private void onShutDown() {
 260         List<Future<Boolean>> stopFutures = new ArrayList<>(localShards.size());
 261         for (ShardInformation info : localShards.values()) {
 262             if (info.getActor() != null) {
 263                 LOG.debug("{}: Issuing gracefulStop to shard {}", persistenceId(), info.getShardId());
 264
 265                 FiniteDuration duration = info.getDatastoreContext().getShardRaftConfig().getElectionTimeOutInterval().$times(2);
 266                 stopFutures.add(Patterns.gracefulStop(info.getActor(), duration, Shutdown.INSTANCE));
 267             }
 268         }
 269
 270         LOG.info("Shutting down ShardManager {} - waiting on {} shards", persistenceId(), stopFutures.size());
 271
 272         ExecutionContext dispatcher = new Dispatchers(context().system().dispatchers()).getDispatcher(Dispatchers.DispatcherType.Client);
 273         Future<Iterable<Boolean>> combinedFutures = Futures.sequence(stopFutures, dispatcher);
 274
 275         combinedFutures.onComplete(new OnComplete<Iterable<Boolean>>() {
 276             @Override
 277             public void onComplete(Throwable failure, Iterable<Boolean> results) {
 278                 LOG.debug("{}: All shards shutdown - sending PoisonPill to self", persistenceId());
 279
 280                 self().tell(PoisonPill.getInstance(), self());
 281
 282                 if(failure != null) {
 283                     LOG.warn("{}: An error occurred attempting to shut down the shards", persistenceId(), failure);
 284                 } else {
 285                     int nfailed = 0;
 286                     for(Boolean r: results) {
 287                         if(!r) {
 288                             nfailed++;
 289                         }
 290                     }
 291
 292                     if(nfailed > 0) {
 293                         LOG.warn("{}: {} shards did not shut down gracefully", persistenceId(), nfailed);
 294                     }
 295                 }
 296             }
 297         }, dispatcher);
 298     }
 299
 300     private void onWrappedShardResponse(WrappedShardResponse message) {
 301         if (message.getResponse() instanceof RemoveServerReply) {
 302             onRemoveServerReply(getSender(), message.getShardId(), (RemoveServerReply) message.getResponse(),
 303                     message.getLeaderPath());
 304         }
 305     }
 306
 307     private void onRemoveServerReply(ActorRef originalSender, ShardIdentifier shardId, RemoveServerReply replyMsg,
 308             String leaderPath) {
 309         shardReplicaOperationsInProgress.remove(shardId);
 310
 311         LOG.debug ("{}: Received {} for shard {}", persistenceId(), replyMsg, shardId.getShardName());
 312
 313         if (replyMsg.getStatus() == ServerChangeStatus.OK) {
 314             LOG.debug ("{}: Leader shard successfully removed the replica shard {}", persistenceId(),
 315                     shardId.getShardName());
 316             originalSender.tell(new akka.actor.Status.Success(null), getSelf());
 317         } else {
 318             LOG.warn ("{}: Leader failed to remove shard replica {} with status {}",
 319                     persistenceId(), shardId, replyMsg.getStatus());
 320
 321             Exception failure = getServerChangeException(RemoveServer.class, replyMsg.getStatus(),
 322                     leaderPath, shardId);
 323             originalSender.tell(new akka.actor.Status.Failure(failure), getSelf());
 324         }
 325     }
 326
 327     private void onPrimaryShardFoundContext(PrimaryShardFoundForContext primaryShardFoundContext) {
 328         if(primaryShardFoundContext.getContextMessage() instanceof AddShardReplica) {
 329             addShard(primaryShardFoundContext.getShardName(), primaryShardFoundContext.getRemotePrimaryShardFound(),
 330                     getSender());
 331         } else if(primaryShardFoundContext.getContextMessage() instanceof RemoveShardReplica){
 332             removeShardReplica((RemoveShardReplica) primaryShardFoundContext.getContextMessage(),
 333                     primaryShardFoundContext.getShardName(), primaryShardFoundContext.getPrimaryPath(), getSender());
 334         }
 335     }
 336
 337     private void removeShardReplica(RemoveShardReplica contextMessage, final String shardName, final String primaryPath,
 338             final ActorRef sender) {
 339         if(isShardReplicaOperationInProgress(shardName, sender)) {
 340             return;
 341         }
 342
 343         shardReplicaOperationsInProgress.add(shardName);
 344
 345         final ShardIdentifier shardId = getShardIdentifier(contextMessage.getMemberName(), shardName);
 346
 347         final DatastoreContext datastoreContext = newShardDatastoreContextBuilder(shardName).build();
 348
 349         //inform ShardLeader to remove this shard as a replica by sending an RemoveServer message
 350         LOG.debug ("{}: Sending RemoveServer message to peer {} for shard {}", persistenceId(),
 351                 primaryPath, shardId);
 352
 353         Timeout removeServerTimeout = new Timeout(datastoreContext.getShardLeaderElectionTimeout().
 354                 duration());
 355         Future<Object> futureObj = ask(getContext().actorSelection(primaryPath),
 356                 new RemoveServer(shardId.toString()), removeServerTimeout);
 357
 358         futureObj.onComplete(new OnComplete<Object>() {
 359             @Override
 360             public void onComplete(Throwable failure, Object response) {
 361                 if (failure != null) {
 362                     String msg = String.format("RemoveServer request to leader %s for shard %s failed",
 363                             primaryPath, shardName);
 364
 365                     LOG.debug ("{}: {}", persistenceId(), msg, failure);
 366
 367                     // FAILURE
 368                     sender.tell(new Status.Failure(new RuntimeException(msg, failure)), self());
 369                 } else {
 370                     // SUCCESS
 371                     self().tell(new WrappedShardResponse(shardId, response, primaryPath), sender);
 372                 }
 373             }
 374         }, new Dispatchers(context().system().dispatchers()).getDispatcher(Dispatchers.DispatcherType.Client));
 375     }
 376
 377     private void onShardReplicaRemoved(ServerRemoved message) {
 378         final ShardIdentifier shardId = new ShardIdentifier.Builder().fromShardIdString(message.getServerId()).build();
 379         final ShardInformation shardInformation = localShards.remove(shardId.getShardName());
 380         if(shardInformation == null) {
 381             LOG.debug("{} : Shard replica {} is not present in list", persistenceId(), shardId.toString());
 382             return;
 383         } else if(shardInformation.getActor() != null) {
 384             LOG.debug("{} : Sending Shutdown to Shard actor {}", persistenceId(), shardInformation.getActor());
 385             shardInformation.getActor().tell(Shutdown.INSTANCE, self());
 386         }
 387         LOG.debug("{} : Local Shard replica for shard {} has been removed", persistenceId(), shardId.getShardName());
 388         persistShardList();
 389     }
 390
 391     private void onGetSnapshot() {
 392         LOG.debug("{}: onGetSnapshot", persistenceId());
 393
 394         List<String> notInitialized = null;
 395         for(ShardInformation shardInfo: localShards.values()) {
 396             if(!shardInfo.isShardInitialized()) {
 397                 if(notInitialized == null) {
 398                     notInitialized = new ArrayList<>();
 399                 }
 400
 401                 notInitialized.add(shardInfo.getShardName());
 402             }
 403         }
 404
 405         if(notInitialized != null) {
 406             getSender().tell(new akka.actor.Status.Failure(new IllegalStateException(String.format(
 407                     "%d shard(s) %s are not initialized", notInitialized.size(), notInitialized))), getSelf());
 408             return;
 409         }
 410
 411         byte[] shardManagerSnapshot = null;
 412         if(currentSnapshot != null) {
 413             shardManagerSnapshot = SerializationUtils.serialize(currentSnapshot);
 414         }
 415
 416         ActorRef replyActor = getContext().actorOf(ShardManagerGetSnapshotReplyActor.props(
 417                 new ArrayList<>(localShards.keySet()), type, shardManagerSnapshot , getSender(), persistenceId(),
 418                 datastoreContextFactory.getBaseDatastoreContext().getShardInitializationTimeout().duration()));
 419
 420         for(ShardInformation shardInfo: localShards.values()) {
 421             shardInfo.getActor().tell(GetSnapshot.INSTANCE, replyActor);
 422         }
 423     }
 424
 425     private void onCreateShard(CreateShard createShard) {
 426         LOG.debug("{}: onCreateShard: {}", persistenceId(), createShard);
 427
 428         Object reply;
 429         try {
 430             String shardName = createShard.getModuleShardConfig().getShardName();
 431             if(localShards.containsKey(shardName)) {
 432                 LOG.debug("{}: Shard {} already exists", persistenceId(), shardName);
 433                 reply = new akka.actor.Status.Success(String.format("Shard with name %s already exists", shardName));
 434             } else {
 435                 doCreateShard(createShard);
 436                 reply = new akka.actor.Status.Success(null);
 437             }
 438         } catch (Exception e) {
 439             LOG.error("{}: onCreateShard failed", persistenceId(), e);
 440             reply = new akka.actor.Status.Failure(e);
 441         }
 442
 443         if(getSender() != null && !getContext().system().deadLetters().equals(getSender())) {
 444             getSender().tell(reply, getSelf());
 445         }
 446     }
 447
 448     private void doCreateShard(CreateShard createShard) {
 449         ModuleShardConfiguration moduleShardConfig = createShard.getModuleShardConfig();
 450         String shardName = moduleShardConfig.getShardName();
 451
 452         configuration.addModuleShardConfiguration(moduleShardConfig);
 453
 454         DatastoreContext shardDatastoreContext = createShard.getDatastoreContext();
 455         if(shardDatastoreContext == null) {
 456             shardDatastoreContext = newShardDatastoreContext(shardName);
 457         } else {
 458             shardDatastoreContext = DatastoreContext.newBuilderFrom(shardDatastoreContext).shardPeerAddressResolver(
 459                     peerAddressResolver).build();
 460         }
 461
 462         ShardIdentifier shardId = getShardIdentifier(cluster.getCurrentMemberName(), shardName);
 463
 464         boolean shardWasInRecoveredSnapshot = currentSnapshot != null &&
 465                 currentSnapshot.getShardList().contains(shardName);
 466
 467         Map<String, String> peerAddresses;
 468         boolean isActiveMember;
 469         if(shardWasInRecoveredSnapshot || configuration.getMembersFromShardName(shardName).
 470                 contains(cluster.getCurrentMemberName())) {
 471             peerAddresses = getPeerAddresses(shardName);
 472             isActiveMember = true;
 473         } else {
 474             // The local member is not in the static shard member configuration and the shard did not
 475             // previously exist (ie !shardWasInRecoveredSnapshot). In this case we'll create
 476             // the shard with no peers and with elections disabled so it stays as follower. A
 477             // subsequent AddServer request will be needed to make it an active member.
 478             isActiveMember = false;
 479             peerAddresses = Collections.emptyMap();
 480             shardDatastoreContext = DatastoreContext.newBuilderFrom(shardDatastoreContext).
 481                     customRaftPolicyImplementation(DisableElectionsRaftPolicy.class.getName()).build();
 482         }
 483
 484         LOG.debug("{} doCreateShard: shardId: {}, memberNames: {}, peerAddresses: {}, isActiveMember: {}",
 485                 persistenceId(), shardId, moduleShardConfig.getShardMemberNames(), peerAddresses,
 486                 isActiveMember);
 487
 488         ShardInformation info = new ShardInformation(shardName, shardId, peerAddresses,
 489                 shardDatastoreContext, createShard.getShardBuilder(), peerAddressResolver);
 490         info.setActiveMember(isActiveMember);
 491         localShards.put(info.getShardName(), info);
 492
 493         mBean.addLocalShard(shardId.toString());
 494
 495         if(schemaContext != null) {
 496             info.setActor(newShardActor(schemaContext, info));
 497         }
 498     }
 499
 500     private DatastoreContext.Builder newShardDatastoreContextBuilder(String shardName) {
 501         return DatastoreContext.newBuilderFrom(datastoreContextFactory.getShardDatastoreContext(shardName)).
 502                 shardPeerAddressResolver(peerAddressResolver);
 503     }
 504
 505     private DatastoreContext newShardDatastoreContext(String shardName) {
 506         return newShardDatastoreContextBuilder(shardName).build();
 507     }
 508
 509     private void checkReady(){
 510         if (isReadyWithLeaderId()) {
 511             LOG.info("{}: All Shards are ready - data store {} is ready, available count is {}",
 512                     persistenceId(), type, waitTillReadyCountdownLatch.getCount());
 513
 514             waitTillReadyCountdownLatch.countDown();
 515         }
 516     }
 517
 518     private void onLeaderStateChanged(ShardLeaderStateChanged leaderStateChanged) {
 519         LOG.info("{}: Received LeaderStateChanged message: {}", persistenceId(), leaderStateChanged);
 520
 521         ShardInformation shardInformation = findShardInformation(leaderStateChanged.getMemberId());
 522         if(shardInformation != null) {
 523             shardInformation.setLocalDataTree(leaderStateChanged.getLocalShardDataTree());
 524             shardInformation.setLeaderVersion(leaderStateChanged.getLeaderPayloadVersion());
 525             if(shardInformation.setLeaderId(leaderStateChanged.getLeaderId())) {
 526                 primaryShardInfoCache.remove(shardInformation.getShardName());
 527             }
 528
 529             checkReady();
 530         } else {
 531             LOG.debug("No shard found with member Id {}", leaderStateChanged.getMemberId());
 532         }
 533     }
 534
 535     private void onShardNotInitializedTimeout(ShardNotInitializedTimeout message) {
 536         ShardInformation shardInfo = message.getShardInfo();
 537
 538         LOG.debug("{}: Received ShardNotInitializedTimeout message for shard {}", persistenceId(),
 539                 shardInfo.getShardName());
 540
 541         shardInfo.removeOnShardInitialized(message.getOnShardInitialized());
 542
 543         if(!shardInfo.isShardInitialized()) {
 544             LOG.debug("{}: Returning NotInitializedException for shard {}", persistenceId(), shardInfo.getShardName());
 545             message.getSender().tell(createNotInitializedException(shardInfo.shardId), getSelf());
 546         } else {
 547             LOG.debug("{}: Returning NoShardLeaderException for shard {}", persistenceId(), shardInfo.getShardName());
 548             message.getSender().tell(createNoShardLeaderException(shardInfo.shardId), getSelf());
 549         }
 550     }
 551
 552     private void onFollowerInitialSyncStatus(FollowerInitialSyncUpStatus status) {
 553         LOG.info("{} Received follower initial sync status for {} status sync done {}", persistenceId(),
 554                 status.getName(), status.isInitialSyncDone());
 555
 556         ShardInformation shardInformation = findShardInformation(status.getName());
 557
 558         if(shardInformation != null) {
 559             shardInformation.setFollowerSyncStatus(status.isInitialSyncDone());
 560
 561             mBean.setSyncStatus(isInSync());
 562         }
 563
 564     }
 565
 566     private void onRoleChangeNotification(RoleChangeNotification roleChanged) {
 567         LOG.info("{}: Received role changed for {} from {} to {}", persistenceId(), roleChanged.getMemberId(),
 568                 roleChanged.getOldRole(), roleChanged.getNewRole());
 569
 570         ShardInformation shardInformation = findShardInformation(roleChanged.getMemberId());
 571         if(shardInformation != null) {
 572             shardInformation.setRole(roleChanged.getNewRole());
 573             checkReady();
 574             mBean.setSyncStatus(isInSync());
 575         }
 576     }
 577
 578
 579     private ShardInformation findShardInformation(String memberId) {
 580         for(ShardInformation info : localShards.values()){
 581             if(info.getShardId().toString().equals(memberId)){
 582                 return info;
 583             }
 584         }
 585
 586         return null;
 587     }
 588
 589     private boolean isReadyWithLeaderId() {
 590         boolean isReady = true;
 591         for (ShardInformation info : localShards.values()) {
 592             if(!info.isShardReadyWithLeaderId()){
 593                 isReady = false;
 594                 break;
 595             }
 596         }
 597         return isReady;
 598     }
 599
 600     private boolean isInSync(){
 601         for (ShardInformation info : localShards.values()) {
 602             if(!info.isInSync()){
 603                 return false;
 604             }
 605         }
 606         return true;
 607     }
 608
 609     private void onActorInitialized(Object message) {
 610         final ActorRef sender = getSender();
 611
 612         if (sender == null) {
 613             return; //why is a non-actor sending this message? Just ignore.
 614         }
 615
 616         String actorName = sender.path().name();
 617         //find shard name from actor name; actor name is stringified shardId
 618         ShardIdentifier shardId = ShardIdentifier.builder().fromShardIdString(actorName).build();
 619
 620         if (shardId.getShardName() == null) {
 621             return;
 622         }
 623
 624         markShardAsInitialized(shardId.getShardName());
 625     }
 626
 627     private void markShardAsInitialized(String shardName) {
 628         LOG.debug("{}: Initializing shard [{}]", persistenceId(), shardName);
 629
 630         ShardInformation shardInformation = localShards.get(shardName);
 631         if (shardInformation != null) {
 632             shardInformation.setActorInitialized();
 633
 634             shardInformation.getActor().tell(new RegisterRoleChangeListener(), self());
 635         }
 636     }
 637
 638     @Override
 639     protected void handleRecover(Object message) throws Exception {
 640         if (message instanceof RecoveryCompleted) {
 641             onRecoveryCompleted();
 642         } else if (message instanceof SnapshotOffer) {
 643             applyShardManagerSnapshot((ShardManagerSnapshot)((SnapshotOffer) message).snapshot());
 644         }
 645     }
 646
 647     private void onRecoveryCompleted() {
 648         LOG.info("Recovery complete : {}", persistenceId());
 649
 650         // We no longer persist SchemaContext modules so delete all the prior messages from the akka
 651         // journal on upgrade from Helium.
 652         deleteMessages(lastSequenceNr());
 653
 654         if(currentSnapshot == null && restoreFromSnapshot != null &&
 655                 restoreFromSnapshot.getShardManagerSnapshot() != null) {
 656             try(ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(
 657                     restoreFromSnapshot.getShardManagerSnapshot()))) {
 658                 ShardManagerSnapshot snapshot = (ShardManagerSnapshot) ois.readObject();
 659
 660                 LOG.debug("{}: Deserialized restored ShardManagerSnapshot: {}", persistenceId(), snapshot);
 661
 662                 applyShardManagerSnapshot(snapshot);
 663             } catch(Exception e) {
 664                 LOG.error("{}: Error deserializing restored ShardManagerSnapshot", persistenceId(), e);
 665             }
 666         }
 667
 668         createLocalShards();
 669     }
 670
 671     private void findLocalShard(FindLocalShard message) {
 672         final ShardInformation shardInformation = localShards.get(message.getShardName());
 673
 674         if(shardInformation == null){
 675             getSender().tell(new LocalShardNotFound(message.getShardName()), getSelf());
 676             return;
 677         }
 678
 679         sendResponse(shardInformation, message.isWaitUntilInitialized(), false, new Supplier<Object>() {
 680             @Override
 681             public Object get() {
 682                 return new LocalShardFound(shardInformation.getActor());
 683             }
 684         });
 685     }
 686
 687     private void sendResponse(ShardInformation shardInformation, boolean doWait,
 688             boolean wantShardReady, final Supplier<Object> messageSupplier) {
 689         if (!shardInformation.isShardInitialized() || (wantShardReady && !shardInformation.isShardReadyWithLeaderId())) {
 690             if(doWait) {
 691                 final ActorRef sender = getSender();
 692                 final ActorRef self = self();
 693
 694                 Runnable replyRunnable = new Runnable() {
 695                     @Override
 696                     public void run() {
 697                         sender.tell(messageSupplier.get(), self);
 698                     }
 699                 };
 700
 701                 OnShardInitialized onShardInitialized = wantShardReady ? new OnShardReady(replyRunnable) :
 702                     new OnShardInitialized(replyRunnable);
 703
 704                 shardInformation.addOnShardInitialized(onShardInitialized);
 705
 706                 FiniteDuration timeout = shardInformation.getDatastoreContext().getShardInitializationTimeout().duration();
 707                 if(shardInformation.isShardInitialized()) {
 708                     // If the shard is already initialized then we'll wait enough time for the shard to
 709                     // elect a leader, ie 2 times the election timeout.
 710                     timeout = FiniteDuration.create(shardInformation.getDatastoreContext().getShardRaftConfig()
 711                             .getElectionTimeOutInterval().toMillis() * 2, TimeUnit.MILLISECONDS);
 712                 }
 713
 714                 LOG.debug("{}: Scheduling {} ms timer to wait for shard {}", persistenceId(), timeout.toMillis(),
 715                         shardInformation.getShardName());
 716
 717                 Cancellable timeoutSchedule = getContext().system().scheduler().scheduleOnce(
 718                         timeout, getSelf(),
 719                         new ShardNotInitializedTimeout(shardInformation, onShardInitialized, sender),
 720                         getContext().dispatcher(), getSelf());
 721
 722                 onShardInitialized.setTimeoutSchedule(timeoutSchedule);
 723
 724             } else if (!shardInformation.isShardInitialized()) {
 725                 LOG.debug("{}: Returning NotInitializedException for shard {}", persistenceId(),
 726                         shardInformation.getShardName());
 727                 getSender().tell(createNotInitializedException(shardInformation.shardId), getSelf());
 728             } else {
 729                 LOG.debug("{}: Returning NoShardLeaderException for shard {}", persistenceId(),
 730                         shardInformation.getShardName());
 731                 getSender().tell(createNoShardLeaderException(shardInformation.shardId), getSelf());
 732             }
 733
 734             return;
 735         }
 736
 737         getSender().tell(messageSupplier.get(), getSelf());
 738     }
 739
 740     private static NoShardLeaderException createNoShardLeaderException(ShardIdentifier shardId) {
 741         return new NoShardLeaderException(null, shardId.toString());
 742     }
 743
 744     private static NotInitializedException createNotInitializedException(ShardIdentifier shardId) {
 745         return new NotInitializedException(String.format(
 746                 "Found primary shard %s but it's not initialized yet. Please try again later", shardId));
 747     }
 748
 749     private void memberRemoved(ClusterEvent.MemberRemoved message) {
 750         String memberName = message.member().roles().iterator().next();
 751
 752         LOG.debug("{}: Received MemberRemoved: memberName: {}, address: {}", persistenceId(), memberName,
 753                 message.member().address());
 754
 755         peerAddressResolver.removePeerAddress(memberName);
 756
 757         for(ShardInformation info : localShards.values()){
 758             info.peerDown(memberName, getShardIdentifier(memberName, info.getShardName()).toString(), getSelf());
 759         }
 760     }
 761
 762     private void memberExited(ClusterEvent.MemberExited message) {
 763         String memberName = message.member().roles().iterator().next();
 764
 765         LOG.debug("{}: Received MemberExited: memberName: {}, address: {}", persistenceId(), memberName,
 766                 message.member().address());
 767
 768         peerAddressResolver.removePeerAddress(memberName);
 769
 770         for(ShardInformation info : localShards.values()){
 771             info.peerDown(memberName, getShardIdentifier(memberName, info.getShardName()).toString(), getSelf());
 772         }
 773     }
 774
 775     private void memberUp(ClusterEvent.MemberUp message) {
 776         String memberName = message.member().roles().iterator().next();
 777
 778         LOG.debug("{}: Received MemberUp: memberName: {}, address: {}", persistenceId(), memberName,
 779                 message.member().address());
 780
 781         addPeerAddress(memberName, message.member().address());
 782
 783         checkReady();
 784     }
 785
 786     private void addPeerAddress(String memberName, Address address) {
 787         peerAddressResolver.addPeerAddress(memberName, address);
 788
 789         for(ShardInformation info : localShards.values()){
 790             String shardName = info.getShardName();
 791             String peerId = getShardIdentifier(memberName, shardName).toString();
 792             info.updatePeerAddress(peerId, peerAddressResolver.getShardActorAddress(shardName, memberName), getSelf());
 793
 794             info.peerUp(memberName, peerId, getSelf());
 795         }
 796     }
 797
 798     private void memberReachable(ClusterEvent.ReachableMember message) {
 799         String memberName = message.member().roles().iterator().next();
 800         LOG.debug("Received ReachableMember: memberName {}, address: {}", memberName, message.member().address());
 801
 802         addPeerAddress(memberName, message.member().address());
 803
 804         markMemberAvailable(memberName);
 805     }
 806
 807     private void memberUnreachable(ClusterEvent.UnreachableMember message) {
 808         String memberName = message.member().roles().iterator().next();
 809         LOG.debug("Received UnreachableMember: memberName {}, address: {}", memberName, message.member().address());
 810
 811         markMemberUnavailable(memberName);
 812     }
 813
 814     private void markMemberUnavailable(final String memberName) {
 815         for(ShardInformation info : localShards.values()){
 816             String leaderId = info.getLeaderId();
 817             if(leaderId != null && leaderId.contains(memberName)) {
 818                 LOG.debug("Marking Leader {} as unavailable.", leaderId);
 819                 info.setLeaderAvailable(false);
 820
 821                 primaryShardInfoCache.remove(info.getShardName());
 822             }
 823
 824             info.peerDown(memberName, getShardIdentifier(memberName, info.getShardName()).toString(), getSelf());
 825         }
 826     }
 827
 828     private void markMemberAvailable(final String memberName) {
 829         for(ShardInformation info : localShards.values()){
 830             String leaderId = info.getLeaderId();
 831             if(leaderId != null && leaderId.contains(memberName)) {
 832                 LOG.debug("Marking Leader {} as available.", leaderId);
 833                 info.setLeaderAvailable(true);
 834             }
 835
 836             info.peerUp(memberName, getShardIdentifier(memberName, info.getShardName()).toString(), getSelf());
 837         }
 838     }
 839
 840     private void onDatastoreContextFactory(DatastoreContextFactory factory) {
 841         datastoreContextFactory = factory;
 842         for (ShardInformation info : localShards.values()) {
 843             info.setDatastoreContext(newShardDatastoreContext(info.getShardName()), getSelf());
 844         }
 845     }
 846
 847     private void onSwitchShardBehavior(SwitchShardBehavior message) {
 848         ShardIdentifier identifier = ShardIdentifier.builder().fromShardIdString(message.getShardName()).build();
 849
 850         ShardInformation shardInformation = localShards.get(identifier.getShardName());
 851
 852         if(shardInformation != null && shardInformation.getActor() != null) {
 853             shardInformation.getActor().tell(
 854                     new SwitchBehavior(message.getNewState(), message.getTerm()), getSelf());
 855         } else {
 856             LOG.warn("Could not switch the behavior of shard {} to {} - shard is not yet available",
 857                     message.getShardName(), message.getNewState());
 858         }
 859     }
 860
 861     /**
 862      * Notifies all the local shards of a change in the schema context
 863      *
 864      * @param message
 865      */
 866     private void updateSchemaContext(final Object message) {
 867         schemaContext = ((UpdateSchemaContext) message).getSchemaContext();
 868
 869         LOG.debug("Got updated SchemaContext: # of modules {}", schemaContext.getAllModuleIdentifiers().size());
 870
 871         for (ShardInformation info : localShards.values()) {
 872             if (info.getActor() == null) {
 873                 LOG.debug("Creating Shard {}", info.getShardId());
 874                 info.setActor(newShardActor(schemaContext, info));
 875             } else {
 876                 info.getActor().tell(message, getSelf());
 877             }
 878         }
 879     }
 880
 881     @VisibleForTesting
 882     protected ClusterWrapper getCluster() {
 883         return cluster;
 884     }
 885
 886     @VisibleForTesting
 887     protected ActorRef newShardActor(final SchemaContext schemaContext, ShardInformation info) {
 888         return getContext().actorOf(info.newProps(schemaContext)
 889                 .withDispatcher(shardDispatcherPath), info.getShardId().toString());
 890     }
 891
 892     private void findPrimary(FindPrimary message) {
 893         LOG.debug("{}: In findPrimary: {}", persistenceId(), message);
 894
 895         final String shardName = message.getShardName();
 896         final boolean canReturnLocalShardState = !(message instanceof RemoteFindPrimary);
 897
 898         // First see if the there is a local replica for the shard
 899         final ShardInformation info = localShards.get(shardName);
 900         if (info != null && info.isActiveMember()) {
 901             sendResponse(info, message.isWaitUntilReady(), true, new Supplier<Object>() {
 902                 @Override
 903                 public Object get() {
 904                     String primaryPath = info.getSerializedLeaderActor();
 905                     Object found = canReturnLocalShardState && info.isLeader() ?
 906                             new LocalPrimaryShardFound(primaryPath, info.getLocalShardDataTree().get()) :
 907                                 new RemotePrimaryShardFound(primaryPath, info.getLeaderVersion());
 908
 909                             if(LOG.isDebugEnabled()) {
 910                                 LOG.debug("{}: Found primary for {}: {}", persistenceId(), shardName, found);
 911                             }
 912
 913                             return found;
 914                 }
 915             });
 916
 917             return;
 918         }
 919
 920         final Collection<String> visitedAddresses;
 921         if(message instanceof RemoteFindPrimary) {
 922             visitedAddresses = ((RemoteFindPrimary)message).getVisitedAddresses();
 923         } else {
 924             visitedAddresses = new ArrayList<>(1);
 925         }
 926
 927         visitedAddresses.add(peerAddressResolver.getShardManagerActorPathBuilder(cluster.getSelfAddress()).toString());
 928
 929         for(String address: peerAddressResolver.getShardManagerPeerActorAddresses()) {
 930             if(visitedAddresses.contains(address)) {
 931                 continue;
 932             }
 933
 934             LOG.debug("{}: findPrimary for {} forwarding to remote ShardManager {}, visitedAddresses: {}",
 935                     persistenceId(), shardName, address, visitedAddresses);
 936
 937             getContext().actorSelection(address).forward(new RemoteFindPrimary(shardName,
 938                     message.isWaitUntilReady(), visitedAddresses), getContext());
 939             return;
 940         }
 941
 942         LOG.debug("{}: No shard found for {}", persistenceId(), shardName);
 943
 944         getSender().tell(new PrimaryNotFoundException(
 945                 String.format("No primary shard found for %s.", shardName)), getSelf());
 946     }
 947
 948     /**
 949      * Construct the name of the shard actor given the name of the member on
 950      * which the shard resides and the name of the shard
 951      *
 952      * @param memberName
 953      * @param shardName
 954      * @return
 955      */
 956     private ShardIdentifier getShardIdentifier(String memberName, String shardName){
 957         return peerAddressResolver.getShardIdentifier(memberName, shardName);
 958     }
 959
 960     /**
 961      * Create shards that are local to the member on which the ShardManager
 962      * runs
 963      *
 964      */
 965     private void createLocalShards() {
 966         String memberName = this.cluster.getCurrentMemberName();
 967         Collection<String> memberShardNames = this.configuration.getMemberShardNames(memberName);
 968
 969         Map<String, DatastoreSnapshot.ShardSnapshot> shardSnapshots = new HashMap<>();
 970         if(restoreFromSnapshot != null)
 971         {
 972             for(DatastoreSnapshot.ShardSnapshot snapshot: restoreFromSnapshot.getShardSnapshots()) {
 973                 shardSnapshots.put(snapshot.getName(), snapshot);
 974             }
 975         }
 976
 977         restoreFromSnapshot = null; // null out to GC
 978
 979         for(String shardName : memberShardNames){
 980             ShardIdentifier shardId = getShardIdentifier(memberName, shardName);
 981
 982             LOG.debug("{}: Creating local shard: {}", persistenceId(), shardId);
 983
 984             Map<String, String> peerAddresses = getPeerAddresses(shardName);
 985             localShards.put(shardName, new ShardInformation(shardName, shardId, peerAddresses,
 986                     newShardDatastoreContext(shardName), Shard.builder().restoreFromSnapshot(
 987                         shardSnapshots.get(shardName)), peerAddressResolver));
 988             mBean.addLocalShard(shardId.toString());
 989         }
 990     }
 991
 992     /**
 993      * Given the name of the shard find the addresses of all it's peers
 994      *
 995      * @param shardName
 996      */
 997     private Map<String, String> getPeerAddresses(String shardName) {
 998         Collection<String> members = configuration.getMembersFromShardName(shardName);
 999         Map<String, String> peerAddresses = new HashMap<>();
1000
1001         String currentMemberName = this.cluster.getCurrentMemberName();
1002
1003         for(String memberName : members) {
1004             if(!currentMemberName.equals(memberName)) {
1005                 ShardIdentifier shardId = getShardIdentifier(memberName, shardName);
1006                 String address = peerAddressResolver.getShardActorAddress(shardName, memberName);
1007                 peerAddresses.put(shardId.toString(), address);
1008             }
1009         }
1010         return peerAddresses;
1011     }
1012
1013     @Override
1014     public SupervisorStrategy supervisorStrategy() {
1015
1016         return new OneForOneStrategy(10, Duration.create("1 minute"),
1017                 new Function<Throwable, SupervisorStrategy.Directive>() {
1018             @Override
1019             public SupervisorStrategy.Directive apply(Throwable t) {
1020                 LOG.warn("Supervisor Strategy caught unexpected exception - resuming", t);
1021                 return SupervisorStrategy.resume();
1022             }
1023         }
1024                 );
1025
1026     }
1027
1028     @Override
1029     public String persistenceId() {
1030         return persistenceId;
1031     }
1032
1033     @VisibleForTesting
1034     ShardManagerInfoMBean getMBean(){
1035         return mBean;
1036     }
1037
1038     private boolean isShardReplicaOperationInProgress(final String shardName, final ActorRef sender) {
1039         if (shardReplicaOperationsInProgress.contains(shardName)) {
1040             String msg = String.format("A shard replica operation for %s is already in progress", shardName);
1041             LOG.debug ("{}: {}", persistenceId(), msg);
1042             sender.tell(new akka.actor.Status.Failure(new IllegalStateException(msg)), getSelf());
1043             return true;
1044         }
1045
1046         return false;
1047     }
1048
1049     private void onAddShardReplica (final AddShardReplica shardReplicaMsg) {
1050         final String shardName = shardReplicaMsg.getShardName();
1051
1052         LOG.debug("{}: onAddShardReplica: {}", persistenceId(), shardReplicaMsg);
1053
1054         // verify the shard with the specified name is present in the cluster configuration
1055         if (!(this.configuration.isShardConfigured(shardName))) {
1056             String msg = String.format("No module configuration exists for shard %s", shardName);
1057             LOG.debug ("{}: {}", persistenceId(), msg);
1058             getSender().tell(new akka.actor.Status.Failure(new IllegalArgumentException(msg)), getSelf());
1059             return;
1060         }
1061
1062         // Create the localShard
1063         if (schemaContext == null) {
1064             String msg = String.format(
1065                   "No SchemaContext is available in order to create a local shard instance for %s", shardName);
1066             LOG.debug ("{}: {}", persistenceId(), msg);
1067             getSender().tell(new akka.actor.Status.Failure(new IllegalStateException(msg)), getSelf());
1068             return;
1069         }
1070
1071         findPrimary(shardName, new AutoFindPrimaryFailureResponseHandler(getSender(), shardName, persistenceId(), getSelf()) {
1072             @Override
1073             public void onRemotePrimaryShardFound(RemotePrimaryShardFound response) {
1074                 getSelf().tell(new PrimaryShardFoundForContext(getShardName(), shardReplicaMsg, response), getTargetActor());
1075             }
1076
1077             @Override
1078             public void onLocalPrimaryFound(LocalPrimaryShardFound message) {
1079                 sendLocalReplicaAlreadyExistsReply(getShardName(), getTargetActor());
1080             }
1081
1082         });
1083     }
1084
1085     private void sendLocalReplicaAlreadyExistsReply(String shardName, ActorRef sender) {
1086         String msg = String.format("Local shard %s already exists", shardName);
1087         LOG.debug ("{}: {}", persistenceId(), msg);
1088         sender.tell(new akka.actor.Status.Failure(new AlreadyExistsException(msg)), getSelf());
1089     }
1090
1091     private void addShard(final String shardName, final RemotePrimaryShardFound response, final ActorRef sender) {
1092         if(isShardReplicaOperationInProgress(shardName, sender)) {
1093             return;
1094         }
1095
1096         shardReplicaOperationsInProgress.add(shardName);
1097
1098         final ShardInformation shardInfo;
1099         final boolean removeShardOnFailure;
1100         ShardInformation existingShardInfo = localShards.get(shardName);
1101         if(existingShardInfo == null) {
1102             removeShardOnFailure = true;
1103             ShardIdentifier shardId = getShardIdentifier(cluster.getCurrentMemberName(), shardName);
1104
1105             DatastoreContext datastoreContext = newShardDatastoreContextBuilder(shardName).customRaftPolicyImplementation(
1106                     DisableElectionsRaftPolicy.class.getName()).build();
1107
1108             shardInfo = new ShardInformation(shardName, shardId, getPeerAddresses(shardName), datastoreContext,
1109                     Shard.builder(), peerAddressResolver);
1110             shardInfo.setActiveMember(false);
1111             localShards.put(shardName, shardInfo);
1112             shardInfo.setActor(newShardActor(schemaContext, shardInfo));
1113         } else {
1114             removeShardOnFailure = false;
1115             shardInfo = existingShardInfo;
1116         }
1117
1118         String localShardAddress = peerAddressResolver.getShardActorAddress(shardName, cluster.getCurrentMemberName());
1119
1120         //inform ShardLeader to add this shard as a replica by sending an AddServer message
1121         LOG.debug ("{}: Sending AddServer message to peer {} for shard {}", persistenceId(),
1122                 response.getPrimaryPath(), shardInfo.getShardId());
1123
1124         Timeout addServerTimeout = new Timeout(shardInfo.getDatastoreContext().getShardLeaderElectionTimeout().
1125                 duration());
1126         Future<Object> futureObj = ask(getContext().actorSelection(response.getPrimaryPath()),
1127             new AddServer(shardInfo.getShardId().toString(), localShardAddress, true), addServerTimeout);
1128
1129         futureObj.onComplete(new OnComplete<Object>() {
1130             @Override
1131             public void onComplete(Throwable failure, Object addServerResponse) {
1132                 if (failure != null) {
1133                     LOG.debug ("{}: AddServer request to {} for {} failed", persistenceId(),
1134                             response.getPrimaryPath(), shardName, failure);
1135
1136                     String msg = String.format("AddServer request to leader %s for shard %s failed",
1137                             response.getPrimaryPath(), shardName);
1138                     self().tell(new ForwardedAddServerFailure(shardName, msg, failure, removeShardOnFailure), sender);
1139                 } else {
1140                     self().tell(new ForwardedAddServerReply(shardInfo, (AddServerReply)addServerResponse,
1141                             response.getPrimaryPath(), removeShardOnFailure), sender);
1142                 }
1143             }
1144         }, new Dispatchers(context().system().dispatchers()).getDispatcher(Dispatchers.DispatcherType.Client));
1145     }
1146
1147     private void onAddServerFailure(String shardName, String message, Throwable failure, ActorRef sender,
1148             boolean removeShardOnFailure) {
1149         shardReplicaOperationsInProgress.remove(shardName);
1150
1151         if(removeShardOnFailure) {
1152             ShardInformation shardInfo = localShards.remove(shardName);
1153             if (shardInfo.getActor() != null) {
1154                 shardInfo.getActor().tell(PoisonPill.getInstance(), getSelf());
1155             }
1156         }
1157
1158         sender.tell(new akka.actor.Status.Failure(message == null ? failure :
1159             new RuntimeException(message, failure)), getSelf());
1160     }
1161
1162     private void onAddServerReply(ShardInformation shardInfo, AddServerReply replyMsg, ActorRef sender,
1163             String leaderPath, boolean removeShardOnFailure) {
1164         String shardName = shardInfo.getShardName();
1165         shardReplicaOperationsInProgress.remove(shardName);
1166
1167         LOG.debug ("{}: Received {} for shard {} from leader {}", persistenceId(), replyMsg, shardName, leaderPath);
1168
1169         if (replyMsg.getStatus() == ServerChangeStatus.OK) {
1170             LOG.debug ("{}: Leader shard successfully added the replica shard {}", persistenceId(), shardName);
1171
1172             // Make the local shard voting capable
1173             shardInfo.setDatastoreContext(newShardDatastoreContext(shardName), getSelf());
1174             shardInfo.setActiveMember(true);
1175             persistShardList();
1176
1177             mBean.addLocalShard(shardInfo.getShardId().toString());
1178             sender.tell(new akka.actor.Status.Success(null), getSelf());
1179         } else if(replyMsg.getStatus() == ServerChangeStatus.ALREADY_EXISTS) {
1180             sendLocalReplicaAlreadyExistsReply(shardName, sender);
1181         } else {
1182             LOG.warn ("{}: Leader failed to add shard replica {} with status {}",
1183                     persistenceId(), shardName, replyMsg.getStatus());
1184
1185             Exception failure = getServerChangeException(AddServer.class, replyMsg.getStatus(), leaderPath, shardInfo.getShardId());
1186
1187             onAddServerFailure(shardName, null, failure, sender, removeShardOnFailure);
1188         }
1189     }
1190
1191     private static Exception getServerChangeException(Class<?> serverChange, ServerChangeStatus serverChangeStatus,
1192                                                String leaderPath, ShardIdentifier shardId) {
1193         Exception failure;
1194         switch (serverChangeStatus) {
1195             case TIMEOUT:
1196                 failure = new TimeoutException(String.format(
1197                         "The shard leader %s timed out trying to replicate the initial data to the new shard %s." +
1198                         "Possible causes - there was a problem replicating the data or shard leadership changed while replicating the shard data",
1199                         leaderPath, shardId.getShardName()));
1200                 break;
1201             case NO_LEADER:
1202                 failure = createNoShardLeaderException(shardId);
1203                 break;
1204             case NOT_SUPPORTED:
1205                 failure = new UnsupportedOperationException(String.format("%s request is not supported for shard %s",
1206                         serverChange.getSimpleName(), shardId.getShardName()));
1207                 break;
1208             default :
1209                 failure = new RuntimeException(String.format(
1210                         "%s request to leader %s for shard %s failed with status %s",
1211                         serverChange.getSimpleName(), leaderPath, shardId.getShardName(), serverChangeStatus));
1212         }
1213         return failure;
1214     }
1215
1216     private void onRemoveShardReplica (final RemoveShardReplica shardReplicaMsg) {
1217         LOG.debug("{}: onRemoveShardReplica: {}", persistenceId(), shardReplicaMsg);
1218
1219         findPrimary(shardReplicaMsg.getShardName(), new AutoFindPrimaryFailureResponseHandler(getSender(),
1220                 shardReplicaMsg.getShardName(), persistenceId(), getSelf()) {
1221             @Override
1222             public void onRemotePrimaryShardFound(RemotePrimaryShardFound response) {
1223                 getSelf().tell(new PrimaryShardFoundForContext(getShardName(), shardReplicaMsg, response), getTargetActor());
1224             }
1225
1226             @Override
1227             public void onLocalPrimaryFound(LocalPrimaryShardFound response) {
1228                 getSelf().tell(new PrimaryShardFoundForContext(getShardName(), shardReplicaMsg, response), getTargetActor());
1229             }
1230         });
1231     }
1232
1233     private void persistShardList() {
1234         List<String> shardList = new ArrayList<>(localShards.keySet());
1235         for (ShardInformation shardInfo : localShards.values()) {
1236             if (!shardInfo.isActiveMember()) {
1237                 shardList.remove(shardInfo.getShardName());
1238             }
1239         }
1240         LOG.debug ("{}: persisting the shard list {}", persistenceId(), shardList);
1241         saveSnapshot(updateShardManagerSnapshot(shardList));
1242     }
1243
1244     private ShardManagerSnapshot updateShardManagerSnapshot(List<String> shardList) {
1245         currentSnapshot = new ShardManagerSnapshot(shardList);
1246         return currentSnapshot;
1247     }
1248
1249     private void applyShardManagerSnapshot(ShardManagerSnapshot snapshot) {
1250         currentSnapshot = snapshot;
1251
1252         LOG.debug ("{}: onSnapshotOffer: {}", persistenceId(), currentSnapshot);
1253
1254         String currentMember = cluster.getCurrentMemberName();
1255         Set<String> configuredShardList =
1256             new HashSet<>(configuration.getMemberShardNames(currentMember));
1257         for (String shard : currentSnapshot.getShardList()) {
1258             if (!configuredShardList.contains(shard)) {
1259                 // add the current member as a replica for the shard
1260                 LOG.debug ("{}: adding shard {}", persistenceId(), shard);
1261                 configuration.addMemberReplicaForShard(shard, currentMember);
1262             } else {
1263                 configuredShardList.remove(shard);
1264             }
1265         }
1266         for (String shard : configuredShardList) {
1267             // remove the member as a replica for the shard
1268             LOG.debug ("{}: removing shard {}", persistenceId(), shard);
1269             configuration.removeMemberReplicaForShard(shard, currentMember);
1270         }
1271     }
1272
1273     private void onSaveSnapshotSuccess (SaveSnapshotSuccess successMessage) {
1274         LOG.debug ("{} saved ShardManager snapshot successfully. Deleting the prev snapshot if available",
1275             persistenceId());
1276         deleteSnapshots(new SnapshotSelectionCriteria(scala.Long.MaxValue(), successMessage.metadata().timestamp() - 1,
1277             0, 0));
1278     }
1279
1280     private static class ForwardedAddServerReply {
1281         ShardInformation shardInfo;
1282         AddServerReply addServerReply;
1283         String leaderPath;
1284         boolean removeShardOnFailure;
1285
1286         ForwardedAddServerReply(ShardInformation shardInfo, AddServerReply addServerReply, String leaderPath,
1287                 boolean removeShardOnFailure) {
1288             this.shardInfo = shardInfo;
1289             this.addServerReply = addServerReply;
1290             this.leaderPath = leaderPath;
1291             this.removeShardOnFailure = removeShardOnFailure;
1292         }
1293     }
1294
1295     private static class ForwardedAddServerFailure {
1296         String shardName;
1297         String failureMessage;
1298         Throwable failure;
1299         boolean removeShardOnFailure;
1300
1301         ForwardedAddServerFailure(String shardName, String failureMessage, Throwable failure,
1302                 boolean removeShardOnFailure) {
1303             this.shardName = shardName;
1304             this.failureMessage = failureMessage;
1305             this.failure = failure;
1306             this.removeShardOnFailure = removeShardOnFailure;
1307         }
1308     }
1309
1310     @VisibleForTesting
1311     protected static class ShardInformation {
1312         private final ShardIdentifier shardId;
1313         private final String shardName;
1314         private ActorRef actor;
1315         private final Map<String, String> initialPeerAddresses;
1316         private Optional<DataTree> localShardDataTree;
1317         private boolean leaderAvailable = false;
1318
1319         // flag that determines if the actor is ready for business
1320         private boolean actorInitialized = false;
1321
1322         private boolean followerSyncStatus = false;
1323
1324         private final Set<OnShardInitialized> onShardInitializedSet = Sets.newHashSet();
1325         private String role ;
1326         private String leaderId;
1327         private short leaderVersion;
1328
1329         private DatastoreContext datastoreContext;
1330         private Shard.AbstractBuilder<?, ?> builder;
1331         private final ShardPeerAddressResolver addressResolver;
1332         private boolean isActiveMember = true;
1333
1334         private ShardInformation(String shardName, ShardIdentifier shardId,
1335                 Map<String, String> initialPeerAddresses, DatastoreContext datastoreContext,
1336                 Shard.AbstractBuilder<?, ?> builder, ShardPeerAddressResolver addressResolver) {
1337             this.shardName = shardName;
1338             this.shardId = shardId;
1339             this.initialPeerAddresses = initialPeerAddresses;
1340             this.datastoreContext = datastoreContext;
1341             this.builder = builder;
1342             this.addressResolver = addressResolver;
1343         }
1344
1345         Props newProps(SchemaContext schemaContext) {
1346             Preconditions.checkNotNull(builder);
1347             Props props = builder.id(shardId).peerAddresses(initialPeerAddresses).datastoreContext(datastoreContext).
1348                     schemaContext(schemaContext).props();
1349             builder = null;
1350             return props;
1351         }
1352
1353         String getShardName() {
1354             return shardName;
1355         }
1356
1357         @Nullable
1358         ActorRef getActor(){
1359             return actor;
1360         }
1361
1362         void setActor(ActorRef actor) {
1363             this.actor = actor;
1364         }
1365
1366         ShardIdentifier getShardId() {
1367             return shardId;
1368         }
1369
1370         void setLocalDataTree(Optional<DataTree> localShardDataTree) {
1371             this.localShardDataTree = localShardDataTree;
1372         }
1373
1374         Optional<DataTree> getLocalShardDataTree() {
1375             return localShardDataTree;
1376         }
1377
1378         DatastoreContext getDatastoreContext() {
1379             return datastoreContext;
1380         }
1381
1382         void setDatastoreContext(DatastoreContext datastoreContext, ActorRef sender) {
1383             this.datastoreContext = datastoreContext;
1384             if (actor != null) {
1385                 LOG.debug ("Sending new DatastoreContext to {}", shardId);
1386                 actor.tell(this.datastoreContext, sender);
1387             }
1388         }
1389
1390         void updatePeerAddress(String peerId, String peerAddress, ActorRef sender){
1391             LOG.info("updatePeerAddress for peer {} with address {}", peerId, peerAddress);
1392
1393             if(actor != null) {
1394                 if(LOG.isDebugEnabled()) {
1395                     LOG.debug("Sending PeerAddressResolved for peer {} with address {} to {}",
1396                             peerId, peerAddress, actor.path());
1397                 }
1398
1399                 actor.tell(new PeerAddressResolved(peerId, peerAddress), sender);
1400             }
1401
1402             notifyOnShardInitializedCallbacks();
1403         }
1404
1405         void peerDown(String memberName, String peerId, ActorRef sender) {
1406             if(actor != null) {
1407                 actor.tell(new PeerDown(memberName, peerId), sender);
1408             }
1409         }
1410
1411         void peerUp(String memberName, String peerId, ActorRef sender) {
1412             if(actor != null) {
1413                 actor.tell(new PeerUp(memberName, peerId), sender);
1414             }
1415         }
1416
1417         boolean isShardReady() {
1418             return !RaftState.Candidate.name().equals(role) && !Strings.isNullOrEmpty(role);
1419         }
1420
1421         boolean isShardReadyWithLeaderId() {
1422             return leaderAvailable && isShardReady() && !RaftState.IsolatedLeader.name().equals(role) &&
1423                     (isLeader() || addressResolver.resolve(leaderId) != null);
1424         }
1425
1426         boolean isShardInitialized() {
1427             return getActor() != null && actorInitialized;
1428         }
1429
1430         boolean isLeader() {
1431             return Objects.equal(leaderId, shardId.toString());
1432         }
1433
1434         String getSerializedLeaderActor() {
1435             if(isLeader()) {
1436                 return Serialization.serializedActorPath(getActor());
1437             } else {
1438                 return addressResolver.resolve(leaderId);
1439             }
1440         }
1441
1442         void setActorInitialized() {
1443             LOG.debug("Shard {} is initialized", shardId);
1444
1445             this.actorInitialized = true;
1446
1447             notifyOnShardInitializedCallbacks();
1448         }
1449
1450         private void notifyOnShardInitializedCallbacks() {
1451             if(onShardInitializedSet.isEmpty()) {
1452                 return;
1453             }
1454
1455             boolean ready = isShardReadyWithLeaderId();
1456
1457             if(LOG.isDebugEnabled()) {
1458                 LOG.debug("Shard {} is {} - notifying {} OnShardInitialized callbacks", shardId,
1459                         ready ? "ready" : "initialized", onShardInitializedSet.size());
1460             }
1461
1462             Iterator<OnShardInitialized> iter = onShardInitializedSet.iterator();
1463             while(iter.hasNext()) {
1464                 OnShardInitialized onShardInitialized = iter.next();
1465                 if(!(onShardInitialized instanceof OnShardReady) || ready) {
1466                     iter.remove();
1467                     onShardInitialized.getTimeoutSchedule().cancel();
1468                     onShardInitialized.getReplyRunnable().run();
1469                 }
1470             }
1471         }
1472
1473         void addOnShardInitialized(OnShardInitialized onShardInitialized) {
1474             onShardInitializedSet.add(onShardInitialized);
1475         }
1476
1477         void removeOnShardInitialized(OnShardInitialized onShardInitialized) {
1478             onShardInitializedSet.remove(onShardInitialized);
1479         }
1480
1481         void setRole(String newRole) {
1482             this.role = newRole;
1483
1484             notifyOnShardInitializedCallbacks();
1485         }
1486
1487         void setFollowerSyncStatus(boolean syncStatus){
1488             this.followerSyncStatus = syncStatus;
1489         }
1490
1491         boolean isInSync(){
1492             if(RaftState.Follower.name().equals(this.role)){
1493                 return followerSyncStatus;
1494             } else if(RaftState.Leader.name().equals(this.role)){
1495                 return true;
1496             }
1497
1498             return false;
1499         }
1500
1501         boolean setLeaderId(String leaderId) {
1502             boolean changed = !Objects.equal(this.leaderId, leaderId);
1503             this.leaderId = leaderId;
1504             if(leaderId != null) {
1505                 this.leaderAvailable = true;
1506             }
1507             notifyOnShardInitializedCallbacks();
1508
1509             return changed;
1510         }
1511
1512         String getLeaderId() {
1513             return leaderId;
1514         }
1515
1516         void setLeaderAvailable(boolean leaderAvailable) {
1517             this.leaderAvailable = leaderAvailable;
1518
1519             if(leaderAvailable) {
1520                 notifyOnShardInitializedCallbacks();
1521             }
1522         }
1523
1524         short getLeaderVersion() {
1525             return leaderVersion;
1526         }
1527
1528         void setLeaderVersion(short leaderVersion) {
1529             this.leaderVersion = leaderVersion;
1530         }
1531
1532         boolean isActiveMember() {
1533             return isActiveMember;
1534         }
1535
1536         void setActiveMember(boolean isActiveMember) {
1537             this.isActiveMember = isActiveMember;
1538         }
1539     }
1540
1541     private static class OnShardInitialized {
1542         private final Runnable replyRunnable;
1543         private Cancellable timeoutSchedule;
1544
1545         OnShardInitialized(Runnable replyRunnable) {
1546             this.replyRunnable = replyRunnable;
1547         }
1548
1549         Runnable getReplyRunnable() {
1550             return replyRunnable;
1551         }
1552
1553         Cancellable getTimeoutSchedule() {
1554             return timeoutSchedule;
1555         }
1556
1557         void setTimeoutSchedule(Cancellable timeoutSchedule) {
1558             this.timeoutSchedule = timeoutSchedule;
1559         }
1560     }
1561
1562     private static class OnShardReady extends OnShardInitialized {
1563         OnShardReady(Runnable replyRunnable) {
1564             super(replyRunnable);
1565         }
1566     }
1567
1568     private static class ShardNotInitializedTimeout {
1569         private final ActorRef sender;
1570         private final ShardInformation shardInfo;
1571         private final OnShardInitialized onShardInitialized;
1572
1573         ShardNotInitializedTimeout(ShardInformation shardInfo, OnShardInitialized onShardInitialized, ActorRef sender) {
1574             this.sender = sender;
1575             this.shardInfo = shardInfo;
1576             this.onShardInitialized = onShardInitialized;
1577         }
1578
1579         ActorRef getSender() {
1580             return sender;
1581         }
1582
1583         ShardInformation getShardInfo() {
1584             return shardInfo;
1585         }
1586
1587         OnShardInitialized getOnShardInitialized() {
1588             return onShardInitialized;
1589         }
1590     }
1591
1592     private void findPrimary(final String shardName, final FindPrimaryResponseHandler handler) {
1593         Timeout findPrimaryTimeout = new Timeout(datastoreContextFactory.getBaseDatastoreContext().
1594                 getShardInitializationTimeout().duration().$times(2));
1595
1596
1597         Future<Object> futureObj = ask(getSelf(), new FindPrimary(shardName, true), findPrimaryTimeout);
1598         futureObj.onComplete(new OnComplete<Object>() {
1599             @Override
1600             public void onComplete(Throwable failure, Object response) {
1601                 if (failure != null) {
1602                     handler.onFailure(failure);
1603                 } else {
1604                     if(response instanceof RemotePrimaryShardFound) {
1605                         handler.onRemotePrimaryShardFound((RemotePrimaryShardFound) response);
1606                     } else if(response instanceof LocalPrimaryShardFound) {
1607                         handler.onLocalPrimaryFound((LocalPrimaryShardFound) response);
1608                     } else {
1609                         handler.onUnknownResponse(response);
1610                     }
1611                 }
1612             }
1613         }, new Dispatchers(context().system().dispatchers()).getDispatcher(Dispatchers.DispatcherType.Client));
1614     }
1615
1616     /**
1617      * The FindPrimaryResponseHandler provides specific callback methods which are invoked when a response to the
1618      * a remote or local find primary message is processed
1619      */
1620     private static interface FindPrimaryResponseHandler {
1621         /**
1622          * Invoked when a Failure message is received as a response
1623          *
1624          * @param failure
1625          */
1626         void onFailure(Throwable failure);
1627
1628         /**
1629          * Invoked when a RemotePrimaryShardFound response is received
1630          *
1631          * @param response
1632          */
1633         void onRemotePrimaryShardFound(RemotePrimaryShardFound response);
1634
1635         /**
1636          * Invoked when a LocalPrimaryShardFound response is received
1637          * @param response
1638          */
1639         void onLocalPrimaryFound(LocalPrimaryShardFound response);
1640
1641         /**
1642          * Invoked when an unknown response is received. This is another type of failure.
1643          *
1644          * @param response
1645          */
1646         void onUnknownResponse(Object response);
1647     }
1648
1649     /**
1650      * The AutoFindPrimaryFailureResponseHandler automatically processes Failure responses when finding a primary
1651      * replica and sends a wrapped Failure response to some targetActor
1652      */
1653     private static abstract class AutoFindPrimaryFailureResponseHandler implements FindPrimaryResponseHandler {
1654         private final ActorRef targetActor;
1655         private final String shardName;
1656         private final String persistenceId;
1657         private final ActorRef shardManagerActor;
1658
1659         /**
1660          * @param targetActor The actor to whom the Failure response should be sent when a FindPrimary failure occurs
1661          * @param shardName The name of the shard for which the primary replica had to be found
1662          * @param persistenceId The persistenceId for the ShardManager
1663          * @param shardManagerActor The ShardManager actor which triggered the call to FindPrimary
1664          */
1665         protected AutoFindPrimaryFailureResponseHandler(ActorRef targetActor, String shardName, String persistenceId, ActorRef shardManagerActor){
1666             this.targetActor = Preconditions.checkNotNull(targetActor);
1667             this.shardName = Preconditions.checkNotNull(shardName);
1668             this.persistenceId = Preconditions.checkNotNull(persistenceId);
1669             this.shardManagerActor = Preconditions.checkNotNull(shardManagerActor);
1670         }
1671
1672         public ActorRef getTargetActor() {
1673             return targetActor;
1674         }
1675
1676         public String getShardName() {
1677             return shardName;
1678         }
1679
1680         @Override
1681         public void onFailure(Throwable failure) {
1682             LOG.debug ("{}: Received failure from FindPrimary for shard {}", persistenceId, shardName, failure);
1683             targetActor.tell(new akka.actor.Status.Failure(new RuntimeException(
1684                     String.format("Failed to find leader for shard %s", shardName), failure)), shardManagerActor);
1685         }
1686
1687         @Override
1688         public void onUnknownResponse(Object response) {
1689             String msg = String.format("Failed to find leader for shard %s: received response: %s",
1690                     shardName, response);
1691             LOG.debug ("{}: {}", persistenceId, msg);
1692             targetActor.tell(new akka.actor.Status.Failure(response instanceof Throwable ? (Throwable) response :
1693                     new RuntimeException(msg)), shardManagerActor);
1694         }
1695     }
1696
1697
1698     /**
1699      * The PrimaryShardFoundForContext is a DTO which puts together a message (aka 'Context' message) which needs to be
1700      * forwarded to the primary replica of a shard and the message (aka 'PrimaryShardFound' message) that is received
1701      * as a successful response to find primary.
1702      */
1703     private static class PrimaryShardFoundForContext {
1704         private final String shardName;
1705         private final Object contextMessage;
1706         private final RemotePrimaryShardFound remotePrimaryShardFound;
1707         private final LocalPrimaryShardFound localPrimaryShardFound;
1708
1709         public PrimaryShardFoundForContext(@Nonnull String shardName, @Nonnull Object contextMessage,
1710                 @Nonnull Object primaryFoundMessage) {
1711             this.shardName = Preconditions.checkNotNull(shardName);
1712             this.contextMessage = Preconditions.checkNotNull(contextMessage);
1713             Preconditions.checkNotNull(primaryFoundMessage);
1714             this.remotePrimaryShardFound = (primaryFoundMessage instanceof RemotePrimaryShardFound) ?
1715                     (RemotePrimaryShardFound) primaryFoundMessage : null;
1716             this.localPrimaryShardFound = (primaryFoundMessage instanceof LocalPrimaryShardFound) ?
1717                     (LocalPrimaryShardFound) primaryFoundMessage : null;
1718         }
1719
1720         @Nonnull
1721         String getPrimaryPath(){
1722             if(remotePrimaryShardFound != null) {
1723                 return remotePrimaryShardFound.getPrimaryPath();
1724             }
1725             return localPrimaryShardFound.getPrimaryPath();
1726         }
1727
1728         @Nonnull
1729         Object getContextMessage() {
1730             return contextMessage;
1731         }
1732
1733         @Nullable
1734         RemotePrimaryShardFound getRemotePrimaryShardFound() {
1735             return remotePrimaryShardFound;
1736         }
1737
1738         @Nonnull
1739         String getShardName() {
1740             return shardName;
1741         }
1742     }
1743
1744     /**
1745      * The WrappedShardResponse class wraps a response from a Shard.
1746      */
1747     private static class WrappedShardResponse {
1748         private final ShardIdentifier shardId;
1749         private final Object response;
1750         private final String leaderPath;
1751
1752         private WrappedShardResponse(ShardIdentifier shardId, Object response, String leaderPath) {
1753             this.shardId = shardId;
1754             this.response = response;
1755             this.leaderPath = leaderPath;
1756         }
1757
1758         ShardIdentifier getShardId() {
1759             return shardId;
1760         }
1761
1762         Object getResponse() {
1763             return response;
1764         }
1765
1766         String getLeaderPath() {
1767             return leaderPath;
1768         }
1769     }
1770 }
1771
1772
1773