opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/sharding/DistributedShardedDOMDataTree.java

   1 /*
   2  * Copyright (c) 2016, 2017 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.sharding;
  10
  11 import static akka.actor.ActorRef.noSender;
  12
  13 import akka.actor.ActorRef;
  14 import akka.actor.ActorSystem;
  15 import akka.actor.PoisonPill;
  16 import akka.actor.Props;
  17 import akka.dispatch.Mapper;
  18 import akka.dispatch.OnComplete;
  19 import akka.pattern.Patterns;
  20 import akka.util.Timeout;
  21 import com.google.common.base.Optional;
  22 import com.google.common.base.Preconditions;
  23 import com.google.common.base.Throwables;
  24 import com.google.common.collect.ForwardingObject;
  25 import com.google.common.util.concurrent.FutureCallback;
  26 import com.google.common.util.concurrent.Futures;
  27 import com.google.common.util.concurrent.ListenableFuture;
  28 import com.google.common.util.concurrent.SettableFuture;
  29 import com.google.common.util.concurrent.Uninterruptibles;
  30 import java.util.AbstractMap.SimpleEntry;
  31 import java.util.ArrayList;
  32 import java.util.Collection;
  33 import java.util.Collections;
  34 import java.util.EnumMap;
  35 import java.util.HashMap;
  36 import java.util.List;
  37 import java.util.Map;
  38 import java.util.Map.Entry;
  39 import java.util.Set;
  40 import java.util.concurrent.CompletionStage;
  41 import java.util.concurrent.ExecutionException;
  42 import java.util.concurrent.TimeUnit;
  43 import java.util.concurrent.TimeoutException;
  44 import javax.annotation.Nonnull;
  45 import javax.annotation.Nullable;
  46 import javax.annotation.concurrent.GuardedBy;
  47 import org.opendaylight.controller.cluster.ActorSystemProvider;
  48 import org.opendaylight.controller.cluster.access.concepts.MemberName;
  49 import org.opendaylight.controller.cluster.databroker.actors.dds.DataStoreClient;
  50 import org.opendaylight.controller.cluster.databroker.actors.dds.SimpleDataStoreClientActor;
  51 import org.opendaylight.controller.cluster.datastore.AbstractDataStore;
  52 import org.opendaylight.controller.cluster.datastore.Shard;
  53 import org.opendaylight.controller.cluster.datastore.config.Configuration;
  54 import org.opendaylight.controller.cluster.datastore.config.ModuleShardConfiguration;
  55 import org.opendaylight.controller.cluster.datastore.messages.CreateShard;
  56 import org.opendaylight.controller.cluster.datastore.shardstrategy.ModuleShardStrategy;
  57 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  58 import org.opendaylight.controller.cluster.datastore.utils.ClusterUtils;
  59 import org.opendaylight.controller.cluster.dom.api.CDSDataTreeProducer;
  60 import org.opendaylight.controller.cluster.dom.api.CDSShardAccess;
  61 import org.opendaylight.controller.cluster.sharding.ShardedDataTreeActor.ShardedDataTreeActorCreator;
  62 import org.opendaylight.controller.cluster.sharding.messages.InitConfigListener;
  63 import org.opendaylight.controller.cluster.sharding.messages.LookupPrefixShard;
  64 import org.opendaylight.controller.cluster.sharding.messages.PrefixShardRemovalLookup;
  65 import org.opendaylight.controller.cluster.sharding.messages.ProducerCreated;
  66 import org.opendaylight.controller.cluster.sharding.messages.ProducerRemoved;
  67 import org.opendaylight.controller.cluster.sharding.messages.StartConfigShardLookup;
  68 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  69 import org.opendaylight.mdsal.dom.api.DOMDataTreeCursorAwareTransaction;
  70 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  71 import org.opendaylight.mdsal.dom.api.DOMDataTreeListener;
  72 import org.opendaylight.mdsal.dom.api.DOMDataTreeLoopException;
  73 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducer;
  74 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducerException;
  75 import org.opendaylight.mdsal.dom.api.DOMDataTreeService;
  76 import org.opendaylight.mdsal.dom.api.DOMDataTreeShard;
  77 import org.opendaylight.mdsal.dom.api.DOMDataTreeShardingConflictException;
  78 import org.opendaylight.mdsal.dom.api.DOMDataTreeShardingService;
  79 import org.opendaylight.mdsal.dom.broker.DOMDataTreeShardRegistration;
  80 import org.opendaylight.mdsal.dom.broker.ShardedDOMDataTree;
  81 import org.opendaylight.mdsal.dom.spi.DOMDataTreePrefixTable;
  82 import org.opendaylight.mdsal.dom.spi.DOMDataTreePrefixTableEntry;
  83 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.clustering.prefix.shard.configuration.rev170110.PrefixShards;
  84 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  85 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  86 import org.slf4j.Logger;
  87 import org.slf4j.LoggerFactory;
  88 import scala.compat.java8.FutureConverters;
  89 import scala.concurrent.Future;
  90 import scala.concurrent.Promise;
  91 import scala.concurrent.duration.FiniteDuration;
  92
  93 /**
  94  * A layer on top of DOMDataTreeService that distributes producer/shard registrations to remote nodes via
  95  * {@link ShardedDataTreeActor}. Also provides QoL method for addition of prefix based clustered shard into the system.
  96  */
  97 public class DistributedShardedDOMDataTree implements DOMDataTreeService, DOMDataTreeShardingService,
  98         DistributedShardFactory {
  99
 100     private static final Logger LOG = LoggerFactory.getLogger(DistributedShardedDOMDataTree.class);
 101
 102     private static final int MAX_ACTOR_CREATION_RETRIES = 100;
 103     private static final int ACTOR_RETRY_DELAY = 100;
 104     private static final TimeUnit ACTOR_RETRY_TIME_UNIT = TimeUnit.MILLISECONDS;
 105     private static final int LOOKUP_TASK_MAX_RETRIES = 100;
 106     static final FiniteDuration SHARD_FUTURE_TIMEOUT_DURATION =
 107             new FiniteDuration(LOOKUP_TASK_MAX_RETRIES * LOOKUP_TASK_MAX_RETRIES * 3, TimeUnit.SECONDS);
 108     static final Timeout SHARD_FUTURE_TIMEOUT = new Timeout(SHARD_FUTURE_TIMEOUT_DURATION);
 109
 110     static final String ACTOR_ID = "ShardedDOMDataTreeFrontend";
 111
 112     private final ShardedDOMDataTree shardedDOMDataTree;
 113     private final ActorSystem actorSystem;
 114     private final AbstractDataStore distributedOperDatastore;
 115     private final AbstractDataStore distributedConfigDatastore;
 116
 117     private final ActorRef shardedDataTreeActor;
 118     private final MemberName memberName;
 119
 120     @GuardedBy("shards")
 121     private final DOMDataTreePrefixTable<DOMDataTreeShardRegistration<DOMDataTreeShard>> shards =
 122             DOMDataTreePrefixTable.create();
 123
 124     private final EnumMap<LogicalDatastoreType, Entry<DataStoreClient, ActorRef>> configurationShardMap =
 125             new EnumMap<>(LogicalDatastoreType.class);
 126
 127     private final EnumMap<LogicalDatastoreType, PrefixedShardConfigWriter> writerMap =
 128             new EnumMap<>(LogicalDatastoreType.class);
 129
 130     private final PrefixedShardConfigUpdateHandler updateHandler;
 131
 132     public DistributedShardedDOMDataTree(final ActorSystemProvider actorSystemProvider,
 133                                          final AbstractDataStore distributedOperDatastore,
 134                                          final AbstractDataStore distributedConfigDatastore) {
 135         this.actorSystem = Preconditions.checkNotNull(actorSystemProvider).getActorSystem();
 136         this.distributedOperDatastore = Preconditions.checkNotNull(distributedOperDatastore);
 137         this.distributedConfigDatastore = Preconditions.checkNotNull(distributedConfigDatastore);
 138         shardedDOMDataTree = new ShardedDOMDataTree();
 139
 140         shardedDataTreeActor = createShardedDataTreeActor(actorSystem,
 141                 new ShardedDataTreeActorCreator()
 142                         .setShardingService(this)
 143                         .setActorSystem(actorSystem)
 144                         .setClusterWrapper(distributedConfigDatastore.getActorContext().getClusterWrapper())
 145                         .setDistributedConfigDatastore(distributedConfigDatastore)
 146                         .setDistributedOperDatastore(distributedOperDatastore)
 147                         .setLookupTaskMaxRetries(LOOKUP_TASK_MAX_RETRIES),
 148                 ACTOR_ID);
 149
 150         this.memberName = distributedConfigDatastore.getActorContext().getCurrentMemberName();
 151
 152         updateHandler = new PrefixedShardConfigUpdateHandler(shardedDataTreeActor,
 153                 distributedConfigDatastore.getActorContext().getCurrentMemberName());
 154
 155         LOG.debug("{} - Starting prefix configuration shards", memberName);
 156         createPrefixConfigShard(distributedConfigDatastore);
 157         createPrefixConfigShard(distributedOperDatastore);
 158     }
 159
 160     private void createPrefixConfigShard(final AbstractDataStore dataStore) {
 161         Configuration configuration = dataStore.getActorContext().getConfiguration();
 162         Collection<MemberName> memberNames = configuration.getUniqueMemberNamesForAllShards();
 163         CreateShard createShardMessage =
 164                 new CreateShard(new ModuleShardConfiguration(PrefixShards.QNAME.getNamespace(),
 165                         "prefix-shard-configuration", ClusterUtils.PREFIX_CONFIG_SHARD_ID, ModuleShardStrategy.NAME,
 166                         memberNames),
 167                         Shard.builder(), dataStore.getActorContext().getDatastoreContext());
 168
 169         dataStore.getActorContext().getShardManager().tell(createShardMessage, noSender());
 170     }
 171
 172     /**
 173      * This will try to initialize prefix configuration shards upon their
 174      * successful start. We need to create writers to these shards, so we can
 175      * satisfy future {@link #createDistributedShard} and
 176      * {@link #resolveShardAdditions} requests and update prefix configuration
 177      * shards accordingly.
 178      *
 179      * <p>
 180      * We also need to initialize listeners on these shards, so we can react
 181      * on changes made on them by other cluster members or even by ourselves.
 182      *
 183      * <p>
 184      * Finally, we need to be sure that default shards for both operational and
 185      * configuration data stores are up and running and we have distributed
 186      * shards frontend created for them.
 187      *
 188      * <p>
 189      * This is intended to be invoked by blueprint as initialization method.
 190      */
 191     public void init() {
 192         // create our writers to the configuration
 193         try {
 194             LOG.debug("{} - starting config shard lookup.", memberName);
 195
 196             // We have to wait for prefix config shards to be up and running
 197             // so we can create datastore clients for them
 198             handleConfigShardLookup().get(SHARD_FUTURE_TIMEOUT_DURATION.length(), SHARD_FUTURE_TIMEOUT_DURATION.unit());
 199         } catch (InterruptedException | ExecutionException | TimeoutException e) {
 200             throw new IllegalStateException("Prefix config shards not found", e);
 201         }
 202
 203         try {
 204             LOG.debug("{}: Prefix configuration shards ready - creating clients", memberName);
 205             configurationShardMap.put(LogicalDatastoreType.CONFIGURATION,
 206                     createDatastoreClient(ClusterUtils.PREFIX_CONFIG_SHARD_ID,
 207                             distributedConfigDatastore.getActorContext()));
 208         } catch (final DOMDataTreeShardCreationFailedException e) {
 209             throw new IllegalStateException(
 210                     "Unable to create datastoreClient for config DS prefix configuration shard.", e);
 211         }
 212
 213         try {
 214             configurationShardMap.put(LogicalDatastoreType.OPERATIONAL,
 215                     createDatastoreClient(ClusterUtils.PREFIX_CONFIG_SHARD_ID,
 216                             distributedOperDatastore.getActorContext()));
 217
 218         } catch (final DOMDataTreeShardCreationFailedException e) {
 219             throw new IllegalStateException(
 220                         "Unable to create datastoreClient for oper DS prefix configuration shard.", e);
 221         }
 222
 223         writerMap.put(LogicalDatastoreType.CONFIGURATION, new PrefixedShardConfigWriter(
 224                 configurationShardMap.get(LogicalDatastoreType.CONFIGURATION).getKey()));
 225
 226         writerMap.put(LogicalDatastoreType.OPERATIONAL, new PrefixedShardConfigWriter(
 227                 configurationShardMap.get(LogicalDatastoreType.OPERATIONAL).getKey()));
 228
 229         updateHandler.initListener(distributedConfigDatastore, LogicalDatastoreType.CONFIGURATION);
 230         updateHandler.initListener(distributedOperDatastore, LogicalDatastoreType.OPERATIONAL);
 231
 232         distributedConfigDatastore.getActorContext().getShardManager().tell(InitConfigListener.INSTANCE, noSender());
 233         distributedOperDatastore.getActorContext().getShardManager().tell(InitConfigListener.INSTANCE, noSender());
 234
 235
 236         //create shard registration for DEFAULT_SHARD
 237         try {
 238             initDefaultShard(LogicalDatastoreType.CONFIGURATION);
 239         } catch (final InterruptedException | ExecutionException e) {
 240             throw new IllegalStateException("Unable to create default shard frontend for config shard", e);
 241         }
 242
 243         try {
 244             initDefaultShard(LogicalDatastoreType.OPERATIONAL);
 245         } catch (final InterruptedException | ExecutionException e) {
 246             throw new IllegalStateException("Unable to create default shard frontend for operational shard", e);
 247         }
 248     }
 249
 250     private ListenableFuture<List<Void>> handleConfigShardLookup() {
 251
 252         final ListenableFuture<Void> configFuture = lookupConfigShard(LogicalDatastoreType.CONFIGURATION);
 253         final ListenableFuture<Void> operFuture = lookupConfigShard(LogicalDatastoreType.OPERATIONAL);
 254
 255         return Futures.allAsList(configFuture, operFuture);
 256     }
 257
 258     private ListenableFuture<Void> lookupConfigShard(final LogicalDatastoreType type) {
 259         final SettableFuture<Void> future = SettableFuture.create();
 260
 261         final Future<Object> ask =
 262                 Patterns.ask(shardedDataTreeActor, new StartConfigShardLookup(type), SHARD_FUTURE_TIMEOUT);
 263
 264         ask.onComplete(new OnComplete<Object>() {
 265             @Override
 266             public void onComplete(final Throwable throwable, final Object result) throws Throwable {
 267                 if (throwable != null) {
 268                     future.setException(throwable);
 269                 } else {
 270                     future.set(null);
 271                 }
 272             }
 273         }, actorSystem.dispatcher());
 274
 275         return future;
 276     }
 277
 278     @Nonnull
 279     @Override
 280     public <T extends DOMDataTreeListener> ListenerRegistration<T> registerListener(
 281             final T listener, final Collection<DOMDataTreeIdentifier> subtrees,
 282             final boolean allowRxMerges, final Collection<DOMDataTreeProducer> producers)
 283             throws DOMDataTreeLoopException {
 284         return shardedDOMDataTree.registerListener(listener, subtrees, allowRxMerges, producers);
 285     }
 286
 287     @Nonnull
 288     @Override
 289     public DOMDataTreeProducer createProducer(@Nonnull final Collection<DOMDataTreeIdentifier> subtrees) {
 290         LOG.debug("{} - Creating producer for {}", memberName, subtrees);
 291         final DOMDataTreeProducer producer = shardedDOMDataTree.createProducer(subtrees);
 292
 293         final Object response = distributedConfigDatastore.getActorContext()
 294                 .executeOperation(shardedDataTreeActor, new ProducerCreated(subtrees));
 295         if (response == null) {
 296             LOG.debug("{} - Received success from remote nodes, creating producer:{}", memberName, subtrees);
 297             return new ProxyProducer(producer, subtrees, shardedDataTreeActor,
 298                     distributedConfigDatastore.getActorContext(), shards);
 299         } else if (response instanceof Exception) {
 300             closeProducer(producer);
 301             throw Throwables.propagate((Exception) response);
 302         } else {
 303             closeProducer(producer);
 304             throw new RuntimeException("Unexpected response to create producer received." + response);
 305         }
 306     }
 307
 308     @Override
 309     public CompletionStage<DistributedShardRegistration> createDistributedShard(
 310             final DOMDataTreeIdentifier prefix, final Collection<MemberName> replicaMembers)
 311             throws DOMDataTreeShardingConflictException {
 312
 313         synchronized (shards) {
 314             final DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> lookup =
 315                     shards.lookup(prefix);
 316             if (lookup != null && lookup.getValue().getPrefix().equals(prefix)) {
 317                 throw new DOMDataTreeShardingConflictException(
 318                         "Prefix " + prefix + " is already occupied by another shard.");
 319             }
 320         }
 321
 322         final PrefixedShardConfigWriter writer = writerMap.get(prefix.getDatastoreType());
 323
 324         final ListenableFuture<Void> writeFuture =
 325                 writer.writeConfig(prefix.getRootIdentifier(), replicaMembers);
 326
 327         final Promise<DistributedShardRegistration> shardRegistrationPromise = akka.dispatch.Futures.promise();
 328         Futures.addCallback(writeFuture, new FutureCallback<Void>() {
 329             @Override
 330             public void onSuccess(@Nullable final Void result) {
 331
 332                 final Future<Object> ask =
 333                         Patterns.ask(shardedDataTreeActor, new LookupPrefixShard(prefix), SHARD_FUTURE_TIMEOUT);
 334
 335                 shardRegistrationPromise.completeWith(ask.transform(
 336                         new Mapper<Object, DistributedShardRegistration>() {
 337                             @Override
 338                             public DistributedShardRegistration apply(final Object parameter) {
 339                                 return new DistributedShardRegistrationImpl(
 340                                         prefix, shardedDataTreeActor, DistributedShardedDOMDataTree.this);
 341                             }
 342                         },
 343                         new Mapper<Throwable, Throwable>() {
 344                             @Override
 345                             public Throwable apply(final Throwable throwable) {
 346                                 return new DOMDataTreeShardCreationFailedException(
 347                                         "Unable to create a cds shard.", throwable);
 348                             }
 349                         }, actorSystem.dispatcher()));
 350             }
 351
 352             @Override
 353             public void onFailure(final Throwable throwable) {
 354                 shardRegistrationPromise.failure(
 355                         new DOMDataTreeShardCreationFailedException("Unable to create a cds shard.", throwable));
 356             }
 357         });
 358
 359         return FutureConverters.toJava(shardRegistrationPromise.future());
 360     }
 361
 362     void resolveShardAdditions(final Set<DOMDataTreeIdentifier> additions) {
 363         LOG.debug("{}: Resolving additions : {}", memberName, additions);
 364         final ArrayList<DOMDataTreeIdentifier> list = new ArrayList<>(additions);
 365         // we need to register the shards from top to bottom, so we need to atleast make sure the ordering reflects that
 366         Collections.sort(list, (o1, o2) -> {
 367             if (o1.getRootIdentifier().getPathArguments().size() < o2.getRootIdentifier().getPathArguments().size()) {
 368                 return -1;
 369             } else if (o1.getRootIdentifier().getPathArguments().size()
 370                     == o2.getRootIdentifier().getPathArguments().size()) {
 371                 return 0;
 372             } else {
 373                 return 1;
 374             }
 375         });
 376         list.forEach(this::createShardFrontend);
 377     }
 378
 379     void resolveShardRemovals(final Set<DOMDataTreeIdentifier> removals) {
 380         LOG.debug("{}: Resolving removals : {}", memberName, removals);
 381
 382         // do we need to go from bottom to top?
 383         removals.forEach(this::despawnShardFrontend);
 384     }
 385
 386     private void createShardFrontend(final DOMDataTreeIdentifier prefix) {
 387         LOG.debug("{}: Creating CDS shard for prefix: {}", memberName, prefix);
 388         final String shardName = ClusterUtils.getCleanShardName(prefix.getRootIdentifier());
 389         final AbstractDataStore distributedDataStore =
 390                 prefix.getDatastoreType().equals(org.opendaylight.mdsal.common.api.LogicalDatastoreType.CONFIGURATION)
 391                         ? distributedConfigDatastore : distributedOperDatastore;
 392
 393         try (DOMDataTreeProducer producer = localCreateProducer(Collections.singletonList(prefix))) {
 394             final Entry<DataStoreClient, ActorRef> entry =
 395                     createDatastoreClient(shardName, distributedDataStore.getActorContext());
 396
 397             final DistributedShardFrontend shard =
 398                     new DistributedShardFrontend(distributedDataStore, entry.getKey(), prefix);
 399
 400             @SuppressWarnings("unchecked")
 401             final DOMDataTreeShardRegistration<DOMDataTreeShard> reg =
 402                     (DOMDataTreeShardRegistration) shardedDOMDataTree.registerDataTreeShard(prefix, shard, producer);
 403
 404             synchronized (shards) {
 405                 shards.store(prefix, reg);
 406             }
 407
 408         } catch (final DOMDataTreeShardingConflictException e) {
 409             LOG.error("{}: Prefix {} is already occupied by another shard",
 410                     distributedConfigDatastore.getActorContext().getClusterWrapper().getCurrentMemberName(), prefix, e);
 411         } catch (DOMDataTreeProducerException e) {
 412             LOG.error("Unable to close producer", e);
 413         } catch (DOMDataTreeShardCreationFailedException e) {
 414             LOG.error("Unable to create datastore client for shard {}", prefix, e);
 415         }
 416     }
 417
 418     private void despawnShardFrontend(final DOMDataTreeIdentifier prefix) {
 419         LOG.debug("{}: Removing CDS shard for prefix: {}", memberName, prefix);
 420         final DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> lookup;
 421         synchronized (shards) {
 422             lookup = shards.lookup(prefix);
 423         }
 424
 425         if (lookup == null || !lookup.getValue().getPrefix().equals(prefix)) {
 426             LOG.debug("{}: Received despawn for non-existing CDS shard frontend, prefix: {}, ignoring..",
 427                     memberName, prefix);
 428             return;
 429         }
 430
 431         lookup.getValue().close();
 432         // need to remove from our local table thats used for tracking
 433         synchronized (shards) {
 434             shards.remove(prefix);
 435         }
 436
 437         final PrefixedShardConfigWriter writer = writerMap.get(prefix.getDatastoreType());
 438         final ListenableFuture<Void> future = writer.removeConfig(prefix.getRootIdentifier());
 439
 440         Futures.addCallback(future, new FutureCallback<Void>() {
 441             @Override
 442             public void onSuccess(@Nullable Void result) {
 443                 LOG.debug("{} - Succesfuly removed shard for {}", memberName, prefix);
 444             }
 445
 446             @Override
 447             public void onFailure(Throwable throwable) {
 448                 LOG.error("Removal of shard {} from configuration failed.", prefix, throwable);
 449             }
 450         });
 451     }
 452
 453     DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> lookupShardFrontend(
 454             final DOMDataTreeIdentifier prefix) {
 455         synchronized (shards) {
 456             return shards.lookup(prefix);
 457         }
 458     }
 459
 460     DOMDataTreeProducer localCreateProducer(final Collection<DOMDataTreeIdentifier> prefix) {
 461         return shardedDOMDataTree.createProducer(prefix);
 462     }
 463
 464     @Nonnull
 465     @Override
 466     public <T extends DOMDataTreeShard> ListenerRegistration<T> registerDataTreeShard(
 467             @Nonnull final DOMDataTreeIdentifier prefix,
 468             @Nonnull final T shard,
 469             @Nonnull final DOMDataTreeProducer producer)
 470             throws DOMDataTreeShardingConflictException {
 471
 472         LOG.debug("Registering shard[{}] at prefix: {}", shard, prefix);
 473
 474         if (producer instanceof ProxyProducer) {
 475             return shardedDOMDataTree.registerDataTreeShard(prefix, shard, ((ProxyProducer) producer).delegate());
 476         }
 477
 478         return shardedDOMDataTree.registerDataTreeShard(prefix, shard, producer);
 479     }
 480
 481     @SuppressWarnings("checkstyle:IllegalCatch")
 482     private Entry<DataStoreClient, ActorRef> createDatastoreClient(
 483             final String shardName, final ActorContext actorContext)
 484             throws DOMDataTreeShardCreationFailedException {
 485
 486         LOG.debug("{}: Creating distributed datastore client for shard {}", memberName, shardName);
 487         final Props distributedDataStoreClientProps =
 488                 SimpleDataStoreClientActor.props(memberName, "Shard-" + shardName, actorContext, shardName);
 489
 490         final ActorRef clientActor = actorSystem.actorOf(distributedDataStoreClientProps);
 491         try {
 492             return new SimpleEntry<>(SimpleDataStoreClientActor
 493                     .getDistributedDataStoreClient(clientActor, 30, TimeUnit.SECONDS), clientActor);
 494         } catch (final Exception e) {
 495             LOG.error("{}: Failed to get actor for {}", distributedDataStoreClientProps, memberName, e);
 496             clientActor.tell(PoisonPill.getInstance(), noSender());
 497             throw new DOMDataTreeShardCreationFailedException(
 498                     "Unable to create datastore client for shard{" + shardName + "}", e);
 499         }
 500     }
 501
 502     @SuppressWarnings("checkstyle:IllegalCatch")
 503     private void initDefaultShard(final LogicalDatastoreType logicalDatastoreType)
 504             throws ExecutionException, InterruptedException {
 505
 506         final PrefixedShardConfigWriter writer = writerMap.get(logicalDatastoreType);
 507
 508         if (writer.checkDefaultIsPresent()) {
 509             LOG.debug("{}: Default shard for {} is already present in the config. Possibly saved in snapshot.",
 510                     memberName, logicalDatastoreType);
 511         } else {
 512             try {
 513                 // Currently the default shard configuration is present in the out-of-box modules.conf and is
 514                 // expected to be present. So look up the local default shard here and create the frontend.
 515
 516                 // TODO we don't have to do it for config and operational default shard separately. Just one of them
 517                 // should be enough
 518                 final ActorContext actorContext = logicalDatastoreType == LogicalDatastoreType.CONFIGURATION
 519                         ? distributedConfigDatastore.getActorContext() : distributedOperDatastore.getActorContext();
 520
 521                 final Optional<ActorRef> defaultLocalShardOptional =
 522                         actorContext.findLocalShard(ClusterUtils.getCleanShardName(YangInstanceIdentifier.EMPTY));
 523
 524                 if (defaultLocalShardOptional.isPresent()) {
 525                     LOG.debug("{}: Default shard for {} is already started, creating just frontend", memberName,
 526                             logicalDatastoreType);
 527                     createShardFrontend(new DOMDataTreeIdentifier(logicalDatastoreType, YangInstanceIdentifier.EMPTY));
 528                 }
 529
 530                 // The local shard isn't present - we assume that means the local member isn't in the replica list
 531                 // and will be dynamically created later via an explicit add-shard-replica request. This is the
 532                 // bootstrapping mechanism to add a new node into an existing cluster. The following code to create
 533                 // the default shard as a prefix shard is problematic in this scenario so it is commented out. Since
 534                 // the default shard is a module-based shard by default, it makes sense to always treat it as such,
 535                 // ie bootstrap it in the same manner as the special prefix-configuration and EOS shards.
 536 //                final Collection<MemberName> names = distributedConfigDatastore.getActorContext().getConfiguration()
 537 //                        .getUniqueMemberNamesForAllShards();
 538 //                Await.result(FutureConverters.toScala(createDistributedShard(
 539 //                        new DOMDataTreeIdentifier(logicalDatastoreType, YangInstanceIdentifier.EMPTY), names)),
 540 //                        SHARD_FUTURE_TIMEOUT_DURATION);
 541 //            } catch (DOMDataTreeShardingConflictException e) {
 542 //                LOG.debug("{}: Default shard for {} already registered, possibly due to other node doing it faster",
 543 //                        memberName, logicalDatastoreType);
 544             } catch (Exception e) {
 545                 LOG.error("{}: Default shard initialization for {} failed", memberName, logicalDatastoreType, e);
 546                 throw new RuntimeException(e);
 547             }
 548         }
 549     }
 550
 551     private static void closeProducer(final DOMDataTreeProducer producer) {
 552         try {
 553             producer.close();
 554         } catch (final DOMDataTreeProducerException e) {
 555             LOG.error("Unable to close producer", e);
 556         }
 557     }
 558
 559     @SuppressWarnings("checkstyle:IllegalCatch")
 560     private static ActorRef createShardedDataTreeActor(final ActorSystem actorSystem,
 561                                                        final ShardedDataTreeActorCreator creator,
 562                                                        final String shardDataTreeActorId) {
 563         Exception lastException = null;
 564
 565         for (int i = 0; i < MAX_ACTOR_CREATION_RETRIES; i++) {
 566             try {
 567                 return actorSystem.actorOf(creator.props(), shardDataTreeActorId);
 568             } catch (final Exception e) {
 569                 lastException = e;
 570                 Uninterruptibles.sleepUninterruptibly(ACTOR_RETRY_DELAY, ACTOR_RETRY_TIME_UNIT);
 571                 LOG.debug("Could not create actor {} because of {} -"
 572                                 + " waiting for sometime before retrying (retry count = {})",
 573                         shardDataTreeActorId, e.getMessage(), i);
 574             }
 575         }
 576
 577         throw new IllegalStateException("Failed to create actor for ShardedDOMDataTree", lastException);
 578     }
 579
 580     private class DistributedShardRegistrationImpl implements DistributedShardRegistration {
 581
 582         private final DOMDataTreeIdentifier prefix;
 583         private final ActorRef shardedDataTreeActor;
 584         private final DistributedShardedDOMDataTree distributedShardedDOMDataTree;
 585
 586         DistributedShardRegistrationImpl(final DOMDataTreeIdentifier prefix,
 587                                          final ActorRef shardedDataTreeActor,
 588                                          final DistributedShardedDOMDataTree distributedShardedDOMDataTree) {
 589             this.prefix = prefix;
 590             this.shardedDataTreeActor = shardedDataTreeActor;
 591             this.distributedShardedDOMDataTree = distributedShardedDOMDataTree;
 592         }
 593
 594         @Override
 595         public CompletionStage<Void> close() {
 596             // first despawn on the local node
 597             distributedShardedDOMDataTree.despawnShardFrontend(prefix);
 598             // update the config so the remote nodes are updated
 599             final Future<Object> ask =
 600                     Patterns.ask(shardedDataTreeActor, new PrefixShardRemovalLookup(prefix), SHARD_FUTURE_TIMEOUT);
 601
 602             final Future<Void> closeFuture = ask.transform(
 603                     new Mapper<Object, Void>() {
 604                         @Override
 605                         public Void apply(final Object parameter) {
 606                             return null;
 607                         }
 608                     },
 609                     new Mapper<Throwable, Throwable>() {
 610                         @Override
 611                         public Throwable apply(final Throwable throwable) {
 612                             return throwable;
 613                         }
 614                     }, actorSystem.dispatcher());
 615
 616             return FutureConverters.toJava(closeFuture);
 617         }
 618     }
 619
 620     // TODO what about producers created by this producer?
 621     // They should also be CDSProducers
 622     private static final class ProxyProducer extends ForwardingObject implements CDSDataTreeProducer {
 623
 624         private final DOMDataTreeProducer delegate;
 625         private final Collection<DOMDataTreeIdentifier> subtrees;
 626         private final ActorRef shardDataTreeActor;
 627         private final ActorContext actorContext;
 628         @GuardedBy("shardAccessMap")
 629         private final Map<DOMDataTreeIdentifier, CDSShardAccessImpl> shardAccessMap = new HashMap<>();
 630
 631         // We don't have to guard access to shardTable in ProxyProducer.
 632         // ShardTable's entries relevant to this ProxyProducer shouldn't
 633         // change during producer's lifetime.
 634         private final DOMDataTreePrefixTable<DOMDataTreeShardRegistration<DOMDataTreeShard>> shardTable;
 635
 636         ProxyProducer(final DOMDataTreeProducer delegate,
 637                       final Collection<DOMDataTreeIdentifier> subtrees,
 638                       final ActorRef shardDataTreeActor,
 639                       final ActorContext actorContext,
 640                       final DOMDataTreePrefixTable<DOMDataTreeShardRegistration<DOMDataTreeShard>> shardLayout) {
 641             this.delegate = Preconditions.checkNotNull(delegate);
 642             this.subtrees = Preconditions.checkNotNull(subtrees);
 643             this.shardDataTreeActor = Preconditions.checkNotNull(shardDataTreeActor);
 644             this.actorContext = Preconditions.checkNotNull(actorContext);
 645             this.shardTable = Preconditions.checkNotNull(shardLayout);
 646         }
 647
 648         @Nonnull
 649         @Override
 650         public DOMDataTreeCursorAwareTransaction createTransaction(final boolean isolated) {
 651             return delegate.createTransaction(isolated);
 652         }
 653
 654         @Nonnull
 655         @Override
 656         public DOMDataTreeProducer createProducer(@Nonnull final Collection<DOMDataTreeIdentifier> subtrees) {
 657             // TODO we probably don't need to distribute this on the remote nodes since once we have this producer
 658             // open we surely have the rights to all the subtrees.
 659             return delegate.createProducer(subtrees);
 660         }
 661
 662         @Override
 663         @SuppressWarnings("checkstyle:IllegalCatch")
 664         public void close() throws DOMDataTreeProducerException {
 665             delegate.close();
 666
 667             synchronized (shardAccessMap) {
 668                 shardAccessMap.values().forEach(CDSShardAccessImpl::close);
 669             }
 670
 671             final Object o = actorContext.executeOperation(shardDataTreeActor, new ProducerRemoved(subtrees));
 672             if (o instanceof DOMDataTreeProducerException) {
 673                 throw (DOMDataTreeProducerException) o;
 674             } else if (o instanceof Throwable) {
 675                 throw new DOMDataTreeProducerException("Unable to close producer", (Throwable) o);
 676             }
 677         }
 678
 679         @Override
 680         protected DOMDataTreeProducer delegate() {
 681             return delegate;
 682         }
 683
 684         @Nonnull
 685         @Override
 686         public CDSShardAccess getShardAccess(@Nonnull final DOMDataTreeIdentifier subtree) {
 687             Preconditions.checkArgument(
 688                     subtrees.stream().anyMatch(dataTreeIdentifier -> dataTreeIdentifier.contains(subtree)),
 689                     "Subtree %s is not controlled by this producer %s", subtree, this);
 690
 691             final DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> lookup =
 692                     shardTable.lookup(subtree);
 693             Preconditions.checkState(lookup != null, "Subtree %s is not contained in any registered shard.", subtree);
 694
 695             final DOMDataTreeIdentifier lookupId = lookup.getValue().getPrefix();
 696
 697             synchronized (shardAccessMap) {
 698                 if (shardAccessMap.get(lookupId) != null) {
 699                     return shardAccessMap.get(lookupId);
 700                 }
 701
 702                 // TODO Maybe we can have static factory method and return the same instance
 703                 // for same subtrees. But maybe it is not needed since there can be only one
 704                 // producer attached to some subtree at a time. And also how we can close ShardAccess
 705                 // then
 706                 final CDSShardAccessImpl shardAccess = new CDSShardAccessImpl(lookupId, actorContext);
 707                 shardAccessMap.put(lookupId, shardAccess);
 708                 return shardAccess;
 709             }
 710         }
 711     }
 712 }