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.collect.ImmutableMap;
  26 import com.google.common.util.concurrent.FutureCallback;
  27 import com.google.common.util.concurrent.Futures;
  28 import com.google.common.util.concurrent.ListenableFuture;
  29 import com.google.common.util.concurrent.MoreExecutors;
  30 import com.google.common.util.concurrent.SettableFuture;
  31 import com.google.common.util.concurrent.Uninterruptibles;
  32 import java.util.AbstractMap.SimpleEntry;
  33 import java.util.ArrayList;
  34 import java.util.Collection;
  35 import java.util.Collections;
  36 import java.util.EnumMap;
  37 import java.util.HashMap;
  38 import java.util.List;
  39 import java.util.Map;
  40 import java.util.Map.Entry;
  41 import java.util.Set;
  42 import java.util.concurrent.CompletionStage;
  43 import java.util.concurrent.ExecutionException;
  44 import java.util.concurrent.TimeUnit;
  45 import java.util.concurrent.TimeoutException;
  46 import javax.annotation.Nonnull;
  47 import javax.annotation.Nullable;
  48 import javax.annotation.concurrent.GuardedBy;
  49 import org.opendaylight.controller.cluster.ActorSystemProvider;
  50 import org.opendaylight.controller.cluster.access.concepts.MemberName;
  51 import org.opendaylight.controller.cluster.databroker.actors.dds.DataStoreClient;
  52 import org.opendaylight.controller.cluster.databroker.actors.dds.SimpleDataStoreClientActor;
  53 import org.opendaylight.controller.cluster.datastore.AbstractDataStore;
  54 import org.opendaylight.controller.cluster.datastore.Shard;
  55 import org.opendaylight.controller.cluster.datastore.config.Configuration;
  56 import org.opendaylight.controller.cluster.datastore.config.ModuleShardConfiguration;
  57 import org.opendaylight.controller.cluster.datastore.messages.CreateShard;
  58 import org.opendaylight.controller.cluster.datastore.shardstrategy.ModuleShardStrategy;
  59 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  60 import org.opendaylight.controller.cluster.datastore.utils.ClusterUtils;
  61 import org.opendaylight.controller.cluster.dom.api.CDSDataTreeProducer;
  62 import org.opendaylight.controller.cluster.dom.api.CDSShardAccess;
  63 import org.opendaylight.controller.cluster.sharding.ShardedDataTreeActor.ShardedDataTreeActorCreator;
  64 import org.opendaylight.controller.cluster.sharding.messages.InitConfigListener;
  65 import org.opendaylight.controller.cluster.sharding.messages.LookupPrefixShard;
  66 import org.opendaylight.controller.cluster.sharding.messages.PrefixShardRemovalLookup;
  67 import org.opendaylight.controller.cluster.sharding.messages.ProducerCreated;
  68 import org.opendaylight.controller.cluster.sharding.messages.ProducerRemoved;
  69 import org.opendaylight.controller.cluster.sharding.messages.StartConfigShardLookup;
  70 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  71 import org.opendaylight.mdsal.dom.api.DOMDataTreeCursorAwareTransaction;
  72 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  73 import org.opendaylight.mdsal.dom.api.DOMDataTreeListener;
  74 import org.opendaylight.mdsal.dom.api.DOMDataTreeLoopException;
  75 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducer;
  76 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducerException;
  77 import org.opendaylight.mdsal.dom.api.DOMDataTreeService;
  78 import org.opendaylight.mdsal.dom.api.DOMDataTreeServiceExtension;
  79 import org.opendaylight.mdsal.dom.api.DOMDataTreeShard;
  80 import org.opendaylight.mdsal.dom.api.DOMDataTreeShardingConflictException;
  81 import org.opendaylight.mdsal.dom.api.DOMDataTreeShardingService;
  82 import org.opendaylight.mdsal.dom.broker.DOMDataTreeShardRegistration;
  83 import org.opendaylight.mdsal.dom.broker.ShardedDOMDataTree;
  84 import org.opendaylight.mdsal.dom.spi.DOMDataTreePrefixTable;
  85 import org.opendaylight.mdsal.dom.spi.DOMDataTreePrefixTableEntry;
  86 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.clustering.prefix.shard.configuration.rev170110.PrefixShards;
  87 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  88 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  89 import org.slf4j.Logger;
  90 import org.slf4j.LoggerFactory;
  91 import scala.compat.java8.FutureConverters;
  92 import scala.concurrent.Future;
  93 import scala.concurrent.Promise;
  94 import scala.concurrent.duration.FiniteDuration;
  95
  96 /**
  97  * A layer on top of DOMDataTreeService that distributes producer/shard registrations to remote nodes via
  98  * {@link ShardedDataTreeActor}. Also provides QoL method for addition of prefix based clustered shard into the system.
  99  */
 100 public class DistributedShardedDOMDataTree implements DOMDataTreeService, DOMDataTreeShardingService,
 101         DistributedShardFactory {
 102
 103     private static final Logger LOG = LoggerFactory.getLogger(DistributedShardedDOMDataTree.class);
 104
 105     private static final int MAX_ACTOR_CREATION_RETRIES = 100;
 106     private static final int ACTOR_RETRY_DELAY = 100;
 107     private static final TimeUnit ACTOR_RETRY_TIME_UNIT = TimeUnit.MILLISECONDS;
 108     private static final int LOOKUP_TASK_MAX_RETRIES = 100;
 109     static final FiniteDuration SHARD_FUTURE_TIMEOUT_DURATION =
 110             new FiniteDuration(LOOKUP_TASK_MAX_RETRIES * LOOKUP_TASK_MAX_RETRIES * 3, TimeUnit.SECONDS);
 111     static final Timeout SHARD_FUTURE_TIMEOUT = new Timeout(SHARD_FUTURE_TIMEOUT_DURATION);
 112
 113     static final String ACTOR_ID = "ShardedDOMDataTreeFrontend";
 114
 115     private final ShardedDOMDataTree shardedDOMDataTree;
 116     private final ActorSystem actorSystem;
 117     private final AbstractDataStore distributedOperDatastore;
 118     private final AbstractDataStore distributedConfigDatastore;
 119
 120     private final ActorRef shardedDataTreeActor;
 121     private final MemberName memberName;
 122
 123     @GuardedBy("shards")
 124     private final DOMDataTreePrefixTable<DOMDataTreeShardRegistration<DOMDataTreeShard>> shards =
 125             DOMDataTreePrefixTable.create();
 126
 127     private final EnumMap<LogicalDatastoreType, Entry<DataStoreClient, ActorRef>> configurationShardMap =
 128             new EnumMap<>(LogicalDatastoreType.class);
 129
 130     private final EnumMap<LogicalDatastoreType, PrefixedShardConfigWriter> writerMap =
 131             new EnumMap<>(LogicalDatastoreType.class);
 132
 133     private final PrefixedShardConfigUpdateHandler updateHandler;
 134
 135     public DistributedShardedDOMDataTree(final ActorSystemProvider actorSystemProvider,
 136                                          final AbstractDataStore distributedOperDatastore,
 137                                          final AbstractDataStore distributedConfigDatastore) {
 138         this.actorSystem = Preconditions.checkNotNull(actorSystemProvider).getActorSystem();
 139         this.distributedOperDatastore = Preconditions.checkNotNull(distributedOperDatastore);
 140         this.distributedConfigDatastore = Preconditions.checkNotNull(distributedConfigDatastore);
 141         shardedDOMDataTree = new ShardedDOMDataTree();
 142
 143         shardedDataTreeActor = createShardedDataTreeActor(actorSystem,
 144                 new ShardedDataTreeActorCreator()
 145                         .setShardingService(this)
 146                         .setActorSystem(actorSystem)
 147                         .setClusterWrapper(distributedConfigDatastore.getActorContext().getClusterWrapper())
 148                         .setDistributedConfigDatastore(distributedConfigDatastore)
 149                         .setDistributedOperDatastore(distributedOperDatastore)
 150                         .setLookupTaskMaxRetries(LOOKUP_TASK_MAX_RETRIES),
 151                 ACTOR_ID);
 152
 153         this.memberName = distributedConfigDatastore.getActorContext().getCurrentMemberName();
 154
 155         updateHandler = new PrefixedShardConfigUpdateHandler(shardedDataTreeActor,
 156                 distributedConfigDatastore.getActorContext().getCurrentMemberName());
 157
 158         LOG.debug("{} - Starting prefix configuration shards", memberName);
 159         createPrefixConfigShard(distributedConfigDatastore);
 160         createPrefixConfigShard(distributedOperDatastore);
 161     }
 162
 163     private static void createPrefixConfigShard(final AbstractDataStore dataStore) {
 164         Configuration configuration = dataStore.getActorContext().getConfiguration();
 165         Collection<MemberName> memberNames = configuration.getUniqueMemberNamesForAllShards();
 166         CreateShard createShardMessage =
 167                 new CreateShard(new ModuleShardConfiguration(PrefixShards.QNAME.getNamespace(),
 168                         "prefix-shard-configuration", ClusterUtils.PREFIX_CONFIG_SHARD_ID, ModuleShardStrategy.NAME,
 169                         memberNames),
 170                         Shard.builder(), dataStore.getActorContext().getDatastoreContext());
 171
 172         dataStore.getActorContext().getShardManager().tell(createShardMessage, noSender());
 173     }
 174
 175     /**
 176      * This will try to initialize prefix configuration shards upon their
 177      * successful start. We need to create writers to these shards, so we can
 178      * satisfy future {@link #createDistributedShard} and
 179      * {@link #resolveShardAdditions} requests and update prefix configuration
 180      * shards accordingly.
 181      *
 182      * <p>
 183      * We also need to initialize listeners on these shards, so we can react
 184      * on changes made on them by other cluster members or even by ourselves.
 185      *
 186      * <p>
 187      * Finally, we need to be sure that default shards for both operational and
 188      * configuration data stores are up and running and we have distributed
 189      * shards frontend created for them.
 190      *
 191      * <p>
 192      * This is intended to be invoked by blueprint as initialization method.
 193      */
 194     public void init() {
 195         // create our writers to the configuration
 196         try {
 197             LOG.debug("{} - starting config shard lookup.", memberName);
 198
 199             // We have to wait for prefix config shards to be up and running
 200             // so we can create datastore clients for them
 201             handleConfigShardLookup().get(SHARD_FUTURE_TIMEOUT_DURATION.length(), SHARD_FUTURE_TIMEOUT_DURATION.unit());
 202         } catch (InterruptedException | ExecutionException | TimeoutException e) {
 203             throw new IllegalStateException("Prefix config shards not found", e);
 204         }
 205
 206         try {
 207             LOG.debug("{}: Prefix configuration shards ready - creating clients", memberName);
 208             configurationShardMap.put(LogicalDatastoreType.CONFIGURATION,
 209                     createDatastoreClient(ClusterUtils.PREFIX_CONFIG_SHARD_ID,
 210                             distributedConfigDatastore.getActorContext()));
 211         } catch (final DOMDataTreeShardCreationFailedException e) {
 212             throw new IllegalStateException(
 213                     "Unable to create datastoreClient for config DS prefix configuration shard.", e);
 214         }
 215
 216         try {
 217             configurationShardMap.put(LogicalDatastoreType.OPERATIONAL,
 218                     createDatastoreClient(ClusterUtils.PREFIX_CONFIG_SHARD_ID,
 219                             distributedOperDatastore.getActorContext()));
 220
 221         } catch (final DOMDataTreeShardCreationFailedException e) {
 222             throw new IllegalStateException(
 223                         "Unable to create datastoreClient for oper DS prefix configuration shard.", e);
 224         }
 225
 226         writerMap.put(LogicalDatastoreType.CONFIGURATION, new PrefixedShardConfigWriter(
 227                 configurationShardMap.get(LogicalDatastoreType.CONFIGURATION).getKey()));
 228
 229         writerMap.put(LogicalDatastoreType.OPERATIONAL, new PrefixedShardConfigWriter(
 230                 configurationShardMap.get(LogicalDatastoreType.OPERATIONAL).getKey()));
 231
 232         updateHandler.initListener(distributedConfigDatastore, LogicalDatastoreType.CONFIGURATION);
 233         updateHandler.initListener(distributedOperDatastore, LogicalDatastoreType.OPERATIONAL);
 234
 235         distributedConfigDatastore.getActorContext().getShardManager().tell(InitConfigListener.INSTANCE, noSender());
 236         distributedOperDatastore.getActorContext().getShardManager().tell(InitConfigListener.INSTANCE, noSender());
 237
 238
 239         //create shard registration for DEFAULT_SHARD
 240         try {
 241             initDefaultShard(LogicalDatastoreType.CONFIGURATION);
 242         } catch (final InterruptedException | ExecutionException e) {
 243             throw new IllegalStateException("Unable to create default shard frontend for config shard", e);
 244         }
 245
 246         try {
 247             initDefaultShard(LogicalDatastoreType.OPERATIONAL);
 248         } catch (final InterruptedException | ExecutionException e) {
 249             throw new IllegalStateException("Unable to create default shard frontend for operational shard", e);
 250         }
 251     }
 252
 253     private ListenableFuture<List<Void>> handleConfigShardLookup() {
 254
 255         final ListenableFuture<Void> configFuture = lookupConfigShard(LogicalDatastoreType.CONFIGURATION);
 256         final ListenableFuture<Void> operFuture = lookupConfigShard(LogicalDatastoreType.OPERATIONAL);
 257
 258         return Futures.allAsList(configFuture, operFuture);
 259     }
 260
 261     private ListenableFuture<Void> lookupConfigShard(final LogicalDatastoreType type) {
 262         final SettableFuture<Void> future = SettableFuture.create();
 263
 264         final Future<Object> ask =
 265                 Patterns.ask(shardedDataTreeActor, new StartConfigShardLookup(type), SHARD_FUTURE_TIMEOUT);
 266
 267         ask.onComplete(new OnComplete<Object>() {
 268             @Override
 269             public void onComplete(final Throwable throwable, final Object result) throws Throwable {
 270                 if (throwable != null) {
 271                     future.setException(throwable);
 272                 } else {
 273                     future.set(null);
 274                 }
 275             }
 276         }, actorSystem.dispatcher());
 277
 278         return future;
 279     }
 280
 281     @Nonnull
 282     @Override
 283     public <T extends DOMDataTreeListener> ListenerRegistration<T> registerListener(
 284             final T listener, final Collection<DOMDataTreeIdentifier> subtrees,
 285             final boolean allowRxMerges, final Collection<DOMDataTreeProducer> producers)
 286             throws DOMDataTreeLoopException {
 287         return shardedDOMDataTree.registerListener(listener, subtrees, allowRxMerges, producers);
 288     }
 289
 290     @Override
 291     public Map<Class<? extends DOMDataTreeServiceExtension>, DOMDataTreeServiceExtension> getSupportedExtensions() {
 292         return ImmutableMap.of();
 293     }
 294
 295     @Nonnull
 296     @Override
 297     public DOMDataTreeProducer createProducer(@Nonnull final Collection<DOMDataTreeIdentifier> subtrees) {
 298         LOG.debug("{} - Creating producer for {}", memberName, subtrees);
 299         final DOMDataTreeProducer producer = shardedDOMDataTree.createProducer(subtrees);
 300
 301         final Object response = distributedConfigDatastore.getActorContext()
 302                 .executeOperation(shardedDataTreeActor, new ProducerCreated(subtrees));
 303         if (response == null) {
 304             LOG.debug("{} - Received success from remote nodes, creating producer:{}", memberName, subtrees);
 305             return new ProxyProducer(producer, subtrees, shardedDataTreeActor,
 306                     distributedConfigDatastore.getActorContext(), shards);
 307         }
 308
 309         closeProducer(producer);
 310
 311         if (response instanceof Throwable) {
 312             Throwables.throwIfUnchecked((Throwable) response);
 313             throw new RuntimeException((Throwable) response);
 314         }
 315         throw new RuntimeException("Unexpected response to create producer received." + response);
 316     }
 317
 318     @Override
 319     public CompletionStage<DistributedShardRegistration> createDistributedShard(
 320             final DOMDataTreeIdentifier prefix, final Collection<MemberName> replicaMembers)
 321             throws DOMDataTreeShardingConflictException {
 322
 323         synchronized (shards) {
 324             final DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> lookup =
 325                     shards.lookup(prefix);
 326             if (lookup != null && lookup.getValue().getPrefix().equals(prefix)) {
 327                 throw new DOMDataTreeShardingConflictException(
 328                         "Prefix " + prefix + " is already occupied by another shard.");
 329             }
 330         }
 331
 332         final PrefixedShardConfigWriter writer = writerMap.get(prefix.getDatastoreType());
 333
 334         final ListenableFuture<Void> writeFuture =
 335                 writer.writeConfig(prefix.getRootIdentifier(), replicaMembers);
 336
 337         final Promise<DistributedShardRegistration> shardRegistrationPromise = akka.dispatch.Futures.promise();
 338         Futures.addCallback(writeFuture, new FutureCallback<Void>() {
 339             @Override
 340             public void onSuccess(@Nullable final Void result) {
 341
 342                 final Future<Object> ask =
 343                         Patterns.ask(shardedDataTreeActor, new LookupPrefixShard(prefix), SHARD_FUTURE_TIMEOUT);
 344
 345                 shardRegistrationPromise.completeWith(ask.transform(
 346                         new Mapper<Object, DistributedShardRegistration>() {
 347                             @Override
 348                             public DistributedShardRegistration apply(final Object parameter) {
 349                                 return new DistributedShardRegistrationImpl(
 350                                         prefix, shardedDataTreeActor, DistributedShardedDOMDataTree.this);
 351                             }
 352                         },
 353                         new Mapper<Throwable, Throwable>() {
 354                             @Override
 355                             public Throwable apply(final Throwable throwable) {
 356                                 return new DOMDataTreeShardCreationFailedException(
 357                                         "Unable to create a cds shard.", throwable);
 358                             }
 359                         }, actorSystem.dispatcher()));
 360             }
 361
 362             @Override
 363             public void onFailure(final Throwable throwable) {
 364                 shardRegistrationPromise.failure(
 365                         new DOMDataTreeShardCreationFailedException("Unable to create a cds shard.", throwable));
 366             }
 367         }, MoreExecutors.directExecutor());
 368
 369         return FutureConverters.toJava(shardRegistrationPromise.future());
 370     }
 371
 372     void resolveShardAdditions(final Set<DOMDataTreeIdentifier> additions) {
 373         LOG.debug("{}: Resolving additions : {}", memberName, additions);
 374         final ArrayList<DOMDataTreeIdentifier> list = new ArrayList<>(additions);
 375         // we need to register the shards from top to bottom, so we need to atleast make sure the ordering reflects that
 376         Collections.sort(list, (o1, o2) -> {
 377             if (o1.getRootIdentifier().getPathArguments().size() < o2.getRootIdentifier().getPathArguments().size()) {
 378                 return -1;
 379             } else if (o1.getRootIdentifier().getPathArguments().size()
 380                     == o2.getRootIdentifier().getPathArguments().size()) {
 381                 return 0;
 382             } else {
 383                 return 1;
 384             }
 385         });
 386         list.forEach(this::createShardFrontend);
 387     }
 388
 389     void resolveShardRemovals(final Set<DOMDataTreeIdentifier> removals) {
 390         LOG.debug("{}: Resolving removals : {}", memberName, removals);
 391
 392         // do we need to go from bottom to top?
 393         removals.forEach(this::despawnShardFrontend);
 394     }
 395
 396     private void createShardFrontend(final DOMDataTreeIdentifier prefix) {
 397         LOG.debug("{}: Creating CDS shard for prefix: {}", memberName, prefix);
 398         final String shardName = ClusterUtils.getCleanShardName(prefix.getRootIdentifier());
 399         final AbstractDataStore distributedDataStore =
 400                 prefix.getDatastoreType().equals(org.opendaylight.mdsal.common.api.LogicalDatastoreType.CONFIGURATION)
 401                         ? distributedConfigDatastore : distributedOperDatastore;
 402
 403         try (DOMDataTreeProducer producer = localCreateProducer(Collections.singletonList(prefix))) {
 404             final Entry<DataStoreClient, ActorRef> entry =
 405                     createDatastoreClient(shardName, distributedDataStore.getActorContext());
 406
 407             final DistributedShardFrontend shard =
 408                     new DistributedShardFrontend(distributedDataStore, entry.getKey(), prefix);
 409
 410             final DOMDataTreeShardRegistration<DOMDataTreeShard> reg =
 411                     shardedDOMDataTree.registerDataTreeShard(prefix, shard, producer);
 412
 413             synchronized (shards) {
 414                 shards.store(prefix, reg);
 415             }
 416
 417         } catch (final DOMDataTreeShardingConflictException e) {
 418             LOG.error("{}: Prefix {} is already occupied by another shard",
 419                     distributedConfigDatastore.getActorContext().getClusterWrapper().getCurrentMemberName(), prefix, e);
 420         } catch (DOMDataTreeProducerException e) {
 421             LOG.error("Unable to close producer", e);
 422         } catch (DOMDataTreeShardCreationFailedException e) {
 423             LOG.error("Unable to create datastore client for shard {}", prefix, e);
 424         }
 425     }
 426
 427     private void despawnShardFrontend(final DOMDataTreeIdentifier prefix) {
 428         LOG.debug("{}: Removing CDS shard for prefix: {}", memberName, prefix);
 429         final DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> lookup;
 430         synchronized (shards) {
 431             lookup = shards.lookup(prefix);
 432         }
 433
 434         if (lookup == null || !lookup.getValue().getPrefix().equals(prefix)) {
 435             LOG.debug("{}: Received despawn for non-existing CDS shard frontend, prefix: {}, ignoring..",
 436                     memberName, prefix);
 437             return;
 438         }
 439
 440         lookup.getValue().close();
 441         // need to remove from our local table thats used for tracking
 442         synchronized (shards) {
 443             shards.remove(prefix);
 444         }
 445
 446         final PrefixedShardConfigWriter writer = writerMap.get(prefix.getDatastoreType());
 447         final ListenableFuture<Void> future = writer.removeConfig(prefix.getRootIdentifier());
 448
 449         Futures.addCallback(future, new FutureCallback<Void>() {
 450             @Override
 451             public void onSuccess(@Nullable final Void result) {
 452                 LOG.debug("{} - Succesfuly removed shard for {}", memberName, prefix);
 453             }
 454
 455             @Override
 456             public void onFailure(final Throwable throwable) {
 457                 LOG.error("Removal of shard {} from configuration failed.", prefix, throwable);
 458             }
 459         }, MoreExecutors.directExecutor());
 460     }
 461
 462     DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> lookupShardFrontend(
 463             final DOMDataTreeIdentifier prefix) {
 464         synchronized (shards) {
 465             return shards.lookup(prefix);
 466         }
 467     }
 468
 469     DOMDataTreeProducer localCreateProducer(final Collection<DOMDataTreeIdentifier> prefix) {
 470         return shardedDOMDataTree.createProducer(prefix);
 471     }
 472
 473     @Nonnull
 474     @Override
 475     public <T extends DOMDataTreeShard> ListenerRegistration<T> registerDataTreeShard(
 476             @Nonnull final DOMDataTreeIdentifier prefix,
 477             @Nonnull final T shard,
 478             @Nonnull final DOMDataTreeProducer producer)
 479             throws DOMDataTreeShardingConflictException {
 480
 481         LOG.debug("Registering shard[{}] at prefix: {}", shard, prefix);
 482
 483         if (producer instanceof ProxyProducer) {
 484             return shardedDOMDataTree.registerDataTreeShard(prefix, shard, ((ProxyProducer) producer).delegate());
 485         }
 486
 487         return shardedDOMDataTree.registerDataTreeShard(prefix, shard, producer);
 488     }
 489
 490     @SuppressWarnings("checkstyle:IllegalCatch")
 491     private Entry<DataStoreClient, ActorRef> createDatastoreClient(
 492             final String shardName, final ActorContext actorContext)
 493             throws DOMDataTreeShardCreationFailedException {
 494
 495         LOG.debug("{}: Creating distributed datastore client for shard {}", memberName, shardName);
 496         final Props distributedDataStoreClientProps =
 497                 SimpleDataStoreClientActor.props(memberName, "Shard-" + shardName, actorContext, shardName);
 498
 499         final ActorRef clientActor = actorSystem.actorOf(distributedDataStoreClientProps);
 500         try {
 501             return new SimpleEntry<>(SimpleDataStoreClientActor
 502                     .getDistributedDataStoreClient(clientActor, 30, TimeUnit.SECONDS), clientActor);
 503         } catch (final Exception e) {
 504             LOG.error("{}: Failed to get actor for {}", distributedDataStoreClientProps, memberName, e);
 505             clientActor.tell(PoisonPill.getInstance(), noSender());
 506             throw new DOMDataTreeShardCreationFailedException(
 507                     "Unable to create datastore client for shard{" + shardName + "}", e);
 508         }
 509     }
 510
 511     @SuppressWarnings("checkstyle:IllegalCatch")
 512     private void initDefaultShard(final LogicalDatastoreType logicalDatastoreType)
 513             throws ExecutionException, InterruptedException {
 514
 515         final PrefixedShardConfigWriter writer = writerMap.get(logicalDatastoreType);
 516
 517         if (writer.checkDefaultIsPresent()) {
 518             LOG.debug("{}: Default shard for {} is already present in the config. Possibly saved in snapshot.",
 519                     memberName, logicalDatastoreType);
 520         } else {
 521             try {
 522                 // Currently the default shard configuration is present in the out-of-box modules.conf and is
 523                 // expected to be present. So look up the local default shard here and create the frontend.
 524
 525                 // TODO we don't have to do it for config and operational default shard separately. Just one of them
 526                 // should be enough
 527                 final ActorContext actorContext = logicalDatastoreType == LogicalDatastoreType.CONFIGURATION
 528                         ? distributedConfigDatastore.getActorContext() : distributedOperDatastore.getActorContext();
 529
 530                 final Optional<ActorRef> defaultLocalShardOptional =
 531                         actorContext.findLocalShard(ClusterUtils.getCleanShardName(YangInstanceIdentifier.EMPTY));
 532
 533                 if (defaultLocalShardOptional.isPresent()) {
 534                     LOG.debug("{}: Default shard for {} is already started, creating just frontend", memberName,
 535                             logicalDatastoreType);
 536                     createShardFrontend(new DOMDataTreeIdentifier(logicalDatastoreType, YangInstanceIdentifier.EMPTY));
 537                 }
 538
 539                 // The local shard isn't present - we assume that means the local member isn't in the replica list
 540                 // and will be dynamically created later via an explicit add-shard-replica request. This is the
 541                 // bootstrapping mechanism to add a new node into an existing cluster. The following code to create
 542                 // the default shard as a prefix shard is problematic in this scenario so it is commented out. Since
 543                 // the default shard is a module-based shard by default, it makes sense to always treat it as such,
 544                 // ie bootstrap it in the same manner as the special prefix-configuration and EOS shards.
 545 //                final Collection<MemberName> names = distributedConfigDatastore.getActorContext().getConfiguration()
 546 //                        .getUniqueMemberNamesForAllShards();
 547 //                Await.result(FutureConverters.toScala(createDistributedShard(
 548 //                        new DOMDataTreeIdentifier(logicalDatastoreType, YangInstanceIdentifier.EMPTY), names)),
 549 //                        SHARD_FUTURE_TIMEOUT_DURATION);
 550 //            } catch (DOMDataTreeShardingConflictException e) {
 551 //                LOG.debug("{}: Default shard for {} already registered, possibly due to other node doing it faster",
 552 //                        memberName, logicalDatastoreType);
 553             } catch (Exception e) {
 554                 LOG.error("{}: Default shard initialization for {} failed", memberName, logicalDatastoreType, e);
 555                 throw new RuntimeException(e);
 556             }
 557         }
 558     }
 559
 560     private static void closeProducer(final DOMDataTreeProducer producer) {
 561         try {
 562             producer.close();
 563         } catch (final DOMDataTreeProducerException e) {
 564             LOG.error("Unable to close producer", e);
 565         }
 566     }
 567
 568     @SuppressWarnings("checkstyle:IllegalCatch")
 569     private static ActorRef createShardedDataTreeActor(final ActorSystem actorSystem,
 570                                                        final ShardedDataTreeActorCreator creator,
 571                                                        final String shardDataTreeActorId) {
 572         Exception lastException = null;
 573
 574         for (int i = 0; i < MAX_ACTOR_CREATION_RETRIES; i++) {
 575             try {
 576                 return actorSystem.actorOf(creator.props(), shardDataTreeActorId);
 577             } catch (final Exception e) {
 578                 lastException = e;
 579                 Uninterruptibles.sleepUninterruptibly(ACTOR_RETRY_DELAY, ACTOR_RETRY_TIME_UNIT);
 580                 LOG.debug("Could not create actor {} because of {} -"
 581                                 + " waiting for sometime before retrying (retry count = {})",
 582                         shardDataTreeActorId, e.getMessage(), i);
 583             }
 584         }
 585
 586         throw new IllegalStateException("Failed to create actor for ShardedDOMDataTree", lastException);
 587     }
 588
 589     private class DistributedShardRegistrationImpl implements DistributedShardRegistration {
 590
 591         private final DOMDataTreeIdentifier prefix;
 592         private final ActorRef shardedDataTreeActor;
 593         private final DistributedShardedDOMDataTree distributedShardedDOMDataTree;
 594
 595         DistributedShardRegistrationImpl(final DOMDataTreeIdentifier prefix,
 596                                          final ActorRef shardedDataTreeActor,
 597                                          final DistributedShardedDOMDataTree distributedShardedDOMDataTree) {
 598             this.prefix = prefix;
 599             this.shardedDataTreeActor = shardedDataTreeActor;
 600             this.distributedShardedDOMDataTree = distributedShardedDOMDataTree;
 601         }
 602
 603         @Override
 604         public CompletionStage<Void> close() {
 605             // first despawn on the local node
 606             distributedShardedDOMDataTree.despawnShardFrontend(prefix);
 607             // update the config so the remote nodes are updated
 608             final Future<Object> ask =
 609                     Patterns.ask(shardedDataTreeActor, new PrefixShardRemovalLookup(prefix), SHARD_FUTURE_TIMEOUT);
 610
 611             final Future<Void> closeFuture = ask.transform(
 612                     new Mapper<Object, Void>() {
 613                         @Override
 614                         public Void apply(final Object parameter) {
 615                             return null;
 616                         }
 617                     },
 618                     new Mapper<Throwable, Throwable>() {
 619                         @Override
 620                         public Throwable apply(final Throwable throwable) {
 621                             return throwable;
 622                         }
 623                     }, actorSystem.dispatcher());
 624
 625             return FutureConverters.toJava(closeFuture);
 626         }
 627     }
 628
 629     // TODO what about producers created by this producer?
 630     // They should also be CDSProducers
 631     private static final class ProxyProducer extends ForwardingObject implements CDSDataTreeProducer {
 632
 633         private final DOMDataTreeProducer delegate;
 634         private final Collection<DOMDataTreeIdentifier> subtrees;
 635         private final ActorRef shardDataTreeActor;
 636         private final ActorContext actorContext;
 637         @GuardedBy("shardAccessMap")
 638         private final Map<DOMDataTreeIdentifier, CDSShardAccessImpl> shardAccessMap = new HashMap<>();
 639
 640         // We don't have to guard access to shardTable in ProxyProducer.
 641         // ShardTable's entries relevant to this ProxyProducer shouldn't
 642         // change during producer's lifetime.
 643         private final DOMDataTreePrefixTable<DOMDataTreeShardRegistration<DOMDataTreeShard>> shardTable;
 644
 645         ProxyProducer(final DOMDataTreeProducer delegate,
 646                       final Collection<DOMDataTreeIdentifier> subtrees,
 647                       final ActorRef shardDataTreeActor,
 648                       final ActorContext actorContext,
 649                       final DOMDataTreePrefixTable<DOMDataTreeShardRegistration<DOMDataTreeShard>> shardLayout) {
 650             this.delegate = Preconditions.checkNotNull(delegate);
 651             this.subtrees = Preconditions.checkNotNull(subtrees);
 652             this.shardDataTreeActor = Preconditions.checkNotNull(shardDataTreeActor);
 653             this.actorContext = Preconditions.checkNotNull(actorContext);
 654             this.shardTable = Preconditions.checkNotNull(shardLayout);
 655         }
 656
 657         @Nonnull
 658         @Override
 659         public DOMDataTreeCursorAwareTransaction createTransaction(final boolean isolated) {
 660             return delegate.createTransaction(isolated);
 661         }
 662
 663         @Nonnull
 664         @Override
 665         @SuppressWarnings("checkstyle:hiddenField")
 666         public DOMDataTreeProducer createProducer(@Nonnull final Collection<DOMDataTreeIdentifier> subtrees) {
 667             // TODO we probably don't need to distribute this on the remote nodes since once we have this producer
 668             // open we surely have the rights to all the subtrees.
 669             return delegate.createProducer(subtrees);
 670         }
 671
 672         @Override
 673         @SuppressWarnings("checkstyle:IllegalCatch")
 674         public void close() throws DOMDataTreeProducerException {
 675             delegate.close();
 676
 677             synchronized (shardAccessMap) {
 678                 shardAccessMap.values().forEach(CDSShardAccessImpl::close);
 679             }
 680
 681             final Object o = actorContext.executeOperation(shardDataTreeActor, new ProducerRemoved(subtrees));
 682             if (o instanceof DOMDataTreeProducerException) {
 683                 throw (DOMDataTreeProducerException) o;
 684             } else if (o instanceof Throwable) {
 685                 throw new DOMDataTreeProducerException("Unable to close producer", (Throwable) o);
 686             }
 687         }
 688
 689         @Override
 690         protected DOMDataTreeProducer delegate() {
 691             return delegate;
 692         }
 693
 694         @Nonnull
 695         @Override
 696         public CDSShardAccess getShardAccess(@Nonnull final DOMDataTreeIdentifier subtree) {
 697             Preconditions.checkArgument(
 698                     subtrees.stream().anyMatch(dataTreeIdentifier -> dataTreeIdentifier.contains(subtree)),
 699                     "Subtree %s is not controlled by this producer %s", subtree, this);
 700
 701             final DOMDataTreePrefixTableEntry<DOMDataTreeShardRegistration<DOMDataTreeShard>> lookup =
 702                     shardTable.lookup(subtree);
 703             Preconditions.checkState(lookup != null, "Subtree %s is not contained in any registered shard.", subtree);
 704
 705             final DOMDataTreeIdentifier lookupId = lookup.getValue().getPrefix();
 706
 707             synchronized (shardAccessMap) {
 708                 if (shardAccessMap.get(lookupId) != null) {
 709                     return shardAccessMap.get(lookupId);
 710                 }
 711
 712                 // TODO Maybe we can have static factory method and return the same instance
 713                 // for same subtrees. But maybe it is not needed since there can be only one
 714                 // producer attached to some subtree at a time. And also how we can close ShardAccess
 715                 // then
 716                 final CDSShardAccessImpl shardAccess = new CDSShardAccessImpl(lookupId, actorContext);
 717                 shardAccessMap.put(lookupId, shardAccess);
 718                 return shardAccess;
 719             }
 720         }
 721     }
 722 }