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

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.controller.cluster.datastore;
  10
  11 import akka.actor.ActorSelection;
  12 import akka.dispatch.Mapper;
  13 import akka.dispatch.OnComplete;
  14 import com.google.common.annotations.VisibleForTesting;
  15 import com.google.common.base.FinalizablePhantomReference;
  16 import com.google.common.base.FinalizableReferenceQueue;
  17 import com.google.common.base.Optional;
  18 import com.google.common.base.Preconditions;
  19 import com.google.common.collect.Lists;
  20 import com.google.common.util.concurrent.CheckedFuture;
  21 import com.google.common.util.concurrent.FutureCallback;
  22 import com.google.common.util.concurrent.Futures;
  23 import com.google.common.util.concurrent.SettableFuture;
  24 import java.util.HashMap;
  25 import java.util.List;
  26 import java.util.Map;
  27 import java.util.concurrent.ConcurrentHashMap;
  28 import java.util.concurrent.TimeUnit;
  29 import java.util.concurrent.atomic.AtomicBoolean;
  30 import java.util.concurrent.atomic.AtomicLong;
  31 import javax.annotation.concurrent.GuardedBy;
  32 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  33 import org.opendaylight.controller.cluster.datastore.identifiers.TransactionIdentifier;
  34 import org.opendaylight.controller.cluster.datastore.messages.CloseTransaction;
  35 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  36 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  37 import org.opendaylight.controller.cluster.datastore.messages.DataExists;
  38 import org.opendaylight.controller.cluster.datastore.messages.DataExistsReply;
  39 import org.opendaylight.controller.cluster.datastore.messages.DeleteData;
  40 import org.opendaylight.controller.cluster.datastore.messages.MergeData;
  41 import org.opendaylight.controller.cluster.datastore.messages.ReadData;
  42 import org.opendaylight.controller.cluster.datastore.messages.ReadDataReply;
  43 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransaction;
  44 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
  45 import org.opendaylight.controller.cluster.datastore.messages.WriteData;
  46 import org.opendaylight.controller.cluster.datastore.shardstrategy.ShardStrategyFactory;
  47 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  48 import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
  49 import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadWriteTransaction;
  50 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  51 import org.opendaylight.yangtools.util.concurrent.MappingCheckedFuture;
  52 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  53 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  54 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  55 import org.slf4j.Logger;
  56 import org.slf4j.LoggerFactory;
  57 import scala.concurrent.Future;
  58 import scala.concurrent.Promise;
  59 import scala.concurrent.duration.FiniteDuration;
  60
  61 /**
  62  * TransactionProxy acts as a proxy for one or more transactions that were created on a remote shard
  63  * <p>
  64  * Creating a transaction on the consumer side will create one instance of a transaction proxy. If during
  65  * the transaction reads and writes are done on data that belongs to different shards then a separate transaction will
  66  * be created on each of those shards by the TransactionProxy
  67  *</p>
  68  * <p>
  69  * The TransactionProxy does not make any guarantees about atomicity or order in which the transactions on the various
  70  * shards will be executed.
  71  * </p>
  72  */
  73 public class TransactionProxy implements DOMStoreReadWriteTransaction {
  74
  75     public static enum TransactionType {
  76         READ_ONLY,
  77         WRITE_ONLY,
  78         READ_WRITE
  79     }
  80
  81     static final Mapper<Throwable, Throwable> SAME_FAILURE_TRANSFORMER =
  82                                                               new Mapper<Throwable, Throwable>() {
  83         @Override
  84         public Throwable apply(Throwable failure) {
  85             return failure;
  86         }
  87     };
  88
  89     private static final AtomicLong counter = new AtomicLong();
  90
  91     private static final Logger LOG = LoggerFactory.getLogger(TransactionProxy.class);
  92
  93     /**
  94      * Time interval in between transaction create retries.
  95      */
  96     private static final FiniteDuration CREATE_TX_TRY_INTERVAL =
  97             FiniteDuration.create(1, TimeUnit.SECONDS);
  98
  99     /**
 100      * Used to enqueue the PhantomReferences for read-only TransactionProxy instances. The
 101      * FinalizableReferenceQueue is safe to use statically in an OSGi environment as it uses some
 102      * trickery to clean up its internal thread when the bundle is unloaded.
 103      */
 104     private static final FinalizableReferenceQueue phantomReferenceQueue =
 105                                                                   new FinalizableReferenceQueue();
 106
 107     /**
 108      * This stores the TransactionProxyCleanupPhantomReference instances statically, This is
 109      * necessary because PhantomReferences need a hard reference so they're not garbage collected.
 110      * Once finalized, the TransactionProxyCleanupPhantomReference removes itself from this map
 111      * and thus becomes eligible for garbage collection.
 112      */
 113     private static final Map<TransactionProxyCleanupPhantomReference,
 114                              TransactionProxyCleanupPhantomReference> phantomReferenceCache =
 115                                                                         new ConcurrentHashMap<>();
 116
 117     /**
 118      * A PhantomReference that closes remote transactions for a TransactionProxy when it's
 119      * garbage collected. This is used for read-only transactions as they're not explicitly closed
 120      * by clients. So the only way to detect that a transaction is no longer in use and it's safe
 121      * to clean up is when it's garbage collected. It's inexact as to when an instance will be GC'ed
 122      * but TransactionProxy instances should generally be short-lived enough to avoid being moved
 123      * to the old generation space and thus should be cleaned up in a timely manner as the GC
 124      * runs on the young generation (eden, swap1...) space much more frequently.
 125      */
 126     private static class TransactionProxyCleanupPhantomReference
 127                                            extends FinalizablePhantomReference<TransactionProxy> {
 128
 129         private final List<ActorSelection> remoteTransactionActors;
 130         private final AtomicBoolean remoteTransactionActorsMB;
 131         private final ActorContext actorContext;
 132         private final TransactionIdentifier identifier;
 133
 134         protected TransactionProxyCleanupPhantomReference(TransactionProxy referent) {
 135             super(referent, phantomReferenceQueue);
 136
 137             // Note we need to cache the relevant fields from the TransactionProxy as we can't
 138             // have a hard reference to the TransactionProxy instance itself.
 139
 140             remoteTransactionActors = referent.remoteTransactionActors;
 141             remoteTransactionActorsMB = referent.remoteTransactionActorsMB;
 142             actorContext = referent.actorContext;
 143             identifier = referent.identifier;
 144         }
 145
 146         @Override
 147         public void finalizeReferent() {
 148             LOG.trace("Cleaning up {} Tx actors for TransactionProxy {}",
 149                     remoteTransactionActors.size(), identifier);
 150
 151             phantomReferenceCache.remove(this);
 152
 153             // Access the memory barrier volatile to ensure all previous updates to the
 154             // remoteTransactionActors list are visible to this thread.
 155
 156             if(remoteTransactionActorsMB.get()) {
 157                 for(ActorSelection actor : remoteTransactionActors) {
 158                     LOG.trace("Sending CloseTransaction to {}", actor);
 159                     actorContext.sendOperationAsync(actor,
 160                             new CloseTransaction().toSerializable());
 161                 }
 162             }
 163         }
 164     }
 165
 166     /**
 167      * Stores the remote Tx actors for each requested data store path to be used by the
 168      * PhantomReference to close the remote Tx's. This is only used for read-only Tx's. The
 169      * remoteTransactionActorsMB volatile serves as a memory barrier to publish updates to the
 170      * remoteTransactionActors list so they will be visible to the thread accessing the
 171      * PhantomReference.
 172      */
 173     private List<ActorSelection> remoteTransactionActors;
 174     private AtomicBoolean remoteTransactionActorsMB;
 175
 176     /**
 177      * Stores the create transaction results per shard.
 178      */
 179     private final Map<String, TransactionFutureCallback> txFutureCallbackMap = new HashMap<>();
 180
 181     private final TransactionType transactionType;
 182     private final ActorContext actorContext;
 183     private final TransactionIdentifier identifier;
 184     private final String transactionChainId;
 185     private final SchemaContext schemaContext;
 186     private boolean inReadyState;
 187
 188     public TransactionProxy(ActorContext actorContext, TransactionType transactionType) {
 189         this(actorContext, transactionType, "");
 190     }
 191
 192     public TransactionProxy(ActorContext actorContext, TransactionType transactionType,
 193             String transactionChainId) {
 194         this.actorContext = Preconditions.checkNotNull(actorContext,
 195             "actorContext should not be null");
 196         this.transactionType = Preconditions.checkNotNull(transactionType,
 197             "transactionType should not be null");
 198         this.schemaContext = Preconditions.checkNotNull(actorContext.getSchemaContext(),
 199             "schemaContext should not be null");
 200         this.transactionChainId = transactionChainId;
 201
 202         String memberName = actorContext.getCurrentMemberName();
 203         if(memberName == null){
 204             memberName = "UNKNOWN-MEMBER";
 205         }
 206
 207         this.identifier = TransactionIdentifier.builder().memberName(memberName).counter(
 208             counter.getAndIncrement()).build();
 209
 210         if(transactionType == TransactionType.READ_ONLY) {
 211             // Read-only Tx's aren't explicitly closed by the client so we create a PhantomReference
 212             // to close the remote Tx's when this instance is no longer in use and is garbage
 213             // collected.
 214
 215             remoteTransactionActors = Lists.newArrayList();
 216             remoteTransactionActorsMB = new AtomicBoolean();
 217
 218             TransactionProxyCleanupPhantomReference cleanup =
 219                 new TransactionProxyCleanupPhantomReference(this);
 220             phantomReferenceCache.put(cleanup, cleanup);
 221         }
 222
 223         LOG.debug("Created txn {} of type {} on chain {}", identifier, transactionType, transactionChainId);
 224     }
 225
 226     @VisibleForTesting
 227     List<Future<Object>> getRecordedOperationFutures() {
 228         List<Future<Object>> recordedOperationFutures = Lists.newArrayList();
 229         for(TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) {
 230             TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 231             if(transactionContext != null) {
 232                 recordedOperationFutures.addAll(transactionContext.getRecordedOperationFutures());
 233             }
 234         }
 235
 236         return recordedOperationFutures;
 237     }
 238
 239     @VisibleForTesting
 240     boolean hasTransactionContext() {
 241         for(TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) {
 242             TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 243             if(transactionContext != null) {
 244                 return true;
 245             }
 246         }
 247
 248         return false;
 249     }
 250
 251     @Override
 252     public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> read(
 253             final YangInstanceIdentifier path) {
 254
 255         Preconditions.checkState(transactionType != TransactionType.WRITE_ONLY,
 256                 "Read operation on write-only transaction is not allowed");
 257
 258         LOG.debug("Tx {} read {}", identifier, path);
 259
 260         TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path);
 261         TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 262
 263         CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> future;
 264         if(transactionContext != null) {
 265             future = transactionContext.readData(path);
 266         } else {
 267             // The shard Tx hasn't been created yet so add the Tx operation to the Tx Future
 268             // callback to be executed after the Tx is created.
 269             final SettableFuture<Optional<NormalizedNode<?, ?>>> proxyFuture = SettableFuture.create();
 270             txFutureCallback.addTxOperationOnComplete(new TransactionOperation() {
 271                 @Override
 272                 public void invoke(TransactionContext transactionContext) {
 273                     Futures.addCallback(transactionContext.readData(path),
 274                         new FutureCallback<Optional<NormalizedNode<?, ?>>>() {
 275                             @Override
 276                             public void onSuccess(Optional<NormalizedNode<?, ?>> data) {
 277                                 proxyFuture.set(data);
 278                             }
 279
 280                             @Override
 281                             public void onFailure(Throwable t) {
 282                                 proxyFuture.setException(t);
 283                             }
 284                         });
 285                 }
 286             });
 287
 288             future = MappingCheckedFuture.create(proxyFuture, ReadFailedException.MAPPER);
 289         }
 290
 291         return future;
 292     }
 293
 294     @Override
 295     public CheckedFuture<Boolean, ReadFailedException> exists(final YangInstanceIdentifier path) {
 296
 297         Preconditions.checkState(transactionType != TransactionType.WRITE_ONLY,
 298                 "Exists operation on write-only transaction is not allowed");
 299
 300         LOG.debug("Tx {} exists {}", identifier, path);
 301
 302         TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path);
 303         TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 304
 305         CheckedFuture<Boolean, ReadFailedException> future;
 306         if(transactionContext != null) {
 307             future = transactionContext.dataExists(path);
 308         } else {
 309             // The shard Tx hasn't been created yet so add the Tx operation to the Tx Future
 310             // callback to be executed after the Tx is created.
 311             final SettableFuture<Boolean> proxyFuture = SettableFuture.create();
 312             txFutureCallback.addTxOperationOnComplete(new TransactionOperation() {
 313                 @Override
 314                 public void invoke(TransactionContext transactionContext) {
 315                     Futures.addCallback(transactionContext.dataExists(path),
 316                         new FutureCallback<Boolean>() {
 317                             @Override
 318                             public void onSuccess(Boolean exists) {
 319                                 proxyFuture.set(exists);
 320                             }
 321
 322                             @Override
 323                             public void onFailure(Throwable t) {
 324                                 proxyFuture.setException(t);
 325                             }
 326                         });
 327                 }
 328             });
 329
 330             future = MappingCheckedFuture.create(proxyFuture, ReadFailedException.MAPPER);
 331         }
 332
 333         return future;
 334     }
 335
 336     private void checkModificationState() {
 337         Preconditions.checkState(transactionType != TransactionType.READ_ONLY,
 338                 "Modification operation on read-only transaction is not allowed");
 339         Preconditions.checkState(!inReadyState,
 340                 "Transaction is sealed - further modifications are not allowed");
 341     }
 342
 343     @Override
 344     public void write(final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
 345
 346         checkModificationState();
 347
 348         LOG.debug("Tx {} write {}", identifier, path);
 349
 350         TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path);
 351         TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 352         if(transactionContext != null) {
 353             transactionContext.writeData(path, data);
 354         } else {
 355             // The shard Tx hasn't been created yet so add the Tx operation to the Tx Future
 356             // callback to be executed after the Tx is created.
 357             txFutureCallback.addTxOperationOnComplete(new TransactionOperation() {
 358                 @Override
 359                 public void invoke(TransactionContext transactionContext) {
 360                     transactionContext.writeData(path, data);
 361                 }
 362             });
 363         }
 364     }
 365
 366     @Override
 367     public void merge(final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
 368
 369         checkModificationState();
 370
 371         LOG.debug("Tx {} merge {}", identifier, path);
 372
 373         TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path);
 374         TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 375         if(transactionContext != null) {
 376             transactionContext.mergeData(path, data);
 377         } else {
 378             // The shard Tx hasn't been created yet so add the Tx operation to the Tx Future
 379             // callback to be executed after the Tx is created.
 380             txFutureCallback.addTxOperationOnComplete(new TransactionOperation() {
 381                 @Override
 382                 public void invoke(TransactionContext transactionContext) {
 383                     transactionContext.mergeData(path, data);
 384                 }
 385             });
 386         }
 387     }
 388
 389     @Override
 390     public void delete(final YangInstanceIdentifier path) {
 391
 392         checkModificationState();
 393
 394         LOG.debug("Tx {} delete {}", identifier, path);
 395
 396         TransactionFutureCallback txFutureCallback = getOrCreateTxFutureCallback(path);
 397         TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 398         if(transactionContext != null) {
 399             transactionContext.deleteData(path);
 400         } else {
 401             // The shard Tx hasn't been created yet so add the Tx operation to the Tx Future
 402             // callback to be executed after the Tx is created.
 403             txFutureCallback.addTxOperationOnComplete(new TransactionOperation() {
 404                 @Override
 405                 public void invoke(TransactionContext transactionContext) {
 406                     transactionContext.deleteData(path);
 407                 }
 408             });
 409         }
 410     }
 411
 412     @Override
 413     public DOMStoreThreePhaseCommitCohort ready() {
 414
 415         checkModificationState();
 416
 417         inReadyState = true;
 418
 419         LOG.debug("Tx {} Readying {} transactions for commit", identifier,
 420                     txFutureCallbackMap.size());
 421
 422         List<Future<ActorSelection>> cohortFutures = Lists.newArrayList();
 423
 424         for(TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) {
 425
 426             LOG.debug("Tx {} Readying transaction for shard {} chain {}", identifier,
 427                         txFutureCallback.getShardName(), transactionChainId);
 428
 429             TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 430             if(transactionContext != null) {
 431                 cohortFutures.add(transactionContext.readyTransaction());
 432             } else {
 433                 // The shard Tx hasn't been created yet so create a promise to ready the Tx later
 434                 // after it's created.
 435                 final Promise<ActorSelection> cohortPromise = akka.dispatch.Futures.promise();
 436                 txFutureCallback.addTxOperationOnComplete(new TransactionOperation() {
 437                     @Override
 438                     public void invoke(TransactionContext transactionContext) {
 439                         cohortPromise.completeWith(transactionContext.readyTransaction());
 440                     }
 441                 });
 442
 443                 cohortFutures.add(cohortPromise.future());
 444             }
 445         }
 446
 447         onTransactionReady(cohortFutures);
 448
 449         return new ThreePhaseCommitCohortProxy(actorContext, cohortFutures,
 450                 identifier.toString());
 451     }
 452
 453     /**
 454      * Method for derived classes to be notified when the transaction has been readied.
 455      *
 456      * @param cohortFutures the cohort Futures for each shard transaction.
 457      */
 458     protected void onTransactionReady(List<Future<ActorSelection>> cohortFutures) {
 459     }
 460
 461     /**
 462      * Method called to send a CreateTransaction message to a shard.
 463      *
 464      * @param shard the shard actor to send to
 465      * @param serializedCreateMessage the serialized message to send
 466      * @return the response Future
 467      */
 468     protected Future<Object> sendCreateTransaction(ActorSelection shard,
 469             Object serializedCreateMessage) {
 470         return actorContext.executeOperationAsync(shard, serializedCreateMessage);
 471     }
 472
 473     @Override
 474     public Object getIdentifier() {
 475         return this.identifier;
 476     }
 477
 478     @Override
 479     public void close() {
 480         for(TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) {
 481             TransactionContext transactionContext = txFutureCallback.getTransactionContext();
 482             if(transactionContext != null) {
 483                 transactionContext.closeTransaction();
 484             } else {
 485                 txFutureCallback.addTxOperationOnComplete(new TransactionOperation() {
 486                     @Override
 487                     public void invoke(TransactionContext transactionContext) {
 488                         transactionContext.closeTransaction();
 489                     }
 490                 });
 491             }
 492         }
 493
 494         txFutureCallbackMap.clear();
 495
 496         if(transactionType == TransactionType.READ_ONLY) {
 497             remoteTransactionActors.clear();
 498             remoteTransactionActorsMB.set(true);
 499         }
 500     }
 501
 502     private String shardNameFromIdentifier(YangInstanceIdentifier path){
 503         return ShardStrategyFactory.getStrategy(path).findShard(path);
 504     }
 505
 506     private TransactionFutureCallback getOrCreateTxFutureCallback(YangInstanceIdentifier path) {
 507         String shardName = shardNameFromIdentifier(path);
 508         TransactionFutureCallback txFutureCallback = txFutureCallbackMap.get(shardName);
 509         if(txFutureCallback == null) {
 510             Future<ActorSelection> findPrimaryFuture = actorContext.findPrimaryShardAsync(shardName);
 511
 512             final TransactionFutureCallback newTxFutureCallback =
 513                     new TransactionFutureCallback(shardName);
 514
 515             txFutureCallback = newTxFutureCallback;
 516             txFutureCallbackMap.put(shardName, txFutureCallback);
 517
 518             findPrimaryFuture.onComplete(new OnComplete<ActorSelection>() {
 519                 @Override
 520                 public void onComplete(Throwable failure, ActorSelection primaryShard) {
 521                     if(failure != null) {
 522                         newTxFutureCallback.onComplete(failure, null);
 523                     } else {
 524                         newTxFutureCallback.setPrimaryShard(primaryShard);
 525                     }
 526                 }
 527             }, actorContext.getActorSystem().dispatcher());
 528         }
 529
 530         return txFutureCallback;
 531     }
 532
 533     public String getTransactionChainId() {
 534         return transactionChainId;
 535     }
 536
 537     protected ActorContext getActorContext() {
 538         return actorContext;
 539     }
 540
 541     /**
 542      * Interface for a transaction operation to be invoked later.
 543      */
 544     private static interface TransactionOperation {
 545         void invoke(TransactionContext transactionContext);
 546     }
 547
 548     /**
 549      * Implements a Future OnComplete callback for a CreateTransaction message. This class handles
 550      * retries, up to a limit, if the shard doesn't have a leader yet. This is done by scheduling a
 551      * retry task after a short delay.
 552      * <p>
 553      * The end result from a completed CreateTransaction message is a TransactionContext that is
 554      * used to perform transaction operations. Transaction operations that occur before the
 555      * CreateTransaction completes are cache and executed once the CreateTransaction completes,
 556      * successfully or not.
 557      */
 558     private class TransactionFutureCallback extends OnComplete<Object> {
 559
 560         /**
 561          * The list of transaction operations to execute once the CreateTransaction completes.
 562          */
 563         @GuardedBy("txOperationsOnComplete")
 564         private final List<TransactionOperation> txOperationsOnComplete = Lists.newArrayList();
 565
 566         /**
 567          * The TransactionContext resulting from the CreateTransaction reply.
 568          */
 569         private volatile TransactionContext transactionContext;
 570
 571         /**
 572          * The target primary shard.
 573          */
 574         private volatile ActorSelection primaryShard;
 575
 576         private volatile int createTxTries = (int) (actorContext.getDatastoreContext().
 577                 getShardLeaderElectionTimeout().duration().toMillis() /
 578                 CREATE_TX_TRY_INTERVAL.toMillis());
 579
 580         private final String shardName;
 581
 582         TransactionFutureCallback(String shardName) {
 583             this.shardName = shardName;
 584         }
 585
 586         String getShardName() {
 587             return shardName;
 588         }
 589
 590         TransactionContext getTransactionContext() {
 591             return transactionContext;
 592         }
 593
 594
 595         /**
 596          * Sets the target primary shard and initiates a CreateTransaction try.
 597          */
 598         void setPrimaryShard(ActorSelection primaryShard) {
 599             LOG.debug("Tx {} Primary shard found - trying create transaction", identifier);
 600
 601             this.primaryShard = primaryShard;
 602             tryCreateTransaction();
 603         }
 604
 605         /**
 606          * Adds a TransactionOperation to be executed after the CreateTransaction completes.
 607          */
 608         void addTxOperationOnComplete(TransactionOperation operation) {
 609             synchronized(txOperationsOnComplete) {
 610                 if(transactionContext == null) {
 611                     LOG.debug("Tx {} Adding operation on complete {}", identifier);
 612
 613                     txOperationsOnComplete.add(operation);
 614                 } else {
 615                     operation.invoke(transactionContext);
 616                 }
 617             }
 618         }
 619
 620         /**
 621          * Performs a CreateTransaction try async.
 622          */
 623         private void tryCreateTransaction() {
 624             Future<Object> createTxFuture = sendCreateTransaction(primaryShard,
 625                     new CreateTransaction(identifier.toString(),
 626                             TransactionProxy.this.transactionType.ordinal(),
 627                             getTransactionChainId()).toSerializable());
 628
 629             createTxFuture.onComplete(this, actorContext.getActorSystem().dispatcher());
 630         }
 631
 632         @Override
 633         public void onComplete(Throwable failure, Object response) {
 634             if(failure instanceof NoShardLeaderException) {
 635                 // There's no leader for the shard yet - schedule and try again, unless we're out
 636                 // of retries. Note: createTxTries is volatile as it may be written by different
 637                 // threads however not concurrently, therefore decrementing it non-atomically here
 638                 // is ok.
 639                 if(--createTxTries > 0) {
 640                     LOG.debug("Tx {} Shard {} has no leader yet - scheduling create Tx retry",
 641                             identifier, shardName);
 642
 643                     actorContext.getActorSystem().scheduler().scheduleOnce(CREATE_TX_TRY_INTERVAL,
 644                             new Runnable() {
 645                                 @Override
 646                                 public void run() {
 647                                     tryCreateTransaction();
 648                                 }
 649                             }, actorContext.getActorSystem().dispatcher());
 650                     return;
 651                 }
 652             }
 653
 654             // Create the TransactionContext from the response or failure and execute delayed
 655             // TransactionOperations. This entire section is done atomically (ie synchronized) with
 656             // respect to #addTxOperationOnComplete to handle timing issues and ensure no
 657             // TransactionOperation is missed and that they are processed in the order they occurred.
 658             synchronized(txOperationsOnComplete) {
 659                 // Store the new TransactionContext locally until we've completed invoking the
 660                 // TransactionOperations. This avoids thread timing issues which could cause
 661                 // out-of-order TransactionOperations. Eg, on a modification operation, if the
 662                 // TransactionContext is non-null, then we directly call the TransactionContext.
 663                 // However, at the same time, the code may be executing the cached
 664                 // TransactionOperations. So to avoid thus timing, we don't publish the
 665                 // TransactionContext until after we've executed all cached TransactionOperations.
 666                 TransactionContext localTransactionContext;
 667                 if(failure != null) {
 668                     LOG.debug("Tx {} Creating NoOpTransaction because of error: {}", identifier,
 669                             failure.getMessage());
 670
 671                     localTransactionContext = new NoOpTransactionContext(failure, identifier);
 672                 } else if (response.getClass().equals(CreateTransactionReply.SERIALIZABLE_CLASS)) {
 673                     localTransactionContext = createValidTransactionContext(
 674                             CreateTransactionReply.fromSerializable(response));
 675                 } else {
 676                     IllegalArgumentException exception = new IllegalArgumentException(String.format(
 677                         "Invalid reply type %s for CreateTransaction", response.getClass()));
 678
 679                     localTransactionContext = new NoOpTransactionContext(exception, identifier);
 680                 }
 681
 682                 for(TransactionOperation oper: txOperationsOnComplete) {
 683                     oper.invoke(localTransactionContext);
 684                 }
 685
 686                 txOperationsOnComplete.clear();
 687
 688                 // We're done invoking the TransactionOperations so we can now publish the
 689                 // TransactionContext.
 690                 transactionContext = localTransactionContext;
 691             }
 692         }
 693
 694         private TransactionContext createValidTransactionContext(CreateTransactionReply reply) {
 695             String transactionPath = reply.getTransactionPath();
 696
 697             LOG.debug("Tx {} Received transaction actor path {}", identifier, transactionPath);
 698
 699             ActorSelection transactionActor = actorContext.actorSelection(transactionPath);
 700
 701             if (transactionType == TransactionType.READ_ONLY) {
 702                 // Add the actor to the remoteTransactionActors list for access by the
 703                 // cleanup PhantonReference.
 704                 remoteTransactionActors.add(transactionActor);
 705
 706                 // Write to the memory barrier volatile to publish the above update to the
 707                 // remoteTransactionActors list for thread visibility.
 708                 remoteTransactionActorsMB.set(true);
 709             }
 710
 711             // TxActor is always created where the leader of the shard is.
 712             // Check if TxActor is created in the same node
 713             boolean isTxActorLocal = actorContext.isLocalPath(transactionPath);
 714
 715             return new TransactionContextImpl(transactionPath, transactionActor, identifier,
 716                 actorContext, schemaContext, isTxActorLocal, reply.getVersion());
 717         }
 718     }
 719
 720     private interface TransactionContext {
 721         void closeTransaction();
 722
 723         Future<ActorSelection> readyTransaction();
 724
 725         void writeData(YangInstanceIdentifier path, NormalizedNode<?, ?> data);
 726
 727         void deleteData(YangInstanceIdentifier path);
 728
 729         void mergeData(YangInstanceIdentifier path, NormalizedNode<?, ?> data);
 730
 731         CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> readData(
 732                 final YangInstanceIdentifier path);
 733
 734         CheckedFuture<Boolean, ReadFailedException> dataExists(YangInstanceIdentifier path);
 735
 736         List<Future<Object>> getRecordedOperationFutures();
 737     }
 738
 739     private static abstract class AbstractTransactionContext implements TransactionContext {
 740
 741         protected final TransactionIdentifier identifier;
 742         protected final List<Future<Object>> recordedOperationFutures = Lists.newArrayList();
 743
 744         AbstractTransactionContext(TransactionIdentifier identifier) {
 745             this.identifier = identifier;
 746         }
 747
 748         @Override
 749         public List<Future<Object>> getRecordedOperationFutures() {
 750             return recordedOperationFutures;
 751         }
 752     }
 753
 754     private static class TransactionContextImpl extends AbstractTransactionContext {
 755         private final Logger LOG = LoggerFactory.getLogger(TransactionContextImpl.class);
 756
 757         private final ActorContext actorContext;
 758         private final SchemaContext schemaContext;
 759         private final String transactionPath;
 760         private final ActorSelection actor;
 761         private final boolean isTxActorLocal;
 762         private final int remoteTransactionVersion;
 763
 764         private TransactionContextImpl(String transactionPath, ActorSelection actor, TransactionIdentifier identifier,
 765                 ActorContext actorContext, SchemaContext schemaContext,
 766                 boolean isTxActorLocal, int remoteTransactionVersion) {
 767             super(identifier);
 768             this.transactionPath = transactionPath;
 769             this.actor = actor;
 770             this.actorContext = actorContext;
 771             this.schemaContext = schemaContext;
 772             this.isTxActorLocal = isTxActorLocal;
 773             this.remoteTransactionVersion = remoteTransactionVersion;
 774         }
 775
 776         private ActorSelection getActor() {
 777             return actor;
 778         }
 779
 780         @Override
 781         public void closeTransaction() {
 782             LOG.debug("Tx {} closeTransaction called", identifier);
 783
 784             actorContext.sendOperationAsync(getActor(), new CloseTransaction().toSerializable());
 785         }
 786
 787         @Override
 788         public Future<ActorSelection> readyTransaction() {
 789             LOG.debug("Tx {} readyTransaction called with {} previous recorded operations pending",
 790                     identifier, recordedOperationFutures.size());
 791
 792             // Send the ReadyTransaction message to the Tx actor.
 793
 794             ReadyTransaction readyTransaction = new ReadyTransaction();
 795             final Future<Object> replyFuture = actorContext.executeOperationAsync(getActor(),
 796                 isTxActorLocal ? readyTransaction : readyTransaction.toSerializable());
 797
 798             // Combine all the previously recorded put/merge/delete operation reply Futures and the
 799             // ReadyTransactionReply Future into one Future. If any one fails then the combined
 800             // Future will fail. We need all prior operations and the ready operation to succeed
 801             // in order to attempt commit.
 802
 803             List<Future<Object>> futureList =
 804                     Lists.newArrayListWithCapacity(recordedOperationFutures.size() + 1);
 805             futureList.addAll(recordedOperationFutures);
 806             futureList.add(replyFuture);
 807
 808             Future<Iterable<Object>> combinedFutures = akka.dispatch.Futures.sequence(futureList,
 809                     actorContext.getActorSystem().dispatcher());
 810
 811             // Transform the combined Future into a Future that returns the cohort actor path from
 812             // the ReadyTransactionReply. That's the end result of the ready operation.
 813
 814             return combinedFutures.transform(new Mapper<Iterable<Object>, ActorSelection>() {
 815                 @Override
 816                 public ActorSelection checkedApply(Iterable<Object> notUsed) {
 817                     LOG.debug("Tx {} readyTransaction: pending recorded operations succeeded",
 818                             identifier);
 819
 820                     // At this point all the Futures succeeded and we need to extract the cohort
 821                     // actor path from the ReadyTransactionReply. For the recorded operations, they
 822                     // don't return any data so we're only interested that they completed
 823                     // successfully. We could be paranoid and verify the correct reply types but
 824                     // that really should never happen so it's not worth the overhead of
 825                     // de-serializing each reply.
 826
 827                     // Note the Future get call here won't block as it's complete.
 828                     Object serializedReadyReply = replyFuture.value().get().get();
 829                     if (serializedReadyReply instanceof ReadyTransactionReply) {
 830                         return actorContext.actorSelection(((ReadyTransactionReply)serializedReadyReply).getCohortPath());
 831
 832                     } else if(serializedReadyReply.getClass().equals(ReadyTransactionReply.SERIALIZABLE_CLASS)) {
 833                         ReadyTransactionReply reply = ReadyTransactionReply.fromSerializable(serializedReadyReply);
 834                         String cohortPath = reply.getCohortPath();
 835
 836                         // In Helium we used to return the local path of the actor which represented
 837                         // a remote ThreePhaseCommitCohort. The local path would then be converted to
 838                         // a remote path using this resolvePath method. To maintain compatibility with
 839                         // a Helium node we need to continue to do this conversion.
 840                         // At some point in the future when upgrades from Helium are not supported
 841                         // we could remove this code to resolvePath and just use the cohortPath as the
 842                         // resolved cohortPath
 843                         if(TransactionContextImpl.this.remoteTransactionVersion < CreateTransaction.HELIUM_1_VERSION) {
 844                             cohortPath = actorContext.resolvePath(transactionPath, cohortPath);
 845                         }
 846
 847                         return actorContext.actorSelection(cohortPath);
 848
 849                     } else {
 850                         // Throwing an exception here will fail the Future.
 851                         throw new IllegalArgumentException(String.format("Invalid reply type {}",
 852                                 serializedReadyReply.getClass()));
 853                     }
 854                 }
 855             }, SAME_FAILURE_TRANSFORMER, actorContext.getActorSystem().dispatcher());
 856         }
 857
 858         @Override
 859         public void deleteData(YangInstanceIdentifier path) {
 860             LOG.debug("Tx {} deleteData called path = {}", identifier, path);
 861
 862             DeleteData deleteData = new DeleteData(path);
 863             recordedOperationFutures.add(actorContext.executeOperationAsync(getActor(),
 864                 isTxActorLocal ? deleteData : deleteData.toSerializable()));
 865         }
 866
 867         @Override
 868         public void mergeData(YangInstanceIdentifier path, NormalizedNode<?, ?> data) {
 869             LOG.debug("Tx {} mergeData called path = {}", identifier, path);
 870
 871             MergeData mergeData = new MergeData(path, data, schemaContext);
 872             recordedOperationFutures.add(actorContext.executeOperationAsync(getActor(),
 873                 isTxActorLocal ? mergeData : mergeData.toSerializable()));
 874         }
 875
 876         @Override
 877         public void writeData(YangInstanceIdentifier path, NormalizedNode<?, ?> data) {
 878             LOG.debug("Tx {} writeData called path = {}", identifier, path);
 879
 880             WriteData writeData = new WriteData(path, data, schemaContext);
 881             recordedOperationFutures.add(actorContext.executeOperationAsync(getActor(),
 882                 isTxActorLocal ? writeData : writeData.toSerializable()));
 883         }
 884
 885         @Override
 886         public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> readData(
 887                 final YangInstanceIdentifier path) {
 888
 889             LOG.debug("Tx {} readData called path = {}", identifier, path);
 890
 891             final SettableFuture<Optional<NormalizedNode<?, ?>>> returnFuture = SettableFuture.create();
 892
 893             // If there were any previous recorded put/merge/delete operation reply Futures then we
 894             // must wait for them to successfully complete. This is necessary to honor the read
 895             // uncommitted semantics of the public API contract. If any one fails then fail the read.
 896
 897             if(recordedOperationFutures.isEmpty()) {
 898                 finishReadData(path, returnFuture);
 899             } else {
 900                 LOG.debug("Tx {} readData: verifying {} previous recorded operations",
 901                         identifier, recordedOperationFutures.size());
 902
 903                 // Note: we make a copy of recordedOperationFutures to be on the safe side in case
 904                 // Futures#sequence accesses the passed List on a different thread, as
 905                 // recordedOperationFutures is not synchronized.
 906
 907                 Future<Iterable<Object>> combinedFutures = akka.dispatch.Futures.sequence(
 908                         Lists.newArrayList(recordedOperationFutures),
 909                         actorContext.getActorSystem().dispatcher());
 910
 911                 OnComplete<Iterable<Object>> onComplete = new OnComplete<Iterable<Object>>() {
 912                     @Override
 913                     public void onComplete(Throwable failure, Iterable<Object> notUsed)
 914                             throws Throwable {
 915                         if(failure != null) {
 916                             LOG.debug("Tx {} readData: a recorded operation failed: {}",
 917                                     identifier, failure);
 918                             returnFuture.setException(new ReadFailedException(
 919                                     "The read could not be performed because a previous put, merge,"
 920                                     + "or delete operation failed", failure));
 921                         } else {
 922                             finishReadData(path, returnFuture);
 923                         }
 924                     }
 925                 };
 926
 927                 combinedFutures.onComplete(onComplete, actorContext.getActorSystem().dispatcher());
 928             }
 929
 930             return MappingCheckedFuture.create(returnFuture, ReadFailedException.MAPPER);
 931         }
 932
 933         private void finishReadData(final YangInstanceIdentifier path,
 934                 final SettableFuture<Optional<NormalizedNode<?, ?>>> returnFuture) {
 935
 936             LOG.debug("Tx {} finishReadData called path = {}", identifier, path);
 937
 938             OnComplete<Object> onComplete = new OnComplete<Object>() {
 939                 @Override
 940                 public void onComplete(Throwable failure, Object readResponse) throws Throwable {
 941                     if(failure != null) {
 942                         LOG.debug("Tx {} read operation failed: {}", identifier, failure);
 943                         returnFuture.setException(new ReadFailedException(
 944                                 "Error reading data for path " + path, failure));
 945
 946                     } else {
 947                         LOG.debug("Tx {} read operation succeeded", identifier, failure);
 948
 949                         if (readResponse instanceof ReadDataReply) {
 950                             ReadDataReply reply = (ReadDataReply) readResponse;
 951                             returnFuture.set(Optional.<NormalizedNode<?, ?>>fromNullable(reply.getNormalizedNode()));
 952
 953                         } else if (readResponse.getClass().equals(ReadDataReply.SERIALIZABLE_CLASS)) {
 954                             ReadDataReply reply = ReadDataReply.fromSerializable(schemaContext, path, readResponse);
 955                             returnFuture.set(Optional.<NormalizedNode<?, ?>>fromNullable(reply.getNormalizedNode()));
 956
 957                         } else {
 958                             returnFuture.setException(new ReadFailedException(
 959                                 "Invalid response reading data for path " + path));
 960                         }
 961                     }
 962                 }
 963             };
 964
 965             ReadData readData = new ReadData(path);
 966             Future<Object> readFuture = actorContext.executeOperationAsync(getActor(),
 967                 isTxActorLocal ? readData : readData.toSerializable());
 968
 969             readFuture.onComplete(onComplete, actorContext.getActorSystem().dispatcher());
 970         }
 971
 972         @Override
 973         public CheckedFuture<Boolean, ReadFailedException> dataExists(
 974                 final YangInstanceIdentifier path) {
 975
 976             LOG.debug("Tx {} dataExists called path = {}", identifier, path);
 977
 978             final SettableFuture<Boolean> returnFuture = SettableFuture.create();
 979
 980             // If there were any previous recorded put/merge/delete operation reply Futures then we
 981             // must wait for them to successfully complete. This is necessary to honor the read
 982             // uncommitted semantics of the public API contract. If any one fails then fail this
 983             // request.
 984
 985             if(recordedOperationFutures.isEmpty()) {
 986                 finishDataExists(path, returnFuture);
 987             } else {
 988                 LOG.debug("Tx {} dataExists: verifying {} previous recorded operations",
 989                         identifier, recordedOperationFutures.size());
 990
 991                 // Note: we make a copy of recordedOperationFutures to be on the safe side in case
 992                 // Futures#sequence accesses the passed List on a different thread, as
 993                 // recordedOperationFutures is not synchronized.
 994
 995                 Future<Iterable<Object>> combinedFutures = akka.dispatch.Futures.sequence(
 996                         Lists.newArrayList(recordedOperationFutures),
 997                         actorContext.getActorSystem().dispatcher());
 998                 OnComplete<Iterable<Object>> onComplete = new OnComplete<Iterable<Object>>() {
 999                     @Override
1000                     public void onComplete(Throwable failure, Iterable<Object> notUsed)
1001                             throws Throwable {
1002                         if(failure != null) {
1003                             LOG.debug("Tx {} dataExists: a recorded operation failed: {}",
1004                                     identifier, failure);
1005                             returnFuture.setException(new ReadFailedException(
1006                                     "The data exists could not be performed because a previous "
1007                                     + "put, merge, or delete operation failed", failure));
1008                         } else {
1009                             finishDataExists(path, returnFuture);
1010                         }
1011                     }
1012                 };
1013
1014                 combinedFutures.onComplete(onComplete, actorContext.getActorSystem().dispatcher());
1015             }
1016
1017             return MappingCheckedFuture.create(returnFuture, ReadFailedException.MAPPER);
1018         }
1019
1020         private void finishDataExists(final YangInstanceIdentifier path,
1021                 final SettableFuture<Boolean> returnFuture) {
1022
1023             LOG.debug("Tx {} finishDataExists called path = {}", identifier, path);
1024
1025             OnComplete<Object> onComplete = new OnComplete<Object>() {
1026                 @Override
1027                 public void onComplete(Throwable failure, Object response) throws Throwable {
1028                     if(failure != null) {
1029                         LOG.debug("Tx {} dataExists operation failed: {}", identifier, failure);
1030                         returnFuture.setException(new ReadFailedException(
1031                                 "Error checking data exists for path " + path, failure));
1032                     } else {
1033                         LOG.debug("Tx {} dataExists operation succeeded", identifier, failure);
1034
1035                         if (response instanceof DataExistsReply) {
1036                             returnFuture.set(Boolean.valueOf(((DataExistsReply) response).exists()));
1037
1038                         } else if (response.getClass().equals(DataExistsReply.SERIALIZABLE_CLASS)) {
1039                             returnFuture.set(Boolean.valueOf(DataExistsReply.fromSerializable(response).exists()));
1040
1041                         } else {
1042                             returnFuture.setException(new ReadFailedException(
1043                                     "Invalid response checking exists for path " + path));
1044                         }
1045                     }
1046                 }
1047             };
1048
1049             DataExists dataExists = new DataExists(path);
1050             Future<Object> future = actorContext.executeOperationAsync(getActor(),
1051                 isTxActorLocal ? dataExists : dataExists.toSerializable());
1052
1053             future.onComplete(onComplete, actorContext.getActorSystem().dispatcher());
1054         }
1055     }
1056
1057     private static class NoOpTransactionContext extends AbstractTransactionContext {
1058
1059         private final Logger LOG = LoggerFactory.getLogger(NoOpTransactionContext.class);
1060
1061         private final Throwable failure;
1062
1063         public NoOpTransactionContext(Throwable failure, TransactionIdentifier identifier){
1064             super(identifier);
1065             this.failure = failure;
1066         }
1067
1068         @Override
1069         public void closeTransaction() {
1070             LOG.debug("NoOpTransactionContext {} closeTransaction called", identifier);
1071         }
1072
1073         @Override
1074         public Future<ActorSelection> readyTransaction() {
1075             LOG.debug("Tx {} readyTransaction called", identifier);
1076             return akka.dispatch.Futures.failed(failure);
1077         }
1078
1079         @Override
1080         public void deleteData(YangInstanceIdentifier path) {
1081             LOG.debug("Tx {} deleteData called path = {}", identifier, path);
1082         }
1083
1084         @Override
1085         public void mergeData(YangInstanceIdentifier path, NormalizedNode<?, ?> data) {
1086             LOG.debug("Tx {} mergeData called path = {}", identifier, path);
1087         }
1088
1089         @Override
1090         public void writeData(YangInstanceIdentifier path, NormalizedNode<?, ?> data) {
1091             LOG.debug("Tx {} writeData called path = {}", identifier, path);
1092         }
1093
1094         @Override
1095         public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> readData(
1096                 YangInstanceIdentifier path) {
1097             LOG.debug("Tx {} readData called path = {}", identifier, path);
1098             return Futures.immediateFailedCheckedFuture(new ReadFailedException(
1099                     "Error reading data for path " + path, failure));
1100         }
1101
1102         @Override
1103         public CheckedFuture<Boolean, ReadFailedException> dataExists(
1104                 YangInstanceIdentifier path) {
1105             LOG.debug("Tx {} dataExists called path = {}", identifier, path);
1106             return Futures.immediateFailedCheckedFuture(new ReadFailedException(
1107                     "Error checking exists for path " + path, failure));
1108         }
1109     }
1110 }