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

   1 /*
   2  * Copyright (c) 2015 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 package org.opendaylight.controller.cluster.datastore;
   9
  10 import akka.actor.ActorRef;
  11 import akka.util.Timeout;
  12 import com.google.common.annotations.VisibleForTesting;
  13 import com.google.common.base.Optional;
  14 import com.google.common.base.Preconditions;
  15 import com.google.common.base.Stopwatch;
  16 import com.google.common.base.Verify;
  17 import com.google.common.collect.ImmutableList;
  18 import com.google.common.collect.ImmutableMap;
  19 import com.google.common.collect.ImmutableMap.Builder;
  20 import com.google.common.primitives.UnsignedLong;
  21 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  22 import java.io.File;
  23 import java.io.IOException;
  24 import java.util.AbstractMap.SimpleEntry;
  25 import java.util.ArrayDeque;
  26 import java.util.ArrayList;
  27 import java.util.Collection;
  28 import java.util.HashMap;
  29 import java.util.Iterator;
  30 import java.util.Map;
  31 import java.util.Map.Entry;
  32 import java.util.Queue;
  33 import java.util.concurrent.ExecutionException;
  34 import java.util.concurrent.TimeUnit;
  35 import java.util.concurrent.TimeoutException;
  36 import java.util.function.UnaryOperator;
  37 import javax.annotation.Nonnull;
  38 import javax.annotation.concurrent.NotThreadSafe;
  39 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  40 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  41 import org.opendaylight.controller.cluster.datastore.DataTreeCohortActorRegistry.CohortRegistryCommand;
  42 import org.opendaylight.controller.cluster.datastore.ShardDataTreeCohort.State;
  43 import org.opendaylight.controller.cluster.datastore.persisted.CommitTransactionPayload;
  44 import org.opendaylight.controller.cluster.datastore.persisted.MetadataShardDataTreeSnapshot;
  45 import org.opendaylight.controller.cluster.datastore.persisted.ShardDataTreeSnapshot;
  46 import org.opendaylight.controller.cluster.datastore.persisted.ShardDataTreeSnapshotMetadata;
  47 import org.opendaylight.controller.cluster.datastore.utils.DataTreeModificationOutput;
  48 import org.opendaylight.controller.cluster.datastore.utils.PruningDataTreeModification;
  49 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
  50 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker.DataChangeScope;
  51 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener;
  52 import org.opendaylight.controller.md.sal.common.api.data.OptimisticLockFailedException;
  53 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
  54 import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeListener;
  55 import org.opendaylight.controller.md.sal.dom.store.impl.DataChangeListenerRegistration;
  56 import org.opendaylight.yangtools.concepts.Identifier;
  57 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  58 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  59 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  60 import org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException;
  61 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  62 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidateTip;
  63 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidates;
  64 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
  65 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
  66 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  67 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  68 import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree;
  69 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
  70 import org.opendaylight.yangtools.yang.data.impl.schema.tree.InMemoryDataTreeFactory;
  71 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  72 import org.slf4j.Logger;
  73 import org.slf4j.LoggerFactory;
  74 import scala.concurrent.duration.Duration;
  75
  76 /**
  77  * Internal shard state, similar to a DOMStore, but optimized for use in the actor system,
  78  * e.g. it does not expose public interfaces and assumes it is only ever called from a
  79  * single thread.
  80  *
  81  * <p>
  82  * This class is not part of the API contract and is subject to change at any time.
  83  */
  84 @NotThreadSafe
  85 public class ShardDataTree extends ShardDataTreeTransactionParent {
  86     private static final class CommitEntry {
  87         final SimpleShardDataTreeCohort cohort;
  88         long lastAccess;
  89
  90         CommitEntry(final SimpleShardDataTreeCohort cohort, final long now) {
  91             this.cohort = Preconditions.checkNotNull(cohort);
  92             lastAccess = now;
  93         }
  94     }
  95
  96     private static final Timeout COMMIT_STEP_TIMEOUT = new Timeout(Duration.create(5, TimeUnit.SECONDS));
  97     private static final Logger LOG = LoggerFactory.getLogger(ShardDataTree.class);
  98
  99     private final Map<LocalHistoryIdentifier, ShardDataTreeTransactionChain> transactionChains = new HashMap<>();
 100     private final DataTreeCohortActorRegistry cohortRegistry = new DataTreeCohortActorRegistry();
 101     private final Queue<CommitEntry> pendingTransactions = new ArrayDeque<>();
 102     private final ShardDataTreeChangeListenerPublisher treeChangeListenerPublisher;
 103     private final ShardDataChangeListenerPublisher dataChangeListenerPublisher;
 104     private final Collection<ShardDataTreeMetadata<?>> metadata;
 105     private final TipProducingDataTree dataTree;
 106     private final String logContext;
 107     private final Shard shard;
 108     private Runnable runOnPendingTransactionsComplete;
 109
 110     private SchemaContext schemaContext;
 111
 112     public ShardDataTree(final Shard shard, final SchemaContext schemaContext, final TipProducingDataTree dataTree,
 113             final ShardDataTreeChangeListenerPublisher treeChangeListenerPublisher,
 114             final ShardDataChangeListenerPublisher dataChangeListenerPublisher, final String logContext,
 115             final ShardDataTreeMetadata<?>... metadata) {
 116         this.dataTree = Preconditions.checkNotNull(dataTree);
 117         updateSchemaContext(schemaContext);
 118
 119         this.shard = Preconditions.checkNotNull(shard);
 120         this.treeChangeListenerPublisher = Preconditions.checkNotNull(treeChangeListenerPublisher);
 121         this.dataChangeListenerPublisher = Preconditions.checkNotNull(dataChangeListenerPublisher);
 122         this.logContext = Preconditions.checkNotNull(logContext);
 123         this.metadata = ImmutableList.copyOf(metadata);
 124     }
 125
 126     public ShardDataTree(final Shard shard, final SchemaContext schemaContext, final TreeType treeType,
 127             final ShardDataTreeChangeListenerPublisher treeChangeListenerPublisher,
 128             final ShardDataChangeListenerPublisher dataChangeListenerPublisher, final String logContext) {
 129         this(shard, schemaContext, InMemoryDataTreeFactory.getInstance().create(treeType),
 130                 treeChangeListenerPublisher, dataChangeListenerPublisher, logContext);
 131     }
 132
 133     @VisibleForTesting
 134     public ShardDataTree(final Shard shard, final SchemaContext schemaContext, final TreeType treeType) {
 135         this(shard, schemaContext, treeType, new DefaultShardDataTreeChangeListenerPublisher(),
 136                 new DefaultShardDataChangeListenerPublisher(), "");
 137     }
 138
 139     String logContext() {
 140         return logContext;
 141     }
 142
 143     public TipProducingDataTree getDataTree() {
 144         return dataTree;
 145     }
 146
 147     SchemaContext getSchemaContext() {
 148         return schemaContext;
 149     }
 150
 151     void updateSchemaContext(final SchemaContext newSchemaContext) {
 152         dataTree.setSchemaContext(newSchemaContext);
 153         this.schemaContext = Preconditions.checkNotNull(newSchemaContext);
 154     }
 155
 156     /**
 157      * Take a snapshot of current state for later recovery.
 158      *
 159      * @return A state snapshot
 160      */
 161     @Nonnull ShardDataTreeSnapshot takeStateSnapshot() {
 162         final NormalizedNode<?, ?> rootNode = dataTree.takeSnapshot().readNode(YangInstanceIdentifier.EMPTY).get();
 163         final Builder<Class<? extends ShardDataTreeSnapshotMetadata<?>>, ShardDataTreeSnapshotMetadata<?>> metaBuilder =
 164                 ImmutableMap.builder();
 165
 166         for (ShardDataTreeMetadata<?> m : metadata) {
 167             final ShardDataTreeSnapshotMetadata<?> meta = m.toSnapshot();
 168             if (meta != null) {
 169                 metaBuilder.put(meta.getType(), meta);
 170             }
 171         }
 172
 173         return new MetadataShardDataTreeSnapshot(rootNode, metaBuilder.build());
 174     }
 175
 176     private void applySnapshot(@Nonnull final ShardDataTreeSnapshot snapshot,
 177             final UnaryOperator<DataTreeModification> wrapper) throws DataValidationFailedException {
 178         final Stopwatch elapsed = Stopwatch.createStarted();
 179
 180         if (!pendingTransactions.isEmpty()) {
 181             LOG.warn("{}: applying state snapshot with pending transactions", logContext);
 182         }
 183
 184         final Map<Class<? extends ShardDataTreeSnapshotMetadata<?>>, ShardDataTreeSnapshotMetadata<?>> snapshotMeta;
 185         if (snapshot instanceof MetadataShardDataTreeSnapshot) {
 186             snapshotMeta = ((MetadataShardDataTreeSnapshot) snapshot).getMetadata();
 187         } else {
 188             snapshotMeta = ImmutableMap.of();
 189         }
 190
 191         for (ShardDataTreeMetadata<?> m : metadata) {
 192             final ShardDataTreeSnapshotMetadata<?> s = snapshotMeta.get(m.getSupportedType());
 193             if (s != null) {
 194                 m.applySnapshot(s);
 195             } else {
 196                 m.reset();
 197             }
 198         }
 199
 200         final DataTreeModification mod = wrapper.apply(dataTree.takeSnapshot().newModification());
 201         // delete everything first
 202         mod.delete(YangInstanceIdentifier.EMPTY);
 203
 204         final java.util.Optional<NormalizedNode<?, ?>> maybeNode = snapshot.getRootNode();
 205         if (maybeNode.isPresent()) {
 206             // Add everything from the remote node back
 207             mod.write(YangInstanceIdentifier.EMPTY, maybeNode.get());
 208         }
 209         mod.ready();
 210
 211         final DataTreeModification unwrapped = unwrap(mod);
 212         dataTree.validate(unwrapped);
 213         DataTreeCandidateTip candidate = dataTree.prepare(unwrapped);
 214         dataTree.commit(candidate);
 215         notifyListeners(candidate);
 216
 217         LOG.debug("{}: state snapshot applied in %s", logContext, elapsed);
 218     }
 219
 220     /**
 221      * Apply a snapshot coming from the leader. This method assumes the leader and follower SchemaContexts match and
 222      * does not perform any pruning.
 223      *
 224      * @param snapshot Snapshot that needs to be applied
 225      * @throws DataValidationFailedException when the snapshot fails to apply
 226      */
 227     void applySnapshot(@Nonnull final ShardDataTreeSnapshot snapshot) throws DataValidationFailedException {
 228         applySnapshot(snapshot, UnaryOperator.identity());
 229     }
 230
 231     private PruningDataTreeModification wrapWithPruning(final DataTreeModification delegate) {
 232         return new PruningDataTreeModification(delegate, dataTree, schemaContext);
 233     }
 234
 235     private static DataTreeModification unwrap(final DataTreeModification modification) {
 236         if (modification instanceof PruningDataTreeModification) {
 237             return ((PruningDataTreeModification)modification).delegate();
 238         }
 239         return modification;
 240     }
 241
 242     /**
 243      * Apply a snapshot coming from recovery. This method does not assume the SchemaContexts match and performs data
 244      * pruning in an attempt to adjust the state to our current SchemaContext.
 245      *
 246      * @param snapshot Snapshot that needs to be applied
 247      * @throws DataValidationFailedException when the snapshot fails to apply
 248      */
 249     void applyRecoverySnapshot(final @Nonnull ShardDataTreeSnapshot snapshot) throws DataValidationFailedException {
 250         applySnapshot(snapshot, this::wrapWithPruning);
 251     }
 252
 253     @SuppressWarnings("checkstyle:IllegalCatch")
 254     private void applyRecoveryCandidate(final DataTreeCandidate candidate) throws DataValidationFailedException {
 255         final PruningDataTreeModification mod = wrapWithPruning(dataTree.takeSnapshot().newModification());
 256         DataTreeCandidates.applyToModification(mod, candidate);
 257         mod.ready();
 258
 259         final DataTreeModification unwrapped = mod.delegate();
 260         LOG.trace("{}: Applying recovery modification {}", logContext, unwrapped);
 261
 262         try {
 263             dataTree.validate(unwrapped);
 264             dataTree.commit(dataTree.prepare(unwrapped));
 265         } catch (Exception e) {
 266             File file = new File(System.getProperty("karaf.data", "."),
 267                     "failed-recovery-payload-" + logContext + ".out");
 268             DataTreeModificationOutput.toFile(file, unwrapped);
 269             throw new IllegalStateException(String.format(
 270                     "%s: Failed to apply recovery payload. Modification data was written to file %s",
 271                     logContext, file), e);
 272         }
 273     }
 274
 275     /**
 276      * Apply a payload coming from recovery. This method does not assume the SchemaContexts match and performs data
 277      * pruning in an attempt to adjust the state to our current SchemaContext.
 278      *
 279      * @param payload Payload
 280      * @throws IOException when the snapshot fails to deserialize
 281      * @throws DataValidationFailedException when the snapshot fails to apply
 282      */
 283     void applyRecoveryPayload(final @Nonnull Payload payload) throws IOException, DataValidationFailedException {
 284         if (payload instanceof CommitTransactionPayload) {
 285             final Entry<TransactionIdentifier, DataTreeCandidate> e =
 286                     ((CommitTransactionPayload) payload).getCandidate();
 287             applyRecoveryCandidate(e.getValue());
 288             allMetadataCommittedTransaction(e.getKey());
 289         } else if (payload instanceof DataTreeCandidatePayload) {
 290             applyRecoveryCandidate(((DataTreeCandidatePayload) payload).getCandidate());
 291         } else {
 292             LOG.debug("{}: ignoring unhandled payload {}", logContext, payload);
 293         }
 294     }
 295
 296     private void applyReplicatedCandidate(final Identifier identifier, final DataTreeCandidate foreign)
 297             throws DataValidationFailedException {
 298         LOG.debug("{}: Applying foreign transaction {}", logContext, identifier);
 299
 300         final DataTreeModification mod = dataTree.takeSnapshot().newModification();
 301         DataTreeCandidates.applyToModification(mod, foreign);
 302         mod.ready();
 303
 304         LOG.trace("{}: Applying foreign modification {}", logContext, mod);
 305         dataTree.validate(mod);
 306         final DataTreeCandidate candidate = dataTree.prepare(mod);
 307         dataTree.commit(candidate);
 308
 309         notifyListeners(candidate);
 310     }
 311
 312     /**
 313      * Apply a payload coming from the leader, which could actually be us. This method assumes the leader and follower
 314      * SchemaContexts match and does not perform any pruning.
 315      *
 316      * @param identifier Payload identifier as returned from RaftActor
 317      * @param payload Payload
 318      * @throws IOException when the snapshot fails to deserialize
 319      * @throws DataValidationFailedException when the snapshot fails to apply
 320      */
 321     void applyReplicatedPayload(final Identifier identifier, final Payload payload) throws IOException,
 322             DataValidationFailedException {
 323         /*
 324          * This is a bit more involved than it needs to be due to to the fact we do not want to be touching the payload
 325          * if we are the leader and it has originated with us.
 326          *
 327          * The identifier will only ever be non-null when we were the leader which achieved consensus. Unfortunately,
 328          * though, this may not be the case anymore, as we are being called some time afterwards and we may not be
 329          * acting in that capacity anymore.
 330          *
 331          * In any case, we know that this is an entry coming from replication, hence we can be sure we will not observe
 332          * pre-Boron state -- which limits the number of options here.
 333          */
 334         if (payload instanceof CommitTransactionPayload) {
 335             if (identifier == null) {
 336                 final Entry<TransactionIdentifier, DataTreeCandidate> e =
 337                         ((CommitTransactionPayload) payload).getCandidate();
 338                 applyReplicatedCandidate(e.getKey(), e.getValue());
 339                 allMetadataCommittedTransaction(e.getKey());
 340             } else {
 341                 Verify.verify(identifier instanceof TransactionIdentifier);
 342                 payloadReplicationComplete((TransactionIdentifier) identifier);
 343             }
 344         } else {
 345             LOG.warn("{}: ignoring unhandled identifier {} payload {}", logContext, identifier, payload);
 346         }
 347     }
 348
 349     private void payloadReplicationComplete(final TransactionIdentifier txId) {
 350         final CommitEntry current = pendingTransactions.peek();
 351         if (current == null) {
 352             LOG.warn("{}: No outstanding transactions, ignoring consensus on transaction {}", logContext, txId);
 353             return;
 354         }
 355
 356         if (!current.cohort.getIdentifier().equals(txId)) {
 357             LOG.warn("{}: Head of queue is {}, ignoring consensus on transaction {}", logContext,
 358                 current.cohort.getIdentifier(), txId);
 359             return;
 360         }
 361
 362         finishCommit(current.cohort);
 363     }
 364
 365     private void allMetadataCommittedTransaction(final TransactionIdentifier txId) {
 366         for (ShardDataTreeMetadata<?> m : metadata) {
 367             m.onTransactionCommitted(txId);
 368         }
 369     }
 370
 371     ShardDataTreeTransactionChain ensureTransactionChain(final LocalHistoryIdentifier localHistoryIdentifier) {
 372         ShardDataTreeTransactionChain chain = transactionChains.get(localHistoryIdentifier);
 373         if (chain == null) {
 374             chain = new ShardDataTreeTransactionChain(localHistoryIdentifier, this);
 375             transactionChains.put(localHistoryIdentifier, chain);
 376         }
 377
 378         return chain;
 379     }
 380
 381     ReadOnlyShardDataTreeTransaction newReadOnlyTransaction(final TransactionIdentifier txId) {
 382         if (txId.getHistoryId().getHistoryId() == 0) {
 383             return new ReadOnlyShardDataTreeTransaction(txId, dataTree.takeSnapshot());
 384         }
 385
 386         return ensureTransactionChain(txId.getHistoryId()).newReadOnlyTransaction(txId);
 387     }
 388
 389     ReadWriteShardDataTreeTransaction newReadWriteTransaction(final TransactionIdentifier txId) {
 390         if (txId.getHistoryId().getHistoryId() == 0) {
 391             return new ReadWriteShardDataTreeTransaction(ShardDataTree.this, txId, dataTree.takeSnapshot()
 392                     .newModification());
 393         }
 394
 395         return ensureTransactionChain(txId.getHistoryId()).newReadWriteTransaction(txId);
 396     }
 397
 398     @VisibleForTesting
 399     public void notifyListeners(final DataTreeCandidate candidate) {
 400         treeChangeListenerPublisher.publishChanges(candidate, logContext);
 401         dataChangeListenerPublisher.publishChanges(candidate, logContext);
 402     }
 403
 404     void notifyOfInitialData(final DataChangeListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
 405             NormalizedNode<?, ?>>> listenerReg, final Optional<DataTreeCandidate> currentState) {
 406         if (currentState.isPresent()) {
 407             ShardDataChangeListenerPublisher localPublisher = dataChangeListenerPublisher.newInstance();
 408             localPublisher.registerDataChangeListener(listenerReg.getPath(), listenerReg.getInstance(),
 409                     listenerReg.getScope());
 410             localPublisher.publishChanges(currentState.get(), logContext);
 411         }
 412     }
 413
 414     void notifyOfInitialData(final YangInstanceIdentifier path, final DOMDataTreeChangeListener listener,
 415             final Optional<DataTreeCandidate> currentState) {
 416         if (currentState.isPresent()) {
 417             ShardDataTreeChangeListenerPublisher localPublisher = treeChangeListenerPublisher.newInstance();
 418             localPublisher.registerTreeChangeListener(path, listener);
 419             localPublisher.publishChanges(currentState.get(), logContext);
 420         }
 421     }
 422
 423     void closeAllTransactionChains() {
 424         for (ShardDataTreeTransactionChain chain : transactionChains.values()) {
 425             chain.close();
 426         }
 427
 428         transactionChains.clear();
 429     }
 430
 431     void closeTransactionChain(final LocalHistoryIdentifier transactionChainId) {
 432         final ShardDataTreeTransactionChain chain = transactionChains.remove(transactionChainId);
 433         if (chain != null) {
 434             chain.close();
 435         } else {
 436             LOG.debug("{}: Closing non-existent transaction chain {}", logContext, transactionChainId);
 437         }
 438     }
 439
 440     Entry<DataChangeListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>,
 441             Optional<DataTreeCandidate>> registerChangeListener(final YangInstanceIdentifier path,
 442                     final AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>> listener,
 443                     final DataChangeScope scope) {
 444         DataChangeListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>> reg =
 445                 dataChangeListenerPublisher.registerDataChangeListener(path, listener, scope);
 446
 447         return new SimpleEntry<>(reg, readCurrentData());
 448     }
 449
 450     private Optional<DataTreeCandidate> readCurrentData() {
 451         final Optional<NormalizedNode<?, ?>> currentState =
 452                 dataTree.takeSnapshot().readNode(YangInstanceIdentifier.EMPTY);
 453         return currentState.isPresent() ? Optional.of(DataTreeCandidates.fromNormalizedNode(
 454             YangInstanceIdentifier.EMPTY, currentState.get())) : Optional.<DataTreeCandidate>absent();
 455     }
 456
 457     public Entry<ListenerRegistration<DOMDataTreeChangeListener>, Optional<DataTreeCandidate>>
 458             registerTreeChangeListener(final YangInstanceIdentifier path, final DOMDataTreeChangeListener listener) {
 459         final ListenerRegistration<DOMDataTreeChangeListener> reg =
 460                 treeChangeListenerPublisher.registerTreeChangeListener(path, listener);
 461
 462         return new SimpleEntry<>(reg, readCurrentData());
 463     }
 464
 465     int getQueueSize() {
 466         return pendingTransactions.size();
 467     }
 468
 469     @Override
 470     void abortTransaction(final AbstractShardDataTreeTransaction<?> transaction) {
 471         // Intentional no-op
 472     }
 473
 474     @Override
 475     ShardDataTreeCohort finishTransaction(final ReadWriteShardDataTreeTransaction transaction) {
 476         final DataTreeModification snapshot = transaction.getSnapshot();
 477         snapshot.ready();
 478
 479         return createReadyCohort(transaction.getIdentifier(), snapshot);
 480     }
 481
 482     public Optional<NormalizedNode<?, ?>> readNode(final YangInstanceIdentifier path) {
 483         return dataTree.takeSnapshot().readNode(path);
 484     }
 485
 486     DataTreeSnapshot takeSnapshot() {
 487         return dataTree.takeSnapshot();
 488     }
 489
 490     @VisibleForTesting
 491     public DataTreeModification newModification() {
 492         return dataTree.takeSnapshot().newModification();
 493     }
 494
 495     /**
 496      * Commits a modification.
 497      *
 498      * @deprecated This method violates DataTree containment and will be removed.
 499      */
 500     @VisibleForTesting
 501     @Deprecated
 502     public DataTreeCandidate commit(final DataTreeModification modification) throws DataValidationFailedException {
 503         modification.ready();
 504         dataTree.validate(modification);
 505         DataTreeCandidate candidate = dataTree.prepare(modification);
 506         dataTree.commit(candidate);
 507         return candidate;
 508     }
 509
 510     public Collection<ShardDataTreeCohort> getAndClearPendingTransactions() {
 511         Collection<ShardDataTreeCohort> ret = new ArrayList<>(pendingTransactions.size());
 512         for (CommitEntry entry: pendingTransactions) {
 513             ret.add(entry.cohort);
 514         }
 515
 516         pendingTransactions.clear();
 517         return ret;
 518     }
 519
 520     @SuppressWarnings("checkstyle:IllegalCatch")
 521     private void processNextTransaction() {
 522         while (!pendingTransactions.isEmpty()) {
 523             final CommitEntry entry = pendingTransactions.peek();
 524             final SimpleShardDataTreeCohort cohort = entry.cohort;
 525             final DataTreeModification modification = cohort.getDataTreeModification();
 526
 527             if (cohort.getState() != State.CAN_COMMIT_PENDING) {
 528                 break;
 529             }
 530
 531             LOG.debug("{}: Validating transaction {}", logContext, cohort.getIdentifier());
 532             Exception cause;
 533             try {
 534                 dataTree.validate(modification);
 535                 LOG.debug("{}: Transaction {} validated", logContext, cohort.getIdentifier());
 536                 cohort.successfulCanCommit();
 537                 entry.lastAccess = shard.ticker().read();
 538                 return;
 539             } catch (ConflictingModificationAppliedException e) {
 540                 LOG.warn("{}: Store Tx {}: Conflicting modification for path {}.", logContext, cohort.getIdentifier(),
 541                     e.getPath());
 542                 cause = new OptimisticLockFailedException("Optimistic lock failed.", e);
 543             } catch (DataValidationFailedException e) {
 544                 LOG.warn("{}: Store Tx {}: Data validation failed for path {}.", logContext, cohort.getIdentifier(),
 545                     e.getPath(), e);
 546
 547                 // For debugging purposes, allow dumping of the modification. Coupled with the above
 548                 // precondition log, it should allow us to understand what went on.
 549                 LOG.debug("{}: Store Tx {}: modifications: {} tree: {}", cohort.getIdentifier(), modification,
 550                         dataTree);
 551                 cause = new TransactionCommitFailedException("Data did not pass validation.", e);
 552             } catch (Exception e) {
 553                 LOG.warn("{}: Unexpected failure in validation phase", logContext, e);
 554                 cause = e;
 555             }
 556
 557             // Failure path: propagate the failure, remove the transaction from the queue and loop to the next one
 558             pendingTransactions.poll().cohort.failedCanCommit(cause);
 559         }
 560
 561         maybeRunOperationOnPendingTransactionsComplete();
 562     }
 563
 564     void startCanCommit(final SimpleShardDataTreeCohort cohort) {
 565         final SimpleShardDataTreeCohort current = pendingTransactions.peek().cohort;
 566         if (!cohort.equals(current)) {
 567             LOG.debug("{}: Transaction {} scheduled for canCommit step", logContext, cohort.getIdentifier());
 568             return;
 569         }
 570
 571         processNextTransaction();
 572     }
 573
 574     private void failPreCommit(final Exception cause) {
 575         shard.getShardMBean().incrementFailedTransactionsCount();
 576         pendingTransactions.poll().cohort.failedPreCommit(cause);
 577         processNextTransaction();
 578     }
 579
 580     @SuppressWarnings("checkstyle:IllegalCatch")
 581     void startPreCommit(final SimpleShardDataTreeCohort cohort) {
 582         final CommitEntry entry = pendingTransactions.peek();
 583         Preconditions.checkState(entry != null, "Attempted to pre-commit of %s when no transactions pending", cohort);
 584
 585         final SimpleShardDataTreeCohort current = entry.cohort;
 586         Verify.verify(cohort.equals(current), "Attempted to pre-commit %s while %s is pending", cohort, current);
 587         final DataTreeCandidateTip candidate;
 588         try {
 589             candidate = dataTree.prepare(cohort.getDataTreeModification());
 590         } catch (Exception e) {
 591             failPreCommit(e);
 592             return;
 593         }
 594
 595         try {
 596             cohort.userPreCommit(candidate);
 597         } catch (ExecutionException | TimeoutException e) {
 598             failPreCommit(e);
 599             return;
 600         }
 601
 602         entry.lastAccess = shard.ticker().read();
 603         cohort.successfulPreCommit(candidate);
 604     }
 605
 606     private void failCommit(final Exception cause) {
 607         shard.getShardMBean().incrementFailedTransactionsCount();
 608         pendingTransactions.poll().cohort.failedCommit(cause);
 609         processNextTransaction();
 610     }
 611
 612     @SuppressWarnings("checkstyle:IllegalCatch")
 613     private void finishCommit(final SimpleShardDataTreeCohort cohort) {
 614         final TransactionIdentifier txId = cohort.getIdentifier();
 615         final DataTreeCandidate candidate = cohort.getCandidate();
 616
 617         LOG.debug("{}: Resuming commit of transaction {}", logContext, txId);
 618
 619         try {
 620             dataTree.commit(candidate);
 621         } catch (Exception e) {
 622             LOG.error("{}: Failed to commit transaction {}", logContext, txId, e);
 623             failCommit(e);
 624             return;
 625         }
 626
 627         shard.getShardMBean().incrementCommittedTransactionCount();
 628         shard.getShardMBean().setLastCommittedTransactionTime(System.currentTimeMillis());
 629
 630         // FIXME: propagate journal index
 631         pendingTransactions.poll().cohort.successfulCommit(UnsignedLong.ZERO);
 632
 633         LOG.trace("{}: Transaction {} committed, proceeding to notify", logContext, txId);
 634         notifyListeners(candidate);
 635
 636         processNextTransaction();
 637     }
 638
 639     void startCommit(final SimpleShardDataTreeCohort cohort, final DataTreeCandidate candidate) {
 640         final CommitEntry entry = pendingTransactions.peek();
 641         Preconditions.checkState(entry != null, "Attempted to start commit of %s when no transactions pending", cohort);
 642
 643         final SimpleShardDataTreeCohort current = entry.cohort;
 644         Verify.verify(cohort.equals(current), "Attempted to commit %s while %s is pending", cohort, current);
 645
 646         if (shard.canSkipPayload() || candidate.getRootNode().getModificationType() == ModificationType.UNMODIFIED) {
 647             LOG.debug("{}: No replication required, proceeding to finish commit", logContext);
 648             finishCommit(cohort);
 649             return;
 650         }
 651
 652         final TransactionIdentifier txId = cohort.getIdentifier();
 653         final Payload payload;
 654         try {
 655             payload = CommitTransactionPayload.create(txId, candidate);
 656         } catch (IOException e) {
 657             LOG.error("{}: Failed to encode transaction {} candidate {}", logContext, txId, candidate, e);
 658             pendingTransactions.poll().cohort.failedCommit(e);
 659             return;
 660         }
 661
 662         // Once completed, we will continue via payloadReplicationComplete
 663         entry.lastAccess = shard.ticker().read();
 664         shard.persistPayload(txId, payload);
 665         LOG.debug("{}: Transaction {} submitted to persistence", logContext, txId);
 666     }
 667
 668     void processCohortRegistryCommand(final ActorRef sender, final CohortRegistryCommand message) {
 669         cohortRegistry.process(sender, message);
 670     }
 671
 672     @Override
 673     ShardDataTreeCohort createReadyCohort(final TransactionIdentifier txId,
 674             final DataTreeModification modification) {
 675         SimpleShardDataTreeCohort cohort = new SimpleShardDataTreeCohort(this, modification, txId,
 676                 cohortRegistry.createCohort(schemaContext, txId, COMMIT_STEP_TIMEOUT));
 677         pendingTransactions.add(new CommitEntry(cohort, shard.ticker().read()));
 678         return cohort;
 679     }
 680
 681     @SuppressFBWarnings(value = {"RV_RETURN_VALUE_IGNORED", "DB_DUPLICATE_SWITCH_CLAUSES"},
 682             justification = "See inline comments below.")
 683     void checkForExpiredTransactions(final long transactionCommitTimeoutMillis) {
 684         final long timeout = TimeUnit.MILLISECONDS.toNanos(transactionCommitTimeoutMillis);
 685         final long now = shard.ticker().read();
 686         final CommitEntry currentTx = pendingTransactions.peek();
 687         if (currentTx != null && currentTx.lastAccess + timeout < now) {
 688             LOG.warn("{}: Current transaction {} has timed out after {} ms in state {}", logContext,
 689                     currentTx.cohort.getIdentifier(), transactionCommitTimeoutMillis, currentTx.cohort.getState());
 690             boolean processNext = true;
 691             switch (currentTx.cohort.getState()) {
 692                 case CAN_COMMIT_PENDING:
 693                     pendingTransactions.poll().cohort.failedCanCommit(new TimeoutException());
 694                     break;
 695                 case CAN_COMMIT_COMPLETE:
 696                     // The suppression of the FindBugs "DB_DUPLICATE_SWITCH_CLAUSES" warning pertains to this clause
 697                     // whose code is duplicated with PRE_COMMIT_COMPLETE. The clauses aren't combined in case the code
 698                     // in PRE_COMMIT_COMPLETE is changed.
 699                     pendingTransactions.poll().cohort.reportFailure(new TimeoutException());
 700                     break;
 701                 case PRE_COMMIT_PENDING:
 702                     pendingTransactions.poll().cohort.failedPreCommit(new TimeoutException());
 703                     break;
 704                 case PRE_COMMIT_COMPLETE:
 705                     // FIXME: this is a legacy behavior problem. Three-phase commit protocol specifies that after we
 706                     //        are ready we should commit the transaction, not abort it. Our current software stack does
 707                     //        not allow us to do that consistently, because we persist at the time of commit, hence
 708                     //        we can end up in a state where we have pre-committed a transaction, then a leader failover
 709                     //        occurred ... the new leader does not see the pre-committed transaction and does not have
 710                     //        a running timer. To fix this we really need two persistence events.
 711                     //
 712                     //        The first one, done at pre-commit time will hold the transaction payload. When consensus
 713                     //        is reached, we exit the pre-commit phase and start the pre-commit timer. Followers do not
 714                     //        apply the state in this event.
 715                     //
 716                     //        The second one, done at commit (or abort) time holds only the transaction identifier and
 717                     //        signals to followers that the state should (or should not) be applied.
 718                     //
 719                     //        In order to make the pre-commit timer working across failovers, though, we need
 720                     //        a per-shard cluster-wide monotonic time, so a follower becoming the leader can accurately
 721                     //        restart the timer.
 722                     pendingTransactions.poll().cohort.reportFailure(new TimeoutException());
 723                     break;
 724                 case COMMIT_PENDING:
 725                     LOG.warn("{}: Transaction {} is still committing, cannot abort", logContext,
 726                         currentTx.cohort.getIdentifier());
 727                     currentTx.lastAccess = now;
 728                     processNext = false;
 729                     return;
 730                 case ABORTED:
 731                 case COMMITTED:
 732                 case FAILED:
 733                 case READY:
 734                 default:
 735                     // The suppression of the FindBugs "RV_RETURN_VALUE_IGNORED" warning pertains to this line. In
 736                     // this case, we just want to drop the current entry that expired and thus ignore the return value.
 737                     // In fact we really shouldn't hit this case but we handle all enums for completeness.
 738                     pendingTransactions.poll();
 739             }
 740
 741             if (processNext) {
 742                 processNextTransaction();
 743             }
 744         }
 745     }
 746
 747     @SuppressFBWarnings(value = "RV_RETURN_VALUE_IGNORED", justification = "See inline comment below.")
 748     void startAbort(final SimpleShardDataTreeCohort cohort) {
 749         final Iterator<CommitEntry> it = pendingTransactions.iterator();
 750         if (!it.hasNext()) {
 751             LOG.debug("{}: no open transaction while attempting to abort {}", logContext, cohort.getIdentifier());
 752             return;
 753         }
 754
 755         // First entry is special, as it may already be committing
 756         final CommitEntry first = it.next();
 757         if (cohort.equals(first.cohort)) {
 758             if (cohort.getState() != State.COMMIT_PENDING) {
 759                 LOG.debug("{}: aborted head of queue {} in state {}", logContext, cohort.getIdentifier(),
 760                     cohort.getIdentifier());
 761
 762                 // The suppression of the FindBugs "RV_RETURN_VALUE_IGNORED" warning pertains to this line. In
 763                 // this case, we've already obtained the head of the queue above via the Iterator and we just want to
 764                 // remove it here.
 765                 pendingTransactions.poll();
 766                 processNextTransaction();
 767             } else {
 768                 LOG.warn("{}: transaction {} is committing, skipping abort", logContext, cohort.getIdentifier());
 769             }
 770
 771             return;
 772         }
 773
 774         while (it.hasNext()) {
 775             final CommitEntry e = it.next();
 776             if (cohort.equals(e.cohort)) {
 777                 LOG.debug("{}: aborting queued transaction {}", logContext, cohort.getIdentifier());
 778                 it.remove();
 779                 return;
 780             }
 781         }
 782
 783         LOG.debug("{}: aborted transaction {} not found in the queue", logContext, cohort.getIdentifier());
 784     }
 785
 786     void setRunOnPendingTransactionsComplete(final Runnable operation) {
 787         runOnPendingTransactionsComplete = operation;
 788         maybeRunOperationOnPendingTransactionsComplete();
 789     }
 790
 791     private void maybeRunOperationOnPendingTransactionsComplete() {
 792         if (runOnPendingTransactionsComplete != null && pendingTransactions.isEmpty()) {
 793             LOG.debug("{}: Pending transactions complete - running operation {}", logContext,
 794                     runOnPendingTransactionsComplete);
 795
 796             runOnPendingTransactionsComplete.run();
 797             runOnPendingTransactionsComplete = null;
 798         }
 799     }
 800 }