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

   1 /*
   2  * Copyright (c) 2014 Brocade Communications 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.databroker;
   9
  10 import static com.google.common.base.Preconditions.checkArgument;
  11 import static java.util.Objects.requireNonNull;
  12 import static org.opendaylight.mdsal.dom.broker.TransactionCommitFailedExceptionMapper.CAN_COMMIT_ERROR_MAPPER;
  13 import static org.opendaylight.mdsal.dom.broker.TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER;
  14 import static org.opendaylight.mdsal.dom.broker.TransactionCommitFailedExceptionMapper.PRE_COMMIT_MAPPER;
  15
  16 import com.google.common.annotations.Beta;
  17 import com.google.common.util.concurrent.AbstractFuture;
  18 import com.google.common.util.concurrent.FluentFuture;
  19 import com.google.common.util.concurrent.FutureCallback;
  20 import com.google.common.util.concurrent.Futures;
  21 import com.google.common.util.concurrent.ListenableFuture;
  22 import com.google.common.util.concurrent.MoreExecutors;
  23 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  24 import java.util.Collection;
  25 import java.util.Iterator;
  26 import java.util.List;
  27 import java.util.Map;
  28 import java.util.concurrent.Executor;
  29 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  30 import org.opendaylight.controller.cluster.datastore.exceptions.ShardLeaderNotRespondingException;
  31 import org.opendaylight.mdsal.common.api.CommitInfo;
  32 import org.opendaylight.mdsal.common.api.DataStoreUnavailableException;
  33 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  34 import org.opendaylight.mdsal.common.api.TransactionCommitFailedException;
  35 import org.opendaylight.mdsal.dom.api.DOMDataTreeWriteTransaction;
  36 import org.opendaylight.mdsal.dom.broker.TransactionCommitFailedExceptionMapper;
  37 import org.opendaylight.mdsal.dom.spi.store.DOMStore;
  38 import org.opendaylight.mdsal.dom.spi.store.DOMStoreThreePhaseCommitCohort;
  39 import org.opendaylight.yangtools.util.DurationStatisticsTracker;
  40 import org.opendaylight.yangtools.yang.common.Empty;
  41 import org.slf4j.Logger;
  42 import org.slf4j.LoggerFactory;
  43
  44 /**
  45  * ConcurrentDOMDataBroker commits transactions concurrently. The 3
  46  * commit phases (canCommit, preCommit, and commit) are performed serially and non-blocking
  47  * (ie async) per transaction but multiple transaction commits can run concurrent.
  48  *
  49  * @author Thomas Pantelis
  50  */
  51 @Beta
  52 public class ConcurrentDOMDataBroker extends AbstractDOMBroker {
  53     private static final Logger LOG = LoggerFactory.getLogger(ConcurrentDOMDataBroker.class);
  54     private static final String CAN_COMMIT = "CAN_COMMIT";
  55     private static final String PRE_COMMIT = "PRE_COMMIT";
  56     private static final String COMMIT = "COMMIT";
  57
  58     private final DurationStatisticsTracker commitStatsTracker;
  59
  60     /**
  61      * This executor is used to execute Future listener callback Runnables async.
  62      */
  63     private final Executor clientFutureCallbackExecutor;
  64
  65     public ConcurrentDOMDataBroker(final Map<LogicalDatastoreType, DOMStore> datastores,
  66             final Executor listenableFutureExecutor) {
  67         this(datastores, listenableFutureExecutor, DurationStatisticsTracker.createConcurrent());
  68     }
  69
  70     public ConcurrentDOMDataBroker(final Map<LogicalDatastoreType, DOMStore> datastores,
  71             final Executor listenableFutureExecutor, final DurationStatisticsTracker commitStatsTracker) {
  72         super(datastores);
  73         clientFutureCallbackExecutor = requireNonNull(listenableFutureExecutor);
  74         this.commitStatsTracker = requireNonNull(commitStatsTracker);
  75     }
  76
  77     public DurationStatisticsTracker getCommitStatsTracker() {
  78         return commitStatsTracker;
  79     }
  80
  81     @Override
  82     protected FluentFuture<? extends CommitInfo> commit(final DOMDataTreeWriteTransaction transaction,
  83             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
  84
  85         checkArgument(transaction != null, "Transaction must not be null.");
  86         checkArgument(cohorts != null, "Cohorts must not be null.");
  87         LOG.debug("Tx: {} is submitted for execution.", transaction.getIdentifier());
  88
  89         if (cohorts.isEmpty()) {
  90             return CommitInfo.emptyFluentFuture();
  91         }
  92
  93         final AsyncNotifyingSettableFuture clientSubmitFuture =
  94                 new AsyncNotifyingSettableFuture(clientFutureCallbackExecutor);
  95
  96         doCanCommit(clientSubmitFuture, transaction, cohorts);
  97
  98         return FluentFuture.from(clientSubmitFuture);
  99     }
 100
 101     private void doCanCommit(final AsyncNotifyingSettableFuture clientSubmitFuture,
 102             final DOMDataTreeWriteTransaction transaction,
 103             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 104
 105         final long startTime = System.nanoTime();
 106
 107         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 108
 109         // Not using Futures.allAsList here to avoid its internal overhead.
 110         FutureCallback<Boolean> futureCallback = new FutureCallback<>() {
 111             @Override
 112             public void onSuccess(final Boolean result) {
 113                 if (result == null || !result) {
 114                     handleException(clientSubmitFuture, transaction, cohorts, CAN_COMMIT, CAN_COMMIT_ERROR_MAPPER,
 115                             new TransactionCommitFailedException("Can Commit failed, no detailed cause available."));
 116                 } else if (!cohortIterator.hasNext()) {
 117                     // All cohorts completed successfully - we can move on to the preCommit phase
 118                     doPreCommit(startTime, clientSubmitFuture, transaction, cohorts);
 119                 } else {
 120                     Futures.addCallback(cohortIterator.next().canCommit(), this, MoreExecutors.directExecutor());
 121                 }
 122             }
 123
 124             @Override
 125             public void onFailure(final Throwable failure) {
 126                 handleException(clientSubmitFuture, transaction, cohorts, CAN_COMMIT, CAN_COMMIT_ERROR_MAPPER, failure);
 127             }
 128         };
 129
 130         Futures.addCallback(cohortIterator.next().canCommit(), futureCallback, MoreExecutors.directExecutor());
 131     }
 132
 133     private void doPreCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 134             final DOMDataTreeWriteTransaction transaction,
 135             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 136
 137         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 138
 139         // Not using Futures.allAsList here to avoid its internal overhead.
 140         FutureCallback<Empty> futureCallback = new FutureCallback<>() {
 141             @Override
 142             public void onSuccess(final Empty result) {
 143                 if (!cohortIterator.hasNext()) {
 144                     // All cohorts completed successfully - we can move on to the commit phase
 145                     doCommit(startTime, clientSubmitFuture, transaction, cohorts);
 146                 } else {
 147                     Futures.addCallback(cohortIterator.next().preCommit(), this, MoreExecutors.directExecutor());
 148                 }
 149             }
 150
 151             @Override
 152             public void onFailure(final Throwable failure) {
 153                 handleException(clientSubmitFuture, transaction, cohorts, PRE_COMMIT, PRE_COMMIT_MAPPER, failure);
 154             }
 155         };
 156
 157         Futures.addCallback(cohortIterator.next().preCommit(), futureCallback, MoreExecutors.directExecutor());
 158     }
 159
 160     private void doCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 161             final DOMDataTreeWriteTransaction transaction,
 162             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 163
 164         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 165
 166         // Not using Futures.allAsList here to avoid its internal overhead.
 167         final FutureCallback<CommitInfo> futureCallback = new FutureCallback<>() {
 168             @Override
 169             public void onSuccess(final CommitInfo result) {
 170                 if (!cohortIterator.hasNext()) {
 171                     // All cohorts completed successfully - we're done.
 172                     commitStatsTracker.addDuration(System.nanoTime() - startTime);
 173
 174                     clientSubmitFuture.set();
 175                 } else {
 176                     Futures.addCallback(cohortIterator.next().commit(), this, MoreExecutors.directExecutor());
 177                 }
 178             }
 179
 180             @Override
 181             public void onFailure(final Throwable throwable) {
 182                 handleException(clientSubmitFuture, transaction, cohorts, COMMIT, COMMIT_ERROR_MAPPER, throwable);
 183             }
 184         };
 185
 186         Futures.addCallback(cohortIterator.next().commit(), futureCallback, MoreExecutors.directExecutor());
 187     }
 188
 189     @SuppressFBWarnings(value = "BC_UNCONFIRMED_CAST_OF_RETURN_VALUE",
 190             justification = "Pertains to the assignment of the 'clientException' var. FindBugs flags this as an "
 191                 + "uncomfirmed cast but the generic type in TransactionCommitFailedExceptionMapper is "
 192                 + "TransactionCommitFailedException and thus should be deemed as confirmed.")
 193     private static void handleException(final AsyncNotifyingSettableFuture clientSubmitFuture,
 194             final DOMDataTreeWriteTransaction transaction,
 195             final Collection<DOMStoreThreePhaseCommitCohort> cohorts,
 196             final String phase, final TransactionCommitFailedExceptionMapper exMapper,
 197             final Throwable throwable) {
 198
 199         if (clientSubmitFuture.isDone()) {
 200             // We must have had failures from multiple cohorts.
 201             return;
 202         }
 203
 204         // Use debug instead of warn level here because this exception gets propagate back to the caller via the Future
 205         LOG.debug("Tx: {} Error during phase {}, starting Abort", transaction.getIdentifier(), phase, throwable);
 206
 207         // Transaction failed - tell all cohorts to abort.
 208         @SuppressWarnings("unchecked")
 209         ListenableFuture<Empty>[] canCommitFutures = new ListenableFuture[cohorts.size()];
 210         int index = 0;
 211         for (DOMStoreThreePhaseCommitCohort cohort : cohorts) {
 212             canCommitFutures[index++] = cohort.abort();
 213         }
 214
 215         // Propagate the original exception
 216         final Exception e;
 217         if (throwable instanceof NoShardLeaderException || throwable instanceof ShardLeaderNotRespondingException) {
 218             e = new DataStoreUnavailableException(throwable.getMessage(), throwable);
 219         } else if (throwable instanceof Exception) {
 220             e = (Exception)throwable;
 221         } else {
 222             e = new RuntimeException("Unexpected error occurred", throwable);
 223         }
 224         clientSubmitFuture.setException(exMapper.apply(e));
 225
 226         ListenableFuture<List<Empty>> combinedFuture = Futures.allAsList(canCommitFutures);
 227         Futures.addCallback(combinedFuture, new FutureCallback<List<Empty>>() {
 228             @Override
 229             public void onSuccess(final List<Empty> result) {
 230                 // Propagate the original exception to the client.
 231                 LOG.debug("Tx: {} aborted successfully", transaction.getIdentifier());
 232             }
 233
 234             @Override
 235             public void onFailure(final Throwable failure) {
 236                 LOG.error("Tx: {} Error during Abort.", transaction.getIdentifier(), failure);
 237             }
 238         }, MoreExecutors.directExecutor());
 239     }
 240
 241     /**
 242      * A settable future that uses an {@link Executor} to execute listener callback Runnables,
 243      * registered via {@link #addListener}, asynchronously when this future completes. This is
 244      * done to guarantee listener executions are off-loaded onto another thread to avoid blocking
 245      * the thread that completed this future, as a common use case is to pass an executor that runs
 246      * tasks in the same thread as the caller (ie MoreExecutors#sameThreadExecutor)
 247      * to {@link #addListener}.
 248      * FIXME: This class should probably be moved to yangtools common utils for re-usability and
 249      * unified with AsyncNotifyingListenableFutureTask.
 250      */
 251     private static class AsyncNotifyingSettableFuture extends AbstractFuture<CommitInfo> {
 252         /**
 253          * ThreadLocal used to detect if the task completion thread is running the future listener Runnables.
 254          */
 255         private static final ThreadLocal<Boolean> ON_TASK_COMPLETION_THREAD_TL = new ThreadLocal<>();
 256
 257         private final Executor listenerExecutor;
 258
 259         AsyncNotifyingSettableFuture(final Executor listenerExecutor) {
 260             this.listenerExecutor = requireNonNull(listenerExecutor);
 261         }
 262
 263         @Override
 264         public void addListener(final Runnable listener, final Executor executor) {
 265             // Wrap the listener Runnable in a DelegatingRunnable. If the specified executor is one
 266             // that runs tasks in the same thread as the caller submitting the task
 267             // (e.g. {@link com.google.common.util.concurrent.MoreExecutors#sameThreadExecutor}) and
 268             // the listener is executed from the #set methods, then the DelegatingRunnable will detect
 269             // this via the ThreadLocal and submit the listener Runnable to the listenerExecutor.
 270             //
 271             // On the other hand, if this task is already complete, the call to ExecutionList#add in
 272             // superclass will execute the listener Runnable immediately and, since the ThreadLocal
 273             // won't be set, the DelegatingRunnable will run the listener Runnable inline.
 274             super.addListener(new DelegatingRunnable(listener, listenerExecutor), executor);
 275         }
 276
 277         boolean set() {
 278             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 279             try {
 280                 return super.set(CommitInfo.empty());
 281             } finally {
 282                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 283             }
 284         }
 285
 286         @Override
 287         protected boolean setException(final Throwable throwable) {
 288             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 289             try {
 290                 return super.setException(throwable);
 291             } finally {
 292                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 293             }
 294         }
 295
 296         private static final class DelegatingRunnable implements Runnable {
 297             private final Runnable delegate;
 298             private final Executor executor;
 299
 300             DelegatingRunnable(final Runnable delegate, final Executor executor) {
 301                 this.delegate = requireNonNull(delegate);
 302                 this.executor = requireNonNull(executor);
 303             }
 304
 305             @Override
 306             public void run() {
 307                 if (ON_TASK_COMPLETION_THREAD_TL.get() != null) {
 308                     // We're running on the task completion thread so off-load to the executor.
 309                     LOG.trace("Submitting ListenenableFuture Runnable from thread {} to executor {}",
 310                             Thread.currentThread().getName(), executor);
 311                     executor.execute(delegate);
 312                 } else {
 313                     // We're not running on the task completion thread so run the delegate inline.
 314                     LOG.trace("Executing ListenenableFuture Runnable on this thread: {}",
 315                             Thread.currentThread().getName());
 316                     delegate.run();
 317                 }
 318             }
 319         }
 320     }
 321
 322     @Override
 323     public String toString() {
 324         return "Clustered ConcurrentDOMDataBroker";
 325     }
 326 }