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 org.opendaylight.mdsal.dom.broker.TransactionCommitFailedExceptionMapper.CAN_COMMIT_ERROR_MAPPER;
  11 import static org.opendaylight.mdsal.dom.broker.TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER;
  12 import static org.opendaylight.mdsal.dom.broker.TransactionCommitFailedExceptionMapper.PRE_COMMIT_MAPPER;
  13
  14 import com.google.common.annotations.Beta;
  15 import com.google.common.base.Preconditions;
  16 import com.google.common.util.concurrent.AbstractFuture;
  17 import com.google.common.util.concurrent.FluentFuture;
  18 import com.google.common.util.concurrent.FutureCallback;
  19 import com.google.common.util.concurrent.Futures;
  20 import com.google.common.util.concurrent.ListenableFuture;
  21 import com.google.common.util.concurrent.MoreExecutors;
  22 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  23 import java.util.Collection;
  24 import java.util.Iterator;
  25 import java.util.List;
  26 import java.util.Map;
  27 import java.util.concurrent.Executor;
  28 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  29 import org.opendaylight.controller.cluster.datastore.exceptions.ShardLeaderNotRespondingException;
  30 import org.opendaylight.mdsal.common.api.CommitInfo;
  31 import org.opendaylight.mdsal.common.api.DataStoreUnavailableException;
  32 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  33 import org.opendaylight.mdsal.common.api.TransactionCommitFailedException;
  34 import org.opendaylight.mdsal.dom.api.DOMDataTreeWriteTransaction;
  35 import org.opendaylight.mdsal.dom.broker.TransactionCommitFailedExceptionMapper;
  36 import org.opendaylight.mdsal.dom.spi.store.DOMStore;
  37 import org.opendaylight.mdsal.dom.spi.store.DOMStoreThreePhaseCommitCohort;
  38 import org.opendaylight.yangtools.util.DurationStatisticsTracker;
  39 import org.slf4j.Logger;
  40 import org.slf4j.LoggerFactory;
  41
  42 /**
  43  * ConcurrentDOMDataBroker commits transactions concurrently. The 3
  44  * commit phases (canCommit, preCommit, and commit) are performed serially and non-blocking
  45  * (ie async) per transaction but multiple transaction commits can run concurrent.
  46  *
  47  * @author Thomas Pantelis
  48  */
  49 @Beta
  50 public class ConcurrentDOMDataBroker extends AbstractDOMBroker {
  51     private static final Logger LOG = LoggerFactory.getLogger(ConcurrentDOMDataBroker.class);
  52     private static final String CAN_COMMIT = "CAN_COMMIT";
  53     private static final String PRE_COMMIT = "PRE_COMMIT";
  54     private static final String COMMIT = "COMMIT";
  55
  56     private final DurationStatisticsTracker commitStatsTracker;
  57
  58     /**
  59      * This executor is used to execute Future listener callback Runnables async.
  60      */
  61     private final Executor clientFutureCallbackExecutor;
  62
  63     public ConcurrentDOMDataBroker(final Map<LogicalDatastoreType, DOMStore> datastores,
  64             final Executor listenableFutureExecutor) {
  65         this(datastores, listenableFutureExecutor, DurationStatisticsTracker.createConcurrent());
  66     }
  67
  68     public ConcurrentDOMDataBroker(final Map<LogicalDatastoreType, DOMStore> datastores,
  69             final Executor listenableFutureExecutor, final DurationStatisticsTracker commitStatsTracker) {
  70         super(datastores);
  71         this.clientFutureCallbackExecutor = Preconditions.checkNotNull(listenableFutureExecutor);
  72         this.commitStatsTracker = Preconditions.checkNotNull(commitStatsTracker);
  73     }
  74
  75     public DurationStatisticsTracker getCommitStatsTracker() {
  76         return commitStatsTracker;
  77     }
  78
  79     @Override
  80     protected FluentFuture<? extends CommitInfo> commit(
  81             final DOMDataTreeWriteTransaction transaction, final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
  82
  83         Preconditions.checkArgument(transaction != null, "Transaction must not be null.");
  84         Preconditions.checkArgument(cohorts != null, "Cohorts must not be null.");
  85         LOG.debug("Tx: {} is submitted for execution.", transaction.getIdentifier());
  86
  87         if (cohorts.isEmpty()) {
  88             return CommitInfo.emptyFluentFuture();
  89         }
  90
  91         final AsyncNotifyingSettableFuture clientSubmitFuture =
  92                 new AsyncNotifyingSettableFuture(clientFutureCallbackExecutor);
  93
  94         doCanCommit(clientSubmitFuture, transaction, cohorts);
  95
  96         return FluentFuture.from(clientSubmitFuture).transform(ignored -> CommitInfo.empty(),
  97                 MoreExecutors.directExecutor());
  98     }
  99
 100     private void doCanCommit(final AsyncNotifyingSettableFuture clientSubmitFuture,
 101             final DOMDataTreeWriteTransaction transaction,
 102             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 103
 104         final long startTime = System.nanoTime();
 105
 106         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 107
 108         // Not using Futures.allAsList here to avoid its internal overhead.
 109         FutureCallback<Boolean> futureCallback = new FutureCallback<Boolean>() {
 110             @Override
 111             public void onSuccess(final Boolean result) {
 112                 if (result == null || !result) {
 113                     handleException(clientSubmitFuture, transaction, cohorts, CAN_COMMIT, CAN_COMMIT_ERROR_MAPPER,
 114                             new TransactionCommitFailedException("Can Commit failed, no detailed cause available."));
 115                 } else if (!cohortIterator.hasNext()) {
 116                     // All cohorts completed successfully - we can move on to the preCommit phase
 117                     doPreCommit(startTime, clientSubmitFuture, transaction, cohorts);
 118                 } else {
 119                     Futures.addCallback(cohortIterator.next().canCommit(), this, MoreExecutors.directExecutor());
 120                 }
 121             }
 122
 123             @Override
 124             public void onFailure(final Throwable failure) {
 125                 handleException(clientSubmitFuture, transaction, cohorts, CAN_COMMIT, CAN_COMMIT_ERROR_MAPPER, failure);
 126             }
 127         };
 128
 129         ListenableFuture<Boolean> canCommitFuture = cohortIterator.next().canCommit();
 130         Futures.addCallback(canCommitFuture, 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<Void> futureCallback = new FutureCallback<Void>() {
 141             @Override
 142             public void onSuccess(final Void notUsed) {
 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                     ListenableFuture<Void> preCommitFuture = cohortIterator.next().preCommit();
 148                     Futures.addCallback(preCommitFuture, this, MoreExecutors.directExecutor());
 149                 }
 150             }
 151
 152             @Override
 153             public void onFailure(final Throwable failure) {
 154                 handleException(clientSubmitFuture, transaction, cohorts, PRE_COMMIT, PRE_COMMIT_MAPPER, failure);
 155             }
 156         };
 157
 158         ListenableFuture<Void> preCommitFuture = cohortIterator.next().preCommit();
 159         Futures.addCallback(preCommitFuture, futureCallback, MoreExecutors.directExecutor());
 160     }
 161
 162     private void doCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 163             final DOMDataTreeWriteTransaction transaction,
 164             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 165
 166         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 167
 168         // Not using Futures.allAsList here to avoid its internal overhead.
 169         FutureCallback<Void> futureCallback = new FutureCallback<Void>() {
 170             @Override
 171             public void onSuccess(final Void notUsed) {
 172                 if (!cohortIterator.hasNext()) {
 173                     // All cohorts completed successfully - we're done.
 174                     commitStatsTracker.addDuration(System.nanoTime() - startTime);
 175
 176                     clientSubmitFuture.set();
 177                 } else {
 178                     ListenableFuture<Void> commitFuture = cohortIterator.next().commit();
 179                     Futures.addCallback(commitFuture, this, MoreExecutors.directExecutor());
 180                 }
 181             }
 182
 183             @Override
 184             public void onFailure(final Throwable throwable) {
 185                 handleException(clientSubmitFuture, transaction, cohorts, COMMIT, COMMIT_ERROR_MAPPER, throwable);
 186             }
 187         };
 188
 189         ListenableFuture<Void> commitFuture = cohortIterator.next().commit();
 190         Futures.addCallback(commitFuture, futureCallback, MoreExecutors.directExecutor());
 191     }
 192
 193     @SuppressFBWarnings(value = "BC_UNCONFIRMED_CAST_OF_RETURN_VALUE",
 194             justification = "Pertains to the assignment of the 'clientException' var. FindBugs flags this as an "
 195                 + "uncomfirmed cast but the generic type in TransactionCommitFailedExceptionMapper is "
 196                 + "TransactionCommitFailedException and thus should be deemed as confirmed.")
 197     private static void handleException(final AsyncNotifyingSettableFuture clientSubmitFuture,
 198             final DOMDataTreeWriteTransaction transaction,
 199             final Collection<DOMStoreThreePhaseCommitCohort> cohorts,
 200             final String phase, final TransactionCommitFailedExceptionMapper exMapper,
 201             final Throwable throwable) {
 202
 203         if (clientSubmitFuture.isDone()) {
 204             // We must have had failures from multiple cohorts.
 205             return;
 206         }
 207
 208         // Use debug instead of warn level here because this exception gets propagate back to the caller via the Future
 209         LOG.debug("Tx: {} Error during phase {}, starting Abort", transaction.getIdentifier(), phase, throwable);
 210
 211         // Transaction failed - tell all cohorts to abort.
 212         @SuppressWarnings("unchecked")
 213         ListenableFuture<Void>[] canCommitFutures = new ListenableFuture[cohorts.size()];
 214         int index = 0;
 215         for (DOMStoreThreePhaseCommitCohort cohort : cohorts) {
 216             canCommitFutures[index++] = cohort.abort();
 217         }
 218
 219         // Propagate the original exception
 220         final Exception e;
 221         if (throwable instanceof NoShardLeaderException || throwable instanceof ShardLeaderNotRespondingException) {
 222             e = new DataStoreUnavailableException(throwable.getMessage(), throwable);
 223         } else if (throwable instanceof Exception) {
 224             e = (Exception)throwable;
 225         } else {
 226             e = new RuntimeException("Unexpected error occurred", throwable);
 227         }
 228         clientSubmitFuture.setException(exMapper.apply(e));
 229
 230         ListenableFuture<List<Void>> combinedFuture = Futures.allAsList(canCommitFutures);
 231         Futures.addCallback(combinedFuture, new FutureCallback<List<Void>>() {
 232             @Override
 233             public void onSuccess(final List<Void> notUsed) {
 234                 // Propagate the original exception to the client.
 235                 LOG.debug("Tx: {} aborted successfully", transaction.getIdentifier());
 236             }
 237
 238             @Override
 239             public void onFailure(final Throwable failure) {
 240                 LOG.error("Tx: {} Error during Abort.", transaction.getIdentifier(), failure);
 241             }
 242         }, MoreExecutors.directExecutor());
 243     }
 244
 245     /**
 246      * A settable future that uses an {@link Executor} to execute listener callback Runnables,
 247      * registered via {@link #addListener}, asynchronously when this future completes. This is
 248      * done to guarantee listener executions are off-loaded onto another thread to avoid blocking
 249      * the thread that completed this future, as a common use case is to pass an executor that runs
 250      * tasks in the same thread as the caller (ie MoreExecutors#sameThreadExecutor)
 251      * to {@link #addListener}.
 252      * FIXME: This class should probably be moved to yangtools common utils for re-usability and
 253      * unified with AsyncNotifyingListenableFutureTask.
 254      */
 255     private static class AsyncNotifyingSettableFuture extends AbstractFuture<Void> {
 256
 257         /**
 258          * ThreadLocal used to detect if the task completion thread is running the future listener Runnables.
 259          */
 260         private static final ThreadLocal<Boolean> ON_TASK_COMPLETION_THREAD_TL = new ThreadLocal<>();
 261
 262         private final Executor listenerExecutor;
 263
 264         AsyncNotifyingSettableFuture(final Executor listenerExecutor) {
 265             this.listenerExecutor = Preconditions.checkNotNull(listenerExecutor);
 266         }
 267
 268         @Override
 269         public void addListener(final Runnable listener, final Executor executor) {
 270             // Wrap the listener Runnable in a DelegatingRunnable. If the specified executor is one
 271             // that runs tasks in the same thread as the caller submitting the task
 272             // (e.g. {@link com.google.common.util.concurrent.MoreExecutors#sameThreadExecutor}) and
 273             // the listener is executed from the #set methods, then the DelegatingRunnable will detect
 274             // this via the ThreadLocal and submit the listener Runnable to the listenerExecutor.
 275             //
 276             // On the other hand, if this task is already complete, the call to ExecutionList#add in
 277             // superclass will execute the listener Runnable immediately and, since the ThreadLocal
 278             // won't be set, the DelegatingRunnable will run the listener Runnable inline.
 279             super.addListener(new DelegatingRunnable(listener, listenerExecutor), executor);
 280         }
 281
 282         boolean set() {
 283             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 284             try {
 285                 return super.set(null);
 286             } finally {
 287                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 288             }
 289         }
 290
 291         @Override
 292         protected boolean setException(final Throwable throwable) {
 293             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 294             try {
 295                 return super.setException(throwable);
 296             } finally {
 297                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 298             }
 299         }
 300
 301         private static final class DelegatingRunnable implements Runnable {
 302             private final Runnable delegate;
 303             private final Executor executor;
 304
 305             DelegatingRunnable(final Runnable delegate, final Executor executor) {
 306                 this.delegate = Preconditions.checkNotNull(delegate);
 307                 this.executor = Preconditions.checkNotNull(executor);
 308             }
 309
 310             @Override
 311             public void run() {
 312                 if (ON_TASK_COMPLETION_THREAD_TL.get() != null) {
 313                     // We're running on the task completion thread so off-load to the executor.
 314                     LOG.trace("Submitting ListenenableFuture Runnable from thread {} to executor {}",
 315                             Thread.currentThread().getName(), executor);
 316                     executor.execute(delegate);
 317                 } else {
 318                     // We're not running on the task completion thread so run the delegate inline.
 319                     LOG.trace("Executing ListenenableFuture Runnable on this thread: {}",
 320                             Thread.currentThread().getName());
 321                     delegate.run();
 322                 }
 323             }
 324         }
 325     }
 326
 327     @Override
 328     public String toString() {
 329         return "Clustered ConcurrentDOMDataBroker";
 330     }
 331 }