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