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

   1 /*
   2  * Copyright (c) 2015 Cisco Systems, Inc. and others.  All rights reserved.
   3  * Copyright (c) 2015 Brocade Communications Systems, Inc. and others.  All rights reserved.
   4  *
   5  * This program and the accompanying materials are made available under the
   6  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   7  * and is available at http://www.eclipse.org/legal/epl-v10.html
   8  */
   9 package org.opendaylight.controller.cluster.datastore;
  10
  11 import static com.google.common.base.Preconditions.checkState;
  12 import static java.util.Objects.requireNonNull;
  13
  14 import akka.actor.ActorSelection;
  15 import akka.dispatch.Futures;
  16 import akka.dispatch.OnComplete;
  17 import com.google.common.annotations.VisibleForTesting;
  18 import com.google.common.util.concurrent.SettableFuture;
  19 import java.util.Optional;
  20 import java.util.SortedSet;
  21 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  22 import org.opendaylight.controller.cluster.datastore.messages.AbstractRead;
  23 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  24 import org.opendaylight.controller.cluster.datastore.messages.CloseTransaction;
  25 import org.opendaylight.controller.cluster.datastore.modification.AbstractModification;
  26 import org.opendaylight.controller.cluster.datastore.modification.DeleteModification;
  27 import org.opendaylight.controller.cluster.datastore.modification.MergeModification;
  28 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  29 import org.opendaylight.controller.cluster.datastore.modification.WriteModification;
  30 import org.opendaylight.controller.cluster.datastore.utils.ActorUtils;
  31 import org.opendaylight.mdsal.common.api.ReadFailedException;
  32 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  33 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  34 import org.slf4j.Logger;
  35 import org.slf4j.LoggerFactory;
  36 import scala.concurrent.Future;
  37
  38 /**
  39  * Redirects front-end transaction operations to a shard for processing. Instances of this class are used
  40  * when the destination shard is remote to the caller.
  41  *
  42  * @author Thomas Pantelis
  43  */
  44 final class RemoteTransactionContext extends TransactionContext {
  45     private static final Logger LOG = LoggerFactory.getLogger(RemoteTransactionContext.class);
  46
  47     private final ActorUtils actorUtils;
  48     private final ActorSelection actor;
  49     private final OperationLimiter limiter;
  50
  51     private BatchedModifications batchedModifications;
  52     private int totalBatchedModificationsSent;
  53     private int batchPermits;
  54
  55     /**
  56      * We have observed a failed modification batch. This transaction context is effectively doomed, as the backend
  57      * does not have a correct view of the world. If this happens, we do not limit operations but rather short-cut them
  58      * to a either a no-op (modifications) or a failure (reads). Once the transaction is ready, though, we send the
  59      * message to resynchronize with the backend, sharing a 'lost message' failure path.
  60      */
  61     private volatile Throwable failedModification;
  62
  63     RemoteTransactionContext(final TransactionIdentifier identifier, final ActorSelection actor,
  64             final ActorUtils actorUtils, final short remoteTransactionVersion, final OperationLimiter limiter) {
  65         super(identifier, remoteTransactionVersion);
  66         this.limiter = requireNonNull(limiter);
  67         this.actor = actor;
  68         this.actorUtils = actorUtils;
  69     }
  70
  71     private ActorSelection getActor() {
  72         return actor;
  73     }
  74
  75     protected ActorUtils getActorUtils() {
  76         return actorUtils;
  77     }
  78
  79     @Override
  80     void closeTransaction() {
  81         LOG.debug("Tx {} closeTransaction called", getIdentifier());
  82         TransactionContextCleanup.untrack(this);
  83
  84         actorUtils.sendOperationAsync(getActor(), new CloseTransaction(getTransactionVersion()).toSerializable());
  85     }
  86
  87     @Override
  88     Future<Object> directCommit(final Boolean havePermit) {
  89         LOG.debug("Tx {} directCommit called", getIdentifier());
  90
  91         // Send the remaining batched modifications, if any, with the ready flag set.
  92         bumpPermits(havePermit);
  93         return sendBatchedModifications(true, true, Optional.empty());
  94     }
  95
  96     @Override
  97     Future<ActorSelection> readyTransaction(final Boolean havePermit,
  98             final Optional<SortedSet<String>> participatingShardNames) {
  99         logModificationCount();
 100
 101         LOG.debug("Tx {} readyTransaction called", getIdentifier());
 102
 103         // Send the remaining batched modifications, if any, with the ready flag set.
 104
 105         bumpPermits(havePermit);
 106         Future<Object> lastModificationsFuture = sendBatchedModifications(true, false, participatingShardNames);
 107
 108         // Transform the last reply Future into a Future that returns the cohort actor path from
 109         // the last reply message. That's the end result of the ready operation.
 110         return TransactionReadyReplyMapper.transform(lastModificationsFuture, actorUtils, getIdentifier());
 111     }
 112
 113     private void bumpPermits(final Boolean havePermit) {
 114         if (Boolean.TRUE.equals(havePermit)) {
 115             ++batchPermits;
 116         }
 117     }
 118
 119     private BatchedModifications newBatchedModifications() {
 120         return new BatchedModifications(getIdentifier(), getTransactionVersion());
 121     }
 122
 123     private void batchModification(final Modification modification, final boolean havePermit) {
 124         incrementModificationCount();
 125         if (havePermit) {
 126             ++batchPermits;
 127         }
 128
 129         if (batchedModifications == null) {
 130             batchedModifications = newBatchedModifications();
 131         }
 132
 133         batchedModifications.addModification(modification);
 134
 135         if (batchedModifications.getModifications().size()
 136                 >= actorUtils.getDatastoreContext().getShardBatchedModificationCount()) {
 137             sendBatchedModifications();
 138         }
 139     }
 140
 141     @VisibleForTesting
 142     Future<Object> sendBatchedModifications() {
 143         return sendBatchedModifications(false, false, Optional.empty());
 144     }
 145
 146     private Future<Object> sendBatchedModifications(final boolean ready, final boolean doCommitOnReady,
 147             final Optional<SortedSet<String>> participatingShardNames) {
 148         Future<Object> sent = null;
 149         if (ready || batchedModifications != null && !batchedModifications.getModifications().isEmpty()) {
 150             if (batchedModifications == null) {
 151                 batchedModifications = newBatchedModifications();
 152             }
 153
 154             LOG.debug("Tx {} sending {} batched modifications, ready: {}", getIdentifier(),
 155                     batchedModifications.getModifications().size(), ready);
 156
 157             batchedModifications.setDoCommitOnReady(doCommitOnReady);
 158             batchedModifications.setTotalMessagesSent(++totalBatchedModificationsSent);
 159
 160             final BatchedModifications toSend = batchedModifications;
 161             final int permitsToRelease = batchPermits;
 162             batchPermits = 0;
 163
 164             if (ready) {
 165                 batchedModifications.setReady(participatingShardNames);
 166                 batchedModifications.setDoCommitOnReady(doCommitOnReady);
 167                 batchedModifications = null;
 168             } else {
 169                 batchedModifications = newBatchedModifications();
 170
 171                 final Throwable failure = failedModification;
 172                 if (failure != null) {
 173                     // We have observed a modification failure, it does not make sense to send this batch. This speeds
 174                     // up the time when the application could be blocked due to messages timing out and operation
 175                     // limiter kicking in.
 176                     LOG.debug("Tx {} modifications previously failed, not sending a non-ready batch", getIdentifier());
 177                     limiter.release(permitsToRelease);
 178                     return Futures.failed(failure);
 179                 }
 180             }
 181
 182             sent = actorUtils.executeOperationAsync(getActor(), toSend.toSerializable(),
 183                 actorUtils.getTransactionCommitOperationTimeout());
 184             sent.onComplete(new OnComplete<>() {
 185                 @Override
 186                 public void onComplete(final Throwable failure, final Object success) {
 187                     if (failure != null) {
 188                         LOG.debug("Tx {} modifications failed", getIdentifier(), failure);
 189                         failedModification = failure;
 190                     } else {
 191                         LOG.debug("Tx {} modifications completed with {}", getIdentifier(), success);
 192                     }
 193                     limiter.release(permitsToRelease);
 194                 }
 195             }, actorUtils.getClientDispatcher());
 196         }
 197
 198         return sent;
 199     }
 200
 201     @Override
 202     void executeDelete(final YangInstanceIdentifier path, final Boolean havePermit) {
 203         LOG.debug("Tx {} executeDelete called path = {}", getIdentifier(), path);
 204         executeModification(new DeleteModification(path), havePermit);
 205     }
 206
 207     @Override
 208     void executeMerge(final YangInstanceIdentifier path, final NormalizedNode data, final Boolean havePermit) {
 209         LOG.debug("Tx {} executeMerge called path = {}", getIdentifier(), path);
 210         executeModification(new MergeModification(path, data), havePermit);
 211     }
 212
 213     @Override
 214     void executeWrite(final YangInstanceIdentifier path, final NormalizedNode data, final Boolean havePermit) {
 215         LOG.debug("Tx {} executeWrite called path = {}", getIdentifier(), path);
 216         executeModification(new WriteModification(path, data), havePermit);
 217     }
 218
 219     private void executeModification(final AbstractModification modification, final Boolean havePermit) {
 220         final boolean permitToRelease;
 221         if (havePermit == null) {
 222             permitToRelease = failedModification == null && acquireOperation();
 223         } else {
 224             permitToRelease = havePermit;
 225         }
 226
 227         batchModification(modification, permitToRelease);
 228     }
 229
 230     @Override
 231     <T> void executeRead(final AbstractRead<T> readCmd, final SettableFuture<T> returnFuture,
 232             final Boolean havePermit) {
 233         LOG.debug("Tx {} executeRead {} called path = {}", getIdentifier(), readCmd.getClass().getSimpleName(),
 234                 readCmd.getPath());
 235
 236         final Throwable failure = failedModification;
 237         if (failure != null) {
 238             // If we know there was a previous modification failure, we must not send a read request, as it risks
 239             // returning incorrect data. We check this before acquiring an operation simply because we want the app
 240             // to complete this transaction as soon as possible.
 241             returnFuture.setException(new ReadFailedException("Previous modification failed, cannot "
 242                     + readCmd.getClass().getSimpleName() + " for path " + readCmd.getPath(), failure));
 243             return;
 244         }
 245
 246         // Send any batched modifications. This is necessary to honor the read uncommitted semantics of the
 247         // public API contract.
 248
 249         final boolean permitToRelease = havePermit == null ? acquireOperation() : havePermit;
 250         sendBatchedModifications();
 251
 252         OnComplete<Object> onComplete = new OnComplete<>() {
 253             @Override
 254             public void onComplete(final Throwable failure, final Object response) {
 255                 // We have previously acquired an operation, now release it, no matter what happened
 256                 if (permitToRelease) {
 257                     limiter.release();
 258                 }
 259
 260                 if (failure != null) {
 261                     LOG.debug("Tx {} {} operation failed", getIdentifier(), readCmd.getClass().getSimpleName(),
 262                         failure);
 263
 264                     returnFuture.setException(new ReadFailedException("Error checking "
 265                         + readCmd.getClass().getSimpleName() + " for path " + readCmd.getPath(), failure));
 266                 } else {
 267                     LOG.debug("Tx {} {} operation succeeded", getIdentifier(), readCmd.getClass().getSimpleName());
 268                     readCmd.processResponse(response, returnFuture);
 269                 }
 270             }
 271         };
 272
 273         final Future<Object> future = actorUtils.executeOperationAsync(getActor(),
 274             readCmd.asVersion(getTransactionVersion()).toSerializable(), actorUtils.getOperationTimeout());
 275         future.onComplete(onComplete, actorUtils.getClientDispatcher());
 276     }
 277
 278     /**
 279      * Acquire operation from the limiter if the hand-off has completed. If the hand-off is still ongoing, this method
 280      * does nothing.
 281      *
 282      * @return True if a permit was successfully acquired, false otherwise
 283      */
 284     private boolean acquireOperation() {
 285         checkState(isOperationHandOffComplete(),
 286             "Attempted to acquire execute operation permit for transaction %s on actor %s during handoff",
 287             getIdentifier(), actor);
 288
 289         if (limiter.acquire()) {
 290             return true;
 291         }
 292
 293         LOG.warn("Failed to acquire execute operation permit for transaction {} on actor {}", getIdentifier(), actor);
 294         return false;
 295     }
 296
 297     @Override
 298     boolean usesOperationLimiting() {
 299         return true;
 300     }
 301 }