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