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

   1 /*
   2  * Copyright (c) 2014 Cisco 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.datastore;
   9
  10 import static com.google.common.base.Preconditions.checkState;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import akka.actor.ActorSelection;
  14 import akka.dispatch.OnComplete;
  15 import com.google.common.base.Supplier;
  16 import com.google.common.collect.Lists;
  17 import com.google.common.util.concurrent.FutureCallback;
  18 import com.google.common.util.concurrent.Futures;
  19 import com.google.common.util.concurrent.ListenableFuture;
  20 import com.google.common.util.concurrent.MoreExecutors;
  21 import com.google.common.util.concurrent.SettableFuture;
  22 import java.util.ArrayList;
  23 import java.util.Iterator;
  24 import java.util.List;
  25 import java.util.concurrent.atomic.AtomicInteger;
  26 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  27 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  28 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
  29 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  30 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransactionReply;
  31 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  32 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
  33 import org.opendaylight.controller.cluster.datastore.utils.ActorUtils;
  34 import org.slf4j.Logger;
  35 import org.slf4j.LoggerFactory;
  36 import scala.concurrent.Future;
  37
  38 /**
  39  * ThreePhaseCommitCohortProxy represents a set of remote cohort proxies.
  40  */
  41 public class ThreePhaseCommitCohortProxy extends AbstractThreePhaseCommitCohort<ActorSelection> {
  42
  43     private static final Logger LOG = LoggerFactory.getLogger(ThreePhaseCommitCohortProxy.class);
  44
  45     private static final MessageSupplier COMMIT_MESSAGE_SUPPLIER = new MessageSupplier() {
  46         @Override
  47         public Object newMessage(final TransactionIdentifier transactionId, final short version) {
  48             return new CommitTransaction(transactionId, version).toSerializable();
  49         }
  50
  51         @Override
  52         public boolean isSerializedReplyType(final Object reply) {
  53             return CommitTransactionReply.isSerializedType(reply);
  54         }
  55     };
  56
  57     private static final MessageSupplier ABORT_MESSAGE_SUPPLIER = new MessageSupplier() {
  58         @Override
  59         public Object newMessage(final TransactionIdentifier transactionId, final short version) {
  60             return new AbortTransaction(transactionId, version).toSerializable();
  61         }
  62
  63         @Override
  64         public boolean isSerializedReplyType(final Object reply) {
  65             return AbortTransactionReply.isSerializedType(reply);
  66         }
  67     };
  68
  69     private final ActorUtils actorUtils;
  70     private final List<CohortInfo> cohorts;
  71     private final SettableFuture<Void> cohortsResolvedFuture = SettableFuture.create();
  72     private final TransactionIdentifier transactionId;
  73     private volatile OperationCallback commitOperationCallback;
  74
  75     public ThreePhaseCommitCohortProxy(final ActorUtils actorUtils, final List<CohortInfo> cohorts,
  76             final TransactionIdentifier transactionId) {
  77         this.actorUtils = actorUtils;
  78         this.cohorts = cohorts;
  79         this.transactionId = requireNonNull(transactionId);
  80
  81         if (cohorts.isEmpty()) {
  82             cohortsResolvedFuture.set(null);
  83         }
  84     }
  85
  86     private ListenableFuture<Void> resolveCohorts() {
  87         if (cohortsResolvedFuture.isDone()) {
  88             return cohortsResolvedFuture;
  89         }
  90
  91         final AtomicInteger completed = new AtomicInteger(cohorts.size());
  92         final Object lock = new Object();
  93         for (final CohortInfo info: cohorts) {
  94             info.getActorFuture().onComplete(new OnComplete<ActorSelection>() {
  95                 @Override
  96                 public void onComplete(final Throwable failure, final ActorSelection actor)  {
  97                     synchronized (lock) {
  98                         boolean done = completed.decrementAndGet() == 0;
  99                         if (failure != null) {
 100                             LOG.debug("Tx {}: a cohort Future failed", transactionId, failure);
 101                             cohortsResolvedFuture.setException(failure);
 102                         } else if (!cohortsResolvedFuture.isDone()) {
 103                             LOG.debug("Tx {}: cohort actor {} resolved", transactionId, actor);
 104
 105                             info.setResolvedActor(actor);
 106                             if (done) {
 107                                 LOG.debug("Tx {}: successfully resolved all cohort actors", transactionId);
 108                                 cohortsResolvedFuture.set(null);
 109                             }
 110                         }
 111                     }
 112                 }
 113             }, actorUtils.getClientDispatcher());
 114         }
 115
 116         return cohortsResolvedFuture;
 117     }
 118
 119     @Override
 120     public ListenableFuture<Boolean> canCommit() {
 121         LOG.debug("Tx {} canCommit", transactionId);
 122
 123         final SettableFuture<Boolean> returnFuture = SettableFuture.create();
 124
 125         // The first phase of canCommit is to gather the list of cohort actor paths that will
 126         // participate in the commit. buildCohortPathsList combines the cohort path Futures into
 127         // one Future which we wait on asynchronously here. The cohort actor paths are
 128         // extracted from ReadyTransactionReply messages by the Futures that were obtained earlier
 129         // and passed to us from upstream processing. If any one fails then  we'll fail canCommit.
 130
 131         Futures.addCallback(resolveCohorts(), new FutureCallback<Void>() {
 132             @Override
 133             public void onSuccess(final Void notUsed) {
 134                 finishCanCommit(returnFuture);
 135             }
 136
 137             @Override
 138             public void onFailure(final Throwable failure) {
 139                 returnFuture.setException(failure);
 140             }
 141         }, MoreExecutors.directExecutor());
 142
 143         return returnFuture;
 144     }
 145
 146     private void finishCanCommit(final SettableFuture<Boolean> returnFuture) {
 147         LOG.debug("Tx {} finishCanCommit", transactionId);
 148
 149         // For empty transactions return immediately
 150         if (cohorts.size() == 0) {
 151             LOG.debug("Tx {}: canCommit returning result true", transactionId);
 152             returnFuture.set(Boolean.TRUE);
 153             return;
 154         }
 155
 156         commitOperationCallback = new TransactionRateLimitingCallback(actorUtils);
 157         commitOperationCallback.run();
 158
 159         final Iterator<CohortInfo> iterator = cohorts.iterator();
 160
 161         final OnComplete<Object> onComplete = new OnComplete<Object>() {
 162             @Override
 163             public void onComplete(final Throwable failure, final Object response) {
 164                 if (failure != null) {
 165                     LOG.debug("Tx {}: a canCommit cohort Future failed", transactionId, failure);
 166
 167                     returnFuture.setException(failure);
 168                     commitOperationCallback.failure();
 169                     return;
 170                 }
 171
 172                 // Only the first call to pause takes effect - subsequent calls before resume are no-ops. So
 173                 // this means we'll only time the first transaction canCommit which should be fine.
 174                 commitOperationCallback.pause();
 175
 176                 boolean result = true;
 177                 if (CanCommitTransactionReply.isSerializedType(response)) {
 178                     CanCommitTransactionReply reply = CanCommitTransactionReply.fromSerializable(response);
 179
 180                     LOG.debug("Tx {}: received {}", transactionId, response);
 181
 182                     if (!reply.getCanCommit()) {
 183                         result = false;
 184                     }
 185                 } else {
 186                     LOG.error("Unexpected response type {}", response.getClass());
 187                     returnFuture.setException(new IllegalArgumentException(
 188                             String.format("Unexpected response type %s", response.getClass())));
 189                     return;
 190                 }
 191
 192                 if (iterator.hasNext() && result) {
 193                     sendCanCommitTransaction(iterator.next(), this);
 194                 } else {
 195                     LOG.debug("Tx {}: canCommit returning result: {}", transactionId, result);
 196                     returnFuture.set(Boolean.valueOf(result));
 197                 }
 198
 199             }
 200         };
 201
 202         sendCanCommitTransaction(iterator.next(), onComplete);
 203     }
 204
 205     private void sendCanCommitTransaction(final CohortInfo toCohortInfo, final OnComplete<Object> onComplete) {
 206         CanCommitTransaction message = new CanCommitTransaction(transactionId, toCohortInfo.getActorVersion());
 207
 208         LOG.debug("Tx {}: sending {} to {}", transactionId, message, toCohortInfo.getResolvedActor());
 209
 210         Future<Object> future = actorUtils.executeOperationAsync(toCohortInfo.getResolvedActor(),
 211                 message.toSerializable(), actorUtils.getTransactionCommitOperationTimeout());
 212         future.onComplete(onComplete, actorUtils.getClientDispatcher());
 213     }
 214
 215     private Future<Iterable<Object>> invokeCohorts(final MessageSupplier messageSupplier) {
 216         List<Future<Object>> futureList = Lists.newArrayListWithCapacity(cohorts.size());
 217         for (CohortInfo cohort : cohorts) {
 218             Object message = messageSupplier.newMessage(transactionId, cohort.getActorVersion());
 219
 220             LOG.debug("Tx {}: Sending {} to cohort {}", transactionId, message , cohort.getResolvedActor());
 221
 222             futureList.add(actorUtils.executeOperationAsync(cohort.getResolvedActor(), message,
 223                     actorUtils.getTransactionCommitOperationTimeout()));
 224         }
 225
 226         return akka.dispatch.Futures.sequence(futureList, actorUtils.getClientDispatcher());
 227     }
 228
 229     @Override
 230     public ListenableFuture<Void> preCommit() {
 231         // We don't need to do anything here - preCommit is done atomically with the commit phase
 232         // by the shard.
 233         return IMMEDIATE_VOID_SUCCESS;
 234     }
 235
 236     @Override
 237     public ListenableFuture<Void> abort() {
 238         // Note - we pass false for propagateException. In the front-end data broker, this method
 239         // is called when one of the 3 phases fails with an exception. We'd rather have that
 240         // original exception propagated to the client. If our abort fails and we propagate the
 241         // exception then that exception will supersede and suppress the original exception. But
 242         // it's the original exception that is the root cause and of more interest to the client.
 243
 244         return voidOperation("abort", ABORT_MESSAGE_SUPPLIER,
 245                 AbortTransactionReply.class, false, OperationCallback.NO_OP_CALLBACK);
 246     }
 247
 248     @Override
 249     public ListenableFuture<Void> commit() {
 250         OperationCallback operationCallback = commitOperationCallback != null ? commitOperationCallback :
 251             OperationCallback.NO_OP_CALLBACK;
 252
 253         return voidOperation("commit", COMMIT_MESSAGE_SUPPLIER,
 254                 CommitTransactionReply.class, true, operationCallback);
 255     }
 256
 257     @SuppressWarnings("checkstyle:IllegalCatch")
 258     private static boolean successfulFuture(final ListenableFuture<Void> future) {
 259         if (!future.isDone()) {
 260             return false;
 261         }
 262
 263         try {
 264             future.get();
 265             return true;
 266         } catch (Exception e) {
 267             return false;
 268         }
 269     }
 270
 271     private ListenableFuture<Void> voidOperation(final String operationName,
 272             final MessageSupplier messageSupplier, final Class<?> expectedResponseClass,
 273             final boolean propagateException, final OperationCallback callback) {
 274         LOG.debug("Tx {} {}", transactionId, operationName);
 275
 276         final SettableFuture<Void> returnFuture = SettableFuture.create();
 277
 278         // The cohort actor list should already be built at this point by the canCommit phase but,
 279         // if not for some reason, we'll try to build it here.
 280
 281         ListenableFuture<Void> future = resolveCohorts();
 282         if (successfulFuture(future)) {
 283             finishVoidOperation(operationName, messageSupplier, expectedResponseClass, propagateException,
 284                     returnFuture, callback);
 285         } else {
 286             Futures.addCallback(future, new FutureCallback<Void>() {
 287                 @Override
 288                 public void onSuccess(final Void notUsed) {
 289                     finishVoidOperation(operationName, messageSupplier, expectedResponseClass,
 290                             propagateException, returnFuture, callback);
 291                 }
 292
 293                 @Override
 294                 public void onFailure(final Throwable failure) {
 295                     LOG.debug("Tx {}: a {} cohort path Future failed", transactionId, operationName, failure);
 296
 297                     if (propagateException) {
 298                         returnFuture.setException(failure);
 299                     } else {
 300                         returnFuture.set(null);
 301                     }
 302                 }
 303             }, MoreExecutors.directExecutor());
 304         }
 305
 306         return returnFuture;
 307     }
 308
 309     private void finishVoidOperation(final String operationName, final MessageSupplier messageSupplier,
 310                                      final Class<?> expectedResponseClass, final boolean propagateException,
 311                                      final SettableFuture<Void> returnFuture, final OperationCallback callback) {
 312         LOG.debug("Tx {} finish {}", transactionId, operationName);
 313
 314         callback.resume();
 315
 316         Future<Iterable<Object>> combinedFuture = invokeCohorts(messageSupplier);
 317
 318         combinedFuture.onComplete(new OnComplete<Iterable<Object>>() {
 319             @Override
 320             public void onComplete(final Throwable failure, final Iterable<Object> responses) {
 321                 Throwable exceptionToPropagate = failure;
 322                 if (exceptionToPropagate == null) {
 323                     for (Object response: responses) {
 324                         if (!response.getClass().equals(expectedResponseClass)) {
 325                             exceptionToPropagate = new IllegalArgumentException(
 326                                     String.format("Unexpected response type %s", response.getClass()));
 327                             break;
 328                         }
 329                     }
 330                 }
 331
 332                 if (exceptionToPropagate != null) {
 333                     LOG.debug("Tx {}: a {} cohort Future failed", transactionId, operationName, exceptionToPropagate);
 334                     if (propagateException) {
 335                         // We don't log the exception here to avoid redundant logging since we're
 336                         // propagating to the caller in MD-SAL core who will log it.
 337                         returnFuture.setException(exceptionToPropagate);
 338                     } else {
 339                         // Since the caller doesn't want us to propagate the exception we'll also
 340                         // not log it normally. But it's usually not good to totally silence
 341                         // exceptions so we'll log it to debug level.
 342                         returnFuture.set(null);
 343                     }
 344
 345                     callback.failure();
 346                 } else {
 347                     LOG.debug("Tx {}: {} succeeded", transactionId, operationName);
 348
 349                     returnFuture.set(null);
 350
 351                     callback.success();
 352                 }
 353             }
 354         }, actorUtils.getClientDispatcher());
 355     }
 356
 357     @Override
 358     List<Future<ActorSelection>> getCohortFutures() {
 359         List<Future<ActorSelection>> cohortFutures = new ArrayList<>(cohorts.size());
 360         for (CohortInfo info: cohorts) {
 361             cohortFutures.add(info.getActorFuture());
 362         }
 363
 364         return cohortFutures;
 365     }
 366
 367     static class CohortInfo {
 368         private final Future<ActorSelection> actorFuture;
 369         private volatile ActorSelection resolvedActor;
 370         private final Supplier<Short> actorVersionSupplier;
 371
 372         CohortInfo(final Future<ActorSelection> actorFuture, final Supplier<Short> actorVersionSupplier) {
 373             this.actorFuture = actorFuture;
 374             this.actorVersionSupplier = actorVersionSupplier;
 375         }
 376
 377         Future<ActorSelection> getActorFuture() {
 378             return actorFuture;
 379         }
 380
 381         ActorSelection getResolvedActor() {
 382             return resolvedActor;
 383         }
 384
 385         void setResolvedActor(final ActorSelection resolvedActor) {
 386             this.resolvedActor = resolvedActor;
 387         }
 388
 389         short getActorVersion() {
 390             checkState(resolvedActor != null, "getActorVersion cannot be called until the actor is resolved");
 391             return actorVersionSupplier.get();
 392         }
 393     }
 394
 395     private interface MessageSupplier {
 396         Object newMessage(TransactionIdentifier transactionId, short version);
 397
 398         boolean isSerializedReplyType(Object reply);
 399     }
 400 }