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
   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.collect.Lists;
  15 import com.google.common.util.concurrent.ListenableFuture;
  16 import com.google.common.util.concurrent.SettableFuture;
  17 import java.util.Collections;
  18 import java.util.Iterator;
  19 import java.util.List;
  20 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
  21 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
  22 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
  23 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransactionReply;
  24 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
  25 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
  26 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  27 import org.slf4j.Logger;
  28 import org.slf4j.LoggerFactory;
  29 import scala.concurrent.Future;
  30 import scala.runtime.AbstractFunction1;
  31
  32 /**
  33  * ThreePhaseCommitCohortProxy represents a set of remote cohort proxies
  34  */
  35 public class ThreePhaseCommitCohortProxy extends AbstractThreePhaseCommitCohort<ActorSelection> {
  36
  37     private static final Logger LOG = LoggerFactory.getLogger(ThreePhaseCommitCohortProxy.class);
  38
  39     private final ActorContext actorContext;
  40     private final List<Future<ActorSelection>> cohortFutures;
  41     private volatile List<ActorSelection> cohorts;
  42     private final String transactionId;
  43     private volatile OperationCallback commitOperationCallback;
  44
  45     public ThreePhaseCommitCohortProxy(ActorContext actorContext,
  46             List<Future<ActorSelection>> cohortFutures, String transactionId) {
  47         this.actorContext = actorContext;
  48         this.cohortFutures = cohortFutures;
  49         this.transactionId = transactionId;
  50     }
  51
  52     private Future<Void> buildCohortList() {
  53
  54         Future<Iterable<ActorSelection>> combinedFutures = Futures.sequence(cohortFutures,
  55                 actorContext.getClientDispatcher());
  56
  57         return combinedFutures.transform(new AbstractFunction1<Iterable<ActorSelection>, Void>() {
  58             @Override
  59             public Void apply(Iterable<ActorSelection> actorSelections) {
  60                 cohorts = Lists.newArrayList(actorSelections);
  61                 if(LOG.isDebugEnabled()) {
  62                     LOG.debug("Tx {} successfully built cohort path list: {}",
  63                         transactionId, cohorts);
  64                 }
  65                 return null;
  66             }
  67         }, TransactionReadyReplyMapper.SAME_FAILURE_TRANSFORMER, actorContext.getClientDispatcher());
  68     }
  69
  70     @Override
  71     public ListenableFuture<Boolean> canCommit() {
  72         if(LOG.isDebugEnabled()) {
  73             LOG.debug("Tx {} canCommit", transactionId);
  74         }
  75         final SettableFuture<Boolean> returnFuture = SettableFuture.create();
  76
  77         // The first phase of canCommit is to gather the list of cohort actor paths that will
  78         // participate in the commit. buildCohortPathsList combines the cohort path Futures into
  79         // one Future which we wait on asynchronously here. The cohort actor paths are
  80         // extracted from ReadyTransactionReply messages by the Futures that were obtained earlier
  81         // and passed to us from upstream processing. If any one fails then  we'll fail canCommit.
  82
  83         buildCohortList().onComplete(new OnComplete<Void>() {
  84             @Override
  85             public void onComplete(Throwable failure, Void notUsed) throws Throwable {
  86                 if(failure != null) {
  87                     if(LOG.isDebugEnabled()) {
  88                         LOG.debug("Tx {}: a cohort Future failed: {}", transactionId, failure);
  89                     }
  90                     returnFuture.setException(failure);
  91                 } else {
  92                     finishCanCommit(returnFuture);
  93                 }
  94             }
  95         }, actorContext.getClientDispatcher());
  96
  97         return returnFuture;
  98     }
  99
 100     private void finishCanCommit(final SettableFuture<Boolean> returnFuture) {
 101         if(LOG.isDebugEnabled()) {
 102             LOG.debug("Tx {} finishCanCommit", transactionId);
 103         }
 104
 105         // For empty transactions return immediately
 106         if(cohorts.size() == 0){
 107             if(LOG.isDebugEnabled()) {
 108                 LOG.debug("Tx {}: canCommit returning result: {}", transactionId, true);
 109             }
 110             returnFuture.set(Boolean.TRUE);
 111             return;
 112         }
 113
 114         commitOperationCallback = cohortFutures.isEmpty() ? OperationCallback.NO_OP_CALLBACK :
 115             new TransactionRateLimitingCallback(actorContext);
 116
 117         commitOperationCallback.run();
 118
 119         final Object message = new CanCommitTransaction(transactionId).toSerializable();
 120
 121         final Iterator<ActorSelection> iterator = cohorts.iterator();
 122
 123         final OnComplete<Object> onComplete = new OnComplete<Object>() {
 124             @Override
 125             public void onComplete(Throwable failure, Object response) throws Throwable {
 126                 if (failure != null) {
 127                     if (LOG.isDebugEnabled()) {
 128                         LOG.debug("Tx {}: a canCommit cohort Future failed: {}", transactionId, failure);
 129                     }
 130                     returnFuture.setException(failure);
 131                     commitOperationCallback.failure();
 132                     return;
 133                 }
 134
 135                 // Only the first call to pause takes effect - subsequent calls before resume are no-ops. So
 136                 // this means we'll only time the first transaction canCommit which should be fine.
 137                 commitOperationCallback.pause();
 138
 139                 boolean result = true;
 140                 if (response.getClass().equals(CanCommitTransactionReply.SERIALIZABLE_CLASS)) {
 141                     CanCommitTransactionReply reply =
 142                             CanCommitTransactionReply.fromSerializable(response);
 143                     if (!reply.getCanCommit()) {
 144                         result = false;
 145                     }
 146                 } else {
 147                     LOG.error("Unexpected response type {}", response.getClass());
 148                     returnFuture.setException(new IllegalArgumentException(
 149                             String.format("Unexpected response type %s", response.getClass())));
 150                     return;
 151                 }
 152
 153                 if(iterator.hasNext() && result){
 154                     Future<Object> future = actorContext.executeOperationAsync(iterator.next(), message,
 155                             actorContext.getTransactionCommitOperationTimeout());
 156                     future.onComplete(this, actorContext.getClientDispatcher());
 157                 } else {
 158                     if(LOG.isDebugEnabled()) {
 159                         LOG.debug("Tx {}: canCommit returning result: {}", transactionId, result);
 160                     }
 161                     returnFuture.set(Boolean.valueOf(result));
 162                 }
 163
 164             }
 165         };
 166
 167         Future<Object> future = actorContext.executeOperationAsync(iterator.next(), message,
 168                 actorContext.getTransactionCommitOperationTimeout());
 169         future.onComplete(onComplete, actorContext.getClientDispatcher());
 170     }
 171
 172     private Future<Iterable<Object>> invokeCohorts(Object message) {
 173         List<Future<Object>> futureList = Lists.newArrayListWithCapacity(cohorts.size());
 174         for(ActorSelection cohort : cohorts) {
 175             if(LOG.isDebugEnabled()) {
 176                 LOG.debug("Tx {}: Sending {} to cohort {}", transactionId, message, cohort);
 177             }
 178             futureList.add(actorContext.executeOperationAsync(cohort, message, actorContext.getTransactionCommitOperationTimeout()));
 179         }
 180
 181         return Futures.sequence(futureList, actorContext.getClientDispatcher());
 182     }
 183
 184     @Override
 185     public ListenableFuture<Void> preCommit() {
 186         // We don't need to do anything here - preCommit is done atomically with the commit phase
 187         // by the shard.
 188         return IMMEDIATE_VOID_SUCCESS;
 189     }
 190
 191     @Override
 192     public ListenableFuture<Void> abort() {
 193         // Note - we pass false for propagateException. In the front-end data broker, this method
 194         // is called when one of the 3 phases fails with an exception. We'd rather have that
 195         // original exception propagated to the client. If our abort fails and we propagate the
 196         // exception then that exception will supersede and suppress the original exception. But
 197         // it's the original exception that is the root cause and of more interest to the client.
 198
 199         return voidOperation("abort", new AbortTransaction(transactionId).toSerializable(),
 200                 AbortTransactionReply.SERIALIZABLE_CLASS, false);
 201     }
 202
 203     @Override
 204     public ListenableFuture<Void> commit() {
 205         OperationCallback operationCallback = commitOperationCallback != null ? commitOperationCallback :
 206             OperationCallback.NO_OP_CALLBACK;
 207
 208         return voidOperation("commit", new CommitTransaction(transactionId).toSerializable(),
 209                 CommitTransactionReply.SERIALIZABLE_CLASS, true, operationCallback);
 210     }
 211
 212     private ListenableFuture<Void> voidOperation(final String operationName, final Object message,
 213                                                  final Class<?> expectedResponseClass, final boolean propagateException) {
 214         return voidOperation(operationName, message, expectedResponseClass, propagateException,
 215                 OperationCallback.NO_OP_CALLBACK);
 216     }
 217
 218     private ListenableFuture<Void> voidOperation(final String operationName, final Object message,
 219                                                  final Class<?> expectedResponseClass, final boolean propagateException, final OperationCallback callback) {
 220
 221         if(LOG.isDebugEnabled()) {
 222             LOG.debug("Tx {} {}", transactionId, operationName);
 223         }
 224         final SettableFuture<Void> returnFuture = SettableFuture.create();
 225
 226         // The cohort actor list should already be built at this point by the canCommit phase but,
 227         // if not for some reason, we'll try to build it here.
 228
 229         if(cohorts != null) {
 230             finishVoidOperation(operationName, message, expectedResponseClass, propagateException,
 231                     returnFuture, callback);
 232         } else {
 233             buildCohortList().onComplete(new OnComplete<Void>() {
 234                 @Override
 235                 public void onComplete(Throwable failure, Void notUsed) throws Throwable {
 236                     if(failure != null) {
 237                         if(LOG.isDebugEnabled()) {
 238                             LOG.debug("Tx {}: a {} cohort path Future failed: {}", transactionId,
 239                                 operationName, failure);
 240                         }
 241                         if(propagateException) {
 242                             returnFuture.setException(failure);
 243                         } else {
 244                             returnFuture.set(null);
 245                         }
 246                     } else {
 247                         finishVoidOperation(operationName, message, expectedResponseClass,
 248                                 propagateException, returnFuture, callback);
 249                     }
 250                 }
 251             }, actorContext.getClientDispatcher());
 252         }
 253
 254         return returnFuture;
 255     }
 256
 257     private void finishVoidOperation(final String operationName, final Object message,
 258                                      final Class<?> expectedResponseClass, final boolean propagateException,
 259                                      final SettableFuture<Void> returnFuture, final OperationCallback callback) {
 260         if(LOG.isDebugEnabled()) {
 261             LOG.debug("Tx {} finish {}", transactionId, operationName);
 262         }
 263
 264         callback.resume();
 265
 266         Future<Iterable<Object>> combinedFuture = invokeCohorts(message);
 267
 268         combinedFuture.onComplete(new OnComplete<Iterable<Object>>() {
 269             @Override
 270             public void onComplete(Throwable failure, Iterable<Object> responses) throws Throwable {
 271
 272                 Throwable exceptionToPropagate = failure;
 273                 if(exceptionToPropagate == null) {
 274                     for(Object response: responses) {
 275                         if(!response.getClass().equals(expectedResponseClass)) {
 276                             exceptionToPropagate = new IllegalArgumentException(
 277                                     String.format("Unexpected response type %s",
 278                                             response.getClass()));
 279                             break;
 280                         }
 281                     }
 282                 }
 283
 284                 if(exceptionToPropagate != null) {
 285
 286                     if(LOG.isDebugEnabled()) {
 287                         LOG.debug("Tx {}: a {} cohort Future failed: {}", transactionId,
 288                             operationName, exceptionToPropagate);
 289                     }
 290                     if(propagateException) {
 291                         // We don't log the exception here to avoid redundant logging since we're
 292                         // propagating to the caller in MD-SAL core who will log it.
 293                         returnFuture.setException(exceptionToPropagate);
 294                     } else {
 295                         // Since the caller doesn't want us to propagate the exception we'll also
 296                         // not log it normally. But it's usually not good to totally silence
 297                         // exceptions so we'll log it to debug level.
 298                         if(LOG.isDebugEnabled()) {
 299                             LOG.debug(String.format("%s failed", message.getClass().getSimpleName()),
 300                                 exceptionToPropagate);
 301                         }
 302                         returnFuture.set(null);
 303                     }
 304
 305                     callback.failure();
 306                 } else {
 307
 308                     if(LOG.isDebugEnabled()) {
 309                         LOG.debug("Tx {}: {} succeeded", transactionId, operationName);
 310                     }
 311                     returnFuture.set(null);
 312
 313                     callback.success();
 314                 }
 315             }
 316         }, actorContext.getClientDispatcher());
 317     }
 318
 319     @Override
 320     List<Future<ActorSelection>> getCohortFutures() {
 321         return Collections.unmodifiableList(cohortFutures);
 322     }
 323 }