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