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.annotations.VisibleForTesting;
  15 import com.google.common.collect.Lists;
  16 import com.google.common.util.concurrent.ListenableFuture;
  17 import com.google.common.util.concurrent.SettableFuture;
  18 import java.util.Collections;
  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.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  28 import org.slf4j.Logger;
  29 import org.slf4j.LoggerFactory;
  30 import scala.concurrent.Future;
  31 import scala.runtime.AbstractFunction1;
  32
  33 /**
  34  * ThreePhaseCommitCohortProxy represents a set of remote cohort proxies
  35  */
  36 public class ThreePhaseCommitCohortProxy implements DOMStoreThreePhaseCommitCohort{
  37
  38     private static final Logger LOG = LoggerFactory.getLogger(ThreePhaseCommitCohortProxy.class);
  39
  40     private static final ListenableFuture<Void> IMMEDIATE_SUCCESS =
  41             com.google.common.util.concurrent.Futures.immediateFuture(null);
  42
  43     private final ActorContext actorContext;
  44     private final List<Future<ActorSelection>> cohortFutures;
  45     private volatile List<ActorSelection> cohorts;
  46     private final String transactionId;
  47     private static final OperationCallback NO_OP_CALLBACK = new OperationCallback() {
  48         @Override
  49         public void run() {
  50         }
  51
  52         @Override
  53         public void success() {
  54         }
  55
  56         @Override
  57         public void failure() {
  58         }
  59     };
  60
  61     public ThreePhaseCommitCohortProxy(ActorContext actorContext,
  62             List<Future<ActorSelection>> cohortFutures, String transactionId) {
  63         this.actorContext = actorContext;
  64         this.cohortFutures = cohortFutures;
  65         this.transactionId = transactionId;
  66     }
  67
  68     private Future<Void> buildCohortList() {
  69
  70         Future<Iterable<ActorSelection>> combinedFutures = Futures.sequence(cohortFutures,
  71                 actorContext.getClientDispatcher());
  72
  73         return combinedFutures.transform(new AbstractFunction1<Iterable<ActorSelection>, Void>() {
  74             @Override
  75             public Void apply(Iterable<ActorSelection> actorSelections) {
  76                 cohorts = Lists.newArrayList(actorSelections);
  77                 if(LOG.isDebugEnabled()) {
  78                     LOG.debug("Tx {} successfully built cohort path list: {}",
  79                         transactionId, cohorts);
  80                 }
  81                 return null;
  82             }
  83         }, TransactionProxy.SAME_FAILURE_TRANSFORMER, actorContext.getClientDispatcher());
  84     }
  85
  86     @Override
  87     public ListenableFuture<Boolean> canCommit() {
  88         if(LOG.isDebugEnabled()) {
  89             LOG.debug("Tx {} canCommit", transactionId);
  90         }
  91         final SettableFuture<Boolean> returnFuture = SettableFuture.create();
  92
  93         // The first phase of canCommit is to gather the list of cohort actor paths that will
  94         // participate in the commit. buildCohortPathsList combines the cohort path Futures into
  95         // one Future which we wait on asynchronously here. The cohort actor paths are
  96         // extracted from ReadyTransactionReply messages by the Futures that were obtained earlier
  97         // and passed to us from upstream processing. If any one fails then  we'll fail canCommit.
  98
  99         buildCohortList().onComplete(new OnComplete<Void>() {
 100             @Override
 101             public void onComplete(Throwable failure, Void notUsed) throws Throwable {
 102                 if(failure != null) {
 103                     if(LOG.isDebugEnabled()) {
 104                         LOG.debug("Tx {}: a cohort Future failed: {}", transactionId, failure);
 105                     }
 106                     returnFuture.setException(failure);
 107                 } else {
 108                     finishCanCommit(returnFuture);
 109                 }
 110             }
 111         }, actorContext.getClientDispatcher());
 112
 113         return returnFuture;
 114     }
 115
 116     private void finishCanCommit(final SettableFuture<Boolean> returnFuture) {
 117         if(LOG.isDebugEnabled()) {
 118             LOG.debug("Tx {} finishCanCommit", transactionId);
 119         }
 120         // The last phase of canCommit is to invoke all the cohort actors asynchronously to perform
 121         // their canCommit processing. If any one fails then we'll fail canCommit.
 122
 123         Future<Iterable<Object>> combinedFuture =
 124                 invokeCohorts(new CanCommitTransaction(transactionId).toSerializable());
 125
 126         combinedFuture.onComplete(new OnComplete<Iterable<Object>>() {
 127             @Override
 128             public void onComplete(Throwable failure, Iterable<Object> responses) throws Throwable {
 129                 if(failure != null) {
 130                     if(LOG.isDebugEnabled()) {
 131                         LOG.debug("Tx {}: a canCommit cohort Future failed: {}", transactionId, failure);
 132                     }
 133                     returnFuture.setException(failure);
 134                     return;
 135                 }
 136
 137                 boolean result = true;
 138                 for(Object response: responses) {
 139                     if (response.getClass().equals(CanCommitTransactionReply.SERIALIZABLE_CLASS)) {
 140                         CanCommitTransactionReply reply =
 141                                 CanCommitTransactionReply.fromSerializable(response);
 142                         if (!reply.getCanCommit()) {
 143                             result = false;
 144                             break;
 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(LOG.isDebugEnabled()) {
 154                     LOG.debug("Tx {}: canCommit returning result: {}", transactionId, result);
 155                 }
 156                 returnFuture.set(Boolean.valueOf(result));
 157             }
 158         }, 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_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.size() == 0) ? 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, NO_OP_CALLBACK);
 204     }
 205
 206     private ListenableFuture<Void> voidOperation(final String operationName, final Object message,
 207                                                  final Class<?> expectedResponseClass, final boolean propagateException, final OperationCallback callback) {
 208
 209         if(LOG.isDebugEnabled()) {
 210             LOG.debug("Tx {} {}", transactionId, operationName);
 211         }
 212         final SettableFuture<Void> returnFuture = SettableFuture.create();
 213
 214         // The cohort actor list should already be built at this point by the canCommit phase but,
 215         // if not for some reason, we'll try to build it here.
 216
 217         if(cohorts != null) {
 218             finishVoidOperation(operationName, message, expectedResponseClass, propagateException,
 219                     returnFuture, callback);
 220         } else {
 221             buildCohortList().onComplete(new OnComplete<Void>() {
 222                 @Override
 223                 public void onComplete(Throwable failure, Void notUsed) throws Throwable {
 224                     if(failure != null) {
 225                         if(LOG.isDebugEnabled()) {
 226                             LOG.debug("Tx {}: a {} cohort path Future failed: {}", transactionId,
 227                                 operationName, failure);
 228                         }
 229                         if(propagateException) {
 230                             returnFuture.setException(failure);
 231                         } else {
 232                             returnFuture.set(null);
 233                         }
 234                     } else {
 235                         finishVoidOperation(operationName, message, expectedResponseClass,
 236                                 propagateException, returnFuture, callback);
 237                     }
 238                 }
 239             }, actorContext.getClientDispatcher());
 240         }
 241
 242         return returnFuture;
 243     }
 244
 245     private void finishVoidOperation(final String operationName, final Object message,
 246                                      final Class<?> expectedResponseClass, final boolean propagateException,
 247                                      final SettableFuture<Void> returnFuture, final OperationCallback callback) {
 248         if(LOG.isDebugEnabled()) {
 249             LOG.debug("Tx {} finish {}", transactionId, operationName);
 250         }
 251
 252         callback.run();
 253
 254         Future<Iterable<Object>> combinedFuture = invokeCohorts(message);
 255
 256         combinedFuture.onComplete(new OnComplete<Iterable<Object>>() {
 257             @Override
 258             public void onComplete(Throwable failure, Iterable<Object> responses) throws Throwable {
 259
 260                 Throwable exceptionToPropagate = failure;
 261                 if(exceptionToPropagate == null) {
 262                     for(Object response: responses) {
 263                         if(!response.getClass().equals(expectedResponseClass)) {
 264                             exceptionToPropagate = new IllegalArgumentException(
 265                                     String.format("Unexpected response type %s",
 266                                             response.getClass()));
 267                             break;
 268                         }
 269                     }
 270                 }
 271
 272                 if(exceptionToPropagate != null) {
 273
 274                     if(LOG.isDebugEnabled()) {
 275                         LOG.debug("Tx {}: a {} cohort Future failed: {}", transactionId,
 276                             operationName, exceptionToPropagate);
 277                     }
 278                     if(propagateException) {
 279                         // We don't log the exception here to avoid redundant logging since we're
 280                         // propagating to the caller in MD-SAL core who will log it.
 281                         returnFuture.setException(exceptionToPropagate);
 282                     } else {
 283                         // Since the caller doesn't want us to propagate the exception we'll also
 284                         // not log it normally. But it's usually not good to totally silence
 285                         // exceptions so we'll log it to debug level.
 286                         if(LOG.isDebugEnabled()) {
 287                             LOG.debug(String.format("%s failed", message.getClass().getSimpleName()),
 288                                 exceptionToPropagate);
 289                         }
 290                         returnFuture.set(null);
 291                     }
 292
 293                     callback.failure();
 294                 } else {
 295
 296                     if(LOG.isDebugEnabled()) {
 297                         LOG.debug("Tx {}: {} succeeded", transactionId, operationName);
 298                     }
 299                     returnFuture.set(null);
 300
 301                     callback.success();
 302                 }
 303             }
 304         }, actorContext.getClientDispatcher());
 305     }
 306
 307     @VisibleForTesting
 308     List<Future<ActorSelection>> getCohortFutures() {
 309         return Collections.unmodifiableList(cohortFutures);
 310     }
 311 }