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

   1 /*
   2  * Copyright (c) 2015 Brocade Communications 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.entityownership;
   9
  10 import akka.actor.ActorRef;
  11 import akka.actor.Cancellable;
  12 import akka.actor.Status.Failure;
  13 import com.google.common.base.Preconditions;
  14 import java.util.Iterator;
  15 import java.util.LinkedList;
  16 import java.util.Queue;
  17 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  18 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
  19 import org.opendaylight.controller.cluster.access.concepts.FrontendType;
  20 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  21 import org.opendaylight.controller.cluster.access.concepts.MemberName;
  22 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  23 import org.opendaylight.controller.cluster.datastore.DataStoreVersions;
  24 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  25 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  26 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
  27 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  28 import org.slf4j.Logger;
  29 import scala.concurrent.duration.FiniteDuration;
  30
  31 /**
  32  * Handles commits and retries for the EntityOwnershipShard.
  33  *
  34  * @author Thomas Pantelis
  35  */
  36 class EntityOwnershipShardCommitCoordinator {
  37     private static final Object COMMIT_RETRY_MESSAGE = new Object() {
  38         @Override
  39         public String toString() {
  40             return "entityCommitRetry";
  41         }
  42     };
  43     private static final FrontendType FRONTEND_TYPE = FrontendType.forName("entity-ownership-internal");
  44
  45     private final Queue<Modification> pendingModifications = new LinkedList<>();
  46     private final LocalHistoryIdentifier historyId;
  47     private final Logger log;
  48
  49     private BatchedModifications inflightCommit;
  50     private Cancellable retryCommitSchedule;
  51     private long transactionIDCounter = 0;
  52
  53     EntityOwnershipShardCommitCoordinator(MemberName localMemberName, Logger log) {
  54         this.log = Preconditions.checkNotNull(log);
  55         historyId = new LocalHistoryIdentifier(
  56                 ClientIdentifier.create(FrontendIdentifier.create(localMemberName, FRONTEND_TYPE), 0), 0);
  57     }
  58
  59     boolean handleMessage(Object message, EntityOwnershipShard shard) {
  60         boolean handled = true;
  61         if(CommitTransactionReply.isSerializedType(message)) {
  62             // Successful reply from a local commit.
  63             inflightCommitSucceeded(shard);
  64         } else if(message instanceof akka.actor.Status.Failure) {
  65             // Failure reply from a local commit.
  66             inflightCommitFailure(((Failure)message).cause(), shard);
  67         } else if(COMMIT_RETRY_MESSAGE.equals(message)) {
  68             retryInflightCommit(shard);
  69         } else {
  70             handled = false;
  71         }
  72
  73         return handled;
  74     }
  75
  76     private void retryInflightCommit(EntityOwnershipShard shard) {
  77         // Shouldn't be null happen but verify anyway
  78         if(inflightCommit == null) {
  79             return;
  80         }
  81
  82         if(shard.hasLeader()) {
  83             log.debug("Retrying commit for BatchedModifications {}", inflightCommit.getTransactionID());
  84
  85             shard.tryCommitModifications(inflightCommit);
  86         } else {
  87             scheduleInflightCommitRetry(shard);
  88         }
  89     }
  90
  91     void inflightCommitFailure(Throwable cause, EntityOwnershipShard shard) {
  92         // This should've originated from a failed inflight commit but verify anyway
  93         if(inflightCommit == null) {
  94             return;
  95         }
  96
  97         log.debug("Inflight BatchedModifications {} commit failed", inflightCommit.getTransactionID(), cause);
  98
  99         if(!(cause instanceof NoShardLeaderException)) {
 100             // If the failure is other than NoShardLeaderException the commit may have been partially
 101             // processed so retry with a new transaction ID to be safe.
 102             newInflightCommitWithDifferentTransactionID();
 103         }
 104
 105         scheduleInflightCommitRetry(shard);
 106     }
 107
 108     private void scheduleInflightCommitRetry(EntityOwnershipShard shard) {
 109         FiniteDuration duration = shard.getDatastoreContext().getShardRaftConfig().getElectionTimeOutInterval();
 110
 111         log.debug("Scheduling retry for BatchedModifications commit {} in {}",
 112                 inflightCommit.getTransactionID(), duration);
 113
 114         retryCommitSchedule = shard.getContext().system().scheduler().scheduleOnce(duration, shard.getSelf(),
 115                 COMMIT_RETRY_MESSAGE, shard.getContext().dispatcher(), ActorRef.noSender());
 116     }
 117
 118     void inflightCommitSucceeded(EntityOwnershipShard shard) {
 119         // Shouldn't be null but verify anyway
 120         if(inflightCommit == null) {
 121             return;
 122         }
 123
 124         if(retryCommitSchedule != null) {
 125             retryCommitSchedule.cancel();
 126         }
 127
 128         log.debug("BatchedModifications commit {} succeeded", inflightCommit.getTransactionID());
 129
 130         inflightCommit = null;
 131         commitNextBatch(shard);
 132     }
 133
 134     void commitNextBatch(EntityOwnershipShard shard) {
 135         if(inflightCommit != null || pendingModifications.isEmpty() || !shard.hasLeader()) {
 136             return;
 137         }
 138
 139         inflightCommit = newBatchedModifications();
 140         Iterator<Modification> iter = pendingModifications.iterator();
 141         while(iter.hasNext()) {
 142             inflightCommit.addModification(iter.next());
 143             iter.remove();
 144             if(inflightCommit.getModifications().size() >=
 145                     shard.getDatastoreContext().getShardBatchedModificationCount()) {
 146                 break;
 147             }
 148         }
 149
 150         log.debug("Committing next BatchedModifications {}, size {}", inflightCommit.getTransactionID(),
 151                 inflightCommit.getModifications().size());
 152
 153         shard.tryCommitModifications(inflightCommit);
 154     }
 155
 156     void commitModification(Modification modification, EntityOwnershipShard shard) {
 157         BatchedModifications modifications = newBatchedModifications();
 158         modifications.addModification(modification);
 159         commitModifications(modifications, shard);
 160     }
 161
 162     void commitModifications(BatchedModifications modifications, EntityOwnershipShard shard) {
 163         if(modifications.getModifications().isEmpty()) {
 164             return;
 165         }
 166
 167         boolean hasLeader = shard.hasLeader();
 168         if(inflightCommit != null || !hasLeader) {
 169             if(log.isDebugEnabled()) {
 170                 log.debug("{} - adding modifications to pending",
 171                         (inflightCommit != null ? "A commit is inflight" : "No shard leader"));
 172             }
 173
 174             pendingModifications.addAll(modifications.getModifications());
 175         } else {
 176             inflightCommit = modifications;
 177             shard.tryCommitModifications(inflightCommit);
 178         }
 179     }
 180
 181     void onStateChanged(EntityOwnershipShard shard, boolean isLeader) {
 182         if(!isLeader && inflightCommit != null) {
 183             // We're no longer the leader but we have an inflight local commit. This likely means we didn't get
 184             // consensus for the commit and switched to follower due to another node with a higher term. We
 185             // can't be sure if the commit was replicated to any node so we retry it here with a new
 186             // transaction ID.
 187             if(retryCommitSchedule != null) {
 188                 retryCommitSchedule.cancel();
 189             }
 190
 191             newInflightCommitWithDifferentTransactionID();
 192             retryInflightCommit(shard);
 193         } else {
 194             commitNextBatch(shard);
 195         }
 196     }
 197
 198     private void newInflightCommitWithDifferentTransactionID() {
 199         BatchedModifications newBatchedModifications = newBatchedModifications();
 200         newBatchedModifications.getModifications().addAll(inflightCommit.getModifications());
 201         inflightCommit = newBatchedModifications;
 202     }
 203
 204     BatchedModifications newBatchedModifications() {
 205         BatchedModifications modifications = new BatchedModifications(
 206             new TransactionIdentifier(historyId, ++transactionIDCounter), DataStoreVersions.CURRENT_VERSION);
 207         modifications.setDoCommitOnReady(true);
 208         modifications.setReady(true);
 209         modifications.setTotalMessagesSent(1);
 210         return modifications;
 211     }
 212 }