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

   1 /*
   2  * Copyright (c) 2017 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.sharding;
   9
  10 import static akka.actor.ActorRef.noSender;
  11 import static com.google.common.base.Preconditions.checkArgument;
  12 import static com.google.common.base.Preconditions.checkState;
  13 import static java.util.Objects.requireNonNull;
  14
  15 import akka.actor.ActorRef;
  16 import akka.actor.PoisonPill;
  17 import akka.dispatch.Futures;
  18 import akka.dispatch.Mapper;
  19 import akka.dispatch.OnComplete;
  20 import akka.util.Timeout;
  21 import com.google.common.base.Optional;
  22 import java.util.Collection;
  23 import java.util.concurrent.CompletionStage;
  24 import java.util.concurrent.ConcurrentHashMap;
  25 import org.opendaylight.controller.cluster.datastore.exceptions.LocalShardNotFoundException;
  26 import org.opendaylight.controller.cluster.datastore.messages.MakeLeaderLocal;
  27 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  28 import org.opendaylight.controller.cluster.datastore.utils.ClusterUtils;
  29 import org.opendaylight.controller.cluster.dom.api.CDSShardAccess;
  30 import org.opendaylight.controller.cluster.dom.api.LeaderLocation;
  31 import org.opendaylight.controller.cluster.dom.api.LeaderLocationListener;
  32 import org.opendaylight.controller.cluster.dom.api.LeaderLocationListenerRegistration;
  33 import org.opendaylight.controller.cluster.raft.LeadershipTransferFailedException;
  34 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  35 import org.slf4j.Logger;
  36 import org.slf4j.LoggerFactory;
  37 import scala.compat.java8.FutureConverters;
  38 import scala.concurrent.Future;
  39
  40 /**
  41  * Default {@link CDSShardAccess} implementation. Listens on leader location
  42  * change events and distributes them to registered listeners. Also updates
  43  * current information about leader location accordingly.
  44  *
  45  * <p>
  46  * Sends {@link MakeLeaderLocal} message to local shards and translates its result
  47  * on behalf users {@link #makeLeaderLocal()} calls.
  48  *
  49  * <p>
  50  * {@link org.opendaylight.controller.cluster.dom.api.CDSDataTreeProducer} that
  51  * creates instances of this class has to call {@link #close()} once it is no
  52  * longer valid.
  53  */
  54 final class CDSShardAccessImpl implements CDSShardAccess, LeaderLocationListener, AutoCloseable {
  55     private static final Logger LOG = LoggerFactory.getLogger(CDSShardAccessImpl.class);
  56
  57     private final Collection<LeaderLocationListener> listeners = ConcurrentHashMap.newKeySet();
  58     private final DOMDataTreeIdentifier prefix;
  59     private final ActorContext actorContext;
  60     private final Timeout makeLeaderLocalTimeout;
  61
  62     private ActorRef roleChangeListenerActor;
  63
  64     private volatile LeaderLocation currentLeader = LeaderLocation.UNKNOWN;
  65     private volatile boolean closed = false;
  66
  67     CDSShardAccessImpl(final DOMDataTreeIdentifier prefix, final ActorContext actorContext) {
  68         this.prefix = requireNonNull(prefix);
  69         this.actorContext = requireNonNull(actorContext);
  70         this.makeLeaderLocalTimeout =
  71                 new Timeout(actorContext.getDatastoreContext().getShardLeaderElectionTimeout().duration().$times(2));
  72
  73         // register RoleChangeListenerActor
  74         // TODO Maybe we should do this in async
  75         final Optional<ActorRef> localShardReply =
  76                 actorContext.findLocalShard(ClusterUtils.getCleanShardName(prefix.getRootIdentifier()));
  77         checkState(localShardReply.isPresent(),
  78                 "Local shard for {} not present. Cannot register RoleChangeListenerActor", prefix);
  79         roleChangeListenerActor =
  80                 actorContext.getActorSystem().actorOf(RoleChangeListenerActor.props(localShardReply.get(), this));
  81     }
  82
  83     private void checkNotClosed() {
  84         checkState(!closed, "CDSDataTreeProducer, that this CDSShardAccess is associated with, is no longer valid");
  85     }
  86
  87     @Override
  88     public DOMDataTreeIdentifier getShardIdentifier() {
  89         checkNotClosed();
  90         return prefix;
  91     }
  92
  93     @Override
  94     public LeaderLocation getLeaderLocation() {
  95         checkNotClosed();
  96         // TODO before getting first notification from roleChangeListenerActor
  97         // we will always return UNKNOWN
  98         return currentLeader;
  99     }
 100
 101     @Override
 102     public CompletionStage<Void> makeLeaderLocal() {
 103         // TODO when we have running make leader local operation
 104         // we should just return the same completion stage
 105         checkNotClosed();
 106
 107         // TODO can we cache local shard actorRef?
 108         final Future<ActorRef> localShardReply =
 109                 actorContext.findLocalShardAsync(ClusterUtils.getCleanShardName(prefix.getRootIdentifier()));
 110
 111         // we have to tell local shard to make leader local
 112         final scala.concurrent.Promise<Object> makeLeaderLocalAsk = Futures.promise();
 113         localShardReply.onComplete(new OnComplete<ActorRef>() {
 114             @Override
 115             public void onComplete(final Throwable failure, final ActorRef actorRef) {
 116                 if (failure instanceof LocalShardNotFoundException) {
 117                     LOG.debug("No local shard found for {} - Cannot request leadership transfer to local shard.",
 118                             getShardIdentifier(), failure);
 119                     makeLeaderLocalAsk.failure(failure);
 120                 } else if (failure != null) {
 121                     // TODO should this be WARN?
 122                     LOG.debug("Failed to find local shard for {} - Cannot request leadership transfer to local shard.",
 123                             getShardIdentifier(), failure);
 124                     makeLeaderLocalAsk.failure(failure);
 125                 } else {
 126                     makeLeaderLocalAsk
 127                             .completeWith(actorContext
 128                                     .executeOperationAsync(actorRef, MakeLeaderLocal.INSTANCE, makeLeaderLocalTimeout));
 129                 }
 130             }
 131         }, actorContext.getClientDispatcher());
 132
 133         // we have to transform make leader local request result
 134         Future<Void> makeLeaderLocalFuture = makeLeaderLocalAsk.future()
 135                 .transform(new Mapper<Object, Void>() {
 136                     @Override
 137                     public Void apply(final Object parameter) {
 138                         return null;
 139                     }
 140                 }, new Mapper<Throwable, Throwable>() {
 141                     @Override
 142                     public Throwable apply(final Throwable parameter) {
 143                         if (parameter instanceof LeadershipTransferFailedException) {
 144                             // do nothing with exception and just pass it as it is
 145                             return parameter;
 146                         }
 147                         // wrap exception in LeadershipTransferFailedEx
 148                         return new LeadershipTransferFailedException("Leadership transfer failed", parameter);
 149                     }
 150                 }, actorContext.getClientDispatcher());
 151
 152         return FutureConverters.toJava(makeLeaderLocalFuture);
 153     }
 154
 155     @Override
 156     public <L extends LeaderLocationListener> LeaderLocationListenerRegistration<L>
 157             registerLeaderLocationListener(final L listener) {
 158         checkNotClosed();
 159         requireNonNull(listener);
 160         checkArgument(!listeners.contains(listener), "Listener %s is already registered with ShardAccess %s", listener,
 161             this);
 162
 163         LOG.debug("Registering LeaderLocationListener {}", listener);
 164
 165         listeners.add(listener);
 166
 167         return new LeaderLocationListenerRegistration<L>() {
 168             @Override
 169             public L getInstance() {
 170                 return listener;
 171             }
 172
 173             @Override
 174             public void close() {
 175                 listeners.remove(listener);
 176             }
 177         };
 178     }
 179
 180     @Override
 181     @SuppressWarnings("checkstyle:IllegalCatch")
 182     public void onLeaderLocationChanged(final LeaderLocation location) {
 183         if (closed) {
 184             // we are closed already. Do not dispatch any new leader location
 185             // change events.
 186             return;
 187         }
 188
 189         LOG.debug("Received leader location change notification. New leader location: {}", location);
 190         currentLeader = location;
 191         listeners.forEach(listener -> {
 192             try {
 193                 listener.onLeaderLocationChanged(location);
 194             } catch (Exception e) {
 195                 LOG.warn("Ignoring uncaught exception thrown be LeaderLocationListener {} "
 196                         + "during processing leader location change {}", listener, location, e);
 197             }
 198         });
 199     }
 200
 201     @Override
 202     public void close() {
 203         // TODO should we also remove all listeners?
 204         LOG.debug("Closing {} ShardAccess", prefix);
 205         closed = true;
 206
 207         if (roleChangeListenerActor != null) {
 208             // stop RoleChangeListenerActor
 209             roleChangeListenerActor.tell(PoisonPill.getInstance(), noSender());
 210             roleChangeListenerActor = null;
 211         }
 212     }
 213 }