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

   1 /*
   2  * Copyright (c) 2020 PANTHEON.tech, s.r.o. 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;
   9
  10 import static com.google.common.base.Verify.verify;
  11 import static com.google.common.base.Verify.verifyNotNull;
  12 import static java.util.Objects.requireNonNull;
  13
  14 import akka.actor.ActorRef;
  15 import akka.actor.ActorSelection;
  16 import akka.actor.PoisonPill;
  17 import akka.dispatch.OnComplete;
  18 import com.google.common.collect.Maps;
  19 import java.util.ArrayList;
  20 import java.util.HashMap;
  21 import java.util.List;
  22 import java.util.Map;
  23 import java.util.Map.Entry;
  24 import java.util.Set;
  25 import org.checkerframework.checker.lock.qual.GuardedBy;
  26 import org.checkerframework.checker.lock.qual.Holding;
  27 import org.eclipse.jdt.annotation.NonNull;
  28 import org.opendaylight.controller.cluster.datastore.messages.CloseDataTreeNotificationListenerRegistration;
  29 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  30 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeNotificationListenerReply;
  31 import org.opendaylight.controller.cluster.datastore.utils.ActorUtils;
  32 import org.opendaylight.mdsal.dom.api.DOMDataTreeChangeListener;
  33 import org.opendaylight.yangtools.concepts.AbstractListenerRegistration;
  34 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  35 import org.slf4j.Logger;
  36 import org.slf4j.LoggerFactory;
  37
  38 final class RootDataTreeChangeListenerProxy<L extends DOMDataTreeChangeListener>
  39         extends AbstractListenerRegistration<L> {
  40     private abstract static class State {
  41
  42     }
  43
  44     private static final class ResolveShards extends State {
  45         final Map<String, Object> localShards = new HashMap<>();
  46         final int shardCount;
  47
  48         ResolveShards(final int shardCount) {
  49             this.shardCount = shardCount;
  50         }
  51     }
  52
  53     private static final class Subscribed extends State {
  54         final List<ActorSelection> subscriptions;
  55         final ActorRef dtclActor;
  56
  57         Subscribed(final ActorRef dtclActor, final int shardCount) {
  58             this.dtclActor = requireNonNull(dtclActor);
  59             subscriptions = new ArrayList<>(shardCount);
  60         }
  61     }
  62
  63     private static final class Terminated extends State {
  64
  65     }
  66
  67     private static final Logger LOG = LoggerFactory.getLogger(RootDataTreeChangeListenerProxy.class);
  68
  69     private final ActorUtils actorUtils;
  70
  71     @GuardedBy("this")
  72     private State state;
  73
  74     RootDataTreeChangeListenerProxy(final ActorUtils actorUtils, final @NonNull L listener,
  75             final Set<String> shardNames) {
  76         super(listener);
  77         this.actorUtils = requireNonNull(actorUtils);
  78         this.state = new ResolveShards(shardNames.size());
  79
  80         for (String shardName : shardNames) {
  81             actorUtils.findLocalShardAsync(shardName).onComplete(new OnComplete<ActorRef>() {
  82                 @Override
  83                 public void onComplete(final Throwable failure, final ActorRef success) {
  84                     onFindLocalShardComplete(shardName, failure, success);
  85                 }
  86             }, actorUtils.getClientDispatcher());
  87         }
  88     }
  89
  90     @Override
  91     protected synchronized void removeRegistration() {
  92         if (state instanceof Terminated) {
  93             // Trivial case: we have already terminated on a failure, so this is a no-op
  94         } else if (state instanceof ResolveShards) {
  95             // Simple case: just mark the fact we were closed, terminating when resolution finishes
  96             state = new Terminated();
  97         } else if (state instanceof Subscribed) {
  98             terminate((Subscribed) state);
  99         } else {
 100             throw new IllegalStateException("Unhandled close in state " + state);
 101         }
 102     }
 103
 104     private synchronized void onFindLocalShardComplete(final String shardName, final Throwable failure,
 105             final ActorRef shard) {
 106         if (state instanceof ResolveShards) {
 107             localShardsResolved((ResolveShards) state, shardName, failure, shard);
 108         } else {
 109             LOG.debug("{}: lookup for shard {} turned into a noop on state {}", logContext(), shardName, state);
 110         }
 111     }
 112
 113     @Holding("this")
 114     private void localShardsResolved(final ResolveShards current, final String shardName, final Throwable failure,
 115             final ActorRef shard) {
 116         final Object result = failure != null ? failure : verifyNotNull(shard);
 117         LOG.debug("{}: lookup for shard {} resulted in {}", logContext(), shardName, result);
 118         current.localShards.put(shardName, result);
 119
 120         if (current.localShards.size() == current.shardCount) {
 121             // We have all the responses we need
 122             if (current.localShards.values().stream().anyMatch(Throwable.class::isInstance)) {
 123                 reportFailure(current.localShards);
 124             } else {
 125                 subscribeToShards(current.localShards);
 126             }
 127         }
 128     }
 129
 130     @Holding("this")
 131     private void reportFailure(final Map<String, Object> localShards) {
 132         for (Entry<String, Object> entry : Maps.filterValues(localShards, Throwable.class::isInstance).entrySet()) {
 133             final Throwable cause = (Throwable) entry.getValue();
 134             LOG.error("{}: Failed to find local shard {}, cannot register {} at root", logContext(), entry.getKey(),
 135                 getInstance(), cause);
 136         }
 137         state = new Terminated();
 138     }
 139
 140     @Holding("this")
 141     private void subscribeToShards(final Map<String, Object> localShards) {
 142         // Safety check before we start doing anything
 143         for (Entry<String, Object> entry : localShards.entrySet()) {
 144             final Object obj = entry.getValue();
 145             verify(obj instanceof ActorRef, "Unhandled response %s for shard %s", obj, entry.getKey());
 146         }
 147
 148         // Instantiate the DTCL actor and update state
 149         final ActorRef dtclActor = actorUtils.getActorSystem().actorOf(
 150             RootDataTreeChangeListenerActor.props(getInstance(), localShards.size())
 151               .withDispatcher(actorUtils.getNotificationDispatcherPath()));
 152         state = new Subscribed(dtclActor, localShards.size());
 153
 154         // Subscribe to all shards
 155         final RegisterDataTreeChangeListener regMessage = new RegisterDataTreeChangeListener(
 156             YangInstanceIdentifier.empty(), dtclActor, true);
 157         for (Entry<String, Object> entry : localShards.entrySet()) {
 158             // Do not retain references to localShards
 159             final String shardName = entry.getKey();
 160             final ActorRef shard = (ActorRef) entry.getValue();
 161
 162             actorUtils.executeOperationAsync(shard, regMessage,
 163                 actorUtils.getDatastoreContext().getShardInitializationTimeout()).onComplete(new OnComplete<>() {
 164                     @Override
 165                     public void onComplete(final Throwable failure, final Object result) {
 166                         onShardSubscribed(shardName, failure, result);
 167                     }
 168                 }, actorUtils.getClientDispatcher());
 169         }
 170     }
 171
 172     private synchronized void onShardSubscribed(final String shardName, final Throwable failure, final Object result) {
 173         if (state instanceof Subscribed) {
 174             final Subscribed current = (Subscribed) state;
 175             if (failure != null) {
 176                 LOG.error("{}: Shard {} failed to subscribe, terminating listener {}", logContext(),
 177                     shardName,getInstance(), failure);
 178                 terminate(current);
 179             } else {
 180                 onSuccessfulSubscription(current, shardName, (RegisterDataTreeNotificationListenerReply) result);
 181             }
 182         } else {
 183             terminateSubscription(shardName, failure, result);
 184         }
 185     }
 186
 187     @Holding("this")
 188     private void onSuccessfulSubscription(final Subscribed current, final String shardName,
 189             final RegisterDataTreeNotificationListenerReply reply) {
 190         final ActorSelection regActor = actorUtils.actorSelection(reply.getListenerRegistrationPath());
 191         LOG.debug("{}: Shard {} subscribed at {}", logContext(), shardName, regActor);
 192         current.subscriptions.add(regActor);
 193     }
 194
 195     @Holding("this")
 196     private void terminate(final Subscribed current) {
 197         // Terminate the listener
 198         current.dtclActor.tell(PoisonPill.getInstance(), ActorRef.noSender());
 199         // Terminate all subscriptions
 200         for (ActorSelection regActor : current.subscriptions) {
 201             regActor.tell(CloseDataTreeNotificationListenerRegistration.getInstance(), ActorRef.noSender());
 202         }
 203         state = new Terminated();
 204     }
 205
 206     // This method should not modify internal state
 207     private void terminateSubscription(final String shardName, final Throwable failure, final Object result) {
 208         if (failure == null) {
 209             final ActorSelection regActor = actorUtils.actorSelection(
 210                 ((RegisterDataTreeNotificationListenerReply) result).getListenerRegistrationPath());
 211             LOG.debug("{}: Shard {} registered late, terminating subscription at {}", logContext(), shardName,
 212                 regActor);
 213             regActor.tell(CloseDataTreeNotificationListenerRegistration.getInstance(), ActorRef.noSender());
 214         } else {
 215             LOG.debug("{}: Shard {} reported late failure", logContext(), shardName, failure);
 216         }
 217     }
 218
 219     private String logContext() {
 220         return actorUtils.getDatastoreContext().getLogicalStoreType().toString();
 221     }
 222 }