opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/databroker/actors/dds/AbstractShardBackendResolver.java

   1 /*
   2  * Copyright (c) 2016 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.databroker.actors.dds;
   9
  10 import static com.google.common.base.Preconditions.checkArgument;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import akka.actor.ActorRef;
  14 import akka.util.Timeout;
  15 import com.google.common.primitives.UnsignedLong;
  16 import java.util.Set;
  17 import java.util.concurrent.CompletableFuture;
  18 import java.util.concurrent.CompletionStage;
  19 import java.util.concurrent.ConcurrentHashMap;
  20 import java.util.concurrent.TimeUnit;
  21 import java.util.concurrent.TimeoutException;
  22 import java.util.concurrent.atomic.AtomicLong;
  23 import java.util.function.Consumer;
  24 import javax.annotation.concurrent.GuardedBy;
  25 import javax.annotation.concurrent.ThreadSafe;
  26 import org.eclipse.jdt.annotation.NonNull;
  27 import org.eclipse.jdt.annotation.Nullable;
  28 import org.opendaylight.controller.cluster.access.ABIVersion;
  29 import org.opendaylight.controller.cluster.access.client.BackendInfoResolver;
  30 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  31 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  32 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
  33 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  34 import org.opendaylight.controller.cluster.access.concepts.RequestFailure;
  35 import org.opendaylight.controller.cluster.common.actor.ExplicitAsk;
  36 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  37 import org.opendaylight.controller.cluster.datastore.exceptions.NotInitializedException;
  38 import org.opendaylight.controller.cluster.datastore.exceptions.PrimaryNotFoundException;
  39 import org.opendaylight.controller.cluster.datastore.messages.PrimaryShardInfo;
  40 import org.opendaylight.controller.cluster.datastore.utils.ActorUtils;
  41 import org.opendaylight.yangtools.concepts.Registration;
  42 import org.slf4j.Logger;
  43 import org.slf4j.LoggerFactory;
  44 import scala.Function1;
  45 import scala.compat.java8.FutureConverters;
  46
  47 /**
  48  * {@link BackendInfoResolver} implementation for static shard configuration based on ShardManager. Each string-named
  49  * shard is assigned a single cookie and this mapping is stored in a bidirectional map. Information about corresponding
  50  * shard leader is resolved via {@link ActorUtils}. The product of resolution is {@link ShardBackendInfo}.
  51  *
  52  * @author Robert Varga
  53  */
  54 @ThreadSafe
  55 abstract class AbstractShardBackendResolver extends BackendInfoResolver<ShardBackendInfo> {
  56     static final class ShardState {
  57         private final CompletionStage<ShardBackendInfo> stage;
  58         @GuardedBy("this")
  59         private ShardBackendInfo result;
  60
  61         ShardState(final CompletionStage<ShardBackendInfo> stage) {
  62             this.stage = requireNonNull(stage);
  63             stage.whenComplete(this::onStageResolved);
  64         }
  65
  66         @NonNull CompletionStage<ShardBackendInfo> getStage() {
  67             return stage;
  68         }
  69
  70         synchronized @Nullable ShardBackendInfo getResult() {
  71             return result;
  72         }
  73
  74         private synchronized void onStageResolved(final ShardBackendInfo info, final Throwable failure) {
  75             if (failure == null) {
  76                 this.result = requireNonNull(info);
  77             } else {
  78                 LOG.warn("Failed to resolve shard", failure);
  79             }
  80         }
  81     }
  82
  83     private static final Logger LOG = LoggerFactory.getLogger(AbstractShardBackendResolver.class);
  84
  85     /**
  86      * Connect request timeout. If the shard does not respond within this interval, we retry the lookup and connection.
  87      */
  88     // TODO: maybe make this configurable somehow?
  89     private static final Timeout CONNECT_TIMEOUT = Timeout.apply(5, TimeUnit.SECONDS);
  90
  91     private final AtomicLong nextSessionId = new AtomicLong();
  92     private final Function1<ActorRef, ?> connectFunction;
  93     private final ActorUtils actorUtils;
  94     private final Set<Consumer<Long>> staleBackendInfoCallbacks = ConcurrentHashMap.newKeySet();
  95
  96     // FIXME: we really need just ActorContext.findPrimaryShardAsync()
  97     AbstractShardBackendResolver(final ClientIdentifier clientId, final ActorUtils actorUtils) {
  98         this.actorUtils = requireNonNull(actorUtils);
  99         this.connectFunction = ExplicitAsk.toScala(t -> new ConnectClientRequest(clientId, t, ABIVersion.BORON,
 100             ABIVersion.current()));
 101     }
 102
 103     @Override
 104     public Registration notifyWhenBackendInfoIsStale(final Consumer<Long> callback) {
 105         staleBackendInfoCallbacks.add(callback);
 106         return () -> staleBackendInfoCallbacks.remove(callback);
 107     }
 108
 109     protected void notifyStaleBackendInfoCallbacks(Long cookie) {
 110         staleBackendInfoCallbacks.forEach(callback -> callback.accept(cookie));
 111     }
 112
 113     protected ActorUtils actorUtils() {
 114         return actorUtils;
 115     }
 116
 117     protected final void flushCache(final String shardName) {
 118         actorUtils.getPrimaryShardInfoCache().remove(shardName);
 119     }
 120
 121     protected final ShardState resolveBackendInfo(final String shardName, final long cookie) {
 122         LOG.debug("Resolving cookie {} to shard {}", cookie, shardName);
 123
 124         final CompletableFuture<ShardBackendInfo> future = new CompletableFuture<>();
 125         FutureConverters.toJava(actorUtils.findPrimaryShardAsync(shardName)).whenComplete((info, failure) -> {
 126             if (failure == null) {
 127                 connectShard(shardName, cookie, info, future);
 128                 return;
 129             }
 130
 131             LOG.debug("Shard {} failed to resolve", shardName, failure);
 132             if (failure instanceof NoShardLeaderException) {
 133                 future.completeExceptionally(wrap("Shard has no current leader", failure));
 134             } else if (failure instanceof NotInitializedException) {
 135                 // FIXME: this actually is an exception we can retry on
 136                 LOG.info("Shard {} has not initialized yet", shardName);
 137                 future.completeExceptionally(failure);
 138             } else if (failure instanceof PrimaryNotFoundException) {
 139                 LOG.info("Failed to find primary for shard {}", shardName);
 140                 future.completeExceptionally(failure);
 141             } else {
 142                 future.completeExceptionally(failure);
 143             }
 144         });
 145
 146         return new ShardState(future);
 147     }
 148
 149     private static TimeoutException wrap(final String message, final Throwable cause) {
 150         final TimeoutException ret = new TimeoutException(message);
 151         ret.initCause(requireNonNull(cause));
 152         return ret;
 153     }
 154
 155     private void connectShard(final String shardName, final long cookie, final PrimaryShardInfo info,
 156             final CompletableFuture<ShardBackendInfo> future) {
 157         LOG.debug("Shard {} resolved to {}, attempting to connect", shardName, info);
 158
 159         FutureConverters.toJava(ExplicitAsk.ask(info.getPrimaryShardActor(), connectFunction, CONNECT_TIMEOUT))
 160             .whenComplete((response, failure) -> onConnectResponse(shardName, cookie, future, response, failure));
 161     }
 162
 163     private void onConnectResponse(final String shardName, final long cookie,
 164             final CompletableFuture<ShardBackendInfo> future, final Object response, final Throwable failure) {
 165         if (failure != null) {
 166             LOG.debug("Connect attempt to {} failed, will retry", shardName, failure);
 167             future.completeExceptionally(wrap("Connection attempt failed", failure));
 168             return;
 169         }
 170         if (response instanceof RequestFailure) {
 171             final Throwable cause = ((RequestFailure<?, ?>) response).getCause().unwrap();
 172             LOG.debug("Connect attempt to {} failed to process", shardName, cause);
 173             final Throwable result = cause instanceof NotLeaderException
 174                     ? wrap("Leader moved during establishment", cause) : cause;
 175             future.completeExceptionally(result);
 176             return;
 177         }
 178
 179         LOG.debug("Resolved backend information to {}", response);
 180         checkArgument(response instanceof ConnectClientSuccess, "Unhandled response %s", response);
 181         final ConnectClientSuccess success = (ConnectClientSuccess) response;
 182         future.complete(new ShardBackendInfo(success.getBackend(), nextSessionId.getAndIncrement(),
 183             success.getVersion(), shardName, UnsignedLong.fromLongBits(cookie), success.getDataTree(),
 184             success.getMaxMessages()));
 185     }
 186 }