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 org.checkerframework.checker.lock.qual.GuardedBy;
  25 import org.eclipse.jdt.annotation.NonNull;
  26 import org.eclipse.jdt.annotation.Nullable;
  27 import org.opendaylight.controller.cluster.access.ABIVersion;
  28 import org.opendaylight.controller.cluster.access.client.BackendInfoResolver;
  29 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  30 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  31 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
  32 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  33 import org.opendaylight.controller.cluster.access.concepts.RequestFailure;
  34 import org.opendaylight.controller.cluster.common.actor.ExplicitAsk;
  35 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  36 import org.opendaylight.controller.cluster.datastore.exceptions.NotInitializedException;
  37 import org.opendaylight.controller.cluster.datastore.exceptions.PrimaryNotFoundException;
  38 import org.opendaylight.controller.cluster.datastore.messages.PrimaryShardInfo;
  39 import org.opendaylight.controller.cluster.datastore.utils.ActorUtils;
  40 import org.opendaylight.yangtools.concepts.Registration;
  41 import org.slf4j.Logger;
  42 import org.slf4j.LoggerFactory;
  43 import scala.Function1;
  44 import scala.compat.java8.FutureConverters;
  45
  46 /**
  47  * {@link BackendInfoResolver} implementation for static shard configuration based on ShardManager. Each string-named
  48  * shard is assigned a single cookie and this mapping is stored in a bidirectional map. Information about corresponding
  49  * shard leader is resolved via {@link ActorUtils}. The product of resolution is {@link ShardBackendInfo}.
  50  *
  51  * <p>
  52  * This class is thread-safe.
  53  *
  54  * @author Robert Varga
  55  */
  56 abstract class AbstractShardBackendResolver extends BackendInfoResolver<ShardBackendInfo> {
  57     static final class ShardState {
  58         private final CompletionStage<ShardBackendInfo> stage;
  59         @GuardedBy("this")
  60         private ShardBackendInfo result;
  61
  62         ShardState(final CompletionStage<ShardBackendInfo> stage) {
  63             this.stage = requireNonNull(stage);
  64             stage.whenComplete(this::onStageResolved);
  65         }
  66
  67         @NonNull CompletionStage<ShardBackendInfo> getStage() {
  68             return stage;
  69         }
  70
  71         synchronized @Nullable ShardBackendInfo getResult() {
  72             return result;
  73         }
  74
  75         private synchronized void onStageResolved(final ShardBackendInfo info, final Throwable failure) {
  76             if (failure == null) {
  77                 this.result = requireNonNull(info);
  78             } else {
  79                 LOG.warn("Failed to resolve shard", failure);
  80             }
  81         }
  82     }
  83
  84     private static final Logger LOG = LoggerFactory.getLogger(AbstractShardBackendResolver.class);
  85
  86     /**
  87      * Connect request timeout. If the shard does not respond within this interval, we retry the lookup and connection.
  88      */
  89     // TODO: maybe make this configurable somehow?
  90     private static final Timeout CONNECT_TIMEOUT = Timeout.apply(5, TimeUnit.SECONDS);
  91
  92     private final AtomicLong nextSessionId = new AtomicLong();
  93     private final Function1<ActorRef, ?> connectFunction;
  94     private final ActorUtils actorUtils;
  95     private final Set<Consumer<Long>> staleBackendInfoCallbacks = ConcurrentHashMap.newKeySet();
  96
  97     // FIXME: we really need just ActorContext.findPrimaryShardAsync()
  98     AbstractShardBackendResolver(final ClientIdentifier clientId, final ActorUtils actorUtils) {
  99         this.actorUtils = requireNonNull(actorUtils);
 100         this.connectFunction = ExplicitAsk.toScala(t -> new ConnectClientRequest(clientId, t, ABIVersion.BORON,
 101             ABIVersion.current()));
 102     }
 103
 104     @Override
 105     public Registration notifyWhenBackendInfoIsStale(final Consumer<Long> callback) {
 106         staleBackendInfoCallbacks.add(callback);
 107         return () -> staleBackendInfoCallbacks.remove(callback);
 108     }
 109
 110     protected void notifyStaleBackendInfoCallbacks(Long cookie) {
 111         staleBackendInfoCallbacks.forEach(callback -> callback.accept(cookie));
 112     }
 113
 114     protected ActorUtils actorUtils() {
 115         return actorUtils;
 116     }
 117
 118     protected final void flushCache(final String shardName) {
 119         actorUtils.getPrimaryShardInfoCache().remove(shardName);
 120     }
 121
 122     protected final ShardState resolveBackendInfo(final String shardName, final long cookie) {
 123         LOG.debug("Resolving cookie {} to shard {}", cookie, shardName);
 124
 125         final CompletableFuture<ShardBackendInfo> future = new CompletableFuture<>();
 126         FutureConverters.toJava(actorUtils.findPrimaryShardAsync(shardName)).whenComplete((info, failure) -> {
 127             if (failure == null) {
 128                 connectShard(shardName, cookie, info, future);
 129                 return;
 130             }
 131
 132             LOG.debug("Shard {} failed to resolve", shardName, failure);
 133             if (failure instanceof NoShardLeaderException) {
 134                 future.completeExceptionally(wrap("Shard has no current leader", failure));
 135             } else if (failure instanceof NotInitializedException) {
 136                 // FIXME: this actually is an exception we can retry on
 137                 LOG.info("Shard {} has not initialized yet", shardName);
 138                 future.completeExceptionally(failure);
 139             } else if (failure instanceof PrimaryNotFoundException) {
 140                 LOG.info("Failed to find primary for shard {}", shardName);
 141                 future.completeExceptionally(failure);
 142             } else {
 143                 future.completeExceptionally(failure);
 144             }
 145         });
 146
 147         return new ShardState(future);
 148     }
 149
 150     private static TimeoutException wrap(final String message, final Throwable cause) {
 151         final TimeoutException ret = new TimeoutException(message);
 152         ret.initCause(requireNonNull(cause));
 153         return ret;
 154     }
 155
 156     private void connectShard(final String shardName, final long cookie, final PrimaryShardInfo info,
 157             final CompletableFuture<ShardBackendInfo> future) {
 158         LOG.debug("Shard {} resolved to {}, attempting to connect", shardName, info);
 159
 160         FutureConverters.toJava(ExplicitAsk.ask(info.getPrimaryShardActor(), connectFunction, CONNECT_TIMEOUT))
 161             .whenComplete((response, failure) -> onConnectResponse(shardName, cookie, future, response, failure));
 162     }
 163
 164     private void onConnectResponse(final String shardName, final long cookie,
 165             final CompletableFuture<ShardBackendInfo> future, final Object response, final Throwable failure) {
 166         if (failure != null) {
 167             LOG.debug("Connect attempt to {} failed, will retry", shardName, failure);
 168             future.completeExceptionally(wrap("Connection attempt failed", failure));
 169             return;
 170         }
 171         if (response instanceof RequestFailure) {
 172             final Throwable cause = ((RequestFailure<?, ?>) response).getCause().unwrap();
 173             LOG.debug("Connect attempt to {} failed to process", shardName, cause);
 174             final Throwable result = cause instanceof NotLeaderException
 175                     ? wrap("Leader moved during establishment", cause) : cause;
 176             future.completeExceptionally(result);
 177             return;
 178         }
 179
 180         LOG.debug("Resolved backend information to {}", response);
 181         checkArgument(response instanceof ConnectClientSuccess, "Unhandled response %s", response);
 182         final ConnectClientSuccess success = (ConnectClientSuccess) response;
 183         future.complete(new ShardBackendInfo(success.getBackend(), nextSessionId.getAndIncrement(),
 184             success.getVersion(), shardName, UnsignedLong.fromLongBits(cookie), success.getDataTree(),
 185             success.getMaxMessages()));
 186     }
 187 }