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