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.concurrent.CompletableFuture;
  15 import java.util.concurrent.CompletionStage;
  16 import java.util.concurrent.TimeUnit;
  17 import java.util.concurrent.atomic.AtomicLong;
  18 import javax.annotation.Nonnull;
  19 import javax.annotation.Nullable;
  20 import javax.annotation.concurrent.GuardedBy;
  21 import javax.annotation.concurrent.ThreadSafe;
  22 import org.opendaylight.controller.cluster.access.ABIVersion;
  23 import org.opendaylight.controller.cluster.access.client.BackendInfoResolver;
  24 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
  25 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
  26 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
  27 import org.opendaylight.controller.cluster.access.concepts.RequestFailure;
  28 import org.opendaylight.controller.cluster.common.actor.ExplicitAsk;
  29 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  30 import org.opendaylight.controller.cluster.datastore.exceptions.NotInitializedException;
  31 import org.opendaylight.controller.cluster.datastore.exceptions.PrimaryNotFoundException;
  32 import org.opendaylight.controller.cluster.datastore.messages.PrimaryShardInfo;
  33 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  34 import org.slf4j.Logger;
  35 import org.slf4j.LoggerFactory;
  36 import scala.Function1;
  37 import scala.compat.java8.FutureConverters;
  38
  39 /**
  40  * {@link BackendInfoResolver} implementation for static shard configuration based on ShardManager. Each string-named
  41  * shard is assigned a single cookie and this mapping is stored in a bidirectional map. Information about corresponding
  42  * shard leader is resolved via {@link ActorContext}. The product of resolution is {@link ShardBackendInfo}.
  43  *
  44  * @author Robert Varga
  45  */
  46 @ThreadSafe
  47 abstract class AbstractShardBackendResolver extends BackendInfoResolver<ShardBackendInfo> {
  48     static final class ShardState {
  49         private final CompletionStage<ShardBackendInfo> stage;
  50         @GuardedBy("this")
  51         private ShardBackendInfo result;
  52
  53         ShardState(final CompletionStage<ShardBackendInfo> stage) {
  54             this.stage = Preconditions.checkNotNull(stage);
  55             stage.whenComplete(this::onStageResolved);
  56         }
  57
  58         @Nonnull CompletionStage<ShardBackendInfo> getStage() {
  59             return stage;
  60         }
  61
  62         @Nullable synchronized ShardBackendInfo getResult() {
  63             return result;
  64         }
  65
  66         private synchronized void onStageResolved(final ShardBackendInfo result, final Throwable failure) {
  67             if (failure == null) {
  68                 this.result = Preconditions.checkNotNull(result);
  69             } else {
  70                 LOG.warn("Failed to resolve shard", failure);
  71             }
  72         }
  73     }
  74
  75     private static final Logger LOG = LoggerFactory.getLogger(AbstractShardBackendResolver.class);
  76
  77     /**
  78      * Connect request timeout. If the shard does not respond within this interval, we retry the lookup and connection.
  79      */
  80     // TODO: maybe make this configurable somehow?
  81     private static final Timeout CONNECT_TIMEOUT = Timeout.apply(5, TimeUnit.SECONDS);
  82
  83     private final AtomicLong nextSessionId = new AtomicLong();
  84     private final Function1<ActorRef, ?> connectFunction;
  85     private final ActorContext actorContext;
  86
  87     // FIXME: we really need just ActorContext.findPrimaryShardAsync()
  88     AbstractShardBackendResolver(final ClientIdentifier clientId, final ActorContext actorContext) {
  89         this.actorContext = Preconditions.checkNotNull(actorContext);
  90         this.connectFunction = ExplicitAsk.toScala(t -> new ConnectClientRequest(clientId, t, ABIVersion.BORON,
  91             ABIVersion.current()));
  92     }
  93
  94     protected final void flushCache(final String shardName) {
  95         actorContext.getPrimaryShardInfoCache().remove(shardName);
  96     }
  97
  98     protected final ShardState resolveBackendInfo(final String shardName, final long cookie) {
  99         LOG.debug("Resolving cookie {} to shard {}", cookie, shardName);
 100
 101         final CompletableFuture<ShardBackendInfo> future = new CompletableFuture<>();
 102         FutureConverters.toJava(actorContext.findPrimaryShardAsync(shardName)).whenComplete((info, failure) -> {
 103             if (failure == null) {
 104                 connectShard(shardName, cookie, info, future);
 105                 return;
 106             }
 107
 108             LOG.debug("Shard {} failed to resolve", shardName, failure);
 109             if (failure instanceof NoShardLeaderException) {
 110                 // FIXME: this actually is an exception we can retry on
 111                 future.completeExceptionally(failure);
 112             } else if (failure instanceof NotInitializedException) {
 113                 // FIXME: this actually is an exception we can retry on
 114                 LOG.info("Shard {} has not initialized yet", shardName);
 115                 future.completeExceptionally(failure);
 116             } else if (failure instanceof PrimaryNotFoundException) {
 117                 LOG.info("Failed to find primary for shard {}", shardName);
 118                 future.completeExceptionally(failure);
 119             } else {
 120                 future.completeExceptionally(failure);
 121             }
 122         });
 123
 124         return new ShardState(future);
 125     }
 126
 127     private void connectShard(final String shardName, final long cookie, final PrimaryShardInfo info,
 128             final CompletableFuture<ShardBackendInfo> future) {
 129         LOG.debug("Shard {} resolved to {}, attempting to connect", shardName, info);
 130
 131         FutureConverters.toJava(ExplicitAsk.ask(info.getPrimaryShardActor(), connectFunction, CONNECT_TIMEOUT))
 132             .whenComplete((response, failure) -> {
 133                 if (failure != null) {
 134                     LOG.debug("Connect attempt to {} failed", shardName, failure);
 135                     future.completeExceptionally(failure);
 136                     return;
 137                 }
 138                 if (response instanceof RequestFailure) {
 139                     final Throwable cause = ((RequestFailure<?, ?>) response).getCause().unwrap();
 140                     LOG.debug("Connect attempt to {} failed to process", shardName, cause);
 141                     future.completeExceptionally(cause);
 142                     return;
 143                 }
 144
 145                 LOG.debug("Resolved backend information to {}", response);
 146                 Preconditions.checkArgument(response instanceof ConnectClientSuccess, "Unhandled response {}",
 147                     response);
 148                 final ConnectClientSuccess success = (ConnectClientSuccess) response;
 149                 future.complete(new ShardBackendInfo(success.getBackend(), nextSessionId.getAndIncrement(),
 150                     success.getVersion(), shardName, UnsignedLong.fromLongBits(cookie), success.getDataTree(),
 151                     success.getMaxMessages()));
 152             });
 153     }
 154 }