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