opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/databroker/actors/dds/ModuleShardBackendResolver.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.dispatch.ExecutionContexts;
  11 import akka.dispatch.OnComplete;
  12 import akka.util.Timeout;
  13 import com.google.common.base.Preconditions;
  14 import com.google.common.collect.BiMap;
  15 import com.google.common.collect.ImmutableBiMap;
  16 import com.google.common.collect.ImmutableBiMap.Builder;
  17 import com.google.common.primitives.UnsignedLong;
  18 import com.google.common.util.concurrent.MoreExecutors;
  19 import java.util.concurrent.CompletableFuture;
  20 import java.util.concurrent.CompletionStage;
  21 import java.util.concurrent.TimeUnit;
  22 import javax.annotation.concurrent.GuardedBy;
  23 import org.opendaylight.controller.cluster.access.ABIVersion;
  24 import org.opendaylight.controller.cluster.access.client.BackendInfo;
  25 import org.opendaylight.controller.cluster.access.client.BackendInfoResolver;
  26 import org.opendaylight.controller.cluster.datastore.DataStoreVersions;
  27 import org.opendaylight.controller.cluster.datastore.messages.PrimaryShardInfo;
  28 import org.opendaylight.controller.cluster.datastore.shardstrategy.DefaultShardStrategy;
  29 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  30 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  31 import org.slf4j.Logger;
  32 import org.slf4j.LoggerFactory;
  33 import scala.concurrent.ExecutionContext;
  34
  35 /**
  36  * {@link BackendInfoResolver} implementation for static shard configuration based on ShardManager. Each string-named
  37  * shard is assigned a single cookie and this mapping is stored in a bidirectional map. Information about corresponding
  38  * shard leader is resolved via {@link ActorContext}. The product of resolution is {@link ShardBackendInfo}.
  39  *
  40  * @author Robert Varga
  41  */
  42 final class ModuleShardBackendResolver extends BackendInfoResolver<ShardBackendInfo> {
  43     private static final ExecutionContext DIRECT_EXECUTION_CONTEXT =
  44             ExecutionContexts.fromExecutor(MoreExecutors.directExecutor());
  45     private static final CompletableFuture<ShardBackendInfo> NULL_FUTURE = CompletableFuture.completedFuture(null);
  46     private static final Logger LOG = LoggerFactory.getLogger(ModuleShardBackendResolver.class);
  47
  48     /**
  49      * Fall-over-dead timeout. If we do not make progress in this long, just fall over and propagate the failure.
  50      * All users are expected to fail, possibly attempting to recover by restarting. It is fair to remain
  51      * non-operational.
  52      */
  53     // TODO: maybe make this configurable somehow?
  54     private static final Timeout DEAD_TIMEOUT = Timeout.apply(15, TimeUnit.MINUTES);
  55
  56     private final ActorContext actorContext;
  57
  58     @GuardedBy("this")
  59     private long nextShard = 1;
  60
  61     private volatile BiMap<String, Long> shards = ImmutableBiMap.of(DefaultShardStrategy.DEFAULT_SHARD, 0L);
  62
  63     // FIXME: we really need just ActorContext.findPrimaryShardAsync()
  64     ModuleShardBackendResolver(final ActorContext actorContext) {
  65         this.actorContext = Preconditions.checkNotNull(actorContext);
  66     }
  67
  68     @Override
  69     protected void invalidateBackendInfo(final CompletionStage<? extends BackendInfo> info) {
  70         LOG.trace("Initiated invalidation of backend information {}", info);
  71         info.thenAccept(this::invalidate);
  72     }
  73
  74     private void invalidate(final BackendInfo result) {
  75         Preconditions.checkArgument(result instanceof ShardBackendInfo);
  76         LOG.debug("Invalidating backend information {}", result);
  77         actorContext.getPrimaryShardInfoCache().remove(((ShardBackendInfo)result).getShardName());
  78     }
  79
  80     Long resolveShardForPath(final YangInstanceIdentifier path) {
  81         final String shardName = actorContext.getShardStrategyFactory().getStrategy(path).findShard(path);
  82         Long cookie = shards.get(shardName);
  83         if (cookie == null) {
  84             synchronized (this) {
  85                 cookie = shards.get(shardName);
  86                 if (cookie == null) {
  87                     cookie = nextShard++;
  88
  89                     Builder<String, Long> b = ImmutableBiMap.builder();
  90                     b.putAll(shards);
  91                     b.put(shardName, cookie);
  92                     shards = b.build();
  93                 }
  94             }
  95         }
  96
  97         return cookie;
  98     }
  99
 100     @Override
 101     protected CompletableFuture<ShardBackendInfo> resolveBackendInfo(final Long cookie) {
 102         final String shardName = shards.inverse().get(cookie);
 103         if (shardName == null) {
 104             LOG.warn("Failing request for non-existent cookie {}", cookie);
 105             return NULL_FUTURE;
 106         }
 107
 108         final CompletableFuture<ShardBackendInfo> ret = new CompletableFuture<>();
 109
 110         actorContext.findPrimaryShardAsync(shardName).onComplete(new OnComplete<PrimaryShardInfo>() {
 111             @Override
 112             public void onComplete(final Throwable t, final PrimaryShardInfo v) {
 113                 if (t != null) {
 114                     ret.completeExceptionally(t);
 115                 } else {
 116                     ret.complete(createBackendInfo(v, shardName, cookie));
 117                 }
 118             }
 119         }, DIRECT_EXECUTION_CONTEXT);
 120
 121         LOG.debug("Resolving cookie {} to shard {}", cookie, shardName);
 122         return ret;
 123     }
 124
 125     private static ABIVersion toABIVersion(final short version) {
 126         switch (version) {
 127             case DataStoreVersions.BORON_VERSION:
 128                 return ABIVersion.BORON;
 129         }
 130
 131         throw new IllegalArgumentException("Unsupported version " + version);
 132     }
 133
 134     private static ShardBackendInfo createBackendInfo(final Object result, final String shardName, final Long cookie) {
 135         Preconditions.checkArgument(result instanceof PrimaryShardInfo);
 136         final PrimaryShardInfo info = (PrimaryShardInfo) result;
 137
 138         LOG.debug("Creating backend information for {}", info);
 139         return new ShardBackendInfo(info.getPrimaryShardActor().resolveOne(DEAD_TIMEOUT).value().get().get(),
 140             toABIVersion(info.getPrimaryShardVersion()), shardName, UnsignedLong.fromLongBits(cookie),
 141             info.getLocalShardDataTree());
 142      }
 143 }