/*
* Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.controller.cluster.datastore;
import akka.actor.ActorPath;
import akka.actor.ActorRef;
import akka.actor.Address;
import akka.actor.Props;
import akka.event.Logging;
import akka.event.LoggingAdapter;
import akka.japi.Creator;
import org.opendaylight.controller.cluster.datastore.messages.FindPrimary;
import org.opendaylight.controller.cluster.datastore.messages.PrimaryFound;
import org.opendaylight.controller.cluster.datastore.messages.PrimaryNotFound;
import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* The ShardManager has the following jobs,
*
*
Create all the local shard replicas that belong on this cluster member
* Find the primary replica for any given shard
* Engage in shard replica elections which decide which replica should be the primary
*
*
* >Creation of Shard replicas
* When the ShardManager is constructed it reads the cluster configuration to find out which shard replicas
* belong on this member. It finds out the name of the current cluster member from the Akka Clustering Service.
*
*
* Replica Elections
*
*
* The Shard Manager uses multiple cues to initiate election.
*
When a member of the cluster dies
* When a local shard replica dies
* When a local shard replica comes alive
*
*/
public class ShardManager extends AbstractUntypedActor {
// Stores a mapping between a shard name and the address of the current primary
private final Map shardNameToPrimaryAddress =
new HashMap<>();
// Stores a mapping between a member name and the address of the member
private final Map memberNameToAddress = new HashMap<>();
// Stores a mapping between the shard name and all the members on which a replica of that shard are available
private final Map> shardNameToMembers =
new HashMap<>();
private final LoggingAdapter log =
Logging.getLogger(getContext().system(), this);
private final Map localShards = new HashMap<>();
private final ClusterWrapper cluster;
/**
* @param type defines the kind of data that goes into shards created by this shard manager. Examples of type would be
* configuration or operational
*/
private ShardManager(String type, ClusterWrapper cluster, Configuration configuration) {
this.cluster = cluster;
String memberName = cluster.getCurrentMemberName();
List memberShardNames =
configuration.getMemberShardNames(memberName);
for(String shardName : memberShardNames){
ActorRef actor = getContext()
.actorOf(Shard.props(memberName + "-shard-" + shardName + "-" + type),
memberName + "-shard-" + shardName + "-" + type);
ActorPath path = actor.path();
localShards.put(shardName, path);
}
}
public static Props props(final String type,
final ClusterWrapper cluster,
final Configuration configuration) {
return Props.create(new Creator() {
@Override
public ShardManager create() throws Exception {
return new ShardManager(type, cluster, configuration);
}
});
}
@Override
public void handleReceive(Object message) throws Exception {
if (message instanceof FindPrimary) {
FindPrimary msg = ((FindPrimary) message);
String shardName = msg.getShardName();
if (Shard.DEFAULT_NAME.equals(shardName)) {
ActorPath defaultShardPath = localShards.get(shardName);
if(defaultShardPath == null){
throw new IllegalStateException("local default shard not found");
}
getSender().tell(new PrimaryFound(defaultShardPath.toString()),
getSelf());
} else {
getSender().tell(new PrimaryNotFound(shardName), getSelf());
}
} else if (message instanceof UpdateSchemaContext) {
for(ActorPath path : localShards.values()){
getContext().system().actorSelection(path)
.forward(message,
getContext());
}
}
}
}