/*
* 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.actor.UntypedActor;
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 UntypedActor {
// 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 ActorPath defaultShardPath;
/**
*
* @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){
ActorRef actor = getContext().actorOf(Shard.props(Shard.DEFAULT_NAME + "-" + type));
defaultShardPath = actor.path();
}
public static Props props(final String type){
return Props.create(new Creator(){
@Override
public ShardManager create() throws Exception {
return new ShardManager(type);
}
});
}
@Override
public void onReceive(Object message) throws Exception {
if (message instanceof FindPrimary) {
FindPrimary msg = ((FindPrimary) message);
String shardName = msg.getShardName();
if(Shard.DEFAULT_NAME.equals(shardName)){
getSender().tell(new PrimaryFound(defaultShardPath.toString()), getSelf());
} else {
getSender().tell(new PrimaryNotFound(shardName), getSelf());
}
} else if(message instanceof UpdateSchemaContext){
// FIXME : Notify all local shards of a context change
getContext().system().actorSelection(defaultShardPath).forward(message, getContext());
}
}
}