/*
* 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.OneForOneStrategy;
import akka.actor.Props;
import akka.actor.SupervisorStrategy;
import akka.cluster.ClusterEvent;
import akka.japi.Creator;
import akka.japi.Function;
import com.google.common.base.Preconditions;
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 scala.concurrent.duration.Duration;
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 member name and the address of the member
private final Map memberNameToAddress = new HashMap<>();
private final Map localShards = new HashMap<>();
private final String type;
private final ClusterWrapper cluster;
private final Configuration configuration;
/**
* @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.type = Preconditions.checkNotNull(type, "type should not be null");
this.cluster = Preconditions.checkNotNull(cluster, "cluster should not be null");
this.configuration = Preconditions.checkNotNull(configuration, "configuration should not be null");
// Subscribe this actor to cluster member events
cluster.subscribeToMemberEvents(getSelf());
// Create all the local Shards and make them a child of the ShardManager
// TODO: This may need to be initiated when we first get the schema context
createLocalShards();
}
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.getClass().equals(FindPrimary.SERIALIZABLE_CLASS)) {
findPrimary(
FindPrimary.fromSerializable(message));
} else if (message instanceof UpdateSchemaContext) {
updateSchemaContext(message);
} else if (message instanceof ClusterEvent.MemberUp){
memberUp((ClusterEvent.MemberUp) message);
} else if(message instanceof ClusterEvent.MemberRemoved) {
memberRemoved((ClusterEvent.MemberRemoved) message);
} else if(message instanceof ClusterEvent.UnreachableMember) {
ignoreMessage(message);
} else{
throw new Exception ("Not recognized message received, message="+message);
}
}
private void ignoreMessage(Object message){
LOG.debug("Unhandled message : " + message);
}
private void memberRemoved(ClusterEvent.MemberRemoved message) {
memberNameToAddress.remove(message.member().roles().head());
}
private void memberUp(ClusterEvent.MemberUp message) {
memberNameToAddress.put(message.member().roles().head(), message.member().address());
}
private void updateSchemaContext(Object message) {
for(ActorPath path : localShards.values()){
getContext().system().actorSelection(path)
.forward(message,
getContext());
}
}
private void findPrimary(FindPrimary message) {
String shardName = message.getShardName();
List members =
configuration.getMembersFromShardName(shardName);
for(String memberName : members) {
if (memberName.equals(cluster.getCurrentMemberName())) {
// This is a local shard
ActorPath shardPath = localShards.get(shardName);
if (shardPath == null) {
getSender()
.tell(new PrimaryNotFound(shardName).toSerializable(), getSelf());
return;
}
getSender().tell(new PrimaryFound(shardPath.toString()).toSerializable(),
getSelf());
return;
} else {
Address address = memberNameToAddress.get(memberName);
if(address != null){
String path =
address.toString() + "/user/shardmanager-" + this.type + "/" + getShardActorName(
memberName, shardName);
getSender().tell(new PrimaryFound(path).toSerializable(), getSelf());
return;
}
}
}
getSender().tell(new PrimaryNotFound(shardName).toSerializable(), getSelf());
}
private String getShardActorName(String memberName, String shardName){
return memberName + "-shard-" + shardName + "-" + this.type;
}
// Create the shards that are local to this member
private void createLocalShards() {
String memberName = this.cluster.getCurrentMemberName();
List memberShardNames =
this.configuration.getMemberShardNames(memberName);
for(String shardName : memberShardNames){
String shardActorName = getShardActorName(memberName, shardName);
ActorRef actor = getContext()
.actorOf(Shard.props(shardActorName), shardActorName);
ActorPath path = actor.path();
localShards.put(shardName, path);
}
}
@Override
public SupervisorStrategy supervisorStrategy() {
return new OneForOneStrategy(10, Duration.create("1 minute"),
new Function() {
@Override
public SupervisorStrategy.Directive apply(Throwable t) {
return SupervisorStrategy.resume();
}
}
);
}
}