2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
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
9 package org.opendaylight.controller.cluster.datastore;
11 import akka.actor.ActorPath;
12 import akka.actor.ActorRef;
13 import akka.actor.Address;
14 import akka.actor.Props;
15 import akka.event.Logging;
16 import akka.event.LoggingAdapter;
17 import akka.japi.Creator;
18 import org.opendaylight.controller.cluster.datastore.messages.FindPrimary;
19 import org.opendaylight.controller.cluster.datastore.messages.PrimaryFound;
20 import org.opendaylight.controller.cluster.datastore.messages.PrimaryNotFound;
21 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
23 import java.util.HashMap;
24 import java.util.List;
28 * The ShardManager has the following jobs,
30 * <li> Create all the local shard replicas that belong on this cluster member
31 * <li> Find the primary replica for any given shard
32 * <li> Engage in shard replica elections which decide which replica should be the primary
35 * <h3>>Creation of Shard replicas</h3
37 * When the ShardManager is constructed it reads the cluster configuration to find out which shard replicas
38 * belong on this member. It finds out the name of the current cluster member from the Akka Clustering Service.
41 * <h3> Replica Elections </h3>
44 * The Shard Manager uses multiple cues to initiate election.
45 * <li> When a member of the cluster dies
46 * <li> When a local shard replica dies
47 * <li> When a local shard replica comes alive
50 public class ShardManager extends AbstractUntypedActor {
52 // Stores a mapping between a shard name and the address of the current primary
53 private final Map<String, Address> shardNameToPrimaryAddress = new HashMap<>();
55 // Stores a mapping between a member name and the address of the member
56 private final Map<String, Address> memberNameToAddress = new HashMap<>();
58 // Stores a mapping between the shard name and all the members on which a replica of that shard are available
59 private final Map<String, List<String>> shardNameToMembers = new HashMap<>();
61 private final LoggingAdapter log = Logging.getLogger(getContext().system(), this);
63 private final ActorPath defaultShardPath;
67 * @param type defines the kind of data that goes into shards created by this shard manager. Examples of type would be
68 * configuration or operational
70 private ShardManager(String type){
71 ActorRef actor = getContext().actorOf(Shard.props("shard-" + Shard.DEFAULT_NAME + "-" + type), "shard-" + Shard.DEFAULT_NAME + "-" + type);
72 defaultShardPath = actor.path();
75 public static Props props(final String type){
76 return Props.create(new Creator<ShardManager>(){
79 public ShardManager create() throws Exception {
80 return new ShardManager(type);
86 public void handleReceive(Object message) throws Exception {
87 if (message instanceof FindPrimary) {
88 FindPrimary msg = ((FindPrimary) message);
89 String shardName = msg.getShardName();
90 if(Shard.DEFAULT_NAME.equals(shardName)){
91 getSender().tell(new PrimaryFound(defaultShardPath.toString()), getSelf());
93 getSender().tell(new PrimaryNotFound(shardName), getSelf());
95 } else if(message instanceof UpdateSchemaContext){
96 // FIXME : Notify all local shards of a context change
97 getContext().system().actorSelection(defaultShardPath).forward(message, getContext());