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Jonathan Hart
Committed by Brian O'Connor
82b9feca 1 parent b5cd581d

Add term information in HazelcastLeadershipService 

Implementation based on Hazelcast IAtomicLong.

Change-Id: I9dca40228a84fdb3edf02ffd2cc32d7d38c90378
Inline Side-by-side
Showing 2 changed files with 63 additions and 24 deletions
......@@ -29,15 +29,16 @@ import java.util.Map;
description = "Finds the leader for particular topic.")
public class LeaderCommand extends AbstractShellCommand {
private static final String FMT = "%-20s: %15s";
private static final String FMT = "%-20s: %15s %5s";
@Override
protected void execute() {
LeadershipService leaderService = get(LeadershipService.class);
Map<String, Leadership> leaderBoard = leaderService.getLeaderBoard();
print(FMT, "Topic", "Leader");
print(FMT, "Topic", "Leader", "Epoch");
for (String topic : leaderBoard.keySet()) {
print(FMT, topic, leaderBoard.get(topic).leader());
Leadership leadership = leaderBoard.get(topic);
print(FMT, topic, leadership.leader(), leadership.epoch());
}
}
......
......@@ -15,22 +15,19 @@
*/
package org.onosproject.store.cluster.impl;
import static com.google.common.base.Preconditions.checkArgument;
import static org.onlab.util.Tools.namedThreads;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.locks.Lock;
import com.google.common.collect.Maps;
import com.hazelcast.config.TopicConfig;
import com.hazelcast.core.IAtomicLong;
import com.hazelcast.core.ITopic;
import com.hazelcast.core.Message;
import com.hazelcast.core.MessageListener;
import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.apache.felix.scr.annotations.Service;
import org.onlab.util.KryoNamespace;
import org.onosproject.cluster.ClusterService;
import org.onosproject.cluster.Leadership;
import org.onosproject.cluster.LeadershipEvent;
......@@ -42,15 +39,18 @@ import org.onosproject.event.EventDeliveryService;
import org.onosproject.store.hz.StoreService;
import org.onosproject.store.serializers.KryoNamespaces;
import org.onosproject.store.serializers.KryoSerializer;
import org.onlab.util.KryoNamespace;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.collect.Maps;
import com.hazelcast.config.TopicConfig;
import com.hazelcast.core.ITopic;
import com.hazelcast.core.Message;
import com.hazelcast.core.MessageListener;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.locks.Lock;
import static com.google.common.base.Preconditions.checkArgument;
import static org.onlab.util.Tools.namedThreads;
/**
* Distributed implementation of LeadershipService that is based on Hazelcast.
......@@ -90,6 +90,9 @@ public class HazelcastLeadershipService implements LeadershipService,
private static final long LEADERSHIP_REMOTE_TIMEOUT_MS = 15 * 1000; // 15s
private static final String TOPIC_HZ_ID = "LeadershipService/AllTopics";
// indicates there is no term value yet
private static final long NO_TERM = 0;
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected ClusterService clusterService;
......@@ -175,7 +178,7 @@ public class HazelcastLeadershipService implements LeadershipService,
for (Topic topic : topics.values()) {
Leadership leadership = new Leadership(topic.topicName(),
topic.leader(),
0L);
topic.term());
result.put(topic.topicName(), leadership);
}
return result;
......@@ -229,6 +232,12 @@ public class HazelcastLeadershipService implements LeadershipService,
private volatile long lastLeadershipUpdateMs = 0;
private ExecutorService leaderElectionExecutor;
private volatile IAtomicLong term;
// This is local state, recording the term number for the last time
// this instance was leader for this topic. The current term could be
// higher if the mastership has changed any times.
private long myLastLeaderTerm = NO_TERM;
private NodeId leader;
private Lock leaderLock;
private Future<?> getLockFuture;
......@@ -262,6 +271,18 @@ public class HazelcastLeadershipService implements LeadershipService,
}
/**
* Gets the current term for the topic.
*
* @return the term for the topic
*/
private long term() {
if (term == null) {
return NO_TERM;
}
return term.get();
}
/**
* Starts operation.
*/
private void start() {
......@@ -290,7 +311,10 @@ public class HazelcastLeadershipService implements LeadershipService,
start();
}
String lockHzId = "LeadershipService/" + topicName + "/lock";
String termHzId = "LeadershipService/" + topicName + "/term";
leaderLock = storeService.getHazelcastInstance().getLock(lockHzId);
term = storeService.getHazelcastInstance().getAtomicLong(termHzId);
getLockFuture = leaderElectionExecutor.submit(new Runnable() {
@Override
public void run() {
......@@ -374,7 +398,7 @@ public class HazelcastLeadershipService implements LeadershipService,
//
leadershipEvent = new LeadershipEvent(
LeadershipEvent.Type.LEADER_REELECTED,
new Leadership(topicName, localNodeId, 0));
new Leadership(topicName, localNodeId, myLastLeaderTerm));
// Dispatch to all instances
leaderTopic.publish(SERIALIZER.encode(leadershipEvent));
} else {
......@@ -386,7 +410,7 @@ public class HazelcastLeadershipService implements LeadershipService,
if (delta > LEADERSHIP_REMOTE_TIMEOUT_MS) {
leadershipEvent = new LeadershipEvent(
LeadershipEvent.Type.LEADER_BOOTED,
new Leadership(topicName, leader, 0));
new Leadership(topicName, leader, myLastLeaderTerm));
// Dispatch only to the local listener(s)
eventDispatcher.post(leadershipEvent);
leader = null;
......@@ -435,10 +459,13 @@ public class HazelcastLeadershipService implements LeadershipService,
// This instance is now the leader
//
log.info("Leader Elected for topic {}", topicName);
updateTerm();
leader = localNodeId;
leadershipEvent = new LeadershipEvent(
LeadershipEvent.Type.LEADER_ELECTED,
new Leadership(topicName, localNodeId, 0));
new Leadership(topicName, localNodeId, myLastLeaderTerm));
leaderTopic.publish(SERIALIZER.encode(leadershipEvent));
}
......@@ -463,11 +490,22 @@ public class HazelcastLeadershipService implements LeadershipService,
}
leadershipEvent = new LeadershipEvent(
LeadershipEvent.Type.LEADER_BOOTED,
new Leadership(topicName, localNodeId, 0));
new Leadership(topicName, localNodeId, myLastLeaderTerm));
leaderTopic.publish(SERIALIZER.encode(leadershipEvent));
leaderLock.unlock();
}
}
}
// Globally guarded by the leadership lock for this term
// Locally guarded by synchronized (this)
private void updateTerm() {
long oldTerm = term.get();
long newTerm = term.incrementAndGet();
myLastLeaderTerm = newTerm;
log.debug("Topic {} updated term from {} to {}", topicName,
oldTerm, newTerm);
}
}
}
......