Madan Jampani
Committed by Brian O'Connor

Updated DistributedLeadershipManager to use ConsistentMap notifications

Change-Id: Ice4e9b295f4216fee13144ec631904f34bdf7b2b
......@@ -15,7 +15,6 @@ 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.ClusterEvent;
import org.onosproject.cluster.ClusterEvent.Type;
import org.onosproject.cluster.ClusterEventListener;
......@@ -28,10 +27,10 @@ import org.onosproject.cluster.NodeId;
import org.onosproject.event.ListenerRegistry;
import org.onosproject.event.EventDeliveryService;
import org.onosproject.store.cluster.messaging.ClusterCommunicationService;
import org.onosproject.store.cluster.messaging.MessageSubject;
import org.onosproject.store.serializers.KryoNamespaces;
import org.onosproject.store.service.ConsistentMap;
import org.onosproject.store.service.ConsistentMapException;
import org.onosproject.store.service.MapEvent;
import org.onosproject.store.service.Serializer;
import org.onosproject.store.service.StorageService;
import org.onosproject.store.service.Versioned;
......@@ -46,7 +45,6 @@ import java.util.Set;
import java.util.List;
import java.util.concurrent.CancellationException;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
......@@ -82,11 +80,7 @@ public class DistributedLeadershipManager implements LeadershipService {
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected EventDeliveryService eventDispatcher;
private static final MessageSubject LEADERSHIP_EVENT_MESSAGE_SUBJECT =
new MessageSubject("distributed-leadership-manager-events");
private final Logger log = getLogger(getClass());
private ExecutorService messageHandlingExecutor;
private ScheduledExecutorService electionRunner;
private ScheduledExecutorService lockExecutor;
private ScheduledExecutorService staleLeadershipPurgeExecutor;
......@@ -104,7 +98,7 @@ public class DistributedLeadershipManager implements LeadershipService {
private Set<String> activeTopics = Sets.newConcurrentHashSet();
private Map<String, CompletableFuture<Leadership>> pendingFutures = Maps.newConcurrentMap();
// The actual delay is randomly chosen between the interval [0, WAIT_BEFORE_RETRY_MILLIS)
// The actual delay is randomly chosen from the interval [0, WAIT_BEFORE_RETRY_MILLIS)
private static final int WAIT_BEFORE_RETRY_MILLIS = 150;
private static final int DELAY_BETWEEN_LEADER_LOCK_ATTEMPTS_SEC = 2;
private static final int LEADERSHIP_REFRESH_INTERVAL_SEC = 2;
......@@ -112,8 +106,7 @@ public class DistributedLeadershipManager implements LeadershipService {
private final AtomicBoolean staleLeadershipPurgeScheduled = new AtomicBoolean(false);
private static final Serializer SERIALIZER = Serializer.using(
new KryoNamespace.Builder().register(KryoNamespaces.API).build());
private static final Serializer SERIALIZER = Serializer.using(KryoNamespaces.API);
@Activate
public void activate() {
......@@ -126,10 +119,38 @@ public class DistributedLeadershipManager implements LeadershipService {
.withSerializer(SERIALIZER)
.withPartitionsDisabled().build();
leaderMap.addListener(event -> {
log.debug("Received {}", event);
LeadershipEvent.Type leadershipEventType = null;
if (event.type() == MapEvent.Type.INSERT || event.type() == MapEvent.Type.UPDATE) {
leadershipEventType = LeadershipEvent.Type.LEADER_ELECTED;
} else if (event.type() == MapEvent.Type.REMOVE) {
leadershipEventType = LeadershipEvent.Type.LEADER_BOOTED;
}
onLeadershipEvent(new LeadershipEvent(
leadershipEventType,
new Leadership(event.key(),
event.value().value(),
event.value().version(),
event.value().creationTime())));
});
candidateMap.addListener(event -> {
log.debug("Received {}", event);
if (event.type() != MapEvent.Type.INSERT && event.type() != MapEvent.Type.UPDATE) {
log.error("Entries must not be removed from candidate map");
return;
}
onLeadershipEvent(new LeadershipEvent(
LeadershipEvent.Type.CANDIDATES_CHANGED,
new Leadership(event.key(),
event.value().value(),
event.value().version(),
event.value().creationTime())));
});
localNodeId = clusterService.getLocalNode().id();
messageHandlingExecutor = Executors.newSingleThreadExecutor(
groupedThreads("onos/store/leadership", "message-handler"));
electionRunner = Executors.newSingleThreadScheduledExecutor(
groupedThreads("onos/store/leadership", "election-runner"));
lockExecutor = Executors.newScheduledThreadPool(
......@@ -138,11 +159,6 @@ public class DistributedLeadershipManager implements LeadershipService {
groupedThreads("onos/store/leadership", "stale-leadership-evictor"));
leadershipRefresher = Executors.newSingleThreadScheduledExecutor(
groupedThreads("onos/store/leadership", "refresh-thread"));
clusterCommunicator.addSubscriber(
LEADERSHIP_EVENT_MESSAGE_SUBJECT,
SERIALIZER::decode,
this::onLeadershipEvent,
messageHandlingExecutor);
clusterService.addListener(clusterEventListener);
......@@ -168,10 +184,8 @@ public class DistributedLeadershipManager implements LeadershipService {
clusterService.removeListener(clusterEventListener);
eventDispatcher.removeSink(LeadershipEvent.class);
clusterCommunicator.removeSubscriber(LEADERSHIP_EVENT_MESSAGE_SUBJECT);
electionRunner.shutdown();
messageHandlingExecutor.shutdown();
lockExecutor.shutdown();
staleLeadershipPurgeExecutor.shutdown();
leadershipRefresher.shutdown();
......@@ -239,12 +253,6 @@ public class DistributedLeadershipManager implements LeadershipService {
return newList;
}
});
publish(new LeadershipEvent(
LeadershipEvent.Type.CANDIDATES_CHANGED,
new Leadership(path,
candidates.value(),
candidates.version(),
candidates.creationTime())));
log.debug("In the leadership race for topic {} with candidates {}", path, candidates);
activeTopics.add(path);
Leadership leadership = electLeader(path, candidates.value());
......@@ -273,41 +281,14 @@ public class DistributedLeadershipManager implements LeadershipService {
future.completeExceptionally(new CancellationException(String.format("%s is now a active topic", path)));
}
try {
Versioned<NodeId> leader = leaderMap.get(path);
if (leader != null && Objects.equals(leader.value(), localNodeId)) {
if (leaderMap.remove(path, leader.version())) {
log.debug("Gave up leadership for {}", path);
future.complete(null);
publish(new LeadershipEvent(
LeadershipEvent.Type.LEADER_BOOTED,
new Leadership(path,
localNodeId,
leader.version(),
leader.creationTime())));
}
}
// else we are not the current leader, can still be a candidate.
Versioned<List<NodeId>> candidates = candidateMap.get(path);
List<NodeId> candidateList = candidates != null
? Lists.newArrayList(candidates.value())
: Lists.newArrayList();
if (!candidateList.remove(localNodeId)) {
future.complete(null);
return;
}
if (candidateMap.replace(path, candidates.version(), candidateList)) {
Versioned<List<NodeId>> newCandidates = candidateMap.get(path);
future.complete(null);
publish(new LeadershipEvent(
LeadershipEvent.Type.CANDIDATES_CHANGED,
new Leadership(path,
newCandidates.value(),
newCandidates.version(),
newCandidates.creationTime())));
} else {
log.debug("Failed to withdraw from candidates list for {}. Will retry", path);
retryWithdraw(path, future);
}
leaderMap.computeIf(path,
localNodeId::equals,
(topic, leader) -> null);
candidateMap.computeIf(path,
candidates -> candidates != null && candidates.contains(localNodeId),
(topic, candidates) -> candidates.stream()
.filter(nodeId -> !localNodeId.equals(nodeId))
.collect(Collectors.toList()));
} catch (Exception e) {
log.debug("Failed to verify (and clear) any lock this node might be holding for {}", path, e);
retryWithdraw(path, future);
......@@ -321,19 +302,9 @@ public class DistributedLeadershipManager implements LeadershipService {
}
try {
Versioned<NodeId> leader = leaderMap.get(path);
if (leader != null && Objects.equals(leader.value(), localNodeId)) {
if (leaderMap.remove(path, leader.version())) {
log.debug("Stepped down from leadership for {}", path);
publish(new LeadershipEvent(
LeadershipEvent.Type.LEADER_BOOTED,
new Leadership(path,
localNodeId,
leader.version(),
leader.creationTime())));
return true;
}
}
return leaderMap.computeIf(path,
localNodeId::equals,
(topic, leader) -> null) == null;
} catch (Exception e) {
log.warn("Error executing stepdown for {}", path, e);
}
......@@ -352,7 +323,7 @@ public class DistributedLeadershipManager implements LeadershipService {
@Override
public boolean makeTopCandidate(String path, NodeId nodeId) {
Versioned<List<NodeId>> newCandidates = candidateMap.computeIf(path,
Versioned<List<NodeId>> candidateList = candidateMap.computeIf(path,
candidates -> candidates != null &&
candidates.contains(nodeId) &&
!nodeId.equals(Iterables.getFirst(candidates, null)),
......@@ -362,13 +333,8 @@ public class DistributedLeadershipManager implements LeadershipService {
candidates.stream().filter(id -> !nodeId.equals(id)).forEach(updatedCandidates::add);
return updatedCandidates;
});
publish(new LeadershipEvent(
LeadershipEvent.Type.CANDIDATES_CHANGED,
new Leadership(path,
newCandidates.value(),
newCandidates.version(),
newCandidates.creationTime())));
return true;
List<NodeId> candidates = candidateList != null ? candidateList.value() : Collections.emptyList();
return candidates.size() > 0 && nodeId.equals(candidates.get(0));
}
private Leadership electLeader(String path, List<NodeId> candidates) {
......@@ -389,9 +355,6 @@ public class DistributedLeadershipManager implements LeadershipService {
leader.value(),
leader.version(),
leader.creationTime());
publish(new LeadershipEvent(
LeadershipEvent.Type.LEADER_ELECTED,
newLeadership));
return newLeadership;
}
} catch (Exception e) {
......@@ -432,11 +395,6 @@ public class DistributedLeadershipManager implements LeadershipService {
}
}
private void publish(LeadershipEvent event) {
onLeadershipEvent(event);
clusterCommunicator.broadcast(event, LEADERSHIP_EVENT_MESSAGE_SUBJECT, SERIALIZER::encode);
}
private void onLeadershipEvent(LeadershipEvent leadershipEvent) {
log.trace("Leadership Event: time = {} type = {} event = {}",
leadershipEvent.time(), leadershipEvent.type(),
......@@ -517,15 +475,8 @@ public class DistributedLeadershipManager implements LeadershipService {
.forEach(entry -> {
String path = entry.getKey();
NodeId nodeId = entry.getValue().value();
long epoch = entry.getValue().version();
long creationTime = entry.getValue().creationTime();
try {
if (leaderMap.remove(path, epoch)) {
log.debug("Purged stale lock held by {} for {}", nodeId, path);
publish(new LeadershipEvent(
LeadershipEvent.Type.LEADER_BOOTED,
new Leadership(path, nodeId, epoch, creationTime)));
}
leaderMap.computeIf(path, nodeId::equals, (topic, leader) -> null);
} catch (Exception e) {
log.debug("Failed to purge stale lock held by {} for {}", nodeId, path, e);
rerunPurge.set(true);
......@@ -548,21 +499,15 @@ public class DistributedLeadershipManager implements LeadershipService {
Sets.difference(Sets.newHashSet(candidatesList),
Sets.newHashSet(activeCandidatesList));
try {
if (candidateMap.replace(path, entry.getValue().version(), activeCandidatesList)) {
log.info("Evicted inactive candidates {} from "
+ "candidate list for {}", removedCandidates, path);
Versioned<List<NodeId>> updatedCandidates = candidateMap.get(path);
publish(new LeadershipEvent(
LeadershipEvent.Type.CANDIDATES_CHANGED,
new Leadership(path,
updatedCandidates.value(),
updatedCandidates.version(),
updatedCandidates.creationTime())));
} else {
// Conflicting update detected. Rerun purge to make sure
// inactive candidates are evicted.
rerunPurge.set(true);
}
candidateMap.computeIf(path,
c -> c.stream()
.filter(n -> clusterService.getState(n) == INACTIVE)
.count() > 0,
(topic, c) -> c.stream()
.filter(n -> clusterService.getState(n) == ACTIVE)
.filter(n -> !localNodeId.equals(n) ||
activeTopics.contains(path))
.collect(Collectors.toList()));
} catch (Exception e) {
log.debug("Failed to evict inactive candidates {} from "
+ "candidate list for {}", removedCandidates, path, e);
......