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
8 package org.opendaylight.controller.remote.rpc.registry.gossip;
10 import static com.google.common.base.Verify.verifyNotNull;
11 import static java.util.Objects.requireNonNull;
13 import akka.actor.ActorRef;
14 import akka.actor.ActorRefProvider;
15 import akka.actor.ActorSelection;
16 import akka.actor.Address;
17 import akka.actor.Cancellable;
18 import akka.actor.Props;
19 import akka.cluster.Cluster;
20 import akka.cluster.ClusterActorRefProvider;
21 import akka.cluster.ClusterEvent;
22 import akka.cluster.Member;
23 import com.google.common.annotations.VisibleForTesting;
24 import com.google.common.collect.Maps;
25 import java.util.ArrayList;
26 import java.util.HashMap;
27 import java.util.HashSet;
28 import java.util.List;
30 import java.util.Map.Entry;
32 import java.util.concurrent.ThreadLocalRandom;
33 import java.util.concurrent.TimeUnit;
34 import org.opendaylight.controller.cluster.common.actor.AbstractUntypedActorWithMetering;
35 import org.opendaylight.controller.remote.rpc.RemoteOpsProviderConfig;
36 import scala.concurrent.duration.FiniteDuration;
39 * Gossiper that syncs bucket store across nodes in the cluster.
42 * It keeps a local scheduler that periodically sends Gossip ticks to
43 * itself to send bucket store's bucket versions to a randomly selected remote
47 * When bucket versions are received from a remote gossiper, it is compared
48 * with bucket store's bucket versions. Which ever buckets are newer
49 * locally, are sent to remote gossiper. If any bucket is older in bucket store,
50 * a gossip status is sent to remote gossiper so that it can send the newer buckets.
53 * When a bucket is received from a remote gossiper, its sent to the bucket store
56 public class Gossiper extends AbstractUntypedActorWithMetering {
57 private static final Object GOSSIP_TICK = new Object() {
59 public String toString() {
64 private final boolean autoStartGossipTicks;
65 private final RemoteOpsProviderConfig config;
68 * All known cluster members.
70 private final List<Address> clusterMembers = new ArrayList<>();
73 * Cached ActorSelections for remote peers.
75 private final Map<Address, ActorSelection> peers = new HashMap<>();
78 * ActorSystem's address for the current cluster node.
80 private Address selfAddress;
82 private Cluster cluster;
84 private Cancellable gossipTask;
86 private BucketStoreAccess bucketStore;
88 Gossiper(final RemoteOpsProviderConfig config, final Boolean autoStartGossipTicks) {
89 this.config = requireNonNull(config);
90 this.autoStartGossipTicks = autoStartGossipTicks.booleanValue();
93 Gossiper(final RemoteOpsProviderConfig config) {
94 this(config, Boolean.TRUE);
97 public static Props props(final RemoteOpsProviderConfig config) {
98 return Props.create(Gossiper.class, config);
101 static Props testProps(final RemoteOpsProviderConfig config) {
102 return Props.create(Gossiper.class, config, Boolean.FALSE);
106 public void preStart() {
107 ActorRefProvider provider = getContext().provider();
108 selfAddress = provider.getDefaultAddress();
110 bucketStore = new BucketStoreAccess(getContext().parent(), getContext().dispatcher(), config.getAskDuration());
112 if (provider instanceof ClusterActorRefProvider) {
113 cluster = Cluster.get(getContext().system());
114 cluster.subscribe(getSelf(),
115 ClusterEvent.initialStateAsEvents(),
116 ClusterEvent.MemberEvent.class,
117 ClusterEvent.ReachableMember.class,
118 ClusterEvent.UnreachableMember.class);
121 if (autoStartGossipTicks) {
122 gossipTask = getContext().system().scheduler().schedule(
123 new FiniteDuration(1, TimeUnit.SECONDS), //initial delay
124 config.getGossipTickInterval(), //interval
126 GOSSIP_TICK, //message
127 getContext().dispatcher(), //execution context
134 public void postStop() {
135 if (cluster != null) {
136 cluster.unsubscribe(getSelf());
138 if (gossipTask != null) {
144 protected void handleReceive(final Object message) {
145 //Usually sent by self via gossip task defined above. But its not enforced.
146 //These ticks can be sent by another actor as well which is esp. useful while testing
147 if (GOSSIP_TICK.equals(message)) {
149 } else if (message instanceof GossipStatus) {
150 // Message from remote gossiper with its bucket versions
151 receiveGossipStatus((GossipStatus) message);
152 } else if (message instanceof GossipEnvelope) {
153 // Message from remote gossiper with buckets. This is usually in response to GossipStatus
154 // message. The contained buckets are newer as determined by the remote gossiper by
155 // comparing the GossipStatus message with its local versions.
156 receiveGossip((GossipEnvelope) message);
157 } else if (message instanceof ClusterEvent.MemberUp) {
158 receiveMemberUpOrReachable(((ClusterEvent.MemberUp) message).member());
160 } else if (message instanceof ClusterEvent.ReachableMember) {
161 receiveMemberUpOrReachable(((ClusterEvent.ReachableMember) message).member());
163 } else if (message instanceof ClusterEvent.MemberRemoved) {
164 receiveMemberRemoveOrUnreachable(((ClusterEvent.MemberRemoved) message).member());
166 } else if (message instanceof ClusterEvent.UnreachableMember) {
167 receiveMemberRemoveOrUnreachable(((ClusterEvent.UnreachableMember) message).member());
175 * Remove member from local copy of member list. If member down is self, then stop the actor
177 * @param member who went down
179 private void receiveMemberRemoveOrUnreachable(final Member member) {
180 LOG.debug("Received memberDown or Unreachable: {}", member);
182 //if its self, then stop itself
183 if (selfAddress.equals(member.address())) {
184 getContext().stop(getSelf());
188 removePeer(member.address());
189 LOG.debug("Removed member [{}], Active member list [{}]", member.address(), clusterMembers);
192 private void addPeer(final Address address) {
193 if (!clusterMembers.contains(address)) {
194 clusterMembers.add(address);
196 peers.computeIfAbsent(address, input -> getContext().system()
197 .actorSelection(input.toString() + getSelf().path().toStringWithoutAddress()));
200 private void removePeer(final Address address) {
201 clusterMembers.remove(address);
202 peers.remove(address);
203 bucketStore.removeRemoteBucket(address);
207 * Add member to the local copy of member list if it doesn't already.
209 * @param member the member to add
211 private void receiveMemberUpOrReachable(final Member member) {
212 LOG.debug("Received memberUp or reachable: {}", member);
214 //ignore up notification for self
215 if (selfAddress.equals(member.address())) {
219 addPeer(member.address());
220 LOG.debug("Added member [{}], Active member list [{}]", member.address(), clusterMembers);
224 * Sends Gossip status to other members in the cluster.
226 * 1. If there are no member, ignore the tick. <br>
227 * 2. If there's only 1 member, send gossip status (bucket versions) to it. <br>
228 * 3. If there are more than one member, randomly pick one and send gossip status (bucket versions) to it.
231 void receiveGossipTick() {
232 final Address address;
233 switch (clusterMembers.size()) {
235 //no members to send gossip status to
238 address = clusterMembers.get(0);
241 final int randomIndex = ThreadLocalRandom.current().nextInt(0, clusterMembers.size());
242 address = clusterMembers.get(randomIndex);
246 LOG.trace("Gossiping to [{}]", address);
247 getLocalStatusAndSendTo(verifyNotNull(peers.get(address)));
251 * Process gossip status received from a remote gossiper. Remote versions are compared with
256 * <li>If local copy is newer, the newer buckets are sent in GossipEnvelope to remote</li>
257 * <li>If local is older, GossipStatus is sent to remote so that it can reply with GossipEnvelope</li>
258 * <li>If both are same, noop</li>
261 * @param status bucket versions from a remote member
264 void receiveGossipStatus(final GossipStatus status) {
265 // Don't accept messages from non-members
266 if (peers.containsKey(status.from())) {
267 // FIXME: sender should be part of GossipStatus
268 final ActorRef sender = getSender();
269 bucketStore.getBucketVersions(versions -> processRemoteStatus(sender, status, versions));
273 private void processRemoteStatus(final ActorRef remote, final GossipStatus status,
274 final Map<Address, Long> localVersions) {
275 final Map<Address, Long> remoteVersions = status.versions();
277 //diff between remote list and local
278 final Set<Address> localIsOlder = new HashSet<>(remoteVersions.keySet());
279 localIsOlder.removeAll(localVersions.keySet());
281 //diff between local list and remote
282 final Set<Address> localIsNewer = new HashSet<>(localVersions.keySet());
283 localIsNewer.removeAll(remoteVersions.keySet());
286 for (Entry<Address, Long> entry : remoteVersions.entrySet()) {
287 Address address = entry.getKey();
288 Long remoteVersion = entry.getValue();
289 Long localVersion = localVersions.get(address);
290 if (localVersion == null || remoteVersion == null) {
291 //this condition is taken care of by above diffs
295 if (localVersion < remoteVersion) {
296 localIsOlder.add(address);
297 } else if (localVersion > remoteVersion) {
298 localIsNewer.add(address);
302 if (!localIsOlder.isEmpty()) {
303 remote.tell(new GossipStatus(selfAddress, localVersions), getSelf());
306 if (!localIsNewer.isEmpty()) {
307 //send newer buckets to remote
308 bucketStore.getBucketsByMembers(localIsNewer, buckets -> {
309 LOG.trace("Buckets to send from {}: {}", selfAddress, buckets);
310 remote.tell(new GossipEnvelope(selfAddress, remote.path().address(), buckets), getSelf());
316 * Sends the received buckets in the envelope to the parent Bucket store.
318 * @param envelope contains buckets from a remote gossiper
321 void receiveGossip(final GossipEnvelope envelope) {
322 //TODO: Add more validations
323 if (!selfAddress.equals(envelope.to())) {
324 LOG.trace("Ignoring message intended for someone else. From [{}] to [{}]", envelope.from(), envelope.to());
328 updateRemoteBuckets(envelope.buckets());
332 * Helper to send received buckets to bucket store.
334 * @param buckets map of Buckets to update
337 void updateRemoteBuckets(final Map<Address, ? extends Bucket<?>> buckets) {
338 // filter this so we only handle buckets for known peers
339 bucketStore.updateRemoteBuckets(Maps.filterKeys(buckets, peers::containsKey));
343 * Gets bucket versions from bucket store and sends to the supplied address.
345 * @param remoteActorSystemAddress remote gossiper to send to
348 void getLocalStatusAndSendTo(final ActorSelection remoteGossiper) {
349 bucketStore.getBucketVersions(versions -> {
350 LOG.trace("Sending bucket versions to [{}]", remoteGossiper);
352 * XXX: we are leaking our reference here. That may be useful for establishing buckets monitoring,
353 * but can we identify which bucket is the local one?
355 remoteGossiper.tell(new GossipStatus(selfAddress, versions), getSelf());
364 void setClusterMembers(final Address... members) {
365 clusterMembers.clear();
368 for (Address addr : members) {