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;
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().scheduleAtFixedRate(
124 new FiniteDuration(1, TimeUnit.SECONDS),
126 config.getGossipTickInterval(),
132 getContext().dispatcher(),
139 public void postStop() {
140 if (cluster != null) {
141 cluster.unsubscribe(getSelf());
143 if (gossipTask != null) {
149 protected void handleReceive(final Object message) {
150 //Usually sent by self via gossip task defined above. But its not enforced.
151 //These ticks can be sent by another actor as well which is esp. useful while testing
152 if (GOSSIP_TICK.equals(message)) {
154 } else if (message instanceof GossipStatus status) {
155 // Message from remote gossiper with its bucket versions
156 receiveGossipStatus(status);
157 } else if (message instanceof GossipEnvelope envelope) {
158 // Message from remote gossiper with buckets. This is usually in response to GossipStatus
159 // message. The contained buckets are newer as determined by the remote gossiper by
160 // comparing the GossipStatus message with its local versions.
161 receiveGossip(envelope);
162 } else if (message instanceof ClusterEvent.MemberUp memberUp) {
163 receiveMemberUpOrReachable(memberUp.member());
165 } else if (message instanceof ClusterEvent.ReachableMember reachableMember) {
166 receiveMemberUpOrReachable(reachableMember.member());
168 } else if (message instanceof ClusterEvent.MemberRemoved memberRemoved) {
169 receiveMemberRemoveOrUnreachable(memberRemoved.member());
171 } else if (message instanceof ClusterEvent.UnreachableMember unreachableMember) {
172 receiveMemberRemoveOrUnreachable(unreachableMember.member());
180 * Remove member from local copy of member list. If member down is self, then stop the actor
182 * @param member who went down
184 private void receiveMemberRemoveOrUnreachable(final Member member) {
185 LOG.debug("Received memberDown or Unreachable: {}", member);
187 //if its self, then stop itself
188 if (selfAddress.equals(member.address())) {
189 getContext().stop(getSelf());
193 removePeer(member.address());
194 LOG.debug("Removed member [{}], Active member list [{}]", member.address(), clusterMembers);
197 private void addPeer(final Address address) {
198 if (!clusterMembers.contains(address)) {
199 clusterMembers.add(address);
201 peers.computeIfAbsent(address, input -> getContext().system()
202 .actorSelection(input.toString() + getSelf().path().toStringWithoutAddress()));
205 private void removePeer(final Address address) {
206 clusterMembers.remove(address);
207 peers.remove(address);
208 bucketStore.removeRemoteBucket(address);
212 * Add member to the local copy of member list if it doesn't already.
214 * @param member the member to add
216 private void receiveMemberUpOrReachable(final Member member) {
217 LOG.debug("Received memberUp or reachable: {}", member);
219 //ignore up notification for self
220 if (selfAddress.equals(member.address())) {
224 addPeer(member.address());
225 LOG.debug("Added member [{}], Active member list [{}]", member.address(), clusterMembers);
229 * Sends Gossip status to other members in the cluster.
231 * 1. If there are no member, ignore the tick. <br>
232 * 2. If there's only 1 member, send gossip status (bucket versions) to it. <br>
233 * 3. If there are more than one member, randomly pick one and send gossip status (bucket versions) to it.
236 void receiveGossipTick() {
237 final Address address;
238 switch (clusterMembers.size()) {
240 //no members to send gossip status to
243 address = clusterMembers.get(0);
246 final int randomIndex = ThreadLocalRandom.current().nextInt(0, clusterMembers.size());
247 address = clusterMembers.get(randomIndex);
251 LOG.trace("Gossiping to [{}]", address);
252 getLocalStatusAndSendTo(verifyNotNull(peers.get(address)));
256 * Process gossip status received from a remote gossiper. Remote versions are compared with
261 * <li>If local copy is newer, the newer buckets are sent in GossipEnvelope to remote</li>
262 * <li>If local is older, GossipStatus is sent to remote so that it can reply with GossipEnvelope</li>
263 * <li>If both are same, noop</li>
266 * @param status bucket versions from a remote member
269 void receiveGossipStatus(final GossipStatus status) {
270 // Don't accept messages from non-members
271 if (peers.containsKey(status.from())) {
272 // FIXME: sender should be part of GossipStatus
273 final ActorRef sender = getSender();
274 bucketStore.getBucketVersions(versions -> processRemoteStatus(sender, status, versions));
278 private void processRemoteStatus(final ActorRef remote, final GossipStatus status,
279 final Map<Address, Long> localVersions) {
280 final Map<Address, Long> remoteVersions = status.versions();
282 //diff between remote list and local
283 final Set<Address> localIsOlder = new HashSet<>(remoteVersions.keySet());
284 localIsOlder.removeAll(localVersions.keySet());
286 //diff between local list and remote
287 final Set<Address> localIsNewer = new HashSet<>(localVersions.keySet());
288 localIsNewer.removeAll(remoteVersions.keySet());
291 for (Entry<Address, Long> entry : remoteVersions.entrySet()) {
292 Address address = entry.getKey();
293 Long remoteVersion = entry.getValue();
294 Long localVersion = localVersions.get(address);
295 if (localVersion == null || remoteVersion == null) {
296 //this condition is taken care of by above diffs
300 if (localVersion < remoteVersion) {
301 localIsOlder.add(address);
302 } else if (localVersion > remoteVersion) {
303 localIsNewer.add(address);
307 if (!localIsOlder.isEmpty()) {
308 remote.tell(new GossipStatus(selfAddress, localVersions), getSelf());
311 if (!localIsNewer.isEmpty()) {
312 //send newer buckets to remote
313 bucketStore.getBucketsByMembers(localIsNewer, buckets -> {
314 LOG.trace("Buckets to send from {}: {}", selfAddress, buckets);
315 remote.tell(new GossipEnvelope(selfAddress, remote.path().address(), buckets), getSelf());
321 * Sends the received buckets in the envelope to the parent Bucket store.
323 * @param envelope contains buckets from a remote gossiper
326 void receiveGossip(final GossipEnvelope envelope) {
327 //TODO: Add more validations
328 if (!selfAddress.equals(envelope.to())) {
329 LOG.trace("Ignoring message intended for someone else. From [{}] to [{}]", envelope.from(), envelope.to());
333 updateRemoteBuckets(envelope.buckets());
337 * Helper to send received buckets to bucket store.
339 * @param buckets map of Buckets to update
342 void updateRemoteBuckets(final Map<Address, ? extends Bucket<?>> buckets) {
343 // filter this so we only handle buckets for known peers
344 bucketStore.updateRemoteBuckets(Maps.filterKeys(buckets, peers::containsKey));
348 * Gets bucket versions from bucket store and sends to the supplied address.
350 * @param remoteActorSystemAddress remote gossiper to send to
353 void getLocalStatusAndSendTo(final ActorSelection remoteGossiper) {
354 bucketStore.getBucketVersions(versions -> {
355 LOG.trace("Sending bucket versions to [{}]", remoteGossiper);
357 * XXX: we are leaking our reference here. That may be useful for establishing buckets monitoring,
358 * but can we identify which bucket is the local one?
360 remoteGossiper.tell(new GossipStatus(selfAddress, versions), getSelf());
369 void setClusterMembers(final Address... members) {
370 clusterMembers.clear();
373 for (Address addr : members) {