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 akka.actor.ActorRef;
11 import akka.actor.ActorSelection;
12 import akka.actor.Address;
13 import akka.actor.Cancellable;
14 import akka.actor.UntypedActor;
15 import akka.cluster.Cluster;
16 import akka.cluster.ClusterEvent;
17 import akka.cluster.Member;
18 import akka.dispatch.Mapper;
19 import akka.event.Logging;
20 import akka.event.LoggingAdapter;
21 import akka.pattern.Patterns;
22 import scala.concurrent.Future;
23 import scala.concurrent.duration.FiniteDuration;
25 import java.util.ArrayList;
26 import java.util.HashSet;
27 import java.util.List;
30 import java.util.concurrent.ThreadLocalRandom;
31 import java.util.concurrent.TimeUnit;
33 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketVersions;
34 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketVersionsReply;
35 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketsByMembers;
36 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketsByMembersReply;
37 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.UpdateRemoteBuckets;
38 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope;
39 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus;
40 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipTick;
43 * Gossiper that syncs bucket store across nodes in the cluster.
45 * It keeps a local scheduler that periodically sends Gossip ticks to
46 * itself to send bucket store's bucket versions to a randomly selected remote
49 * When bucket versions are received from a remote gossiper, it is compared
50 * with bucket store's bucket versions. Which ever buckets are newer
51 * locally, are sent to remote gossiper. If any bucket is older in bucket store,
52 * a gossip status is sent to remote gossiper so that it can send the newer buckets.
54 * When a bucket is received from a remote gossiper, its sent to the bucket store
59 public class Gossiper extends UntypedActor {
61 final LoggingAdapter log = Logging.getLogger(getContext().system(), this);
63 Cluster cluster = Cluster.get(getContext().system());
66 * ActorSystem's address for the current cluster node.
68 private Address selfAddress = cluster.selfAddress();
71 * All known cluster members
73 private List<Address> clusterMembers = new ArrayList<>();
75 private Cancellable gossipTask;
77 private Boolean autoStartGossipTicks = true;
83 * @param autoStartGossipTicks used for turning off gossip ticks during testing.
84 * Gossip tick can be manually sent.
86 public Gossiper(Boolean autoStartGossipTicks){
87 this.autoStartGossipTicks = autoStartGossipTicks;
91 public void preStart(){
93 cluster.subscribe(getSelf(),
94 ClusterEvent.initialStateAsEvents(),
95 ClusterEvent.MemberEvent.class,
96 ClusterEvent.UnreachableMember.class);
98 if (autoStartGossipTicks) {
99 gossipTask = getContext().system().scheduler().schedule(
100 new FiniteDuration(1, TimeUnit.SECONDS), //initial delay
101 new FiniteDuration(500, TimeUnit.MILLISECONDS), //interval
103 new Messages.GossiperMessages.GossipTick(), //message
104 getContext().dispatcher(), //execution context
111 public void postStop(){
113 cluster.unsubscribe(getSelf());
114 if (gossipTask != null)
119 public void onReceive(Object message) throws Exception {
121 log.debug("Received message: node[{}], message[{}]", selfAddress, message);
123 //Usually sent by self via gossip task defined above. But its not enforced.
124 //These ticks can be sent by another actor as well which is esp. useful while testing
125 if (message instanceof GossipTick)
128 //Message from remote gossiper with its bucket versions
129 else if (message instanceof GossipStatus)
130 receiveGossipStatus((GossipStatus) message);
132 //Message from remote gossiper with buckets. This is usually in response to GossipStatus message
133 //The contained buckets are newer as determined by the remote gossiper by comparing the GossipStatus
134 //message with its local versions
135 else if (message instanceof GossipEnvelope)
136 receiveGossip((GossipEnvelope) message);
138 else if (message instanceof ClusterEvent.MemberUp) {
139 receiveMemberUp(((ClusterEvent.MemberUp) message).member());
141 } else if (message instanceof ClusterEvent.MemberRemoved) {
142 receiveMemberRemoveOrUnreachable(((ClusterEvent.MemberRemoved) message).member());
144 } else if ( message instanceof ClusterEvent.UnreachableMember){
145 receiveMemberRemoveOrUnreachable(((ClusterEvent.UnreachableMember) message).member());
152 * Remove member from local copy of member list. If member down is self, then stop the actor
154 * @param member who went down
156 void receiveMemberRemoveOrUnreachable(Member member) {
157 //if its self, then stop itself
158 if (selfAddress.equals(member.address())){
159 getContext().stop(getSelf());
163 clusterMembers.remove(member.address());
164 log.debug("Removed member [{}], Active member list [{}]", member.address(), clusterMembers);
168 * Add member to the local copy of member list if it doesnt already
171 void receiveMemberUp(Member member) {
173 if (selfAddress.equals(member.address()))
174 return; //ignore up notification for self
176 if (!clusterMembers.contains(member.address()))
177 clusterMembers.add(member.address());
179 log.debug("Added member [{}], Active member list [{}]", member.address(), clusterMembers);
183 * Sends Gossip status to other members in the cluster. <br/>
184 * 1. If there are no member, ignore the tick. </br>
185 * 2. If there's only 1 member, send gossip status (bucket versions) to it. <br/>
186 * 3. If there are more than one member, randomly pick one and send gossip status (bucket versions) to it.
188 void receiveGossipTick(){
189 if (clusterMembers.size() == 0) return; //no members to send gossip status to
191 Address remoteMemberToGossipTo = null;
193 if (clusterMembers.size() == 1)
194 remoteMemberToGossipTo = clusterMembers.get(0);
196 Integer randomIndex = ThreadLocalRandom.current().nextInt(0, clusterMembers.size());
197 remoteMemberToGossipTo = clusterMembers.get(randomIndex);
200 log.debug("Gossiping to [{}]", remoteMemberToGossipTo);
201 getLocalStatusAndSendTo(remoteMemberToGossipTo);
205 * Process gossip status received from a remote gossiper. Remote versions are compared with
206 * the local copy. <p>
210 * <li>If local copy is newer, the newer buckets are sent in GossipEnvelope to remote</li>
211 * <li>If local is older, GossipStatus is sent to remote so that it can reply with GossipEnvelope</li>
212 * <li>If both are same, noop</li>
215 * @param status bucket versions from a remote member
217 void receiveGossipStatus(GossipStatus status){
218 //Don't accept messages from non-members
219 if (!clusterMembers.contains(status.from()))
222 final ActorRef sender = getSender();
223 Future<Object> futureReply = Patterns.ask(getContext().parent(), new GetBucketVersions(), 1000);
224 futureReply.map(getMapperToProcessRemoteStatus(sender, status), getContext().dispatcher());
229 * Sends the received buckets in the envelope to the parent Bucket store.
231 * @param envelope contains buckets from a remote gossiper
233 void receiveGossip(GossipEnvelope envelope){
234 //TODO: Add more validations
235 if (!selfAddress.equals(envelope.to())) {
236 log.debug("Ignoring message intended for someone else. From [{}] to [{}]", envelope.from(), envelope.to());
240 updateRemoteBuckets(envelope.getBuckets());
245 * Helper to send received buckets to bucket store
249 void updateRemoteBuckets(Map<Address, Bucket> buckets) {
251 UpdateRemoteBuckets updateRemoteBuckets = new UpdateRemoteBuckets(buckets);
252 getContext().parent().tell(updateRemoteBuckets, getSelf());
256 * Gets the buckets from bucket store for the given node addresses and sends them to remote gossiper
258 * @param remote remote node to send Buckets to
259 * @param addresses node addresses whose buckets needs to be sent
261 void sendGossipTo(final ActorRef remote, final Set<Address> addresses){
263 Future<Object> futureReply = Patterns.ask(getContext().parent(), new GetBucketsByMembers(addresses), 1000);
264 futureReply.map(getMapperToSendGossip(remote), getContext().dispatcher());
268 * Gets bucket versions from bucket store and sends to the supplied address
270 * @param remoteActorSystemAddress remote gossiper to send to
272 void getLocalStatusAndSendTo(Address remoteActorSystemAddress){
274 //Get local status from bucket store and send to remote
275 Future<Object> futureReply = Patterns.ask(getContext().parent(), new GetBucketVersions(), 1000);
276 ActorSelection remoteRef = getContext().system().actorSelection(
277 remoteActorSystemAddress.toString() + getSelf().path().toStringWithoutAddress());
279 log.debug("Sending bucket versions to [{}]", remoteRef);
281 futureReply.map(getMapperToSendLocalStatus(remoteRef), getContext().dispatcher());
286 * Helper to send bucket versions received from local store
287 * @param remote remote gossiper to send versions to
288 * @param localVersions bucket versions received from local store
290 void sendGossipStatusTo(ActorRef remote, Map<Address, Long> localVersions){
292 GossipStatus status = new GossipStatus(selfAddress, localVersions);
293 remote.tell(status, getSelf());
296 void sendGossipStatusTo(ActorSelection remote, Map<Address, Long> localVersions){
298 GossipStatus status = new GossipStatus(selfAddress, localVersions);
299 remote.tell(status, getSelf());
303 /// Private factories to create mappers
306 private Mapper<Object, Void> getMapperToSendLocalStatus(final ActorSelection remote){
308 return new Mapper<Object, Void>() {
310 public Void apply(Object replyMessage) {
311 if (replyMessage instanceof GetBucketVersionsReply) {
312 GetBucketVersionsReply reply = (GetBucketVersionsReply) replyMessage;
313 Map<Address, Long> localVersions = reply.getVersions();
315 sendGossipStatusTo(remote, localVersions);
324 * Process bucket versions received from
325 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.BucketStore}.
326 * Then this method compares remote bucket versions with local bucket versions.
328 * <li>The buckets that are newer locally, send
329 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope}
331 * <li>The buckets that are older locally, send
332 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus}
333 * to remote so that remote sends GossipEnvelop.
336 * @param sender the remote member
337 * @param status bucket versions from a remote member
338 * @return a {@link akka.dispatch.Mapper} that gets evaluated in future
341 private Mapper<Object, Void> getMapperToProcessRemoteStatus(final ActorRef sender, final GossipStatus status){
343 final Map<Address, Long> remoteVersions = status.getVersions();
345 return new Mapper<Object, Void>() {
347 public Void apply(Object replyMessage) {
348 if (replyMessage instanceof GetBucketVersionsReply) {
349 GetBucketVersionsReply reply = (GetBucketVersionsReply) replyMessage;
350 Map<Address, Long> localVersions = reply.getVersions();
352 //diff between remote list and local
353 Set<Address> localIsOlder = new HashSet<>();
354 localIsOlder.addAll(remoteVersions.keySet());
355 localIsOlder.removeAll(localVersions.keySet());
357 //diff between local list and remote
358 Set<Address> localIsNewer = new HashSet<>();
359 localIsNewer.addAll(localVersions.keySet());
360 localIsNewer.removeAll(remoteVersions.keySet());
363 for (Address address : remoteVersions.keySet()){
365 if (localVersions.get(address) == null || remoteVersions.get(address) == null)
366 continue; //this condition is taken care of by above diffs
367 if (localVersions.get(address) < remoteVersions.get(address))
368 localIsOlder.add(address);
369 else if (localVersions.get(address) > remoteVersions.get(address))
370 localIsNewer.add(address);
375 if (!localIsOlder.isEmpty())
376 sendGossipStatusTo(sender, localVersions );
378 if (!localIsNewer.isEmpty())
379 sendGossipTo(sender, localIsNewer);//send newer buckets to remote
388 * Processes the message from {@link org.opendaylight.controller.remote.rpc.registry.gossip.BucketStore}
389 * that contains {@link org.opendaylight.controller.remote.rpc.registry.gossip.Bucket}.
390 * These buckets are sent to a remote member encapsulated in
391 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope}
393 * @param sender the remote member that sent
394 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus}
395 * in reply to which bucket is being sent back
396 * @return a {@link akka.dispatch.Mapper} that gets evaluated in future
399 private Mapper<Object, Void> getMapperToSendGossip(final ActorRef sender) {
401 return new Mapper<Object, Void>() {
403 public Void apply(Object msg) {
404 if (msg instanceof GetBucketsByMembersReply) {
405 Map<Address, Bucket> buckets = ((GetBucketsByMembersReply) msg).getBuckets();
406 log.debug("Buckets to send from {}: {}", selfAddress, buckets);
407 GossipEnvelope envelope = new GossipEnvelope(selfAddress, sender.path().address(), buckets);
408 sender.tell(envelope, getSelf());
418 List<Address> getClusterMembers() {
419 return clusterMembers;
422 void setClusterMembers(List<Address> clusterMembers) {
423 this.clusterMembers = clusterMembers;
426 Address getSelfAddress() {
430 void setSelfAddress(Address selfAddress) {
431 this.selfAddress = selfAddress;