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.ActorRefProvider;
12 import akka.actor.ActorSelection;
13 import akka.actor.Address;
14 import akka.actor.Cancellable;
15 import akka.actor.UntypedActor;
16 import akka.cluster.Cluster;
17 import akka.cluster.ClusterActorRefProvider;
18 import akka.cluster.ClusterEvent;
19 import akka.cluster.Member;
20 import akka.dispatch.Mapper;
21 import akka.event.Logging;
22 import akka.event.LoggingAdapter;
23 import akka.pattern.Patterns;
24 import scala.concurrent.Future;
25 import scala.concurrent.duration.FiniteDuration;
27 import java.util.ArrayList;
28 import java.util.HashSet;
29 import java.util.List;
32 import java.util.concurrent.ThreadLocalRandom;
33 import java.util.concurrent.TimeUnit;
35 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketVersions;
36 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketVersionsReply;
37 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketsByMembers;
38 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketsByMembersReply;
39 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.UpdateRemoteBuckets;
40 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope;
41 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus;
42 import static org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipTick;
45 * Gossiper that syncs bucket store across nodes in the cluster.
47 * It keeps a local scheduler that periodically sends Gossip ticks to
48 * itself to send bucket store's bucket versions to a randomly selected remote
51 * When bucket versions are received from a remote gossiper, it is compared
52 * with bucket store's bucket versions. Which ever buckets are newer
53 * locally, are sent to remote gossiper. If any bucket is older in bucket store,
54 * a gossip status is sent to remote gossiper so that it can send the newer buckets.
56 * When a bucket is received from a remote gossiper, its sent to the bucket store
61 public class Gossiper extends UntypedActor {
63 final LoggingAdapter log = Logging.getLogger(getContext().system(), this);
65 private Cluster cluster;
68 * ActorSystem's address for the current cluster node.
70 private Address selfAddress;
73 * All known cluster members
75 private List<Address> clusterMembers = new ArrayList<>();
77 private Cancellable gossipTask;
79 private Boolean autoStartGossipTicks = true;
85 * @param autoStartGossipTicks used for turning off gossip ticks during testing.
86 * Gossip tick can be manually sent.
88 public Gossiper(Boolean autoStartGossipTicks){
89 this.autoStartGossipTicks = autoStartGossipTicks;
93 public void preStart(){
94 ActorRefProvider provider = getContext().provider();
95 selfAddress = provider.getDefaultAddress();
97 if ( provider instanceof ClusterActorRefProvider ) {
98 cluster = Cluster.get(getContext().system());
99 cluster.subscribe(getSelf(),
100 ClusterEvent.initialStateAsEvents(),
101 ClusterEvent.MemberEvent.class,
102 ClusterEvent.UnreachableMember.class);
105 if (autoStartGossipTicks) {
106 gossipTask = getContext().system().scheduler().schedule(
107 new FiniteDuration(1, TimeUnit.SECONDS), //initial delay
108 new FiniteDuration(500, TimeUnit.MILLISECONDS), //interval
110 new Messages.GossiperMessages.GossipTick(), //message
111 getContext().dispatcher(), //execution context
118 public void postStop(){
120 cluster.unsubscribe(getSelf());
121 if (gossipTask != null)
126 public void onReceive(Object message) throws Exception {
128 log.debug("Received message: node[{}], message[{}]", selfAddress, message);
130 //Usually sent by self via gossip task defined above. But its not enforced.
131 //These ticks can be sent by another actor as well which is esp. useful while testing
132 if (message instanceof GossipTick)
135 //Message from remote gossiper with its bucket versions
136 else if (message instanceof GossipStatus)
137 receiveGossipStatus((GossipStatus) message);
139 //Message from remote gossiper with buckets. This is usually in response to GossipStatus message
140 //The contained buckets are newer as determined by the remote gossiper by comparing the GossipStatus
141 //message with its local versions
142 else if (message instanceof GossipEnvelope)
143 receiveGossip((GossipEnvelope) message);
145 else if (message instanceof ClusterEvent.MemberUp) {
146 receiveMemberUp(((ClusterEvent.MemberUp) message).member());
148 } else if (message instanceof ClusterEvent.MemberRemoved) {
149 receiveMemberRemoveOrUnreachable(((ClusterEvent.MemberRemoved) message).member());
151 } else if ( message instanceof ClusterEvent.UnreachableMember){
152 receiveMemberRemoveOrUnreachable(((ClusterEvent.UnreachableMember) message).member());
159 * Remove member from local copy of member list. If member down is self, then stop the actor
161 * @param member who went down
163 void receiveMemberRemoveOrUnreachable(Member member) {
164 //if its self, then stop itself
165 if (selfAddress.equals(member.address())){
166 getContext().stop(getSelf());
170 clusterMembers.remove(member.address());
171 log.debug("Removed member [{}], Active member list [{}]", member.address(), clusterMembers);
175 * Add member to the local copy of member list if it doesnt already
178 void receiveMemberUp(Member member) {
180 if (selfAddress.equals(member.address()))
181 return; //ignore up notification for self
183 if (!clusterMembers.contains(member.address()))
184 clusterMembers.add(member.address());
186 log.debug("Added member [{}], Active member list [{}]", member.address(), clusterMembers);
190 * Sends Gossip status to other members in the cluster. <br/>
191 * 1. If there are no member, ignore the tick. </br>
192 * 2. If there's only 1 member, send gossip status (bucket versions) to it. <br/>
193 * 3. If there are more than one member, randomly pick one and send gossip status (bucket versions) to it.
195 void receiveGossipTick(){
196 if (clusterMembers.size() == 0) return; //no members to send gossip status to
198 Address remoteMemberToGossipTo = null;
200 if (clusterMembers.size() == 1)
201 remoteMemberToGossipTo = clusterMembers.get(0);
203 Integer randomIndex = ThreadLocalRandom.current().nextInt(0, clusterMembers.size());
204 remoteMemberToGossipTo = clusterMembers.get(randomIndex);
207 log.debug("Gossiping to [{}]", remoteMemberToGossipTo);
208 getLocalStatusAndSendTo(remoteMemberToGossipTo);
212 * Process gossip status received from a remote gossiper. Remote versions are compared with
213 * the local copy. <p>
217 * <li>If local copy is newer, the newer buckets are sent in GossipEnvelope to remote</li>
218 * <li>If local is older, GossipStatus is sent to remote so that it can reply with GossipEnvelope</li>
219 * <li>If both are same, noop</li>
222 * @param status bucket versions from a remote member
224 void receiveGossipStatus(GossipStatus status){
225 //Don't accept messages from non-members
226 if (!clusterMembers.contains(status.from()))
229 final ActorRef sender = getSender();
230 Future<Object> futureReply = Patterns.ask(getContext().parent(), new GetBucketVersions(), 1000);
231 futureReply.map(getMapperToProcessRemoteStatus(sender, status), getContext().dispatcher());
236 * Sends the received buckets in the envelope to the parent Bucket store.
238 * @param envelope contains buckets from a remote gossiper
240 void receiveGossip(GossipEnvelope envelope){
241 //TODO: Add more validations
242 if (!selfAddress.equals(envelope.to())) {
243 log.debug("Ignoring message intended for someone else. From [{}] to [{}]", envelope.from(), envelope.to());
247 updateRemoteBuckets(envelope.getBuckets());
252 * Helper to send received buckets to bucket store
256 void updateRemoteBuckets(Map<Address, Bucket> buckets) {
258 UpdateRemoteBuckets updateRemoteBuckets = new UpdateRemoteBuckets(buckets);
259 getContext().parent().tell(updateRemoteBuckets, getSelf());
263 * Gets the buckets from bucket store for the given node addresses and sends them to remote gossiper
265 * @param remote remote node to send Buckets to
266 * @param addresses node addresses whose buckets needs to be sent
268 void sendGossipTo(final ActorRef remote, final Set<Address> addresses){
270 Future<Object> futureReply = Patterns.ask(getContext().parent(), new GetBucketsByMembers(addresses), 1000);
271 futureReply.map(getMapperToSendGossip(remote), getContext().dispatcher());
275 * Gets bucket versions from bucket store and sends to the supplied address
277 * @param remoteActorSystemAddress remote gossiper to send to
279 void getLocalStatusAndSendTo(Address remoteActorSystemAddress){
281 //Get local status from bucket store and send to remote
282 Future<Object> futureReply = Patterns.ask(getContext().parent(), new GetBucketVersions(), 1000);
283 ActorSelection remoteRef = getContext().system().actorSelection(
284 remoteActorSystemAddress.toString() + getSelf().path().toStringWithoutAddress());
286 log.debug("Sending bucket versions to [{}]", remoteRef);
288 futureReply.map(getMapperToSendLocalStatus(remoteRef), getContext().dispatcher());
293 * Helper to send bucket versions received from local store
294 * @param remote remote gossiper to send versions to
295 * @param localVersions bucket versions received from local store
297 void sendGossipStatusTo(ActorRef remote, Map<Address, Long> localVersions){
299 GossipStatus status = new GossipStatus(selfAddress, localVersions);
300 remote.tell(status, getSelf());
303 void sendGossipStatusTo(ActorSelection remote, Map<Address, Long> localVersions){
305 GossipStatus status = new GossipStatus(selfAddress, localVersions);
306 remote.tell(status, getSelf());
310 /// Private factories to create mappers
313 private Mapper<Object, Void> getMapperToSendLocalStatus(final ActorSelection remote){
315 return new Mapper<Object, Void>() {
317 public Void apply(Object replyMessage) {
318 if (replyMessage instanceof GetBucketVersionsReply) {
319 GetBucketVersionsReply reply = (GetBucketVersionsReply) replyMessage;
320 Map<Address, Long> localVersions = reply.getVersions();
322 sendGossipStatusTo(remote, localVersions);
331 * Process bucket versions received from
332 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.BucketStore}.
333 * Then this method compares remote bucket versions with local bucket versions.
335 * <li>The buckets that are newer locally, send
336 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope}
338 * <li>The buckets that are older locally, send
339 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus}
340 * to remote so that remote sends GossipEnvelop.
343 * @param sender the remote member
344 * @param status bucket versions from a remote member
345 * @return a {@link akka.dispatch.Mapper} that gets evaluated in future
348 private Mapper<Object, Void> getMapperToProcessRemoteStatus(final ActorRef sender, final GossipStatus status){
350 final Map<Address, Long> remoteVersions = status.getVersions();
352 return new Mapper<Object, Void>() {
354 public Void apply(Object replyMessage) {
355 if (replyMessage instanceof GetBucketVersionsReply) {
356 GetBucketVersionsReply reply = (GetBucketVersionsReply) replyMessage;
357 Map<Address, Long> localVersions = reply.getVersions();
359 //diff between remote list and local
360 Set<Address> localIsOlder = new HashSet<>();
361 localIsOlder.addAll(remoteVersions.keySet());
362 localIsOlder.removeAll(localVersions.keySet());
364 //diff between local list and remote
365 Set<Address> localIsNewer = new HashSet<>();
366 localIsNewer.addAll(localVersions.keySet());
367 localIsNewer.removeAll(remoteVersions.keySet());
370 for (Address address : remoteVersions.keySet()){
372 if (localVersions.get(address) == null || remoteVersions.get(address) == null)
373 continue; //this condition is taken care of by above diffs
374 if (localVersions.get(address) < remoteVersions.get(address))
375 localIsOlder.add(address);
376 else if (localVersions.get(address) > remoteVersions.get(address))
377 localIsNewer.add(address);
382 if (!localIsOlder.isEmpty())
383 sendGossipStatusTo(sender, localVersions );
385 if (!localIsNewer.isEmpty())
386 sendGossipTo(sender, localIsNewer);//send newer buckets to remote
395 * Processes the message from {@link org.opendaylight.controller.remote.rpc.registry.gossip.BucketStore}
396 * that contains {@link org.opendaylight.controller.remote.rpc.registry.gossip.Bucket}.
397 * These buckets are sent to a remote member encapsulated in
398 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope}
400 * @param sender the remote member that sent
401 * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus}
402 * in reply to which bucket is being sent back
403 * @return a {@link akka.dispatch.Mapper} that gets evaluated in future
406 private Mapper<Object, Void> getMapperToSendGossip(final ActorRef sender) {
408 return new Mapper<Object, Void>() {
410 public Void apply(Object msg) {
411 if (msg instanceof GetBucketsByMembersReply) {
412 Map<Address, Bucket> buckets = ((GetBucketsByMembersReply) msg).getBuckets();
413 log.debug("Buckets to send from {}: {}", selfAddress, buckets);
414 GossipEnvelope envelope = new GossipEnvelope(selfAddress, sender.path().address(), buckets);
415 sender.tell(envelope, getSelf());
425 List<Address> getClusterMembers() {
426 return clusterMembers;
429 void setClusterMembers(List<Address> clusterMembers) {
430 this.clusterMembers = clusterMembers;
433 Address getSelfAddress() {
437 void setSelfAddress(Address selfAddress) {
438 this.selfAddress = selfAddress;