opendaylight/md-sal/sal-remoterpc-connector/src/main/java/org/opendaylight/controller/remote/rpc/registry/gossip/Gossiper.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   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
   7  */
   8 package org.opendaylight.controller.remote.rpc.registry.gossip;
   9
  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.cluster.Cluster;
  16 import akka.cluster.ClusterActorRefProvider;
  17 import akka.cluster.ClusterEvent;
  18 import akka.cluster.Member;
  19 import akka.dispatch.Mapper;
  20 import akka.pattern.Patterns;
  21 import com.google.common.base.Preconditions;
  22 import java.util.ArrayList;
  23 import java.util.HashSet;
  24 import java.util.List;
  25 import java.util.Map;
  26 import java.util.Set;
  27 import java.util.concurrent.ThreadLocalRandom;
  28 import java.util.concurrent.TimeUnit;
  29 import org.opendaylight.controller.cluster.common.actor.AbstractUntypedActorWithMetering;
  30 import org.opendaylight.controller.remote.rpc.RemoteRpcProviderConfig;
  31 import org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketVersions;
  32 import org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketVersionsReply;
  33 import org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketsByMembers;
  34 import org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.GetBucketsByMembersReply;
  35 import org.opendaylight.controller.remote.rpc.registry.gossip.Messages.BucketStoreMessages.UpdateRemoteBuckets;
  36 import org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope;
  37 import org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus;
  38 import org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipTick;
  39 import org.slf4j.Logger;
  40 import org.slf4j.LoggerFactory;
  41 import scala.concurrent.Future;
  42 import scala.concurrent.duration.FiniteDuration;
  43
  44 /**
  45  * Gossiper that syncs bucket store across nodes in the cluster.
  46  * <p/>
  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
  49  * gossiper.
  50  * <p/>
  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.
  55  * <p/>
  56  * When a bucket is received from a remote gossiper, its sent to the bucket store
  57  * for update.
  58  *
  59  */
  60
  61 public class Gossiper extends AbstractUntypedActorWithMetering {
  62
  63     private final Logger log = LoggerFactory.getLogger(getClass());
  64
  65     private Cluster cluster;
  66
  67     /**
  68      * ActorSystem's address for the current cluster node.
  69      */
  70     private Address selfAddress;
  71
  72     /**
  73      * All known cluster members
  74      */
  75     private List<Address> clusterMembers = new ArrayList<>();
  76
  77     private Cancellable gossipTask;
  78
  79     private Boolean autoStartGossipTicks = true;
  80
  81     private final RemoteRpcProviderConfig config;
  82
  83     public Gossiper(RemoteRpcProviderConfig config){
  84         this.config = Preconditions.checkNotNull(config);
  85     }
  86
  87     /**
  88      * Helpful for testing
  89      * @param autoStartGossipTicks used for turning off gossip ticks during testing.
  90      *                             Gossip tick can be manually sent.
  91      */
  92     public Gossiper(Boolean autoStartGossipTicks, RemoteRpcProviderConfig config){
  93         this(config);
  94         this.autoStartGossipTicks = autoStartGossipTicks;
  95     }
  96
  97     @Override
  98     public void preStart(){
  99         ActorRefProvider provider = getContext().provider();
 100         selfAddress = provider.getDefaultAddress();
 101
 102         if ( provider instanceof ClusterActorRefProvider ) {
 103             cluster = Cluster.get(getContext().system());
 104             cluster.subscribe(getSelf(),
 105                     ClusterEvent.initialStateAsEvents(),
 106                     ClusterEvent.MemberEvent.class,
 107                     ClusterEvent.UnreachableMember.class);
 108         }
 109
 110         if (autoStartGossipTicks) {
 111             gossipTask = getContext().system().scheduler().schedule(
 112                     new FiniteDuration(1, TimeUnit.SECONDS),        //initial delay
 113                     config.getGossipTickInterval(),                 //interval
 114                     getSelf(),                                       //target
 115                     new Messages.GossiperMessages.GossipTick(),      //message
 116                     getContext().dispatcher(),                       //execution context
 117                     getSelf()                                        //sender
 118             );
 119         }
 120     }
 121
 122     @Override
 123     public void postStop(){
 124         if (cluster != null) {
 125             cluster.unsubscribe(getSelf());
 126         }
 127         if (gossipTask != null) {
 128             gossipTask.cancel();
 129         }
 130     }
 131
 132     @Override
 133     protected void handleReceive(Object message) throws Exception {
 134         //Usually sent by self via gossip task defined above. But its not enforced.
 135         //These ticks can be sent by another actor as well which is esp. useful while testing
 136         if (message instanceof GossipTick) {
 137             receiveGossipTick();
 138         } else if (message instanceof GossipStatus) {
 139             // Message from remote gossiper with its bucket versions
 140             receiveGossipStatus((GossipStatus) message);
 141         } else if (message instanceof GossipEnvelope) {
 142             // Message from remote gossiper with buckets. This is usually in response to GossipStatus
 143             // message. The contained buckets are newer as determined by the remote gossiper by
 144             // comparing the GossipStatus message with its local versions.
 145             receiveGossip((GossipEnvelope) message);
 146         } else if (message instanceof ClusterEvent.MemberUp) {
 147             receiveMemberUp(((ClusterEvent.MemberUp) message).member());
 148
 149         } else if (message instanceof ClusterEvent.MemberRemoved) {
 150             receiveMemberRemoveOrUnreachable(((ClusterEvent.MemberRemoved) message).member());
 151
 152         } else if ( message instanceof ClusterEvent.UnreachableMember){
 153             receiveMemberRemoveOrUnreachable(((ClusterEvent.UnreachableMember) message).member());
 154
 155         } else {
 156             unhandled(message);
 157         }
 158     }
 159
 160     /**
 161      * Remove member from local copy of member list. If member down is self, then stop the actor
 162      *
 163      * @param member who went down
 164      */
 165     void receiveMemberRemoveOrUnreachable(Member member) {
 166         //if its self, then stop itself
 167         if (selfAddress.equals(member.address())){
 168             getContext().stop(getSelf());
 169             return;
 170         }
 171
 172         clusterMembers.remove(member.address());
 173         if(log.isDebugEnabled()) {
 174             log.debug("Removed member [{}], Active member list [{}]", member.address(), clusterMembers);
 175         }
 176     }
 177
 178     /**
 179      * Add member to the local copy of member list if it doesnt already
 180      * @param member
 181      */
 182     void receiveMemberUp(Member member) {
 183
 184         if (selfAddress.equals(member.address())) {
 185             return; //ignore up notification for self
 186         }
 187
 188         if (!clusterMembers.contains(member.address())) {
 189             clusterMembers.add(member.address());
 190         }
 191         if(log.isDebugEnabled()) {
 192             log.debug("Added member [{}], Active member list [{}]", member.address(), clusterMembers);
 193         }
 194     }
 195
 196     /**
 197      * Sends Gossip status to other members in the cluster. <br/>
 198      * 1. If there are no member, ignore the tick. </br>
 199      * 2. If there's only 1 member, send gossip status (bucket versions) to it. <br/>
 200      * 3. If there are more than one member, randomly pick one and send gossip status (bucket versions) to it.
 201      */
 202     void receiveGossipTick(){
 203         if (clusterMembers.size() == 0) {
 204             return; //no members to send gossip status to
 205         }
 206
 207         Address remoteMemberToGossipTo;
 208
 209         if (clusterMembers.size() == 1) {
 210             remoteMemberToGossipTo = clusterMembers.get(0);
 211         } else {
 212             Integer randomIndex = ThreadLocalRandom.current().nextInt(0, clusterMembers.size());
 213             remoteMemberToGossipTo = clusterMembers.get(randomIndex);
 214         }
 215         if(log.isTraceEnabled()) {
 216             log.trace("Gossiping to [{}]", remoteMemberToGossipTo);
 217         }
 218         getLocalStatusAndSendTo(remoteMemberToGossipTo);
 219     }
 220
 221     /**
 222      * Process gossip status received from a remote gossiper. Remote versions are compared with
 223      * the local copy. <p>
 224      *
 225      * For each bucket
 226      * <ul>
 227      *  <li>If local copy is newer, the newer buckets are sent in GossipEnvelope to remote</li>
 228      *  <li>If local is older, GossipStatus is sent to remote so that it can reply with GossipEnvelope</li>
 229      *  <li>If both are same, noop</li>
 230      * </ul>
 231      *
 232      * @param status bucket versions from a remote member
 233      */
 234     void receiveGossipStatus(GossipStatus status){
 235         //Don't accept messages from non-members
 236         if (!clusterMembers.contains(status.from())) {
 237             return;
 238         }
 239
 240         final ActorRef sender = getSender();
 241         Future<Object> futureReply =
 242                 Patterns.ask(getContext().parent(), new GetBucketVersions(), config.getAskDuration());
 243
 244         futureReply.map(getMapperToProcessRemoteStatus(sender, status), getContext().dispatcher());
 245
 246     }
 247
 248     /**
 249      * Sends the received buckets in the envelope to the parent Bucket store.
 250      *
 251      * @param envelope contains buckets from a remote gossiper
 252      */
 253     void receiveGossip(GossipEnvelope envelope){
 254         //TODO: Add more validations
 255         if (!selfAddress.equals(envelope.to())) {
 256             if(log.isTraceEnabled()) {
 257                 log.trace("Ignoring message intended for someone else. From [{}] to [{}]", envelope.from(), envelope.to());
 258             }
 259             return;
 260         }
 261
 262         updateRemoteBuckets(envelope.getBuckets());
 263
 264     }
 265
 266     /**
 267      * Helper to send received buckets to bucket store
 268      *
 269      * @param buckets
 270      */
 271     void updateRemoteBuckets(Map<Address, Bucket> buckets) {
 272
 273         UpdateRemoteBuckets updateRemoteBuckets = new UpdateRemoteBuckets(buckets);
 274         getContext().parent().tell(updateRemoteBuckets, getSelf());
 275     }
 276
 277     /**
 278      * Gets the buckets from bucket store for the given node addresses and sends them to remote gossiper
 279      *
 280      * @param remote     remote node to send Buckets to
 281      * @param addresses  node addresses whose buckets needs to be sent
 282      */
 283     void sendGossipTo(final ActorRef remote, final Set<Address> addresses){
 284
 285         Future<Object> futureReply =
 286                 Patterns.ask(getContext().parent(), new GetBucketsByMembers(addresses), config.getAskDuration());
 287         futureReply.map(getMapperToSendGossip(remote), getContext().dispatcher());
 288     }
 289
 290     /**
 291      * Gets bucket versions from bucket store and sends to the supplied address
 292      *
 293      * @param remoteActorSystemAddress remote gossiper to send to
 294      */
 295     void getLocalStatusAndSendTo(Address remoteActorSystemAddress){
 296
 297         //Get local status from bucket store and send to remote
 298         Future<Object> futureReply =
 299                 Patterns.ask(getContext().parent(), new GetBucketVersions(), config.getAskDuration());
 300
 301         //Find gossiper on remote system
 302         ActorSelection remoteRef = getContext().system().actorSelection(
 303                 remoteActorSystemAddress.toString() + getSelf().path().toStringWithoutAddress());
 304
 305         if(log.isTraceEnabled()) {
 306             log.trace("Sending bucket versions to [{}]", remoteRef);
 307         }
 308
 309         futureReply.map(getMapperToSendLocalStatus(remoteRef), getContext().dispatcher());
 310
 311     }
 312
 313     /**
 314      * Helper to send bucket versions received from local store
 315      * @param remote        remote gossiper to send versions to
 316      * @param localVersions bucket versions received from local store
 317      */
 318     void sendGossipStatusTo(ActorRef remote, Map<Address, Long> localVersions){
 319
 320         GossipStatus status = new GossipStatus(selfAddress, localVersions);
 321         remote.tell(status, getSelf());
 322     }
 323
 324     void sendGossipStatusTo(ActorSelection remote, Map<Address, Long> localVersions){
 325
 326         GossipStatus status = new GossipStatus(selfAddress, localVersions);
 327         remote.tell(status, getSelf());
 328     }
 329
 330     ///
 331     /// Private factories to create mappers
 332     ///
 333
 334     private Mapper<Object, Void> getMapperToSendLocalStatus(final ActorSelection remote){
 335
 336         return new Mapper<Object, Void>() {
 337             @Override
 338             public Void apply(Object replyMessage) {
 339                 if (replyMessage instanceof GetBucketVersionsReply) {
 340                     GetBucketVersionsReply reply = (GetBucketVersionsReply) replyMessage;
 341                     Map<Address, Long> localVersions = reply.getVersions();
 342
 343                     sendGossipStatusTo(remote, localVersions);
 344
 345                 }
 346                 return null;
 347             }
 348         };
 349     }
 350
 351     /**
 352      * Process bucket versions received from
 353      * {@link org.opendaylight.controller.remote.rpc.registry.gossip.BucketStore}.
 354      * Then this method compares remote bucket versions with local bucket versions.
 355      * <ul>
 356      *     <li>The buckets that are newer locally, send
 357      *     {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope}
 358      *     to remote
 359      *     <li>The buckets that are older locally, send
 360      *     {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus}
 361      *     to remote so that remote sends GossipEnvelop.
 362      * </ul>
 363      *
 364      * @param sender the remote member
 365      * @param status bucket versions from a remote member
 366      * @return a {@link akka.dispatch.Mapper} that gets evaluated in future
 367      *
 368      */
 369     private Mapper<Object, Void> getMapperToProcessRemoteStatus(final ActorRef sender, final GossipStatus status){
 370
 371         final Map<Address, Long> remoteVersions = status.getVersions();
 372
 373         return new Mapper<Object, Void>() {
 374             @Override
 375             public Void apply(Object replyMessage) {
 376                 if (replyMessage instanceof GetBucketVersionsReply) {
 377                     GetBucketVersionsReply reply = (GetBucketVersionsReply) replyMessage;
 378                     Map<Address, Long> localVersions = reply.getVersions();
 379
 380                     //diff between remote list and local
 381                     Set<Address> localIsOlder = new HashSet<>();
 382                     localIsOlder.addAll(remoteVersions.keySet());
 383                     localIsOlder.removeAll(localVersions.keySet());
 384
 385                     //diff between local list and remote
 386                     Set<Address> localIsNewer = new HashSet<>();
 387                     localIsNewer.addAll(localVersions.keySet());
 388                     localIsNewer.removeAll(remoteVersions.keySet());
 389
 390
 391                     for (Address address : remoteVersions.keySet()){
 392
 393                         if (localVersions.get(address) == null || remoteVersions.get(address) == null) {
 394                             continue; //this condition is taken care of by above diffs
 395                         }
 396                         if (localVersions.get(address) <  remoteVersions.get(address)) {
 397                             localIsOlder.add(address);
 398                         } else if (localVersions.get(address) > remoteVersions.get(address)) {
 399                             localIsNewer.add(address);
 400                         }
 401                     }
 402
 403                     if (!localIsOlder.isEmpty()) {
 404                         sendGossipStatusTo(sender, localVersions );
 405                     }
 406
 407                     if (!localIsNewer.isEmpty()) {
 408                         sendGossipTo(sender, localIsNewer);//send newer buckets to remote
 409                     }
 410
 411                 }
 412                 return null;
 413             }
 414         };
 415     }
 416
 417     /**
 418      * Processes the message from {@link org.opendaylight.controller.remote.rpc.registry.gossip.BucketStore}
 419      * that contains {@link org.opendaylight.controller.remote.rpc.registry.gossip.Bucket}.
 420      * These buckets are sent to a remote member encapsulated in
 421      * {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipEnvelope}
 422      *
 423      * @param sender the remote member that sent
 424      *               {@link org.opendaylight.controller.remote.rpc.registry.gossip.Messages.GossiperMessages.GossipStatus}
 425      *               in reply to which bucket is being sent back
 426      * @return a {@link akka.dispatch.Mapper} that gets evaluated in future
 427      *
 428      */
 429     private Mapper<Object, Void> getMapperToSendGossip(final ActorRef sender) {
 430
 431         return new Mapper<Object, Void>() {
 432             @Override
 433             public Void apply(Object msg) {
 434                 if (msg instanceof GetBucketsByMembersReply) {
 435                     Map<Address, Bucket> buckets = ((GetBucketsByMembersReply) msg).getBuckets();
 436                     if(log.isTraceEnabled()) {
 437                         log.trace("Buckets to send from {}: {}", selfAddress, buckets);
 438                     }
 439                     GossipEnvelope envelope = new GossipEnvelope(selfAddress, sender.path().address(), buckets);
 440                     sender.tell(envelope, getSelf());
 441                 }
 442                 return null;
 443             }
 444         };
 445     }
 446
 447     ///
 448     ///Getter Setters
 449     ///
 450     List<Address> getClusterMembers() {
 451         return clusterMembers;
 452     }
 453
 454     void setClusterMembers(List<Address> clusterMembers) {
 455         this.clusterMembers = clusterMembers;
 456     }
 457
 458     Address getSelfAddress() {
 459         return selfAddress;
 460     }
 461
 462     void setSelfAddress(Address selfAddress) {
 463         this.selfAddress = selfAddress;
 464     }
 465 }