2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
3 * Copyright (c) 2015 Brocade Communications Systems, Inc. and others. All rights reserved.
5 * This program and the accompanying materials are made available under the
6 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
7 * and is available at http://www.eclipse.org/legal/epl-v10.html
10 package org.opendaylight.controller.cluster.raft;
12 import akka.actor.ActorRef;
13 import akka.actor.ActorSelection;
14 import akka.actor.PoisonPill;
15 import akka.japi.Procedure;
16 import com.google.common.annotations.VisibleForTesting;
17 import com.google.common.base.Objects;
18 import com.google.common.base.Optional;
19 import com.google.common.base.Supplier;
20 import com.google.common.collect.Lists;
21 import java.io.Serializable;
22 import java.util.Collection;
23 import java.util.HashMap;
24 import java.util.List;
26 import java.util.concurrent.TimeUnit;
27 import javax.annotation.Nonnull;
28 import org.apache.commons.lang3.time.DurationFormatUtils;
29 import org.opendaylight.controller.cluster.DataPersistenceProvider;
30 import org.opendaylight.controller.cluster.DelegatingPersistentDataProvider;
31 import org.opendaylight.controller.cluster.NonPersistentDataProvider;
32 import org.opendaylight.controller.cluster.PersistentDataProvider;
33 import org.opendaylight.controller.cluster.common.actor.AbstractUntypedPersistentActor;
34 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
35 import org.opendaylight.controller.cluster.notifications.RoleChanged;
36 import org.opendaylight.controller.cluster.raft.base.messages.ApplyJournalEntries;
37 import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
38 import org.opendaylight.controller.cluster.raft.base.messages.InitiateCaptureSnapshot;
39 import org.opendaylight.controller.cluster.raft.base.messages.LeaderTransitioning;
40 import org.opendaylight.controller.cluster.raft.base.messages.Replicate;
41 import org.opendaylight.controller.cluster.raft.base.messages.SwitchBehavior;
42 import org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader;
43 import org.opendaylight.controller.cluster.raft.behaviors.DelegatingRaftActorBehavior;
44 import org.opendaylight.controller.cluster.raft.behaviors.Follower;
45 import org.opendaylight.controller.cluster.raft.behaviors.RaftActorBehavior;
46 import org.opendaylight.controller.cluster.raft.client.messages.FindLeader;
47 import org.opendaylight.controller.cluster.raft.client.messages.FindLeaderReply;
48 import org.opendaylight.controller.cluster.raft.client.messages.FollowerInfo;
49 import org.opendaylight.controller.cluster.raft.client.messages.GetOnDemandRaftState;
50 import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
51 import org.opendaylight.controller.cluster.raft.client.messages.Shutdown;
52 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
53 import org.slf4j.Logger;
54 import org.slf4j.LoggerFactory;
57 * RaftActor encapsulates a state machine that needs to be kept synchronized
58 * in a cluster. It implements the RAFT algorithm as described in the paper
59 * <a href='https://ramcloud.stanford.edu/wiki/download/attachments/11370504/raft.pdf'>
60 * In Search of an Understandable Consensus Algorithm</a>
62 * RaftActor has 3 states and each state has a certain behavior associated
63 * with it. A Raft actor can behave as,
66 * <li> A Follower (or) </li>
67 * <li> A Candidate </li>
71 * A RaftActor MUST be a Leader in order to accept requests from clients to
72 * change the state of it's encapsulated state machine. Once a RaftActor becomes
73 * a Leader it is also responsible for ensuring that all followers ultimately
74 * have the same log and therefore the same state machine as itself.
77 * The current behavior of a RaftActor determines how election for leadership
78 * is initiated and how peer RaftActors react to request for votes.
81 * Each RaftActor also needs to know the current election term. It uses this
82 * information for a couple of things. One is to simply figure out who it
83 * voted for in the last election. Another is to figure out if the message
84 * it received to update it's state is stale.
87 * The RaftActor uses akka-persistence to store it's replicated log.
88 * Furthermore through it's behaviors a Raft Actor determines
91 * <li> when a log entry should be persisted </li>
92 * <li> when a log entry should be applied to the state machine (and) </li>
93 * <li> when a snapshot should be saved </li>
96 public abstract class RaftActor extends AbstractUntypedPersistentActor {
98 private static final long APPLY_STATE_DELAY_THRESHOLD_IN_NANOS = TimeUnit.MILLISECONDS.toNanos(50L); // 50 millis
100 protected final Logger LOG = LoggerFactory.getLogger(getClass());
103 * The current state determines the current behavior of a RaftActor
104 * A Raft Actor always starts off in the Follower State
106 private final DelegatingRaftActorBehavior currentBehavior = new DelegatingRaftActorBehavior();
109 * This context should NOT be passed directly to any other actor it is
110 * only to be consumed by the RaftActorBehaviors
112 private final RaftActorContextImpl context;
114 private final DelegatingPersistentDataProvider delegatingPersistenceProvider;
116 private final PersistentDataProvider persistentProvider;
118 private RaftActorRecoverySupport raftRecovery;
120 private RaftActorSnapshotMessageSupport snapshotSupport;
122 private final BehaviorStateHolder reusableBehaviorStateHolder = new BehaviorStateHolder();
124 private final SwitchBehaviorSupplier reusableSwitchBehaviorSupplier = new SwitchBehaviorSupplier();
126 private RaftActorServerConfigurationSupport serverConfigurationSupport;
128 private RaftActorLeadershipTransferCohort leadershipTransferInProgress;
130 private boolean shuttingDown;
132 public RaftActor(String id, Map<String, String> peerAddresses,
133 Optional<ConfigParams> configParams, short payloadVersion) {
135 persistentProvider = new PersistentDataProvider(this);
136 delegatingPersistenceProvider = new RaftActorDelegatingPersistentDataProvider(null, persistentProvider);
138 context = new RaftActorContextImpl(this.getSelf(),
139 this.getContext(), id, new ElectionTermImpl(persistentProvider, id, LOG),
140 -1, -1, peerAddresses,
141 (configParams.isPresent() ? configParams.get(): new DefaultConfigParamsImpl()),
142 delegatingPersistenceProvider, LOG);
144 context.setPayloadVersion(payloadVersion);
145 context.setReplicatedLog(ReplicatedLogImpl.newInstance(context, currentBehavior));
149 public void preStart() throws Exception {
150 LOG.info("Starting recovery for {} with journal batch size {}", persistenceId(),
151 context.getConfigParams().getJournalRecoveryLogBatchSize());
155 snapshotSupport = newRaftActorSnapshotMessageSupport();
156 serverConfigurationSupport = new RaftActorServerConfigurationSupport(this);
160 public void postStop() {
161 if(currentBehavior.getDelegate() != null) {
163 currentBehavior.close();
164 } catch (Exception e) {
165 LOG.debug("{}: Error closing behavior {}", persistenceId(), currentBehavior.state());
173 public void handleRecover(Object message) {
174 if(raftRecovery == null) {
175 raftRecovery = newRaftActorRecoverySupport();
178 boolean recoveryComplete = raftRecovery.handleRecoveryMessage(message, persistentProvider);
179 if(recoveryComplete) {
180 onRecoveryComplete();
182 initializeBehavior();
186 if (context.getReplicatedLog().size() > 0) {
187 self().tell(new InitiateCaptureSnapshot(), self());
188 LOG.info("{}: Snapshot capture initiated after recovery", persistenceId());
190 LOG.info("{}: Snapshot capture NOT initiated after recovery, journal empty", persistenceId());
195 protected RaftActorRecoverySupport newRaftActorRecoverySupport() {
196 return new RaftActorRecoverySupport(context, currentBehavior, getRaftActorRecoveryCohort());
199 protected void initializeBehavior(){
200 changeCurrentBehavior(new Follower(context));
203 protected void changeCurrentBehavior(RaftActorBehavior newBehavior){
204 reusableBehaviorStateHolder.init(getCurrentBehavior());
205 setCurrentBehavior(newBehavior);
206 handleBehaviorChange(reusableBehaviorStateHolder, getCurrentBehavior());
210 public void handleCommand(final Object message) {
211 if(serverConfigurationSupport.handleMessage(message, getSender())) {
213 } else if (message instanceof ApplyState){
214 ApplyState applyState = (ApplyState) message;
216 long startTime = System.nanoTime();
218 if(LOG.isDebugEnabled()) {
219 LOG.debug("{}: Applying state for log index {} data {}",
220 persistenceId(), applyState.getReplicatedLogEntry().getIndex(),
221 applyState.getReplicatedLogEntry().getData());
224 applyState(applyState.getClientActor(), applyState.getIdentifier(),
225 applyState.getReplicatedLogEntry().getData());
227 long elapsedTime = System.nanoTime() - startTime;
228 if(elapsedTime >= APPLY_STATE_DELAY_THRESHOLD_IN_NANOS){
229 LOG.debug("ApplyState took more time than expected. Elapsed Time = {} ms ApplyState = {}",
230 TimeUnit.NANOSECONDS.toMillis(elapsedTime), applyState);
233 if (!hasFollowers()) {
234 // for single node, the capture should happen after the apply state
235 // as we delete messages from the persistent journal which have made it to the snapshot
236 // capturing the snapshot before applying makes the persistent journal and snapshot out of sync
237 // and recovery shows data missing
238 context.getReplicatedLog().captureSnapshotIfReady(applyState.getReplicatedLogEntry());
240 context.getSnapshotManager().trimLog(context.getLastApplied(), currentBehavior);
243 } else if (message instanceof ApplyJournalEntries){
244 ApplyJournalEntries applyEntries = (ApplyJournalEntries) message;
245 if(LOG.isDebugEnabled()) {
246 LOG.debug("{}: Persisting ApplyLogEntries with index={}", persistenceId(), applyEntries.getToIndex());
249 persistence().persist(applyEntries, NoopProcedure.instance());
251 } else if (message instanceof FindLeader) {
253 new FindLeaderReply(getLeaderAddress()),
256 } else if(message instanceof GetOnDemandRaftState) {
257 onGetOnDemandRaftStats();
258 } else if(message instanceof InitiateCaptureSnapshot) {
260 } else if(message instanceof SwitchBehavior){
261 switchBehavior(((SwitchBehavior) message));
262 } else if(message instanceof LeaderTransitioning) {
263 onLeaderTransitioning();
264 } else if(message instanceof Shutdown) {
266 } else if(message instanceof Runnable) {
267 ((Runnable)message).run();
268 } else if(!snapshotSupport.handleSnapshotMessage(message, getSender())) {
269 switchBehavior(reusableSwitchBehaviorSupplier.handleMessage(getSender(), message));
273 private void initiateLeadershipTransfer(final RaftActorLeadershipTransferCohort.OnComplete onComplete) {
274 LOG.debug("{}: Initiating leader transfer", persistenceId());
276 if(leadershipTransferInProgress == null) {
277 leadershipTransferInProgress = new RaftActorLeadershipTransferCohort(this, getSender());
278 leadershipTransferInProgress.addOnComplete(new RaftActorLeadershipTransferCohort.OnComplete() {
280 public void onSuccess(ActorRef raftActorRef, ActorRef replyTo) {
281 leadershipTransferInProgress = null;
285 public void onFailure(ActorRef raftActorRef, ActorRef replyTo) {
286 leadershipTransferInProgress = null;
290 leadershipTransferInProgress.addOnComplete(onComplete);
291 leadershipTransferInProgress.init();
293 LOG.debug("{}: prior leader transfer in progress - adding callback", persistenceId());
294 leadershipTransferInProgress.addOnComplete(onComplete);
298 private void onShutDown() {
299 LOG.debug("{}: onShutDown", persistenceId());
306 if(currentBehavior.state() == RaftState.Leader && context.hasFollowers()) {
307 initiateLeadershipTransfer(new RaftActorLeadershipTransferCohort.OnComplete() {
309 public void onSuccess(ActorRef raftActorRef, ActorRef replyTo) {
310 LOG.debug("{}: leader transfer succeeded - sending PoisonPill", persistenceId());
311 raftActorRef.tell(PoisonPill.getInstance(), raftActorRef);
315 public void onFailure(ActorRef raftActorRef, ActorRef replyTo) {
316 LOG.debug("{}: leader transfer failed - sending PoisonPill", persistenceId());
317 raftActorRef.tell(PoisonPill.getInstance(), raftActorRef);
320 } else if(currentBehavior.state() == RaftState.Leader) {
321 pauseLeader(new TimedRunnable(context.getConfigParams().getElectionTimeOutInterval(), this) {
323 protected void doRun() {
324 self().tell(PoisonPill.getInstance(), self());
328 protected void doCancel() {
329 self().tell(PoisonPill.getInstance(), self());
333 self().tell(PoisonPill.getInstance(), self());
337 private void onLeaderTransitioning() {
338 LOG.debug("{}: onLeaderTransitioning", persistenceId());
339 Optional<ActorRef> roleChangeNotifier = getRoleChangeNotifier();
340 if(currentBehavior.state() == RaftState.Follower && roleChangeNotifier.isPresent()) {
341 roleChangeNotifier.get().tell(newLeaderStateChanged(getId(), null,
342 currentBehavior.getLeaderPayloadVersion()), getSelf());
346 private void switchBehavior(SwitchBehavior message) {
347 if(!getRaftActorContext().getRaftPolicy().automaticElectionsEnabled()) {
348 RaftState newState = message.getNewState();
349 if( newState == RaftState.Leader || newState == RaftState.Follower) {
350 switchBehavior(reusableSwitchBehaviorSupplier.handleMessage(getSender(), message));
351 getRaftActorContext().getTermInformation().updateAndPersist(message.getNewTerm(), "");
353 LOG.warn("Switching to behavior : {} - not supported", newState);
358 private void switchBehavior(Supplier<RaftActorBehavior> supplier){
359 reusableBehaviorStateHolder.init(getCurrentBehavior());
361 setCurrentBehavior(supplier.get());
363 handleBehaviorChange(reusableBehaviorStateHolder, getCurrentBehavior());
366 protected RaftActorSnapshotMessageSupport newRaftActorSnapshotMessageSupport() {
367 return new RaftActorSnapshotMessageSupport(context, currentBehavior,
368 getRaftActorSnapshotCohort());
371 private void onGetOnDemandRaftStats() {
372 // Debugging message to retrieve raft stats.
374 Map<String, String> peerAddresses = new HashMap<>();
375 for(String peerId: context.getPeerIds()) {
376 peerAddresses.put(peerId, context.getPeerAddress(peerId));
379 OnDemandRaftState.Builder builder = OnDemandRaftState.builder()
380 .commitIndex(context.getCommitIndex())
381 .currentTerm(context.getTermInformation().getCurrentTerm())
382 .inMemoryJournalDataSize(replicatedLog().dataSize())
383 .inMemoryJournalLogSize(replicatedLog().size())
384 .isSnapshotCaptureInitiated(context.getSnapshotManager().isCapturing())
385 .lastApplied(context.getLastApplied())
386 .lastIndex(replicatedLog().lastIndex())
387 .lastTerm(replicatedLog().lastTerm())
388 .leader(getLeaderId())
389 .raftState(currentBehavior.state().toString())
390 .replicatedToAllIndex(currentBehavior.getReplicatedToAllIndex())
391 .snapshotIndex(replicatedLog().getSnapshotIndex())
392 .snapshotTerm(replicatedLog().getSnapshotTerm())
393 .votedFor(context.getTermInformation().getVotedFor())
394 .peerAddresses(peerAddresses)
395 .customRaftPolicyClassName(context.getConfigParams().getCustomRaftPolicyImplementationClass());
397 ReplicatedLogEntry lastLogEntry = getLastLogEntry();
398 if (lastLogEntry != null) {
399 builder.lastLogIndex(lastLogEntry.getIndex());
400 builder.lastLogTerm(lastLogEntry.getTerm());
403 if(getCurrentBehavior() instanceof AbstractLeader) {
404 AbstractLeader leader = (AbstractLeader)getCurrentBehavior();
405 Collection<String> followerIds = leader.getFollowerIds();
406 List<FollowerInfo> followerInfoList = Lists.newArrayListWithCapacity(followerIds.size());
407 for(String id: followerIds) {
408 final FollowerLogInformation info = leader.getFollower(id);
409 followerInfoList.add(new FollowerInfo(id, info.getNextIndex(), info.getMatchIndex(),
410 info.isFollowerActive(), DurationFormatUtils.formatDurationHMS(info.timeSinceLastActivity())));
413 builder.followerInfoList(followerInfoList);
416 sender().tell(builder.build(), self());
420 private void handleBehaviorChange(BehaviorStateHolder oldBehaviorState, RaftActorBehavior currentBehavior) {
421 RaftActorBehavior oldBehavior = oldBehaviorState.getBehavior();
423 if (oldBehavior != currentBehavior){
427 String lastValidLeaderId = oldBehavior == null ? null : oldBehaviorState.getLastValidLeaderId();
428 String oldBehaviorStateName = oldBehavior == null ? null : oldBehavior.state().name();
430 // it can happen that the state has not changed but the leader has changed.
431 Optional<ActorRef> roleChangeNotifier = getRoleChangeNotifier();
432 if(!Objects.equal(lastValidLeaderId, currentBehavior.getLeaderId()) ||
433 oldBehaviorState.getLeaderPayloadVersion() != currentBehavior.getLeaderPayloadVersion()) {
434 if(roleChangeNotifier.isPresent()) {
435 roleChangeNotifier.get().tell(newLeaderStateChanged(getId(), currentBehavior.getLeaderId(),
436 currentBehavior.getLeaderPayloadVersion()), getSelf());
439 onLeaderChanged(lastValidLeaderId, currentBehavior.getLeaderId());
441 if(leadershipTransferInProgress != null) {
442 leadershipTransferInProgress.onNewLeader(currentBehavior.getLeaderId());
446 if (roleChangeNotifier.isPresent() &&
447 (oldBehavior == null || (oldBehavior.state() != currentBehavior.state()))) {
448 roleChangeNotifier.get().tell(new RoleChanged(getId(), oldBehaviorStateName ,
449 currentBehavior.state().name()), getSelf());
453 protected LeaderStateChanged newLeaderStateChanged(String memberId, String leaderId, short leaderPayloadVersion) {
454 return new LeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
458 public long snapshotSequenceNr() {
459 // When we do a snapshot capture, we also capture and save the sequence-number of the persistent journal,
460 // so that we can delete the persistent journal based on the saved sequence-number
461 // However , when akka replays the journal during recovery, it replays it from the sequence number when the snapshot
462 // was saved and not the number we saved.
463 // We would want to override it , by asking akka to use the last-sequence number known to us.
464 return context.getSnapshotManager().getLastSequenceNumber();
468 * When a derived RaftActor needs to persist something it must call
475 protected void persistData(final ActorRef clientActor, final String identifier,
476 final Payload data) {
478 ReplicatedLogEntry replicatedLogEntry = new ReplicatedLogImplEntry(
479 context.getReplicatedLog().lastIndex() + 1,
480 context.getTermInformation().getCurrentTerm(), data);
482 if(LOG.isDebugEnabled()) {
483 LOG.debug("{}: Persist data {}", persistenceId(), replicatedLogEntry);
486 final RaftActorContext raftContext = getRaftActorContext();
488 replicatedLog().appendAndPersist(replicatedLogEntry, new Procedure<ReplicatedLogEntry>() {
490 public void apply(ReplicatedLogEntry replicatedLogEntry) {
491 if (!hasFollowers()){
492 // Increment the Commit Index and the Last Applied values
493 raftContext.setCommitIndex(replicatedLogEntry.getIndex());
494 raftContext.setLastApplied(replicatedLogEntry.getIndex());
496 // Apply the state immediately.
497 self().tell(new ApplyState(clientActor, identifier, replicatedLogEntry), self());
499 // Send a ApplyJournalEntries message so that we write the fact that we applied
500 // the state to durable storage
501 self().tell(new ApplyJournalEntries(replicatedLogEntry.getIndex()), self());
503 } else if (clientActor != null) {
504 context.getReplicatedLog().captureSnapshotIfReady(replicatedLogEntry);
506 // Send message for replication
507 currentBehavior.handleMessage(getSelf(),
508 new Replicate(clientActor, identifier, replicatedLogEntry));
514 private ReplicatedLog replicatedLog() {
515 return context.getReplicatedLog();
518 protected String getId() {
519 return context.getId();
523 void setCurrentBehavior(RaftActorBehavior behavior) {
524 currentBehavior.setDelegate(behavior);
527 protected RaftActorBehavior getCurrentBehavior() {
528 return currentBehavior.getDelegate();
532 * Derived actors can call the isLeader method to check if the current
533 * RaftActor is the Leader or not
535 * @return true it this RaftActor is a Leader false otherwise
537 protected boolean isLeader() {
538 return context.getId().equals(currentBehavior.getLeaderId());
541 protected boolean isLeaderActive() {
542 return currentBehavior.state() != RaftState.IsolatedLeader && !shuttingDown &&
543 !isLeadershipTransferInProgress();
546 private boolean isLeadershipTransferInProgress() {
547 return leadershipTransferInProgress != null && leadershipTransferInProgress.isTransferring();
551 * Derived actor can call getLeader if they need a reference to the Leader.
552 * This would be useful for example in forwarding a request to an actor
553 * which is the leader
555 * @return A reference to the leader if known, null otherwise
557 protected ActorSelection getLeader(){
558 String leaderAddress = getLeaderAddress();
560 if(leaderAddress == null){
564 return context.actorSelection(leaderAddress);
569 * @return the current leader's id
571 protected String getLeaderId(){
572 return currentBehavior.getLeaderId();
575 protected RaftState getRaftState() {
576 return currentBehavior.state();
579 protected ReplicatedLogEntry getLastLogEntry() {
580 return replicatedLog().last();
583 protected Long getCurrentTerm(){
584 return context.getTermInformation().getCurrentTerm();
587 protected Long getCommitIndex(){
588 return context.getCommitIndex();
591 protected Long getLastApplied(){
592 return context.getLastApplied();
595 protected RaftActorContext getRaftActorContext() {
599 protected void updateConfigParams(ConfigParams configParams) {
601 // obtain the RaftPolicy for oldConfigParams and the updated one.
602 String oldRaftPolicy = context.getConfigParams().
603 getCustomRaftPolicyImplementationClass();
604 String newRaftPolicy = configParams.
605 getCustomRaftPolicyImplementationClass();
607 LOG.debug("{}: RaftPolicy used with prev.config {}, RaftPolicy used with newConfig {}", persistenceId(),
608 oldRaftPolicy, newRaftPolicy);
609 context.setConfigParams(configParams);
610 if (!Objects.equal(oldRaftPolicy, newRaftPolicy)) {
611 // The RaftPolicy was modified. If the current behavior is Follower then re-initialize to Follower
612 // but transfer the previous leaderId so it doesn't immediately try to schedule an election. This
613 // avoids potential disruption. Otherwise, switch to Follower normally.
614 RaftActorBehavior behavior = currentBehavior.getDelegate();
615 if(behavior instanceof Follower) {
616 String previousLeaderId = ((Follower)behavior).getLeaderId();
618 LOG.debug("{}: Re-initializing to Follower with previous leaderId {}", persistenceId(), previousLeaderId);
620 changeCurrentBehavior(new Follower(context, previousLeaderId));
622 initializeBehavior();
627 public final DataPersistenceProvider persistence() {
628 return delegatingPersistenceProvider.getDelegate();
631 public void setPersistence(DataPersistenceProvider provider) {
632 delegatingPersistenceProvider.setDelegate(provider);
635 protected void setPersistence(boolean persistent) {
637 setPersistence(new PersistentDataProvider(this));
639 setPersistence(new NonPersistentDataProvider() {
641 * The way snapshotting works is,
643 * <li> RaftActor calls createSnapshot on the Shard
644 * <li> Shard sends a CaptureSnapshotReply and RaftActor then calls saveSnapshot
645 * <li> When saveSnapshot is invoked on the akka-persistence API it uses the SnapshotStore to save
646 * the snapshot. The SnapshotStore sends SaveSnapshotSuccess or SaveSnapshotFailure. When the
647 * RaftActor gets SaveSnapshot success it commits the snapshot to the in-memory journal. This
648 * commitSnapshot is mimicking what is done in SaveSnapshotSuccess.
652 public void saveSnapshot(Object o) {
653 // Make saving Snapshot successful
654 // Committing the snapshot here would end up calling commit in the creating state which would
655 // be a state violation. That's why now we send a message to commit the snapshot.
656 self().tell(RaftActorSnapshotMessageSupport.COMMIT_SNAPSHOT, self());
663 * setPeerAddress sets the address of a known peer at a later time.
665 * This is to account for situations where a we know that a peer
666 * exists but we do not know an address up-front. This may also be used in
667 * situations where a known peer starts off in a different location and we
668 * need to change it's address
670 * Note that if the peerId does not match the list of peers passed to
671 * this actor during construction an IllegalStateException will be thrown.
676 protected void setPeerAddress(String peerId, String peerAddress){
677 context.setPeerAddress(peerId, peerAddress);
681 * The applyState method will be called by the RaftActor when some data
682 * needs to be applied to the actor's state
684 * @param clientActor A reference to the client who sent this message. This
685 * is the same reference that was passed to persistData
686 * by the derived actor. clientActor may be null when
687 * the RaftActor is behaving as a follower or during
689 * @param identifier The identifier of the persisted data. This is also
690 * the same identifier that was passed to persistData by
691 * the derived actor. identifier may be null when
692 * the RaftActor is behaving as a follower or during
694 * @param data A piece of data that was persisted by the persistData call.
695 * This should NEVER be null.
697 protected abstract void applyState(ActorRef clientActor, String identifier,
701 * Returns the RaftActorRecoveryCohort to participate in persistence recovery.
704 protected abstract RaftActorRecoveryCohort getRaftActorRecoveryCohort();
707 * This method is called when recovery is complete.
709 protected abstract void onRecoveryComplete();
712 * Returns the RaftActorSnapshotCohort to participate in persistence recovery.
715 protected abstract RaftActorSnapshotCohort getRaftActorSnapshotCohort();
718 * This method will be called by the RaftActor when the state of the
719 * RaftActor changes. The derived actor can then use methods like
720 * isLeader or getLeader to do something useful
722 protected abstract void onStateChanged();
725 * Notifier Actor for this RaftActor to notify when a role change happens
726 * @return ActorRef - ActorRef of the notifier or Optional.absent if none.
728 protected abstract Optional<ActorRef> getRoleChangeNotifier();
731 * This method is called prior to operations such as leadership transfer and actor shutdown when the leader
732 * must pause or stop its duties. This method allows derived classes to gracefully pause or finish current
733 * work prior to performing the operation. On completion of any work, the run method must be called on the
734 * given Runnable to proceed with the given operation. <b>Important:</b> the run method must be called on
735 * this actor's thread dispatcher as as it modifies internal state.
737 * The default implementation immediately runs the operation.
739 * @param operation the operation to run
741 protected void pauseLeader(Runnable operation) {
745 protected void onLeaderChanged(String oldLeader, String newLeader){};
747 private String getLeaderAddress(){
749 return getSelf().path().toString();
751 String leaderId = currentBehavior.getLeaderId();
752 if (leaderId == null) {
755 String peerAddress = context.getPeerAddress(leaderId);
756 if(LOG.isDebugEnabled()) {
757 LOG.debug("{}: getLeaderAddress leaderId = {} peerAddress = {}",
758 persistenceId(), leaderId, peerAddress);
764 protected boolean hasFollowers(){
765 return getRaftActorContext().hasFollowers();
768 private void captureSnapshot() {
769 SnapshotManager snapshotManager = context.getSnapshotManager();
771 if(!snapshotManager.isCapturing()) {
772 LOG.debug("Take a snapshot of current state. lastReplicatedLog is {} and replicatedToAllIndex is {}",
773 replicatedLog().last(), currentBehavior.getReplicatedToAllIndex());
775 snapshotManager.capture(replicatedLog().last(), currentBehavior.getReplicatedToAllIndex());
780 * @deprecated Deprecated in favor of {@link org.opendaylight.controller.cluster.raft.base.messages.DeleteEntries}
781 * whose type for fromIndex is long instead of int. This class was kept for backwards
782 * compatibility with Helium.
784 // Suppressing this warning as we can't set serialVersionUID to maintain backwards compatibility.
785 @SuppressWarnings("serial")
787 static class DeleteEntries implements Serializable {
788 private final int fromIndex;
790 public DeleteEntries(int fromIndex) {
791 this.fromIndex = fromIndex;
794 public int getFromIndex() {
800 * @deprecated Deprecated in favor of non-inner class {@link org.opendaylight.controller.cluster.raft.base.messages.UpdateElectionTerm}
801 * which has serialVersionUID set. This class was kept for backwards compatibility with Helium.
803 // Suppressing this warning as we can't set serialVersionUID to maintain backwards compatibility.
804 @SuppressWarnings("serial")
806 static class UpdateElectionTerm implements Serializable {
807 private final long currentTerm;
808 private final String votedFor;
810 public UpdateElectionTerm(long currentTerm, String votedFor) {
811 this.currentTerm = currentTerm;
812 this.votedFor = votedFor;
815 public long getCurrentTerm() {
819 public String getVotedFor() {
824 private static class BehaviorStateHolder {
825 private RaftActorBehavior behavior;
826 private String lastValidLeaderId;
827 private short leaderPayloadVersion;
829 void init(RaftActorBehavior behavior) {
830 this.behavior = behavior;
831 this.leaderPayloadVersion = behavior != null ? behavior.getLeaderPayloadVersion() : -1;
833 String behaviorLeaderId = behavior != null ? behavior.getLeaderId() : null;
834 if(behaviorLeaderId != null) {
835 this.lastValidLeaderId = behaviorLeaderId;
839 RaftActorBehavior getBehavior() {
843 String getLastValidLeaderId() {
844 return lastValidLeaderId;
847 short getLeaderPayloadVersion() {
848 return leaderPayloadVersion;
852 private class SwitchBehaviorSupplier implements Supplier<RaftActorBehavior> {
853 private Object message;
854 private ActorRef sender;
856 public SwitchBehaviorSupplier handleMessage(ActorRef sender, Object message){
857 this.sender = sender;
858 this.message = message;
863 public RaftActorBehavior get() {
864 if(this.message instanceof SwitchBehavior){
865 return ((SwitchBehavior) message).getNewState().createBehavior(getRaftActorContext());
867 return currentBehavior.handleMessage(sender, message);