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 elapsedTime = (System.nanoTime() - applyState.getStartTime());
217 if(elapsedTime >= APPLY_STATE_DELAY_THRESHOLD_IN_NANOS){
218 LOG.warn("ApplyState took more time than expected. Elapsed Time = {} ms ApplyState = {}",
219 TimeUnit.NANOSECONDS.toMillis(elapsedTime), applyState);
222 if(LOG.isDebugEnabled()) {
223 LOG.debug("{}: Applying state for log index {} data {}",
224 persistenceId(), applyState.getReplicatedLogEntry().getIndex(),
225 applyState.getReplicatedLogEntry().getData());
228 applyState(applyState.getClientActor(), applyState.getIdentifier(),
229 applyState.getReplicatedLogEntry().getData());
231 if (!hasFollowers()) {
232 // for single node, the capture should happen after the apply state
233 // as we delete messages from the persistent journal which have made it to the snapshot
234 // capturing the snapshot before applying makes the persistent journal and snapshot out of sync
235 // and recovery shows data missing
236 context.getReplicatedLog().captureSnapshotIfReady(applyState.getReplicatedLogEntry());
238 context.getSnapshotManager().trimLog(context.getLastApplied(), currentBehavior);
241 } else if (message instanceof ApplyJournalEntries){
242 ApplyJournalEntries applyEntries = (ApplyJournalEntries) message;
243 if(LOG.isDebugEnabled()) {
244 LOG.debug("{}: Persisting ApplyLogEntries with index={}", persistenceId(), applyEntries.getToIndex());
247 persistence().persist(applyEntries, NoopProcedure.instance());
249 } else if (message instanceof FindLeader) {
251 new FindLeaderReply(getLeaderAddress()),
254 } else if(message instanceof GetOnDemandRaftState) {
255 onGetOnDemandRaftStats();
256 } else if(message instanceof InitiateCaptureSnapshot) {
258 } else if(message instanceof SwitchBehavior){
259 switchBehavior(((SwitchBehavior) message));
260 } else if(message instanceof LeaderTransitioning) {
261 onLeaderTransitioning();
262 } else if(message instanceof Shutdown) {
264 } else if(message instanceof Runnable) {
265 ((Runnable)message).run();
266 } else if(!snapshotSupport.handleSnapshotMessage(message, getSender())) {
267 switchBehavior(reusableSwitchBehaviorSupplier.handleMessage(getSender(), message));
271 private void initiateLeadershipTransfer(final RaftActorLeadershipTransferCohort.OnComplete onComplete) {
272 LOG.debug("{}: Initiating leader transfer", persistenceId());
274 if(leadershipTransferInProgress == null) {
275 leadershipTransferInProgress = new RaftActorLeadershipTransferCohort(this, getSender());
276 leadershipTransferInProgress.addOnComplete(new RaftActorLeadershipTransferCohort.OnComplete() {
278 public void onSuccess(ActorRef raftActorRef, ActorRef replyTo) {
279 leadershipTransferInProgress = null;
283 public void onFailure(ActorRef raftActorRef, ActorRef replyTo) {
284 leadershipTransferInProgress = null;
288 leadershipTransferInProgress.addOnComplete(onComplete);
289 leadershipTransferInProgress.init();
291 LOG.debug("{}: prior leader transfer in progress - adding callback", persistenceId());
292 leadershipTransferInProgress.addOnComplete(onComplete);
296 private void onShutDown() {
297 LOG.debug("{}: onShutDown", persistenceId());
304 if(currentBehavior.state() == RaftState.Leader && context.hasFollowers()) {
305 initiateLeadershipTransfer(new RaftActorLeadershipTransferCohort.OnComplete() {
307 public void onSuccess(ActorRef raftActorRef, ActorRef replyTo) {
308 LOG.debug("{}: leader transfer succeeded - sending PoisonPill", persistenceId());
309 raftActorRef.tell(PoisonPill.getInstance(), raftActorRef);
313 public void onFailure(ActorRef raftActorRef, ActorRef replyTo) {
314 LOG.debug("{}: leader transfer failed - sending PoisonPill", persistenceId());
315 raftActorRef.tell(PoisonPill.getInstance(), raftActorRef);
318 } else if(currentBehavior.state() == RaftState.Leader) {
319 pauseLeader(new Runnable() {
322 self().tell(PoisonPill.getInstance(), self());
326 self().tell(PoisonPill.getInstance(), self());
330 private void onLeaderTransitioning() {
331 LOG.debug("{}: onLeaderTransitioning", persistenceId());
332 Optional<ActorRef> roleChangeNotifier = getRoleChangeNotifier();
333 if(currentBehavior.state() == RaftState.Follower && roleChangeNotifier.isPresent()) {
334 roleChangeNotifier.get().tell(newLeaderStateChanged(getId(), null,
335 currentBehavior.getLeaderPayloadVersion()), getSelf());
339 private void switchBehavior(SwitchBehavior message) {
340 if(!getRaftActorContext().getRaftPolicy().automaticElectionsEnabled()) {
341 RaftState newState = message.getNewState();
342 if( newState == RaftState.Leader || newState == RaftState.Follower) {
343 switchBehavior(reusableSwitchBehaviorSupplier.handleMessage(getSender(), message));
344 getRaftActorContext().getTermInformation().updateAndPersist(message.getNewTerm(), "");
346 LOG.warn("Switching to behavior : {} - not supported", newState);
351 private void switchBehavior(Supplier<RaftActorBehavior> supplier){
352 reusableBehaviorStateHolder.init(getCurrentBehavior());
354 setCurrentBehavior(supplier.get());
356 handleBehaviorChange(reusableBehaviorStateHolder, getCurrentBehavior());
359 protected RaftActorSnapshotMessageSupport newRaftActorSnapshotMessageSupport() {
360 return new RaftActorSnapshotMessageSupport(context, currentBehavior,
361 getRaftActorSnapshotCohort());
364 private void onGetOnDemandRaftStats() {
365 // Debugging message to retrieve raft stats.
367 Map<String, String> peerAddresses = new HashMap<>();
368 for(String peerId: context.getPeerIds()) {
369 peerAddresses.put(peerId, context.getPeerAddress(peerId));
372 OnDemandRaftState.Builder builder = OnDemandRaftState.builder()
373 .commitIndex(context.getCommitIndex())
374 .currentTerm(context.getTermInformation().getCurrentTerm())
375 .inMemoryJournalDataSize(replicatedLog().dataSize())
376 .inMemoryJournalLogSize(replicatedLog().size())
377 .isSnapshotCaptureInitiated(context.getSnapshotManager().isCapturing())
378 .lastApplied(context.getLastApplied())
379 .lastIndex(replicatedLog().lastIndex())
380 .lastTerm(replicatedLog().lastTerm())
381 .leader(getLeaderId())
382 .raftState(currentBehavior.state().toString())
383 .replicatedToAllIndex(currentBehavior.getReplicatedToAllIndex())
384 .snapshotIndex(replicatedLog().getSnapshotIndex())
385 .snapshotTerm(replicatedLog().getSnapshotTerm())
386 .votedFor(context.getTermInformation().getVotedFor())
387 .peerAddresses(peerAddresses)
388 .customRaftPolicyClassName(context.getConfigParams().getCustomRaftPolicyImplementationClass());
390 ReplicatedLogEntry lastLogEntry = getLastLogEntry();
391 if (lastLogEntry != null) {
392 builder.lastLogIndex(lastLogEntry.getIndex());
393 builder.lastLogTerm(lastLogEntry.getTerm());
396 if(getCurrentBehavior() instanceof AbstractLeader) {
397 AbstractLeader leader = (AbstractLeader)getCurrentBehavior();
398 Collection<String> followerIds = leader.getFollowerIds();
399 List<FollowerInfo> followerInfoList = Lists.newArrayListWithCapacity(followerIds.size());
400 for(String id: followerIds) {
401 final FollowerLogInformation info = leader.getFollower(id);
402 followerInfoList.add(new FollowerInfo(id, info.getNextIndex(), info.getMatchIndex(),
403 info.isFollowerActive(), DurationFormatUtils.formatDurationHMS(info.timeSinceLastActivity())));
406 builder.followerInfoList(followerInfoList);
409 sender().tell(builder.build(), self());
413 private void handleBehaviorChange(BehaviorStateHolder oldBehaviorState, RaftActorBehavior currentBehavior) {
414 RaftActorBehavior oldBehavior = oldBehaviorState.getBehavior();
416 if (oldBehavior != currentBehavior){
420 String lastValidLeaderId = oldBehavior == null ? null : oldBehaviorState.getLastValidLeaderId();
421 String oldBehaviorStateName = oldBehavior == null ? null : oldBehavior.state().name();
423 // it can happen that the state has not changed but the leader has changed.
424 Optional<ActorRef> roleChangeNotifier = getRoleChangeNotifier();
425 if(!Objects.equal(lastValidLeaderId, currentBehavior.getLeaderId()) ||
426 oldBehaviorState.getLeaderPayloadVersion() != currentBehavior.getLeaderPayloadVersion()) {
427 if(roleChangeNotifier.isPresent()) {
428 roleChangeNotifier.get().tell(newLeaderStateChanged(getId(), currentBehavior.getLeaderId(),
429 currentBehavior.getLeaderPayloadVersion()), getSelf());
432 onLeaderChanged(lastValidLeaderId, currentBehavior.getLeaderId());
434 if(leadershipTransferInProgress != null) {
435 leadershipTransferInProgress.onNewLeader(currentBehavior.getLeaderId());
439 if (roleChangeNotifier.isPresent() &&
440 (oldBehavior == null || (oldBehavior.state() != currentBehavior.state()))) {
441 roleChangeNotifier.get().tell(new RoleChanged(getId(), oldBehaviorStateName ,
442 currentBehavior.state().name()), getSelf());
446 protected LeaderStateChanged newLeaderStateChanged(String memberId, String leaderId, short leaderPayloadVersion) {
447 return new LeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
451 public long snapshotSequenceNr() {
452 // When we do a snapshot capture, we also capture and save the sequence-number of the persistent journal,
453 // so that we can delete the persistent journal based on the saved sequence-number
454 // However , when akka replays the journal during recovery, it replays it from the sequence number when the snapshot
455 // was saved and not the number we saved.
456 // We would want to override it , by asking akka to use the last-sequence number known to us.
457 return context.getSnapshotManager().getLastSequenceNumber();
461 * When a derived RaftActor needs to persist something it must call
468 protected void persistData(final ActorRef clientActor, final String identifier,
469 final Payload data) {
471 ReplicatedLogEntry replicatedLogEntry = new ReplicatedLogImplEntry(
472 context.getReplicatedLog().lastIndex() + 1,
473 context.getTermInformation().getCurrentTerm(), data);
475 if(LOG.isDebugEnabled()) {
476 LOG.debug("{}: Persist data {}", persistenceId(), replicatedLogEntry);
479 final RaftActorContext raftContext = getRaftActorContext();
481 replicatedLog().appendAndPersist(replicatedLogEntry, new Procedure<ReplicatedLogEntry>() {
483 public void apply(ReplicatedLogEntry replicatedLogEntry) {
484 if (!hasFollowers()){
485 // Increment the Commit Index and the Last Applied values
486 raftContext.setCommitIndex(replicatedLogEntry.getIndex());
487 raftContext.setLastApplied(replicatedLogEntry.getIndex());
489 // Apply the state immediately.
490 self().tell(new ApplyState(clientActor, identifier, replicatedLogEntry), self());
492 // Send a ApplyJournalEntries message so that we write the fact that we applied
493 // the state to durable storage
494 self().tell(new ApplyJournalEntries(replicatedLogEntry.getIndex()), self());
496 } else if (clientActor != null) {
497 context.getReplicatedLog().captureSnapshotIfReady(replicatedLogEntry);
499 // Send message for replication
500 currentBehavior.handleMessage(getSelf(),
501 new Replicate(clientActor, identifier, replicatedLogEntry));
507 private ReplicatedLog replicatedLog() {
508 return context.getReplicatedLog();
511 protected String getId() {
512 return context.getId();
516 void setCurrentBehavior(RaftActorBehavior behavior) {
517 currentBehavior.setDelegate(behavior);
520 protected RaftActorBehavior getCurrentBehavior() {
521 return currentBehavior.getDelegate();
525 * Derived actors can call the isLeader method to check if the current
526 * RaftActor is the Leader or not
528 * @return true it this RaftActor is a Leader false otherwise
530 protected boolean isLeader() {
531 return context.getId().equals(currentBehavior.getLeaderId());
534 protected boolean isLeaderActive() {
535 return currentBehavior.state() != RaftState.IsolatedLeader && !shuttingDown && leadershipTransferInProgress == null;
539 * Derived actor can call getLeader if they need a reference to the Leader.
540 * This would be useful for example in forwarding a request to an actor
541 * which is the leader
543 * @return A reference to the leader if known, null otherwise
545 protected ActorSelection getLeader(){
546 String leaderAddress = getLeaderAddress();
548 if(leaderAddress == null){
552 return context.actorSelection(leaderAddress);
557 * @return the current leader's id
559 protected String getLeaderId(){
560 return currentBehavior.getLeaderId();
563 protected RaftState getRaftState() {
564 return currentBehavior.state();
567 protected ReplicatedLogEntry getLastLogEntry() {
568 return replicatedLog().last();
571 protected Long getCurrentTerm(){
572 return context.getTermInformation().getCurrentTerm();
575 protected Long getCommitIndex(){
576 return context.getCommitIndex();
579 protected Long getLastApplied(){
580 return context.getLastApplied();
583 protected RaftActorContext getRaftActorContext() {
587 protected void updateConfigParams(ConfigParams configParams) {
589 // obtain the RaftPolicy for oldConfigParams and the updated one.
590 String oldRaftPolicy = context.getConfigParams().
591 getCustomRaftPolicyImplementationClass();
592 String newRaftPolicy = configParams.
593 getCustomRaftPolicyImplementationClass();
595 LOG.debug("{}: RaftPolicy used with prev.config {}, RaftPolicy used with newConfig {}", persistenceId(),
596 oldRaftPolicy, newRaftPolicy);
597 context.setConfigParams(configParams);
598 if (!Objects.equal(oldRaftPolicy, newRaftPolicy)) {
599 // The RaftPolicy was modified. If the current behavior is Follower then re-initialize to Follower
600 // but transfer the previous leaderId so it doesn't immediately try to schedule an election. This
601 // avoids potential disruption. Otherwise, switch to Follower normally.
602 RaftActorBehavior behavior = currentBehavior.getDelegate();
603 if(behavior instanceof Follower) {
604 String previousLeaderId = ((Follower)behavior).getLeaderId();
606 LOG.debug("{}: Re-initializing to Follower with previous leaderId {}", persistenceId(), previousLeaderId);
608 changeCurrentBehavior(new Follower(context, previousLeaderId));
610 initializeBehavior();
615 public final DataPersistenceProvider persistence() {
616 return delegatingPersistenceProvider.getDelegate();
619 public void setPersistence(DataPersistenceProvider provider) {
620 delegatingPersistenceProvider.setDelegate(provider);
623 protected void setPersistence(boolean persistent) {
625 setPersistence(new PersistentDataProvider(this));
627 setPersistence(new NonPersistentDataProvider() {
629 * The way snapshotting works is,
631 * <li> RaftActor calls createSnapshot on the Shard
632 * <li> Shard sends a CaptureSnapshotReply and RaftActor then calls saveSnapshot
633 * <li> When saveSnapshot is invoked on the akka-persistence API it uses the SnapshotStore to save
634 * the snapshot. The SnapshotStore sends SaveSnapshotSuccess or SaveSnapshotFailure. When the
635 * RaftActor gets SaveSnapshot success it commits the snapshot to the in-memory journal. This
636 * commitSnapshot is mimicking what is done in SaveSnapshotSuccess.
640 public void saveSnapshot(Object o) {
641 // Make saving Snapshot successful
642 // Committing the snapshot here would end up calling commit in the creating state which would
643 // be a state violation. That's why now we send a message to commit the snapshot.
644 self().tell(RaftActorSnapshotMessageSupport.COMMIT_SNAPSHOT, self());
651 * setPeerAddress sets the address of a known peer at a later time.
653 * This is to account for situations where a we know that a peer
654 * exists but we do not know an address up-front. This may also be used in
655 * situations where a known peer starts off in a different location and we
656 * need to change it's address
658 * Note that if the peerId does not match the list of peers passed to
659 * this actor during construction an IllegalStateException will be thrown.
664 protected void setPeerAddress(String peerId, String peerAddress){
665 context.setPeerAddress(peerId, peerAddress);
669 * The applyState method will be called by the RaftActor when some data
670 * needs to be applied to the actor's state
672 * @param clientActor A reference to the client who sent this message. This
673 * is the same reference that was passed to persistData
674 * by the derived actor. clientActor may be null when
675 * the RaftActor is behaving as a follower or during
677 * @param identifier The identifier of the persisted data. This is also
678 * the same identifier that was passed to persistData by
679 * the derived actor. identifier may be null when
680 * the RaftActor is behaving as a follower or during
682 * @param data A piece of data that was persisted by the persistData call.
683 * This should NEVER be null.
685 protected abstract void applyState(ActorRef clientActor, String identifier,
689 * Returns the RaftActorRecoveryCohort to participate in persistence recovery.
692 protected abstract RaftActorRecoveryCohort getRaftActorRecoveryCohort();
695 * This method is called when recovery is complete.
697 protected abstract void onRecoveryComplete();
700 * Returns the RaftActorSnapshotCohort to participate in persistence recovery.
703 protected abstract RaftActorSnapshotCohort getRaftActorSnapshotCohort();
706 * This method will be called by the RaftActor when the state of the
707 * RaftActor changes. The derived actor can then use methods like
708 * isLeader or getLeader to do something useful
710 protected abstract void onStateChanged();
713 * Notifier Actor for this RaftActor to notify when a role change happens
714 * @return ActorRef - ActorRef of the notifier or Optional.absent if none.
716 protected abstract Optional<ActorRef> getRoleChangeNotifier();
719 * This method is called prior to operations such as leadership transfer and actor shutdown when the leader
720 * must pause or stop its duties. This method allows derived classes to gracefully pause or finish current
721 * work prior to performing the operation. On completion of any work, the run method must be called to
722 * proceed with the given operation.
724 * The default implementation immediately runs the operation.
726 * @param operation the operation to run
728 protected void pauseLeader(Runnable operation) {
732 protected void onLeaderChanged(String oldLeader, String newLeader){};
734 private String getLeaderAddress(){
736 return getSelf().path().toString();
738 String leaderId = currentBehavior.getLeaderId();
739 if (leaderId == null) {
742 String peerAddress = context.getPeerAddress(leaderId);
743 if(LOG.isDebugEnabled()) {
744 LOG.debug("{}: getLeaderAddress leaderId = {} peerAddress = {}",
745 persistenceId(), leaderId, peerAddress);
751 protected boolean hasFollowers(){
752 return getRaftActorContext().hasFollowers();
755 private void captureSnapshot() {
756 SnapshotManager snapshotManager = context.getSnapshotManager();
758 if(!snapshotManager.isCapturing()) {
759 LOG.debug("Take a snapshot of current state. lastReplicatedLog is {} and replicatedToAllIndex is {}",
760 replicatedLog().last(), currentBehavior.getReplicatedToAllIndex());
762 snapshotManager.capture(replicatedLog().last(), currentBehavior.getReplicatedToAllIndex());
767 * @deprecated Deprecated in favor of {@link org.opendaylight.controller.cluster.raft.base.messages.DeleteEntries}
768 * whose type for fromIndex is long instead of int. This class was kept for backwards
769 * compatibility with Helium.
771 // Suppressing this warning as we can't set serialVersionUID to maintain backwards compatibility.
772 @SuppressWarnings("serial")
774 static class DeleteEntries implements Serializable {
775 private final int fromIndex;
777 public DeleteEntries(int fromIndex) {
778 this.fromIndex = fromIndex;
781 public int getFromIndex() {
787 * @deprecated Deprecated in favor of non-inner class {@link org.opendaylight.controller.cluster.raft.base.messages.UpdateElectionTerm}
788 * which has serialVersionUID set. This class was kept for backwards compatibility with Helium.
790 // Suppressing this warning as we can't set serialVersionUID to maintain backwards compatibility.
791 @SuppressWarnings("serial")
793 static class UpdateElectionTerm implements Serializable {
794 private final long currentTerm;
795 private final String votedFor;
797 public UpdateElectionTerm(long currentTerm, String votedFor) {
798 this.currentTerm = currentTerm;
799 this.votedFor = votedFor;
802 public long getCurrentTerm() {
806 public String getVotedFor() {
811 private static class BehaviorStateHolder {
812 private RaftActorBehavior behavior;
813 private String lastValidLeaderId;
814 private short leaderPayloadVersion;
816 void init(RaftActorBehavior behavior) {
817 this.behavior = behavior;
818 this.leaderPayloadVersion = behavior != null ? behavior.getLeaderPayloadVersion() : -1;
820 String behaviorLeaderId = behavior != null ? behavior.getLeaderId() : null;
821 if(behaviorLeaderId != null) {
822 this.lastValidLeaderId = behaviorLeaderId;
826 RaftActorBehavior getBehavior() {
830 String getLastValidLeaderId() {
831 return lastValidLeaderId;
834 short getLeaderPayloadVersion() {
835 return leaderPayloadVersion;
839 private class SwitchBehaviorSupplier implements Supplier<RaftActorBehavior> {
840 private Object message;
841 private ActorRef sender;
843 public SwitchBehaviorSupplier handleMessage(ActorRef sender, Object message){
844 this.sender = sender;
845 this.message = message;
850 public RaftActorBehavior get() {
851 if(this.message instanceof SwitchBehavior){
852 return ((SwitchBehavior) message).getNewState().createBehavior(getRaftActorContext());
854 return currentBehavior.handleMessage(sender, message);