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
9 package org.opendaylight.controller.cluster.raft;
11 import akka.actor.ActorRef;
12 import akka.actor.ActorSelection;
13 import akka.event.Logging;
14 import akka.event.LoggingAdapter;
15 import akka.japi.Procedure;
16 import akka.persistence.RecoveryCompleted;
17 import akka.persistence.SaveSnapshotFailure;
18 import akka.persistence.SaveSnapshotSuccess;
19 import akka.persistence.SnapshotOffer;
20 import akka.persistence.SnapshotSelectionCriteria;
21 import com.google.common.annotations.VisibleForTesting;
22 import com.google.common.base.Optional;
23 import com.google.common.base.Stopwatch;
24 import com.google.protobuf.ByteString;
25 import java.io.Serializable;
27 import org.opendaylight.controller.cluster.DataPersistenceProvider;
28 import org.opendaylight.controller.cluster.common.actor.AbstractUntypedPersistentActor;
29 import org.opendaylight.controller.cluster.notifications.RoleChanged;
30 import org.opendaylight.controller.cluster.raft.base.messages.ApplyLogEntries;
31 import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot;
32 import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
33 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot;
34 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshotReply;
35 import org.opendaylight.controller.cluster.raft.base.messages.Replicate;
36 import org.opendaylight.controller.cluster.raft.base.messages.SendHeartBeat;
37 import org.opendaylight.controller.cluster.raft.base.messages.SendInstallSnapshot;
38 import org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior;
39 import org.opendaylight.controller.cluster.raft.behaviors.Follower;
40 import org.opendaylight.controller.cluster.raft.behaviors.RaftActorBehavior;
41 import org.opendaylight.controller.cluster.raft.client.messages.FindLeader;
42 import org.opendaylight.controller.cluster.raft.client.messages.FindLeaderReply;
43 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
44 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
45 import org.opendaylight.controller.protobuff.messages.cluster.raft.AppendEntriesMessages;
48 * RaftActor encapsulates a state machine that needs to be kept synchronized
49 * in a cluster. It implements the RAFT algorithm as described in the paper
50 * <a href='https://ramcloud.stanford.edu/wiki/download/attachments/11370504/raft.pdf'>
51 * In Search of an Understandable Consensus Algorithm</a>
53 * RaftActor has 3 states and each state has a certain behavior associated
54 * with it. A Raft actor can behave as,
57 * <li> A Follower (or) </li>
58 * <li> A Candidate </li>
62 * A RaftActor MUST be a Leader in order to accept requests from clients to
63 * change the state of it's encapsulated state machine. Once a RaftActor becomes
64 * a Leader it is also responsible for ensuring that all followers ultimately
65 * have the same log and therefore the same state machine as itself.
68 * The current behavior of a RaftActor determines how election for leadership
69 * is initiated and how peer RaftActors react to request for votes.
72 * Each RaftActor also needs to know the current election term. It uses this
73 * information for a couple of things. One is to simply figure out who it
74 * voted for in the last election. Another is to figure out if the message
75 * it received to update it's state is stale.
78 * The RaftActor uses akka-persistence to store it's replicated log.
79 * Furthermore through it's behaviors a Raft Actor determines
82 * <li> when a log entry should be persisted </li>
83 * <li> when a log entry should be applied to the state machine (and) </li>
84 * <li> when a snapshot should be saved </li>
87 public abstract class RaftActor extends AbstractUntypedPersistentActor {
88 protected final LoggingAdapter LOG =
89 Logging.getLogger(getContext().system(), this);
92 * The current state determines the current behavior of a RaftActor
93 * A Raft Actor always starts off in the Follower State
95 private RaftActorBehavior currentBehavior;
98 * This context should NOT be passed directly to any other actor it is
99 * only to be consumed by the RaftActorBehaviors
101 private final RaftActorContext context;
104 * The in-memory journal
106 private ReplicatedLogImpl replicatedLog = new ReplicatedLogImpl();
108 private CaptureSnapshot captureSnapshot = null;
110 private volatile boolean hasSnapshotCaptureInitiated = false;
112 private Stopwatch recoveryTimer;
114 private int currentRecoveryBatchCount;
116 public RaftActor(String id, Map<String, String> peerAddresses) {
117 this(id, peerAddresses, Optional.<ConfigParams>absent());
120 public RaftActor(String id, Map<String, String> peerAddresses,
121 Optional<ConfigParams> configParams) {
123 context = new RaftActorContextImpl(this.getSelf(),
124 this.getContext(), id, new ElectionTermImpl(),
125 -1, -1, replicatedLog, peerAddresses,
126 (configParams.isPresent() ? configParams.get(): new DefaultConfigParamsImpl()),
130 private void initRecoveryTimer() {
131 if(recoveryTimer == null) {
132 recoveryTimer = new Stopwatch();
133 recoveryTimer.start();
138 public void preStart() throws Exception {
139 LOG.info("Starting recovery for {} with journal batch size {}", persistenceId(),
140 context.getConfigParams().getJournalRecoveryLogBatchSize());
146 public void handleRecover(Object message) {
147 if(persistence().isRecoveryApplicable()) {
148 if (message instanceof SnapshotOffer) {
149 onRecoveredSnapshot((SnapshotOffer) message);
150 } else if (message instanceof ReplicatedLogEntry) {
151 onRecoveredJournalLogEntry((ReplicatedLogEntry) message);
152 } else if (message instanceof ApplyLogEntries) {
153 onRecoveredApplyLogEntries((ApplyLogEntries) message);
154 } else if (message instanceof DeleteEntries) {
155 replicatedLog.removeFrom(((DeleteEntries) message).getFromIndex());
156 } else if (message instanceof UpdateElectionTerm) {
157 context.getTermInformation().update(((UpdateElectionTerm) message).getCurrentTerm(),
158 ((UpdateElectionTerm) message).getVotedFor());
159 } else if (message instanceof RecoveryCompleted) {
160 onRecoveryCompletedMessage();
163 if (message instanceof RecoveryCompleted) {
164 // Delete all the messages from the akka journal so that we do not end up with consistency issues
165 // Note I am not using the dataPersistenceProvider and directly using the akka api here
166 deleteMessages(lastSequenceNr());
168 // Delete all the akka snapshots as they will not be needed
169 deleteSnapshots(new SnapshotSelectionCriteria(scala.Long.MaxValue(), scala.Long.MaxValue()));
171 onRecoveryComplete();
173 RaftActorBehavior oldBehavior = currentBehavior;
174 currentBehavior = new Follower(context);
175 handleBehaviorChange(oldBehavior, currentBehavior);
180 private void onRecoveredSnapshot(SnapshotOffer offer) {
181 if(LOG.isDebugEnabled()) {
182 LOG.debug("SnapshotOffer called..");
187 Snapshot snapshot = (Snapshot) offer.snapshot();
189 // Create a replicated log with the snapshot information
190 // The replicated log can be used later on to retrieve this snapshot
191 // when we need to install it on a peer
192 replicatedLog = new ReplicatedLogImpl(snapshot);
194 context.setReplicatedLog(replicatedLog);
195 context.setLastApplied(snapshot.getLastAppliedIndex());
196 context.setCommitIndex(snapshot.getLastAppliedIndex());
198 Stopwatch timer = new Stopwatch();
201 // Apply the snapshot to the actors state
202 applyRecoverySnapshot(ByteString.copyFrom(snapshot.getState()));
205 LOG.info("Recovery snapshot applied for {} in {}: snapshotIndex={}, snapshotTerm={}, journal-size=" +
206 replicatedLog.size(), persistenceId(), timer.toString(),
207 replicatedLog.snapshotIndex, replicatedLog.snapshotTerm);
210 private void onRecoveredJournalLogEntry(ReplicatedLogEntry logEntry) {
211 if(LOG.isDebugEnabled()) {
212 LOG.debug("Received ReplicatedLogEntry for recovery: {}", logEntry.getIndex());
215 replicatedLog.append(logEntry);
218 private void onRecoveredApplyLogEntries(ApplyLogEntries ale) {
219 if(LOG.isDebugEnabled()) {
220 LOG.debug("Received ApplyLogEntries for recovery, applying to state: {} to {}",
221 context.getLastApplied() + 1, ale.getToIndex());
224 for (long i = context.getLastApplied() + 1; i <= ale.getToIndex(); i++) {
225 batchRecoveredLogEntry(replicatedLog.get(i));
228 context.setLastApplied(ale.getToIndex());
229 context.setCommitIndex(ale.getToIndex());
232 private void batchRecoveredLogEntry(ReplicatedLogEntry logEntry) {
235 int batchSize = context.getConfigParams().getJournalRecoveryLogBatchSize();
236 if(currentRecoveryBatchCount == 0) {
237 startLogRecoveryBatch(batchSize);
240 appendRecoveredLogEntry(logEntry.getData());
242 if(++currentRecoveryBatchCount >= batchSize) {
243 endCurrentLogRecoveryBatch();
247 private void endCurrentLogRecoveryBatch() {
248 applyCurrentLogRecoveryBatch();
249 currentRecoveryBatchCount = 0;
252 private void onRecoveryCompletedMessage() {
253 if(currentRecoveryBatchCount > 0) {
254 endCurrentLogRecoveryBatch();
257 onRecoveryComplete();
259 String recoveryTime = "";
260 if(recoveryTimer != null) {
261 recoveryTimer.stop();
262 recoveryTime = " in " + recoveryTimer.toString();
263 recoveryTimer = null;
267 "Recovery completed" + recoveryTime + " - Switching actor to Follower - " +
268 "Persistence Id = " + persistenceId() +
269 " Last index in log={}, snapshotIndex={}, snapshotTerm={}, " +
271 replicatedLog.lastIndex(), replicatedLog.snapshotIndex,
272 replicatedLog.snapshotTerm, replicatedLog.size());
274 RaftActorBehavior oldBehavior = currentBehavior;
275 currentBehavior = new Follower(context);
276 handleBehaviorChange(oldBehavior, currentBehavior);
279 @Override public void handleCommand(Object message) {
280 if (message instanceof ApplyState){
281 ApplyState applyState = (ApplyState) message;
283 if(LOG.isDebugEnabled()) {
284 LOG.debug("Applying state for log index {} data {}",
285 applyState.getReplicatedLogEntry().getIndex(),
286 applyState.getReplicatedLogEntry().getData());
289 applyState(applyState.getClientActor(), applyState.getIdentifier(),
290 applyState.getReplicatedLogEntry().getData());
292 } else if (message instanceof ApplyLogEntries){
293 ApplyLogEntries ale = (ApplyLogEntries) message;
294 if(LOG.isDebugEnabled()) {
295 LOG.debug("Persisting ApplyLogEntries with index={}", ale.getToIndex());
297 persistence().persist(new ApplyLogEntries(ale.getToIndex()), new Procedure<ApplyLogEntries>() {
299 public void apply(ApplyLogEntries param) throws Exception {
303 } else if(message instanceof ApplySnapshot ) {
304 Snapshot snapshot = ((ApplySnapshot) message).getSnapshot();
306 if(LOG.isDebugEnabled()) {
307 LOG.debug("ApplySnapshot called on Follower Actor " +
308 "snapshotIndex:{}, snapshotTerm:{}", snapshot.getLastAppliedIndex(),
309 snapshot.getLastAppliedTerm()
312 applySnapshot(ByteString.copyFrom(snapshot.getState()));
314 //clears the followers log, sets the snapshot index to ensure adjusted-index works
315 replicatedLog = new ReplicatedLogImpl(snapshot);
316 context.setReplicatedLog(replicatedLog);
317 context.setLastApplied(snapshot.getLastAppliedIndex());
319 } else if (message instanceof FindLeader) {
321 new FindLeaderReply(getLeaderAddress()),
325 } else if (message instanceof SaveSnapshotSuccess) {
326 SaveSnapshotSuccess success = (SaveSnapshotSuccess) message;
327 LOG.info("SaveSnapshotSuccess received for snapshot");
329 long sequenceNumber = success.metadata().sequenceNr();
331 commitSnapshot(sequenceNumber);
333 } else if (message instanceof SaveSnapshotFailure) {
334 SaveSnapshotFailure saveSnapshotFailure = (SaveSnapshotFailure) message;
336 LOG.info("saveSnapshotFailure.metadata():{}", saveSnapshotFailure.metadata().toString());
337 LOG.error(saveSnapshotFailure.cause(), "SaveSnapshotFailure received for snapshot Cause:");
339 context.getReplicatedLog().snapshotRollback();
341 LOG.info("Replicated Log rollbacked. Snapshot will be attempted in the next cycle." +
342 "snapshotIndex:{}, snapshotTerm:{}, log-size:{}",
343 context.getReplicatedLog().getSnapshotIndex(),
344 context.getReplicatedLog().getSnapshotTerm(),
345 context.getReplicatedLog().size());
347 } else if (message instanceof CaptureSnapshot) {
348 LOG.info("CaptureSnapshot received by actor");
349 CaptureSnapshot cs = (CaptureSnapshot)message;
350 captureSnapshot = cs;
353 } else if (message instanceof CaptureSnapshotReply){
354 LOG.info("CaptureSnapshotReply received by actor");
355 CaptureSnapshotReply csr = (CaptureSnapshotReply) message;
357 ByteString stateInBytes = csr.getSnapshot();
358 LOG.info("CaptureSnapshotReply stateInBytes size:{}", stateInBytes.size());
359 handleCaptureSnapshotReply(stateInBytes);
362 if (!(message instanceof AppendEntriesMessages.AppendEntries)
363 && !(message instanceof AppendEntriesReply) && !(message instanceof SendHeartBeat)) {
364 if(LOG.isDebugEnabled()) {
365 LOG.debug("onReceiveCommand: message: {}", message.getClass());
369 RaftActorBehavior oldBehavior = currentBehavior;
370 currentBehavior = currentBehavior.handleMessage(getSender(), message);
372 handleBehaviorChange(oldBehavior, currentBehavior);
376 private void handleBehaviorChange(RaftActorBehavior oldBehavior, RaftActorBehavior currentBehavior) {
377 if (oldBehavior != currentBehavior){
380 if (oldBehavior != null) {
381 // it can happen that the state has not changed but the leader has changed.
382 onLeaderChanged(oldBehavior.getLeaderId(), currentBehavior.getLeaderId());
384 if (getRoleChangeNotifier().isPresent() && oldBehavior.state() != currentBehavior.state()) {
385 // we do not want to notify when the behavior/role is set for the first time (i.e follower)
386 getRoleChangeNotifier().get().tell(new RoleChanged(getId(), oldBehavior.state().name(),
387 currentBehavior.state().name()), getSelf());
393 * When a derived RaftActor needs to persist something it must call
400 protected void persistData(ActorRef clientActor, String identifier,
403 ReplicatedLogEntry replicatedLogEntry = new ReplicatedLogImplEntry(
404 context.getReplicatedLog().lastIndex() + 1,
405 context.getTermInformation().getCurrentTerm(), data);
407 if(LOG.isDebugEnabled()) {
408 LOG.debug("Persist data {}", replicatedLogEntry);
412 .appendAndPersist(clientActor, identifier, replicatedLogEntry);
415 protected String getId() {
416 return context.getId();
420 * Derived actors can call the isLeader method to check if the current
421 * RaftActor is the Leader or not
423 * @return true it this RaftActor is a Leader false otherwise
425 protected boolean isLeader() {
426 return context.getId().equals(currentBehavior.getLeaderId());
430 * Derived actor can call getLeader if they need a reference to the Leader.
431 * This would be useful for example in forwarding a request to an actor
432 * which is the leader
434 * @return A reference to the leader if known, null otherwise
436 protected ActorSelection getLeader(){
437 String leaderAddress = getLeaderAddress();
439 if(leaderAddress == null){
443 return context.actorSelection(leaderAddress);
448 * @return the current leader's id
450 protected String getLeaderId(){
451 return currentBehavior.getLeaderId();
454 protected RaftState getRaftState() {
455 return currentBehavior.state();
458 protected ReplicatedLogEntry getLastLogEntry() {
459 return replicatedLog.last();
462 protected Long getCurrentTerm(){
463 return context.getTermInformation().getCurrentTerm();
466 protected Long getCommitIndex(){
467 return context.getCommitIndex();
470 protected Long getLastApplied(){
471 return context.getLastApplied();
474 protected RaftActorContext getRaftActorContext() {
479 * setPeerAddress sets the address of a known peer at a later time.
481 * This is to account for situations where a we know that a peer
482 * exists but we do not know an address up-front. This may also be used in
483 * situations where a known peer starts off in a different location and we
484 * need to change it's address
486 * Note that if the peerId does not match the list of peers passed to
487 * this actor during construction an IllegalStateException will be thrown.
492 protected void setPeerAddress(String peerId, String peerAddress){
493 context.setPeerAddress(peerId, peerAddress);
496 protected void commitSnapshot(long sequenceNumber) {
497 context.getReplicatedLog().snapshotCommit();
499 // TODO: Not sure if we want to be this aggressive with trimming stuff
500 trimPersistentData(sequenceNumber);
504 * The applyState method will be called by the RaftActor when some data
505 * needs to be applied to the actor's state
507 * @param clientActor A reference to the client who sent this message. This
508 * is the same reference that was passed to persistData
509 * by the derived actor. clientActor may be null when
510 * the RaftActor is behaving as a follower or during
512 * @param identifier The identifier of the persisted data. This is also
513 * the same identifier that was passed to persistData by
514 * the derived actor. identifier may be null when
515 * the RaftActor is behaving as a follower or during
517 * @param data A piece of data that was persisted by the persistData call.
518 * This should NEVER be null.
520 protected abstract void applyState(ActorRef clientActor, String identifier,
524 * This method is called during recovery at the start of a batch of state entries. Derived
525 * classes should perform any initialization needed to start a batch.
527 protected abstract void startLogRecoveryBatch(int maxBatchSize);
530 * This method is called during recovery to append state data to the current batch. This method
531 * is called 1 or more times after {@link #startLogRecoveryBatch}.
533 * @param data the state data
535 protected abstract void appendRecoveredLogEntry(Payload data);
538 * This method is called during recovery to reconstruct the state of the actor.
540 * @param snapshot A snapshot of the state of the actor
542 protected abstract void applyRecoverySnapshot(ByteString snapshot);
545 * This method is called during recovery at the end of a batch to apply the current batched
546 * log entries. This method is called after {@link #appendRecoveredLogEntry}.
548 protected abstract void applyCurrentLogRecoveryBatch();
551 * This method is called when recovery is complete.
553 protected abstract void onRecoveryComplete();
556 * This method will be called by the RaftActor when a snapshot needs to be
557 * created. The derived actor should respond with its current state.
559 * During recovery the state that is returned by the derived actor will
560 * be passed back to it by calling the applySnapshot method
562 * @return The current state of the actor
564 protected abstract void createSnapshot();
567 * This method can be called at any other point during normal
568 * operations when the derived actor is out of sync with it's peers
569 * and the only way to bring it in sync is by applying a snapshot
571 * @param snapshot A snapshot of the state of the actor
573 protected abstract void applySnapshot(ByteString snapshot);
576 * This method will be called by the RaftActor when the state of the
577 * RaftActor changes. The derived actor can then use methods like
578 * isLeader or getLeader to do something useful
580 protected abstract void onStateChanged();
582 protected abstract DataPersistenceProvider persistence();
585 * Notifier Actor for this RaftActor to notify when a role change happens
586 * @return ActorRef - ActorRef of the notifier or Optional.absent if none.
588 protected abstract Optional<ActorRef> getRoleChangeNotifier();
590 protected void onLeaderChanged(String oldLeader, String newLeader){};
592 private void trimPersistentData(long sequenceNumber) {
593 // Trim akka snapshots
594 // FIXME : Not sure how exactly the SnapshotSelectionCriteria is applied
595 // For now guessing that it is ANDed.
596 persistence().deleteSnapshots(new SnapshotSelectionCriteria(
597 sequenceNumber - context.getConfigParams().getSnapshotBatchCount(), 43200000));
600 persistence().deleteMessages(sequenceNumber);
603 private String getLeaderAddress(){
605 return getSelf().path().toString();
607 String leaderId = currentBehavior.getLeaderId();
608 if (leaderId == null) {
611 String peerAddress = context.getPeerAddress(leaderId);
612 if(LOG.isDebugEnabled()) {
613 LOG.debug("getLeaderAddress leaderId = {} peerAddress = {}",
614 leaderId, peerAddress);
620 private void handleCaptureSnapshotReply(ByteString stateInBytes) {
621 // create a snapshot object from the state provided and save it
622 // when snapshot is saved async, SaveSnapshotSuccess is raised.
624 Snapshot sn = Snapshot.create(stateInBytes.toByteArray(),
625 context.getReplicatedLog().getFrom(captureSnapshot.getLastAppliedIndex() + 1),
626 captureSnapshot.getLastIndex(), captureSnapshot.getLastTerm(),
627 captureSnapshot.getLastAppliedIndex(), captureSnapshot.getLastAppliedTerm());
629 persistence().saveSnapshot(sn);
631 LOG.info("Persisting of snapshot done:{}", sn.getLogMessage());
633 //be greedy and remove entries from in-mem journal which are in the snapshot
634 // and update snapshotIndex and snapshotTerm without waiting for the success,
636 context.getReplicatedLog().snapshotPreCommit(
637 captureSnapshot.getLastAppliedIndex(),
638 captureSnapshot.getLastAppliedTerm());
640 LOG.info("Removed in-memory snapshotted entries, adjusted snaphsotIndex:{} " +
641 "and term:{}", captureSnapshot.getLastAppliedIndex(),
642 captureSnapshot.getLastAppliedTerm());
644 if (isLeader() && captureSnapshot.isInstallSnapshotInitiated()) {
645 // this would be call straight to the leader and won't initiate in serialization
646 currentBehavior.handleMessage(getSelf(), new SendInstallSnapshot(stateInBytes));
649 captureSnapshot = null;
650 hasSnapshotCaptureInitiated = false;
653 private class ReplicatedLogImpl extends AbstractReplicatedLogImpl {
655 public ReplicatedLogImpl(Snapshot snapshot) {
656 super(snapshot.getLastAppliedIndex(), snapshot.getLastAppliedTerm(),
657 snapshot.getUnAppliedEntries());
660 public ReplicatedLogImpl() {
664 @Override public void removeFromAndPersist(long logEntryIndex) {
665 int adjustedIndex = adjustedIndex(logEntryIndex);
667 if (adjustedIndex < 0) {
671 // FIXME: Maybe this should be done after the command is saved
672 journal.subList(adjustedIndex , journal.size()).clear();
674 persistence().persist(new DeleteEntries(adjustedIndex), new Procedure<DeleteEntries>(){
676 @Override public void apply(DeleteEntries param)
678 //FIXME : Doing nothing for now
680 for(ReplicatedLogEntry entry : journal){
681 dataSize += entry.size();
687 @Override public void appendAndPersist(
688 final ReplicatedLogEntry replicatedLogEntry) {
689 appendAndPersist(null, null, replicatedLogEntry);
693 public int dataSize() {
697 public void appendAndPersist(final ActorRef clientActor,
698 final String identifier,
699 final ReplicatedLogEntry replicatedLogEntry) {
701 if(LOG.isDebugEnabled()) {
702 LOG.debug("Append log entry and persist {} ", replicatedLogEntry);
705 // FIXME : By adding the replicated log entry to the in-memory journal we are not truly ensuring durability of the logs
706 journal.add(replicatedLogEntry);
708 // When persisting events with persist it is guaranteed that the
709 // persistent actor will not receive further commands between the
710 // persist call and the execution(s) of the associated event
711 // handler. This also holds for multiple persist calls in context
712 // of a single command.
713 persistence().persist(replicatedLogEntry,
714 new Procedure<ReplicatedLogEntry>() {
716 public void apply(ReplicatedLogEntry evt) throws Exception {
717 dataSize += replicatedLogEntry.size();
719 long dataThreshold = Runtime.getRuntime().totalMemory() *
720 getRaftActorContext().getConfigParams().getSnapshotDataThresholdPercentage() / 100;
722 // when a snaphsot is being taken, captureSnapshot != null
723 if (hasSnapshotCaptureInitiated == false &&
724 ( journal.size() % context.getConfigParams().getSnapshotBatchCount() == 0 ||
725 dataSize > dataThreshold)) {
727 LOG.info("Initiating Snapshot Capture..");
728 long lastAppliedIndex = -1;
729 long lastAppliedTerm = -1;
731 ReplicatedLogEntry lastAppliedEntry = get(context.getLastApplied());
732 if (lastAppliedEntry != null) {
733 lastAppliedIndex = lastAppliedEntry.getIndex();
734 lastAppliedTerm = lastAppliedEntry.getTerm();
737 if(LOG.isDebugEnabled()) {
738 LOG.debug("Snapshot Capture logSize: {}", journal.size());
739 LOG.debug("Snapshot Capture lastApplied:{} ",
740 context.getLastApplied());
741 LOG.debug("Snapshot Capture lastAppliedIndex:{}", lastAppliedIndex);
742 LOG.debug("Snapshot Capture lastAppliedTerm:{}", lastAppliedTerm);
745 // send a CaptureSnapshot to self to make the expensive operation async.
746 getSelf().tell(new CaptureSnapshot(
747 lastIndex(), lastTerm(), lastAppliedIndex, lastAppliedTerm),
749 hasSnapshotCaptureInitiated = true;
751 // Send message for replication
752 if (clientActor != null) {
753 currentBehavior.handleMessage(getSelf(),
754 new Replicate(clientActor, identifier,
765 static class DeleteEntries implements Serializable {
766 private static final long serialVersionUID = 1L;
767 private final int fromIndex;
769 public DeleteEntries(int fromIndex) {
770 this.fromIndex = fromIndex;
773 public int getFromIndex() {
779 private class ElectionTermImpl implements ElectionTerm {
781 * Identifier of the actor whose election term information this is
783 private long currentTerm = 0;
784 private String votedFor = null;
787 public long getCurrentTerm() {
792 public String getVotedFor() {
796 @Override public void update(long currentTerm, String votedFor) {
797 if(LOG.isDebugEnabled()) {
798 LOG.debug("Set currentTerm={}, votedFor={}", currentTerm, votedFor);
800 this.currentTerm = currentTerm;
801 this.votedFor = votedFor;
805 public void updateAndPersist(long currentTerm, String votedFor){
806 update(currentTerm, votedFor);
807 // FIXME : Maybe first persist then update the state
808 persistence().persist(new UpdateElectionTerm(this.currentTerm, this.votedFor), new Procedure<UpdateElectionTerm>(){
810 @Override public void apply(UpdateElectionTerm param)
818 static class UpdateElectionTerm implements Serializable {
819 private static final long serialVersionUID = 1L;
820 private final long currentTerm;
821 private final String votedFor;
823 public UpdateElectionTerm(long currentTerm, String votedFor) {
824 this.currentTerm = currentTerm;
825 this.votedFor = votedFor;
828 public long getCurrentTerm() {
832 public String getVotedFor() {
837 protected class NonPersistentRaftDataProvider extends NonPersistentDataProvider {
839 public NonPersistentRaftDataProvider(){
844 * The way snapshotting works is,
846 * <li> RaftActor calls createSnapshot on the Shard
847 * <li> Shard sends a CaptureSnapshotReply and RaftActor then calls saveSnapshot
848 * <li> When saveSnapshot is invoked on the akka-persistence API it uses the SnapshotStore to save the snapshot.
849 * The SnapshotStore sends SaveSnapshotSuccess or SaveSnapshotFailure. When the RaftActor gets SaveSnapshot
850 * success it commits the snapshot to the in-memory journal. This commitSnapshot is mimicking what is done
851 * in SaveSnapshotSuccess.
856 public void saveSnapshot(Object o) {
857 // Make saving Snapshot successful
863 void setCurrentBehavior(AbstractRaftActorBehavior behavior) {
864 currentBehavior = behavior;
867 protected RaftActorBehavior getCurrentBehavior() {
868 return currentBehavior;