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 org.opendaylight.controller.cluster.DataPersistenceProvider;
26 import org.opendaylight.controller.cluster.common.actor.AbstractUntypedPersistentActor;
27 import org.opendaylight.controller.cluster.raft.base.messages.ApplyLogEntries;
28 import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot;
29 import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
30 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot;
31 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshotReply;
32 import org.opendaylight.controller.cluster.raft.base.messages.Replicate;
33 import org.opendaylight.controller.cluster.raft.base.messages.SendHeartBeat;
34 import org.opendaylight.controller.cluster.raft.base.messages.SendInstallSnapshot;
35 import org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior;
36 import org.opendaylight.controller.cluster.raft.behaviors.Follower;
37 import org.opendaylight.controller.cluster.raft.behaviors.RaftActorBehavior;
38 import org.opendaylight.controller.cluster.raft.client.messages.FindLeader;
39 import org.opendaylight.controller.cluster.raft.client.messages.FindLeaderReply;
40 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
41 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
42 import org.opendaylight.controller.protobuff.messages.cluster.raft.AppendEntriesMessages;
44 import java.io.Serializable;
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();
172 currentBehavior = new Follower(context);
178 private void onRecoveredSnapshot(SnapshotOffer offer) {
179 if(LOG.isDebugEnabled()) {
180 LOG.debug("SnapshotOffer called..");
185 Snapshot snapshot = (Snapshot) offer.snapshot();
187 // Create a replicated log with the snapshot information
188 // The replicated log can be used later on to retrieve this snapshot
189 // when we need to install it on a peer
190 replicatedLog = new ReplicatedLogImpl(snapshot);
192 context.setReplicatedLog(replicatedLog);
193 context.setLastApplied(snapshot.getLastAppliedIndex());
194 context.setCommitIndex(snapshot.getLastAppliedIndex());
196 Stopwatch timer = new Stopwatch();
199 // Apply the snapshot to the actors state
200 applyRecoverySnapshot(ByteString.copyFrom(snapshot.getState()));
203 LOG.info("Recovery snapshot applied for {} in {}: snapshotIndex={}, snapshotTerm={}, journal-size=" +
204 replicatedLog.size(), persistenceId(), timer.toString(),
205 replicatedLog.snapshotIndex, replicatedLog.snapshotTerm);
208 private void onRecoveredJournalLogEntry(ReplicatedLogEntry logEntry) {
209 if(LOG.isDebugEnabled()) {
210 LOG.debug("Received ReplicatedLogEntry for recovery: {}", logEntry.getIndex());
213 replicatedLog.append(logEntry);
216 private void onRecoveredApplyLogEntries(ApplyLogEntries ale) {
217 if(LOG.isDebugEnabled()) {
218 LOG.debug("Received ApplyLogEntries for recovery, applying to state: {} to {}",
219 context.getLastApplied() + 1, ale.getToIndex());
222 for (long i = context.getLastApplied() + 1; i <= ale.getToIndex(); i++) {
223 batchRecoveredLogEntry(replicatedLog.get(i));
226 context.setLastApplied(ale.getToIndex());
227 context.setCommitIndex(ale.getToIndex());
230 private void batchRecoveredLogEntry(ReplicatedLogEntry logEntry) {
233 int batchSize = context.getConfigParams().getJournalRecoveryLogBatchSize();
234 if(currentRecoveryBatchCount == 0) {
235 startLogRecoveryBatch(batchSize);
238 appendRecoveredLogEntry(logEntry.getData());
240 if(++currentRecoveryBatchCount >= batchSize) {
241 endCurrentLogRecoveryBatch();
245 private void endCurrentLogRecoveryBatch() {
246 applyCurrentLogRecoveryBatch();
247 currentRecoveryBatchCount = 0;
250 private void onRecoveryCompletedMessage() {
251 if(currentRecoveryBatchCount > 0) {
252 endCurrentLogRecoveryBatch();
255 onRecoveryComplete();
257 String recoveryTime = "";
258 if(recoveryTimer != null) {
259 recoveryTimer.stop();
260 recoveryTime = " in " + recoveryTimer.toString();
261 recoveryTimer = null;
265 "Recovery completed" + recoveryTime + " - Switching actor to Follower - " +
266 "Persistence Id = " + persistenceId() +
267 " Last index in log={}, snapshotIndex={}, snapshotTerm={}, " +
269 replicatedLog.lastIndex(), replicatedLog.snapshotIndex,
270 replicatedLog.snapshotTerm, replicatedLog.size());
272 currentBehavior = new Follower(context);
276 @Override public void handleCommand(Object message) {
277 if (message instanceof ApplyState){
278 ApplyState applyState = (ApplyState) message;
280 if(LOG.isDebugEnabled()) {
281 LOG.debug("Applying state for log index {} data {}",
282 applyState.getReplicatedLogEntry().getIndex(),
283 applyState.getReplicatedLogEntry().getData());
286 applyState(applyState.getClientActor(), applyState.getIdentifier(),
287 applyState.getReplicatedLogEntry().getData());
289 } else if (message instanceof ApplyLogEntries){
290 ApplyLogEntries ale = (ApplyLogEntries) message;
291 if(LOG.isDebugEnabled()) {
292 LOG.debug("Persisting ApplyLogEntries with index={}", ale.getToIndex());
294 persistence().persist(new ApplyLogEntries(ale.getToIndex()), new Procedure<ApplyLogEntries>() {
296 public void apply(ApplyLogEntries param) throws Exception {
300 } else if(message instanceof ApplySnapshot ) {
301 Snapshot snapshot = ((ApplySnapshot) message).getSnapshot();
303 if(LOG.isDebugEnabled()) {
304 LOG.debug("ApplySnapshot called on Follower Actor " +
305 "snapshotIndex:{}, snapshotTerm:{}", snapshot.getLastAppliedIndex(),
306 snapshot.getLastAppliedTerm()
309 applySnapshot(ByteString.copyFrom(snapshot.getState()));
311 //clears the followers log, sets the snapshot index to ensure adjusted-index works
312 replicatedLog = new ReplicatedLogImpl(snapshot);
313 context.setReplicatedLog(replicatedLog);
314 context.setLastApplied(snapshot.getLastAppliedIndex());
316 } else if (message instanceof FindLeader) {
318 new FindLeaderReply(getLeaderAddress()),
322 } else if (message instanceof SaveSnapshotSuccess) {
323 SaveSnapshotSuccess success = (SaveSnapshotSuccess) message;
324 LOG.info("SaveSnapshotSuccess received for snapshot");
326 long sequenceNumber = success.metadata().sequenceNr();
328 commitSnapshot(sequenceNumber);
330 } else if (message instanceof SaveSnapshotFailure) {
331 SaveSnapshotFailure saveSnapshotFailure = (SaveSnapshotFailure) message;
333 LOG.info("saveSnapshotFailure.metadata():{}", saveSnapshotFailure.metadata().toString());
334 LOG.error(saveSnapshotFailure.cause(), "SaveSnapshotFailure received for snapshot Cause:");
336 context.getReplicatedLog().snapshotRollback();
338 LOG.info("Replicated Log rollbacked. Snapshot will be attempted in the next cycle." +
339 "snapshotIndex:{}, snapshotTerm:{}, log-size:{}",
340 context.getReplicatedLog().getSnapshotIndex(),
341 context.getReplicatedLog().getSnapshotTerm(),
342 context.getReplicatedLog().size());
344 } else if (message instanceof CaptureSnapshot) {
345 LOG.info("CaptureSnapshot received by actor");
346 CaptureSnapshot cs = (CaptureSnapshot)message;
347 captureSnapshot = cs;
350 } else if (message instanceof CaptureSnapshotReply){
351 LOG.info("CaptureSnapshotReply received by actor");
352 CaptureSnapshotReply csr = (CaptureSnapshotReply) message;
354 ByteString stateInBytes = csr.getSnapshot();
355 LOG.info("CaptureSnapshotReply stateInBytes size:{}", stateInBytes.size());
356 handleCaptureSnapshotReply(stateInBytes);
359 if (!(message instanceof AppendEntriesMessages.AppendEntries)
360 && !(message instanceof AppendEntriesReply) && !(message instanceof SendHeartBeat)) {
361 if(LOG.isDebugEnabled()) {
362 LOG.debug("onReceiveCommand: message: {}", message.getClass());
366 RaftActorBehavior oldBehavior = currentBehavior;
367 currentBehavior = currentBehavior.handleMessage(getSender(), message);
369 if(oldBehavior != currentBehavior){
373 onLeaderChanged(oldBehavior.getLeaderId(), currentBehavior.getLeaderId());
377 public java.util.Set<String> getPeers() {
379 return context.getPeerAddresses().keySet();
382 protected String getReplicatedLogState() {
383 return "snapshotIndex=" + context.getReplicatedLog().getSnapshotIndex()
384 + ", snapshotTerm=" + context.getReplicatedLog().getSnapshotTerm()
385 + ", im-mem journal size=" + context.getReplicatedLog().size();
390 * When a derived RaftActor needs to persist something it must call
397 protected void persistData(ActorRef clientActor, String identifier,
400 ReplicatedLogEntry replicatedLogEntry = new ReplicatedLogImplEntry(
401 context.getReplicatedLog().lastIndex() + 1,
402 context.getTermInformation().getCurrentTerm(), data);
404 if(LOG.isDebugEnabled()) {
405 LOG.debug("Persist data {}", replicatedLogEntry);
409 .appendAndPersist(clientActor, identifier, replicatedLogEntry);
412 protected String getId() {
413 return context.getId();
417 * Derived actors can call the isLeader method to check if the current
418 * RaftActor is the Leader or not
420 * @return true it this RaftActor is a Leader false otherwise
422 protected boolean isLeader() {
423 return context.getId().equals(currentBehavior.getLeaderId());
427 * Derived actor can call getLeader if they need a reference to the Leader.
428 * This would be useful for example in forwarding a request to an actor
429 * which is the leader
431 * @return A reference to the leader if known, null otherwise
433 protected ActorSelection getLeader(){
434 String leaderAddress = getLeaderAddress();
436 if(leaderAddress == null){
440 return context.actorSelection(leaderAddress);
445 * @return the current leader's id
447 protected String getLeaderId(){
448 return currentBehavior.getLeaderId();
451 protected RaftState getRaftState() {
452 return currentBehavior.state();
455 protected ReplicatedLogEntry getLastLogEntry() {
456 return replicatedLog.last();
459 protected Long getCurrentTerm(){
460 return context.getTermInformation().getCurrentTerm();
463 protected Long getCommitIndex(){
464 return context.getCommitIndex();
467 protected Long getLastApplied(){
468 return context.getLastApplied();
471 protected RaftActorContext getRaftActorContext() {
476 * setPeerAddress sets the address of a known peer at a later time.
478 * This is to account for situations where a we know that a peer
479 * exists but we do not know an address up-front. This may also be used in
480 * situations where a known peer starts off in a different location and we
481 * need to change it's address
483 * Note that if the peerId does not match the list of peers passed to
484 * this actor during construction an IllegalStateException will be thrown.
489 protected void setPeerAddress(String peerId, String peerAddress){
490 context.setPeerAddress(peerId, peerAddress);
493 protected void commitSnapshot(long sequenceNumber) {
494 context.getReplicatedLog().snapshotCommit();
496 // TODO: Not sure if we want to be this aggressive with trimming stuff
497 trimPersistentData(sequenceNumber);
501 * The applyState method will be called by the RaftActor when some data
502 * needs to be applied to the actor's state
504 * @param clientActor A reference to the client who sent this message. This
505 * is the same reference that was passed to persistData
506 * by the derived actor. clientActor may be null when
507 * the RaftActor is behaving as a follower or during
509 * @param identifier The identifier of the persisted data. This is also
510 * the same identifier that was passed to persistData by
511 * the derived actor. identifier may be null when
512 * the RaftActor is behaving as a follower or during
514 * @param data A piece of data that was persisted by the persistData call.
515 * This should NEVER be null.
517 protected abstract void applyState(ActorRef clientActor, String identifier,
521 * This method is called during recovery at the start of a batch of state entries. Derived
522 * classes should perform any initialization needed to start a batch.
524 protected abstract void startLogRecoveryBatch(int maxBatchSize);
527 * This method is called during recovery to append state data to the current batch. This method
528 * is called 1 or more times after {@link #startLogRecoveryBatch}.
530 * @param data the state data
532 protected abstract void appendRecoveredLogEntry(Payload data);
535 * This method is called during recovery to reconstruct the state of the actor.
537 * @param snapshot A snapshot of the state of the actor
539 protected abstract void applyRecoverySnapshot(ByteString snapshot);
542 * This method is called during recovery at the end of a batch to apply the current batched
543 * log entries. This method is called after {@link #appendRecoveredLogEntry}.
545 protected abstract void applyCurrentLogRecoveryBatch();
548 * This method is called when recovery is complete.
550 protected abstract void onRecoveryComplete();
553 * This method will be called by the RaftActor when a snapshot needs to be
554 * created. The derived actor should respond with its current state.
556 * During recovery the state that is returned by the derived actor will
557 * be passed back to it by calling the applySnapshot method
559 * @return The current state of the actor
561 protected abstract void createSnapshot();
564 * This method can be called at any other point during normal
565 * operations when the derived actor is out of sync with it's peers
566 * and the only way to bring it in sync is by applying a snapshot
568 * @param snapshot A snapshot of the state of the actor
570 protected abstract void applySnapshot(ByteString snapshot);
573 * This method will be called by the RaftActor when the state of the
574 * RaftActor changes. The derived actor can then use methods like
575 * isLeader or getLeader to do something useful
577 protected abstract void onStateChanged();
579 protected abstract DataPersistenceProvider persistence();
581 protected void onLeaderChanged(String oldLeader, String newLeader){};
583 private void trimPersistentData(long sequenceNumber) {
584 // Trim akka snapshots
585 // FIXME : Not sure how exactly the SnapshotSelectionCriteria is applied
586 // For now guessing that it is ANDed.
587 persistence().deleteSnapshots(new SnapshotSelectionCriteria(
588 sequenceNumber - context.getConfigParams().getSnapshotBatchCount(), 43200000));
591 persistence().deleteMessages(sequenceNumber);
594 private String getLeaderAddress(){
596 return getSelf().path().toString();
598 String leaderId = currentBehavior.getLeaderId();
599 if (leaderId == null) {
602 String peerAddress = context.getPeerAddress(leaderId);
603 if(LOG.isDebugEnabled()) {
604 LOG.debug("getLeaderAddress leaderId = {} peerAddress = {}",
605 leaderId, peerAddress);
611 private void handleCaptureSnapshotReply(ByteString stateInBytes) {
612 // create a snapshot object from the state provided and save it
613 // when snapshot is saved async, SaveSnapshotSuccess is raised.
615 Snapshot sn = Snapshot.create(stateInBytes.toByteArray(),
616 context.getReplicatedLog().getFrom(captureSnapshot.getLastAppliedIndex() + 1),
617 captureSnapshot.getLastIndex(), captureSnapshot.getLastTerm(),
618 captureSnapshot.getLastAppliedIndex(), captureSnapshot.getLastAppliedTerm());
620 persistence().saveSnapshot(sn);
622 LOG.info("Persisting of snapshot done:{}", sn.getLogMessage());
624 //be greedy and remove entries from in-mem journal which are in the snapshot
625 // and update snapshotIndex and snapshotTerm without waiting for the success,
627 context.getReplicatedLog().snapshotPreCommit(
628 captureSnapshot.getLastAppliedIndex(),
629 captureSnapshot.getLastAppliedTerm());
631 LOG.info("Removed in-memory snapshotted entries, adjusted snaphsotIndex:{} " +
632 "and term:{}", captureSnapshot.getLastAppliedIndex(),
633 captureSnapshot.getLastAppliedTerm());
635 if (isLeader() && captureSnapshot.isInstallSnapshotInitiated()) {
636 // this would be call straight to the leader and won't initiate in serialization
637 currentBehavior.handleMessage(getSelf(), new SendInstallSnapshot(stateInBytes));
640 captureSnapshot = null;
641 hasSnapshotCaptureInitiated = false;
644 private class ReplicatedLogImpl extends AbstractReplicatedLogImpl {
646 public ReplicatedLogImpl(Snapshot snapshot) {
647 super(snapshot.getLastAppliedIndex(), snapshot.getLastAppliedTerm(),
648 snapshot.getUnAppliedEntries());
651 public ReplicatedLogImpl() {
655 @Override public void removeFromAndPersist(long logEntryIndex) {
656 int adjustedIndex = adjustedIndex(logEntryIndex);
658 if (adjustedIndex < 0) {
662 // FIXME: Maybe this should be done after the command is saved
663 journal.subList(adjustedIndex , journal.size()).clear();
665 persistence().persist(new DeleteEntries(adjustedIndex), new Procedure<DeleteEntries>(){
667 @Override public void apply(DeleteEntries param)
669 //FIXME : Doing nothing for now
674 @Override public void appendAndPersist(
675 final ReplicatedLogEntry replicatedLogEntry) {
676 appendAndPersist(null, null, replicatedLogEntry);
679 public void appendAndPersist(final ActorRef clientActor,
680 final String identifier,
681 final ReplicatedLogEntry replicatedLogEntry) {
683 if(LOG.isDebugEnabled()) {
684 LOG.debug("Append log entry and persist {} ", replicatedLogEntry);
687 // FIXME : By adding the replicated log entry to the in-memory journal we are not truly ensuring durability of the logs
688 journal.add(replicatedLogEntry);
690 // When persisting events with persist it is guaranteed that the
691 // persistent actor will not receive further commands between the
692 // persist call and the execution(s) of the associated event
693 // handler. This also holds for multiple persist calls in context
694 // of a single command.
695 persistence().persist(replicatedLogEntry,
696 new Procedure<ReplicatedLogEntry>() {
698 public void apply(ReplicatedLogEntry evt) throws Exception {
699 // when a snaphsot is being taken, captureSnapshot != null
700 if (hasSnapshotCaptureInitiated == false &&
701 journal.size() % context.getConfigParams().getSnapshotBatchCount() == 0) {
703 LOG.info("Initiating Snapshot Capture..");
704 long lastAppliedIndex = -1;
705 long lastAppliedTerm = -1;
707 ReplicatedLogEntry lastAppliedEntry = get(context.getLastApplied());
708 if (lastAppliedEntry != null) {
709 lastAppliedIndex = lastAppliedEntry.getIndex();
710 lastAppliedTerm = lastAppliedEntry.getTerm();
713 if(LOG.isDebugEnabled()) {
714 LOG.debug("Snapshot Capture logSize: {}", journal.size());
715 LOG.debug("Snapshot Capture lastApplied:{} ",
716 context.getLastApplied());
717 LOG.debug("Snapshot Capture lastAppliedIndex:{}", lastAppliedIndex);
718 LOG.debug("Snapshot Capture lastAppliedTerm:{}", lastAppliedTerm);
721 // send a CaptureSnapshot to self to make the expensive operation async.
722 getSelf().tell(new CaptureSnapshot(
723 lastIndex(), lastTerm(), lastAppliedIndex, lastAppliedTerm),
725 hasSnapshotCaptureInitiated = true;
727 // Send message for replication
728 if (clientActor != null) {
729 currentBehavior.handleMessage(getSelf(),
730 new Replicate(clientActor, identifier,
741 static class DeleteEntries implements Serializable {
742 private static final long serialVersionUID = 1L;
743 private final int fromIndex;
745 public DeleteEntries(int fromIndex) {
746 this.fromIndex = fromIndex;
749 public int getFromIndex() {
755 private class ElectionTermImpl implements ElectionTerm {
757 * Identifier of the actor whose election term information this is
759 private long currentTerm = 0;
760 private String votedFor = null;
763 public long getCurrentTerm() {
768 public String getVotedFor() {
772 @Override public void update(long currentTerm, String votedFor) {
773 if(LOG.isDebugEnabled()) {
774 LOG.debug("Set currentTerm={}, votedFor={}", currentTerm, votedFor);
776 this.currentTerm = currentTerm;
777 this.votedFor = votedFor;
781 public void updateAndPersist(long currentTerm, String votedFor){
782 update(currentTerm, votedFor);
783 // FIXME : Maybe first persist then update the state
784 persistence().persist(new UpdateElectionTerm(this.currentTerm, this.votedFor), new Procedure<UpdateElectionTerm>(){
786 @Override public void apply(UpdateElectionTerm param)
794 static class UpdateElectionTerm implements Serializable {
795 private static final long serialVersionUID = 1L;
796 private final long currentTerm;
797 private final String votedFor;
799 public UpdateElectionTerm(long currentTerm, String votedFor) {
800 this.currentTerm = currentTerm;
801 this.votedFor = votedFor;
804 public long getCurrentTerm() {
808 public String getVotedFor() {
813 protected class NonPersistentRaftDataProvider extends NonPersistentDataProvider {
815 public NonPersistentRaftDataProvider(){
820 * The way snapshotting works is,
822 * <li> RaftActor calls createSnapshot on the Shard
823 * <li> Shard sends a CaptureSnapshotReply and RaftActor then calls saveSnapshot
824 * <li> When saveSnapshot is invoked on the akka-persistence API it uses the SnapshotStore to save the snapshot.
825 * The SnapshotStore sends SaveSnapshotSuccess or SaveSnapshotFailure. When the RaftActor gets SaveSnapshot
826 * success it commits the snapshot to the in-memory journal. This commitSnapshot is mimicking what is done
827 * in SaveSnapshotSuccess.
832 public void saveSnapshot(Object o) {
833 // Make saving Snapshot successful
839 void setCurrentBehavior(AbstractRaftActorBehavior behavior) {
840 currentBehavior = behavior;
843 protected RaftActorBehavior getCurrentBehavior() {
844 return currentBehavior;