X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-akka-raft%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fraft%2Fbehaviors%2FAbstractLeader.java;h=be51ba069cc5056636646566d1db00b30154073a;hp=e5c5dc752d3a257e9ce2f5852bf3350b006b8116;hb=7d03757a62c1909ee74b42e6acf30d3d7b961bfa;hpb=cf161562786a13b5c68d0da10524359ee3a732e7 diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractLeader.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractLeader.java index e5c5dc752d..be51ba069c 100644 --- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractLeader.java +++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractLeader.java @@ -14,16 +14,18 @@ import akka.actor.Cancellable; import com.google.common.annotations.VisibleForTesting; import com.google.common.base.Optional; import com.google.common.base.Preconditions; +import com.google.common.collect.ImmutableMap; +import com.google.common.collect.ImmutableMap.Builder; import com.google.protobuf.ByteString; import java.io.IOException; -import java.util.ArrayList; +import java.util.Collection; import java.util.Collections; import java.util.HashMap; +import java.util.Iterator; +import java.util.LinkedList; import java.util.List; import java.util.Map; -import java.util.Set; -import java.util.concurrent.TimeUnit; -import java.util.concurrent.atomic.AtomicLong; +import java.util.Map.Entry; import org.opendaylight.controller.cluster.raft.ClientRequestTracker; import org.opendaylight.controller.cluster.raft.ClientRequestTrackerImpl; import org.opendaylight.controller.cluster.raft.FollowerLogInformation; @@ -32,7 +34,6 @@ import org.opendaylight.controller.cluster.raft.RaftActorContext; import org.opendaylight.controller.cluster.raft.RaftState; import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry; import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot; -import org.opendaylight.controller.cluster.raft.base.messages.InitiateInstallSnapshot; import org.opendaylight.controller.cluster.raft.base.messages.Replicate; import org.opendaylight.controller.cluster.raft.base.messages.SendHeartBeat; import org.opendaylight.controller.cluster.raft.base.messages.SendInstallSnapshot; @@ -77,14 +78,12 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { // This would be passed as the hash code of the last chunk when sending the first chunk public static final int INITIAL_LAST_CHUNK_HASH_CODE = -1; - protected final Map followerToLog = new HashMap<>(); - protected final Map mapFollowerToSnapshot = new HashMap<>(); - - protected final Set followers; + private final Map followerToLog; + private final Map mapFollowerToSnapshot = new HashMap<>(); private Cancellable heartbeatSchedule = null; - private List trackerList = new ArrayList<>(); + private final Collection trackerList = new LinkedList<>(); protected final int minReplicationCount; @@ -93,27 +92,24 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { private Optional snapshot; public AbstractLeader(RaftActorContext context) { - super(context); - - followers = context.getPeerAddresses().keySet(); + super(context, RaftState.Leader); - for (String followerId : followers) { + final Builder ftlBuilder = ImmutableMap.builder(); + for (String followerId : context.getPeerAddresses().keySet()) { FollowerLogInformation followerLogInformation = new FollowerLogInformationImpl(followerId, - new AtomicLong(context.getCommitIndex()), - new AtomicLong(-1), + context.getCommitIndex(), -1, context.getConfigParams().getElectionTimeOutInterval()); - followerToLog.put(followerId, followerLogInformation); + ftlBuilder.put(followerId, followerLogInformation); } + followerToLog = ftlBuilder.build(); leaderId = context.getId(); - if(LOG.isDebugEnabled()) { - LOG.debug("Election:Leader has following peers: {}", followers); - } + LOG.debug("{}: Election: Leader has following peers: {}", logName(), getFollowerIds()); - minReplicationCount = getMajorityVoteCount(followers.size()); + minReplicationCount = getMajorityVoteCount(getFollowerIds().size()); // the isolated Leader peer count will be 1 less than the majority vote count. // this is because the vote count has the self vote counted in it @@ -129,11 +125,19 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { // Upon election: send initial empty AppendEntries RPCs // (heartbeat) to each server; repeat during idle periods to // prevent election timeouts (§5.2) - scheduleHeartBeat(new FiniteDuration(0, TimeUnit.SECONDS)); + sendAppendEntries(0, false); + + // It is important to schedule this heartbeat here + scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval()); } - private Optional getSnapshot() { - return snapshot; + /** + * Return an immutable collection of follower identifiers. + * + * @return Collection of follower IDs + */ + protected final Collection getFollowerIds() { + return followerToLog.keySet(); } @VisibleForTesting @@ -145,9 +149,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { protected RaftActorBehavior handleAppendEntries(ActorRef sender, AppendEntries appendEntries) { - if(LOG.isDebugEnabled()) { - LOG.debug(appendEntries.toString()); - } + LOG.debug("{}: handleAppendEntries: {}", logName(), appendEntries); return this; } @@ -156,10 +158,10 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender, AppendEntriesReply appendEntriesReply) { - if(! appendEntriesReply.isSuccess()) { - if(LOG.isDebugEnabled()) { - LOG.debug(appendEntriesReply.toString()); - } + if(LOG.isTraceEnabled()) { + LOG.trace("{}: handleAppendEntriesReply: {}", logName(), appendEntriesReply); + } else if(LOG.isDebugEnabled() && !appendEntriesReply.isSuccess()) { + LOG.debug("{}: handleAppendEntriesReply: {}", logName(), appendEntriesReply); } // Update the FollowerLogInformation @@ -168,10 +170,18 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { followerToLog.get(followerId); if(followerLogInformation == null){ - LOG.error("Unknown follower {}", followerId); + LOG.error("{}: handleAppendEntriesReply - unknown follower {}", logName(), followerId); return this; } + if(followerLogInformation.timeSinceLastActivity() > + context.getConfigParams().getElectionTimeOutInterval().toMillis()) { + LOG.error("{} : handleAppendEntriesReply delayed beyond election timeout, " + + "appendEntriesReply : {}, timeSinceLastActivity : {}, lastApplied : {}, commitIndex : {}", + logName(), appendEntriesReply, followerLogInformation.timeSinceLastActivity(), + context.getLastApplied(), context.getCommitIndex()); + } + followerLogInformation.markFollowerActive(); if (appendEntriesReply.isSuccess()) { @@ -198,7 +208,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { int replicatedCount = 1; for (FollowerLogInformation info : followerToLog.values()) { - if (info.getMatchIndex().get() >= N) { + if (info.getMatchIndex() >= N) { replicatedCount++; } } @@ -216,22 +226,49 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { // Apply the change to the state machine if (context.getCommitIndex() > context.getLastApplied()) { + LOG.debug("{}: handleAppendEntriesReply: applying to log - commitIndex: {}, lastAppliedIndex: {}", + logName(), context.getCommitIndex(), context.getLastApplied()); + applyLogToStateMachine(context.getCommitIndex()); } + if (!context.isSnapshotCaptureInitiated()) { + purgeInMemoryLog(); + } + + //Send the next log entry immediately, if possible, no need to wait for heartbeat to trigger that event + sendUpdatesToFollower(followerId, followerLogInformation, false, false); return this; } - protected ClientRequestTracker removeClientRequestTracker(long logIndex) { + private void purgeInMemoryLog() { + //find the lowest index across followers which has been replicated to all. + // lastApplied if there are no followers, so that we keep clearing the log for single-node + // we would delete the in-mem log from that index on, in-order to minimize mem usage + // we would also share this info thru AE with the followers so that they can delete their log entries as well. + long minReplicatedToAllIndex = followerToLog.isEmpty() ? context.getLastApplied() : Long.MAX_VALUE; + for (FollowerLogInformation info : followerToLog.values()) { + minReplicatedToAllIndex = Math.min(minReplicatedToAllIndex, info.getMatchIndex()); + } + + super.performSnapshotWithoutCapture(minReplicatedToAllIndex); + } - ClientRequestTracker toRemove = findClientRequestTracker(logIndex); - if(toRemove != null) { - trackerList.remove(toRemove); + @Override + protected ClientRequestTracker removeClientRequestTracker(long logIndex) { + final Iterator it = trackerList.iterator(); + while (it.hasNext()) { + final ClientRequestTracker t = it.next(); + if (t.getIndex() == logIndex) { + it.remove(); + return t; + } } - return toRemove; + return null; } + @Override protected ClientRequestTracker findClientRequestTracker(long logIndex) { for (ClientRequestTracker tracker : trackerList) { if (tracker.getIndex() == logIndex) { @@ -247,10 +284,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { return this; } - @Override - public RaftState state() { - return RaftState.Leader; - } + protected void beforeSendHeartbeat(){} @Override public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) { @@ -264,55 +298,62 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { // set currentTerm = T, convert to follower (§5.1) // This applies to all RPC messages and responses if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) { + LOG.debug("{}: Term {} in \"{}\" message is greater than leader's term {} - switching to Follower", + logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm()); + context.getTermInformation().updateAndPersist(rpc.getTerm(), null); return switchBehavior(new Follower(context)); } } - try { - if (message instanceof SendHeartBeat) { - sendHeartBeat(); - return this; - - } else if(message instanceof InitiateInstallSnapshot) { - installSnapshotIfNeeded(); + if (message instanceof SendHeartBeat) { + beforeSendHeartbeat(); + sendHeartBeat(); + scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval()); + return this; - } else if(message instanceof SendInstallSnapshot) { - // received from RaftActor - setSnapshot(Optional.of(((SendInstallSnapshot) message).getSnapshot())); - sendInstallSnapshot(); + } else if(message instanceof SendInstallSnapshot) { + // received from RaftActor + setSnapshot(Optional.of(((SendInstallSnapshot) message).getSnapshot())); + sendInstallSnapshot(); - } else if (message instanceof Replicate) { - replicate((Replicate) message); + } else if (message instanceof Replicate) { + replicate((Replicate) message); - } else if (message instanceof InstallSnapshotReply){ - handleInstallSnapshotReply((InstallSnapshotReply) message); + } else if (message instanceof InstallSnapshotReply){ + handleInstallSnapshotReply((InstallSnapshotReply) message); - } - } finally { - scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval()); } + return super.handleMessage(sender, message); } private void handleInstallSnapshotReply(InstallSnapshotReply reply) { + LOG.debug("{}: handleInstallSnapshotReply: {}", logName(), reply); + String followerId = reply.getFollowerId(); FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId); + + if (followerToSnapshot == null) { + LOG.error("{}: FollowerId {} in InstallSnapshotReply not known to Leader", + logName(), followerId); + return; + } + FollowerLogInformation followerLogInformation = followerToLog.get(followerId); followerLogInformation.markFollowerActive(); - if (followerToSnapshot != null && - followerToSnapshot.getChunkIndex() == reply.getChunkIndex()) { - + if (followerToSnapshot.getChunkIndex() == reply.getChunkIndex()) { + boolean wasLastChunk = false; if (reply.isSuccess()) { if(followerToSnapshot.isLastChunk(reply.getChunkIndex())) { //this was the last chunk reply if(LOG.isDebugEnabled()) { - LOG.debug("InstallSnapshotReply received, " + - "last chunk received, Chunk:{}. Follower:{} Setting nextIndex:{}", - reply.getChunkIndex(), followerId, + LOG.debug("{}: InstallSnapshotReply received, " + + "last chunk received, Chunk: {}. Follower: {} Setting nextIndex: {}", + logName(), reply.getChunkIndex(), followerId, context.getReplicatedLog().getSnapshotIndex() + 1 ); } @@ -323,35 +364,38 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { context.getReplicatedLog().getSnapshotIndex() + 1); mapFollowerToSnapshot.remove(followerId); - if(LOG.isDebugEnabled()) { - LOG.debug("followerToLog.get(followerId).getNextIndex().get()=" + - followerToLog.get(followerId).getNextIndex().get()); - } + LOG.debug("{}: follower: {}, matchIndex set to {}, nextIndex set to {}", + logName(), followerId, followerLogInformation.getMatchIndex(), + followerLogInformation.getNextIndex()); if (mapFollowerToSnapshot.isEmpty()) { // once there are no pending followers receiving snapshots // we can remove snapshot from the memory setSnapshot(Optional.absent()); } + wasLastChunk = true; } else { followerToSnapshot.markSendStatus(true); } } else { - LOG.info("InstallSnapshotReply received, " + - "sending snapshot chunk failed, Will retry, Chunk:{}", - reply.getChunkIndex() - ); + LOG.info("{}: InstallSnapshotReply received sending snapshot chunk failed, Will retry, Chunk: {}", + logName(), reply.getChunkIndex()); followerToSnapshot.markSendStatus(false); } + if (!wasLastChunk && followerToSnapshot.canSendNextChunk()) { + ActorSelection followerActor = context.getPeerActorSelection(followerId); + if(followerActor != null) { + sendSnapshotChunk(followerActor, followerId); + } + } + } else { - LOG.error("ERROR!!" + - "FollowerId in InstallSnapshotReply not known to Leader" + - " or Chunk Index in InstallSnapshotReply not matching {} != {}", - followerToSnapshot.getChunkIndex(), reply.getChunkIndex() - ); + LOG.error("{}: Chunk index {} in InstallSnapshotReply from follower {} does not match expected index {}", + logName(), reply.getChunkIndex(), followerId, + followerToSnapshot.getChunkIndex()); if(reply.getChunkIndex() == INVALID_CHUNK_INDEX){ // Since the Follower did not find this index to be valid we should reset the follower snapshot @@ -364,9 +408,8 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { private void replicate(Replicate replicate) { long logIndex = replicate.getReplicatedLogEntry().getIndex(); - if(LOG.isDebugEnabled()) { - LOG.debug("Replicate message {}", logIndex); - } + LOG.debug("{}: Replicate message: identifier: {}, logIndex: {}", logName(), + replicate.getIdentifier(), logIndex); // Create a tracker entry we will use this later to notify the // client actor @@ -376,168 +419,179 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { logIndex) ); - if (followers.size() == 0) { + if (followerToLog.isEmpty()) { context.setCommitIndex(logIndex); applyLogToStateMachine(logIndex); } else { - sendAppendEntries(); + sendAppendEntries(0, false); } } - private void sendAppendEntries() { + private void sendAppendEntries(long timeSinceLastActivityInterval, boolean isHeartbeat) { // Send an AppendEntries to all followers - for (String followerId : followers) { - ActorSelection followerActor = context.getPeerActorSelection(followerId); + for (Entry e : followerToLog.entrySet()) { + final String followerId = e.getKey(); + final FollowerLogInformation followerLogInformation = e.getValue(); + // This checks helps not to send a repeat message to the follower + if(!followerLogInformation.isFollowerActive() || + followerLogInformation.timeSinceLastActivity() >= timeSinceLastActivityInterval) { + sendUpdatesToFollower(followerId, followerLogInformation, true, isHeartbeat); + } + } + } - if (followerActor != null) { - FollowerLogInformation followerLogInformation = followerToLog.get(followerId); - long followerNextIndex = followerLogInformation.getNextIndex().get(); - boolean isFollowerActive = followerLogInformation.isFollowerActive(); - List entries = null; - - if (mapFollowerToSnapshot.get(followerId) != null) { - // if install snapshot is in process , then sent next chunk if possible - if (isFollowerActive && mapFollowerToSnapshot.get(followerId).canSendNextChunk()) { - sendSnapshotChunk(followerActor, followerId); - } else { - // we send a heartbeat even if we have not received a reply for the last chunk - sendAppendEntriesToFollower(followerActor, followerNextIndex, - Collections.emptyList()); - } + /** + * + * This method checks if any update needs to be sent to the given follower. This includes append log entries, + * sending next snapshot chunk, and initiating a snapshot. + * @return true if any update is sent, false otherwise + */ - } else { - long leaderLastIndex = context.getReplicatedLog().lastIndex(); - long leaderSnapShotIndex = context.getReplicatedLog().getSnapshotIndex(); - - if (isFollowerActive && - context.getReplicatedLog().isPresent(followerNextIndex)) { - // FIXME : Sending one entry at a time - entries = context.getReplicatedLog().getFrom(followerNextIndex, 1); - - } else if (isFollowerActive && followerNextIndex >= 0 && - leaderLastIndex >= followerNextIndex ) { - // if the followers next index is not present in the leaders log, and - // if the follower is just not starting and if leader's index is more than followers index - // then snapshot should be sent - - if(LOG.isDebugEnabled()) { - LOG.debug("InitiateInstallSnapshot to follower:{}," + - "follower-nextIndex:{}, leader-snapshot-index:{}, " + - "leader-last-index:{}", followerId, - followerNextIndex, leaderSnapShotIndex, leaderLastIndex - ); - } - actor().tell(new InitiateInstallSnapshot(), actor()); - - // we would want to sent AE as the capture snapshot might take time - entries = Collections.emptyList(); - - } else { - //we send an AppendEntries, even if the follower is inactive - // in-order to update the followers timestamp, in case it becomes active again - entries = Collections.emptyList(); + private void sendUpdatesToFollower(String followerId, FollowerLogInformation followerLogInformation, + boolean sendHeartbeat, boolean isHeartbeat) { + + ActorSelection followerActor = context.getPeerActorSelection(followerId); + if (followerActor != null) { + long followerNextIndex = followerLogInformation.getNextIndex(); + boolean isFollowerActive = followerLogInformation.isFollowerActive(); + + if (mapFollowerToSnapshot.get(followerId) != null) { + // if install snapshot is in process , then sent next chunk if possible + if (isFollowerActive && mapFollowerToSnapshot.get(followerId).canSendNextChunk()) { + sendSnapshotChunk(followerActor, followerId); + } else if(sendHeartbeat) { + // we send a heartbeat even if we have not received a reply for the last chunk + sendAppendEntriesToFollower(followerActor, followerLogInformation.getNextIndex(), + Collections.emptyList(), followerId); + } + } else { + long leaderLastIndex = context.getReplicatedLog().lastIndex(); + long leaderSnapShotIndex = context.getReplicatedLog().getSnapshotIndex(); + + if(!isHeartbeat || LOG.isTraceEnabled()) { + LOG.debug("{}: Checking sendAppendEntries for follower {}, leaderLastIndex: {}, leaderSnapShotIndex: {}", + logName(), followerId, leaderLastIndex, leaderSnapShotIndex); + } + + if (isFollowerActive && context.getReplicatedLog().isPresent(followerNextIndex)) { + + LOG.debug("{}: sendAppendEntries: {} is present for follower {}", logName(), + followerNextIndex, followerId); + + // FIXME : Sending one entry at a time + final List entries = context.getReplicatedLog().getFrom(followerNextIndex, 1); + + sendAppendEntriesToFollower(followerActor, followerNextIndex, entries, followerId); + + } else if (isFollowerActive && followerNextIndex >= 0 && + leaderLastIndex > followerNextIndex && !context.isSnapshotCaptureInitiated()) { + // if the followers next index is not present in the leaders log, and + // if the follower is just not starting and if leader's index is more than followers index + // then snapshot should be sent + + if (LOG.isDebugEnabled()) { + LOG.debug(String.format("%s: InitiateInstallSnapshot to follower: %s," + + "follower-nextIndex: %d, leader-snapshot-index: %d, " + + "leader-last-index: %d", logName(), followerId, + followerNextIndex, leaderSnapShotIndex, leaderLastIndex)); } - sendAppendEntriesToFollower(followerActor, followerNextIndex, entries); + // Send heartbeat to follower whenever install snapshot is initiated. + sendAppendEntriesToFollower(followerActor, followerLogInformation.getNextIndex(), + Collections.emptyList(), followerId); + + initiateCaptureSnapshot(followerId, followerNextIndex); + } else if(sendHeartbeat) { + //we send an AppendEntries, even if the follower is inactive + // in-order to update the followers timestamp, in case it becomes active again + sendAppendEntriesToFollower(followerActor, followerLogInformation.getNextIndex(), + Collections.emptyList(), followerId); } + } } } private void sendAppendEntriesToFollower(ActorSelection followerActor, long followerNextIndex, - List entries) { - followerActor.tell( - new AppendEntries(currentTerm(), context.getId(), - prevLogIndex(followerNextIndex), - prevLogTerm(followerNextIndex), entries, - context.getCommitIndex()).toSerializable(), - actor() - ); + List entries, String followerId) { + AppendEntries appendEntries = new AppendEntries(currentTerm(), context.getId(), + prevLogIndex(followerNextIndex), + prevLogTerm(followerNextIndex), entries, + context.getCommitIndex(), super.getReplicatedToAllIndex()); + + if(!entries.isEmpty() || LOG.isTraceEnabled()) { + LOG.debug("{}: Sending AppendEntries to follower {}: {}", logName(), followerId, + appendEntries); + } + + followerActor.tell(appendEntries.toSerializable(), actor()); } /** - * An installSnapshot is scheduled at a interval that is a multiple of - * a HEARTBEAT_INTERVAL. This is to avoid the need to check for installing - * snapshots at every heartbeat. - * * Install Snapshot works as follows - * 1. Leader sends a InitiateInstallSnapshot message to self - * 2. Leader then initiates the capture snapshot by sending a CaptureSnapshot message to actor - * 3. RaftActor on receipt of the CaptureSnapshotReply (from Shard), stores the received snapshot in the replicated log + * 1. Leader initiates the capture snapshot by sending a CaptureSnapshot message to actor + * 2. RaftActor on receipt of the CaptureSnapshotReply (from Shard), stores the received snapshot in the replicated log * and makes a call to Leader's handleMessage , with SendInstallSnapshot message. - * 4. Leader , picks the snapshot from im-mem ReplicatedLog and sends it in chunks to the Follower - * 5. On complete, Follower sends back a InstallSnapshotReply. - * 6. On receipt of the InstallSnapshotReply for the last chunk, Leader marks the install complete for that follower + * 3. Leader , picks the snapshot from im-mem ReplicatedLog and sends it in chunks to the Follower + * 4. On complete, Follower sends back a InstallSnapshotReply. + * 5. On receipt of the InstallSnapshotReply for the last chunk, Leader marks the install complete for that follower * and replenishes the memory by deleting the snapshot in Replicated log. - * + * 6. If another follower requires a snapshot and a snapshot has been collected (via CaptureSnapshotReply) + * then send the existing snapshot in chunks to the follower. + * @param followerId + * @param followerNextIndex */ - private void installSnapshotIfNeeded() { - for (String followerId : followers) { - ActorSelection followerActor = - context.getPeerActorSelection(followerId); - - if(followerActor != null) { - FollowerLogInformation followerLogInformation = - followerToLog.get(followerId); - - long nextIndex = followerLogInformation.getNextIndex().get(); - - if (!context.getReplicatedLog().isPresent(nextIndex) && - context.getReplicatedLog().isInSnapshot(nextIndex)) { - LOG.info("{} follower needs a snapshot install", followerId); - if (snapshot.isPresent()) { - // if a snapshot is present in the memory, most likely another install is in progress - // no need to capture snapshot - sendSnapshotChunk(followerActor, followerId); - - } else { - initiateCaptureSnapshot(); - //we just need 1 follower who would need snapshot to be installed. - // when we have the snapshot captured, we would again check (in SendInstallSnapshot) - // who needs an install and send to all who need - break; - } + private void initiateCaptureSnapshot(String followerId, long followerNextIndex) { + if (!context.getReplicatedLog().isPresent(followerNextIndex) && + context.getReplicatedLog().isInSnapshot(followerNextIndex)) { + if (snapshot.isPresent()) { + // if a snapshot is present in the memory, most likely another install is in progress + // no need to capture snapshot. + // This could happen if another follower needs an install when one is going on. + final ActorSelection followerActor = context.getPeerActorSelection(followerId); + sendSnapshotChunk(followerActor, followerId); + + } else if (!context.isSnapshotCaptureInitiated()) { + + LOG.info("{}: Initiating Snapshot Capture to Install Snapshot, Leader:{}", logName(), getLeaderId()); + ReplicatedLogEntry lastAppliedEntry = context.getReplicatedLog().get(context.getLastApplied()); + long lastAppliedIndex = -1; + long lastAppliedTerm = -1; + + if (lastAppliedEntry != null) { + lastAppliedIndex = lastAppliedEntry.getIndex(); + lastAppliedTerm = lastAppliedEntry.getTerm(); + } else if (context.getReplicatedLog().getSnapshotIndex() > -1) { + lastAppliedIndex = context.getReplicatedLog().getSnapshotIndex(); + lastAppliedTerm = context.getReplicatedLog().getSnapshotTerm(); } + + boolean isInstallSnapshotInitiated = true; + long replicatedToAllIndex = super.getReplicatedToAllIndex(); + ReplicatedLogEntry replicatedToAllEntry = context.getReplicatedLog().get(replicatedToAllIndex); + actor().tell(new CaptureSnapshot(lastIndex(), lastTerm(), lastAppliedIndex, lastAppliedTerm, + (replicatedToAllEntry != null ? replicatedToAllEntry.getIndex() : -1), + (replicatedToAllEntry != null ? replicatedToAllEntry.getTerm() : -1), + isInstallSnapshotInitiated), actor()); + context.setSnapshotCaptureInitiated(true); } } } - // on every install snapshot, we try to capture the snapshot. - // Once a capture is going on, another one issued will get ignored by RaftActor. - private void initiateCaptureSnapshot() { - LOG.info("Initiating Snapshot Capture to Install Snapshot, Leader:{}", getLeaderId()); - ReplicatedLogEntry lastAppliedEntry = context.getReplicatedLog().get(context.getLastApplied()); - long lastAppliedIndex = -1; - long lastAppliedTerm = -1; - - if (lastAppliedEntry != null) { - lastAppliedIndex = lastAppliedEntry.getIndex(); - lastAppliedTerm = lastAppliedEntry.getTerm(); - } else if (context.getReplicatedLog().getSnapshotIndex() > -1) { - lastAppliedIndex = context.getReplicatedLog().getSnapshotIndex(); - lastAppliedTerm = context.getReplicatedLog().getSnapshotTerm(); - } - - boolean isInstallSnapshotInitiated = true; - actor().tell(new CaptureSnapshot(lastIndex(), lastTerm(), - lastAppliedIndex, lastAppliedTerm, isInstallSnapshotInitiated), - actor()); - } - private void sendInstallSnapshot() { - for (String followerId : followers) { - ActorSelection followerActor = context.getPeerActorSelection(followerId); + LOG.debug("{}: sendInstallSnapshot", logName()); + for (Entry e : followerToLog.entrySet()) { + ActorSelection followerActor = context.getPeerActorSelection(e.getKey()); - if(followerActor != null) { - FollowerLogInformation followerLogInformation = followerToLog.get(followerId); - long nextIndex = followerLogInformation.getNextIndex().get(); + if (followerActor != null) { + long nextIndex = e.getValue().getNextIndex(); if (!context.getReplicatedLog().isPresent(nextIndex) && context.getReplicatedLog().isInSnapshot(nextIndex)) { - sendSnapshotChunk(followerActor, followerId); + sendSnapshotChunk(followerActor, e.getKey()); } } } @@ -550,23 +604,30 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { private void sendSnapshotChunk(ActorSelection followerActor, String followerId) { try { if (snapshot.isPresent()) { + ByteString nextSnapshotChunk = getNextSnapshotChunk(followerId,snapshot.get()); + + // Note: the previous call to getNextSnapshotChunk has the side-effect of adding + // followerId to the followerToSnapshot map. + FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId); + followerActor.tell( new InstallSnapshot(currentTerm(), context.getId(), context.getReplicatedLog().getSnapshotIndex(), context.getReplicatedLog().getSnapshotTerm(), - getNextSnapshotChunk(followerId,snapshot.get()), - mapFollowerToSnapshot.get(followerId).incrementChunkIndex(), - mapFollowerToSnapshot.get(followerId).getTotalChunks(), - Optional.of(mapFollowerToSnapshot.get(followerId).getLastChunkHashCode()) + nextSnapshotChunk, + followerToSnapshot.incrementChunkIndex(), + followerToSnapshot.getTotalChunks(), + Optional.of(followerToSnapshot.getLastChunkHashCode()) ).toSerializable(), actor() ); - LOG.info("InstallSnapshot sent to follower {}, Chunk: {}/{}", - followerActor.path(), mapFollowerToSnapshot.get(followerId).getChunkIndex(), - mapFollowerToSnapshot.get(followerId).getTotalChunks()); + LOG.info("{}: InstallSnapshot sent to follower {}, Chunk: {}/{}", + logName(), followerActor.path(), + followerToSnapshot.getChunkIndex(), + followerToSnapshot.getTotalChunks()); } } catch (IOException e) { - LOG.error(e, "InstallSnapshot failed for Leader."); + LOG.error("{}: InstallSnapshot failed for Leader.", logName(), e); } } @@ -581,15 +642,16 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { mapFollowerToSnapshot.put(followerId, followerToSnapshot); } ByteString nextChunk = followerToSnapshot.getNextChunk(); - if (LOG.isDebugEnabled()) { - LOG.debug("Leader's snapshot nextChunk size:{}", nextChunk.size()); - } + + LOG.debug("{}: next snapshot chunk size for follower {}: {}", logName(), followerId, nextChunk.size()); + return nextChunk; } private void sendHeartBeat() { - if (followers.size() > 0) { - sendAppendEntries(); + if (!followerToLog.isEmpty()) { + LOG.trace("{}: Sending heartbeat", logName()); + sendAppendEntries(context.getConfigParams().getHeartBeatInterval().toMillis(), true); } } @@ -600,7 +662,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { } private void scheduleHeartBeat(FiniteDuration interval) { - if(followers.size() == 0){ + if (followerToLog.isEmpty()) { // Optimization - do not bother scheduling a heartbeat as there are // no followers return; @@ -646,14 +708,14 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { * snapshot chunks */ protected class FollowerToSnapshot { - private ByteString snapshotBytes; + private final ByteString snapshotBytes; private int offset = 0; // the next snapshot chunk is sent only if the replyReceivedForOffset matches offset private int replyReceivedForOffset; // if replyStatus is false, the previous chunk is attempted private boolean replyStatus = false; private int chunkIndex; - private int totalChunks; + private final int totalChunks; private int lastChunkHashCode = AbstractLeader.INITIAL_LAST_CHUNK_HASH_CODE; private int nextChunkHashCode = AbstractLeader.INITIAL_LAST_CHUNK_HASH_CODE; @@ -663,8 +725,8 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { totalChunks = ( size / context.getConfigParams().getSnapshotChunkSize()) + ((size % context.getConfigParams().getSnapshotChunkSize()) > 0 ? 1 : 0); if(LOG.isDebugEnabled()) { - LOG.debug("Snapshot {} bytes, total chunks to send:{}", - size, totalChunks); + LOG.debug("{}: Snapshot {} bytes, total chunks to send:{}", + logName(), size, totalChunks); } replyReceivedForOffset = -1; chunkIndex = AbstractLeader.FIRST_CHUNK_INDEX; @@ -732,10 +794,10 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { } } - if(LOG.isDebugEnabled()) { - LOG.debug("length={}, offset={},size={}", + + LOG.debug("{}: Next chunk: length={}, offset={},size={}", logName(), snapshotLength, start, size); - } + ByteString substring = getSnapshotBytes().substring(start, start + size); nextChunkHashCode = substring.hashCode(); return substring; @@ -759,17 +821,38 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior { // called from example-actor for printing the follower-states public String printFollowerStates() { - StringBuilder sb = new StringBuilder(); - for(FollowerLogInformation followerLogInformation : followerToLog.values()) { - boolean isFollowerActive = followerLogInformation.isFollowerActive(); - sb.append("{"+followerLogInformation.getId() + " state:" + isFollowerActive + "},"); + final StringBuilder sb = new StringBuilder(); + sb.append('['); + for (FollowerLogInformation followerLogInformation : followerToLog.values()) { + sb.append('{'); + sb.append(followerLogInformation.getId()); + sb.append(" state:"); + sb.append(followerLogInformation.isFollowerActive()); + sb.append("},"); } - return "[" + sb.toString() + "]"; + sb.append(']'); + + return sb.toString(); + } + + @VisibleForTesting + public FollowerLogInformation getFollower(String followerId) { + return followerToLog.get(followerId); + } + + @VisibleForTesting + protected void setFollowerSnapshot(String followerId, FollowerToSnapshot snapshot) { + mapFollowerToSnapshot.put(followerId, snapshot); + } + + @VisibleForTesting + public int followerSnapshotSize() { + return mapFollowerToSnapshot.size(); } @VisibleForTesting - void markFollowerActive(String followerId) { - followerToLog.get(followerId).markFollowerActive(); + public int followerLogSize() { + return followerToLog.size(); } }