scheduleElection(electionDuration());
}
+ private boolean isLogEntryPresent(long index){
+ if(index == context.getReplicatedLog().getSnapshotIndex()){
+ return true;
+ }
+
+ ReplicatedLogEntry previousEntry = context.getReplicatedLog()
+ .get(index);
+
+ return previousEntry != null;
+
+ }
+
+ private long getLogEntryTerm(long index){
+ if(index == context.getReplicatedLog().getSnapshotIndex()){
+ return context.getReplicatedLog().getSnapshotTerm();
+ }
+
+ ReplicatedLogEntry previousEntry = context.getReplicatedLog()
+ .get(index);
+
+ if(previousEntry != null){
+ return previousEntry.getTerm();
+ }
+
+ return -1;
+ }
+
@Override protected RaftActorBehavior handleAppendEntries(ActorRef sender,
- AppendEntries appendEntries) {
+ AppendEntries appendEntries) {
if(appendEntries.getEntries() != null && appendEntries.getEntries().size() > 0) {
if(LOG.isDebugEnabled()) {
// 2. Reply false if log doesn’t contain an entry at prevLogIndex
// whose term matches prevLogTerm (§5.3)
- ReplicatedLogEntry previousEntry = context.getReplicatedLog()
- .get(appendEntries.getPrevLogIndex());
+ long prevLogTerm = getLogEntryTerm(appendEntries.getPrevLogIndex());
+ boolean prevEntryPresent = isLogEntryPresent(appendEntries.getPrevLogIndex());
boolean outOfSync = true;
// First check if the logs are in sync or not
if (lastIndex() == -1
- && appendEntries.getPrevLogIndex() != -1) {
+ && appendEntries.getPrevLogIndex() != -1) {
// The follower's log is out of sync because the leader does have
// an entry at prevLogIndex and this follower has no entries in
if(LOG.isDebugEnabled()) {
LOG.debug("The followers log is empty and the senders prevLogIndex is {}",
- appendEntries.getPrevLogIndex());
+ appendEntries.getPrevLogIndex());
}
} else if (lastIndex() > -1
- && appendEntries.getPrevLogIndex() != -1
- && previousEntry == null) {
+ && appendEntries.getPrevLogIndex() != -1
+ && !prevEntryPresent) {
// The follower's log is out of sync because the Leader's
// prevLogIndex entry was not found in it's log
if(LOG.isDebugEnabled()) {
LOG.debug("The log is not empty but the prevLogIndex {} was not found in it",
- appendEntries.getPrevLogIndex());
+ appendEntries.getPrevLogIndex());
}
} else if (lastIndex() > -1
- && previousEntry != null
- && previousEntry.getTerm()!= appendEntries.getPrevLogTerm()) {
+ && prevEntryPresent
+ && prevLogTerm != appendEntries.getPrevLogTerm()) {
// The follower's log is out of sync because the Leader's
// prevLogIndex entry does exist in the follower's log but it has
// a different term in it
- if(LOG.isDebugEnabled()) {
+ if (LOG.isDebugEnabled()) {
LOG.debug(
- "Cannot append entries because previous entry term {} is not equal to append entries prevLogTerm {}"
- , previousEntry.getTerm()
- , appendEntries.getPrevLogTerm());
+ "Cannot append entries because previous entry term {} is not equal to append entries prevLogTerm {}"
+ , prevLogTerm
+ , appendEntries.getPrevLogTerm());
}
} else {
outOfSync = false;
// We found that the log was out of sync so just send a negative
// reply and return
if(LOG.isDebugEnabled()) {
- LOG.debug("Follower is out-of-sync, " +
+ LOG.debug("Follower ({}) is out-of-sync, " +
"so sending negative reply, lastIndex():{}, lastTerm():{}",
- lastIndex(), lastTerm()
+ context.getId(), lastIndex(), lastTerm()
);
}
sender.tell(