import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
import org.opendaylight.controller.cluster.raft.messages.InstallSnapshot;
+import org.opendaylight.controller.cluster.raft.messages.RaftRPC;
import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
/**
* The behavior of a RaftActor in the Follower state
- *
+ * <p/>
* <ul>
* <li> Respond to RPCs from candidates and leaders
* <li> If election timeout elapses without receiving AppendEntries
* RPC from current leader or granting vote to candidate:
* convert to candidate
* </ul>
- *
*/
public class Follower extends AbstractRaftActorBehavior {
public Follower(RaftActorContext context) {
}
@Override protected RaftState handleAppendEntries(ActorRef sender,
- AppendEntries appendEntries, RaftState suggestedState) {
+ AppendEntries appendEntries) {
// If we got here then we do appear to be talking to the leader
leaderId = appendEntries.getLeaderId();
.get(appendEntries.getPrevLogIndex());
- if (lastIndex() > -1 && previousEntry != null
- && previousEntry.getTerm() != appendEntries
- .getPrevLogTerm()) {
+ boolean noMatchingTerms = true;
+
+ if (lastIndex() == -1
+ && appendEntries.getPrevLogIndex() != -1) {
+
+ context.getLogger().debug(
+ "The followers log is empty and the senders prevLogIndex is {}",
+ appendEntries.getPrevLogIndex());
+
+ } else if (lastIndex() > -1
+ && appendEntries.getPrevLogIndex() != -1
+ && previousEntry == null) {
context.getLogger().debug(
- "Cannot append entries because previous entry term "
- + previousEntry.getTerm()
- + " is not equal to append entries prevLogTerm "
- + appendEntries.getPrevLogTerm());
+ "The log is not empty but the prevLogIndex {} was not found in it",
+ appendEntries.getPrevLogIndex());
+ } else if (lastIndex() > -1
+ && previousEntry != null
+ && previousEntry.getTerm()!= appendEntries.getPrevLogTerm()) {
+
+ context.getLogger().debug(
+ "Cannot append entries because previous entry term {} is not equal to append entries prevLogTerm {}"
+ , previousEntry.getTerm()
+ , appendEntries.getPrevLogTerm());
+ } else {
+ noMatchingTerms = false;
+ }
+
+ if (noMatchingTerms) {
sender.tell(
new AppendEntriesReply(context.getId(), currentTerm(), false,
lastIndex(), lastTerm()), actor()
&& appendEntries.getEntries().size() > 0) {
context.getLogger().debug(
"Number of entries to be appended = " + appendEntries
- .getEntries().size());
+ .getEntries().size()
+ );
// 3. If an existing entry conflicts with a new one (same index
// but different terms), delete the existing entry and all that
.getTerm()) {
context.getLogger().debug(
"Removing entries from log starting at "
- + matchEntry.getIndex());
+ + matchEntry.getIndex()
+ );
context.getReplicatedLog()
- .removeFrom(matchEntry.getIndex());
+ .removeFromAndPersist(matchEntry.getIndex());
break;
}
}
context.getLogger().debug(
"After cleanup entries to be added from = " + (addEntriesFrom
- + lastIndex()));
+ + lastIndex())
+ );
// 4. Append any new entries not already in the log
for (int i = addEntriesFrom;
i < appendEntries.getEntries().size(); i++) {
context.getLogger().debug(
- "Append entry to log " + appendEntries.getEntries().get(i)
- .toString());
+ "Append entry to log " + appendEntries.getEntries().get(i).getData()
+ .toString()
+ );
context.getReplicatedLog()
.appendAndPersist(appendEntries.getEntries().get(i));
}
sender.tell(new AppendEntriesReply(context.getId(), currentTerm(), true,
lastIndex(), lastTerm()), actor());
- return suggestedState;
+ return state();
}
@Override protected RaftState handleAppendEntriesReply(ActorRef sender,
- AppendEntriesReply appendEntriesReply, RaftState suggestedState) {
- return suggestedState;
+ AppendEntriesReply appendEntriesReply) {
+ return state();
}
@Override protected RaftState handleRequestVoteReply(ActorRef sender,
- RequestVoteReply requestVoteReply, RaftState suggestedState) {
- return suggestedState;
+ RequestVoteReply requestVoteReply) {
+ return state();
}
@Override public RaftState state() {
}
@Override public RaftState handleMessage(ActorRef sender, Object message) {
- if(message instanceof ElectionTimeout){
+ if (message instanceof RaftRPC) {
+ RaftRPC rpc = (RaftRPC) message;
+ // If RPC request or response contains term T > currentTerm:
+ // set currentTerm = T, convert to follower (ยง5.1)
+ // This applies to all RPC messages and responses
+ if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) {
+ context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
+ }
+ }
+
+ if (message instanceof ElectionTimeout) {
return RaftState.Candidate;
- } else if(message instanceof InstallSnapshot){
+ } else if (message instanceof InstallSnapshot) {
InstallSnapshot snapshot = (InstallSnapshot) message;
actor().tell(new ApplySnapshot(snapshot), actor());
}