Add more info logging in sal-akka-raft

[controller.git] / opendaylight / md-sal / sal-akka-raft / src / main / java / org / opendaylight / controller / cluster / raft / behaviors / Candidate.java

diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Candidate.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Candidate.java
index 7f73d0cfb0a24a8b85960c2b1fdb031c3131cfdd..da1c9c14d6f279ccdcdd6cd72025544bc5602cea 100644 (file)
--- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Candidate.java
+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Candidate.java
@@ -66,15 +66,24 @@ public class Candidate extends AbstractRaftActorBehavior {
         startNewTerm();
 
         if(votingPeers.isEmpty()){
-            actor().tell(ELECTION_TIMEOUT, actor());
+            actor().tell(ElectionTimeout.INSTANCE, actor());
         } else {
             scheduleElection(electionDuration());
         }
+    }
 
+    @Override
+    public final String getLeaderId() {
+        return null;
+    }
 
+    @Override
+    public final short getLeaderPayloadVersion() {
+        return -1;
     }
 
-    @Override protected RaftActorBehavior handleAppendEntries(ActorRef sender,
+    @Override
+    protected RaftActorBehavior handleAppendEntries(ActorRef sender,
         AppendEntries appendEntries) {
 
         if(LOG.isDebugEnabled()) {
@@ -83,8 +92,8 @@ public class Candidate extends AbstractRaftActorBehavior {
 
         // Some other candidate for the same term became a leader and sent us an append entry
         if(currentTerm() == appendEntries.getTerm()){
-            LOG.debug("{}: New Leader sent an append entry to Candidate for term {} will switch to Follower",
-                    logName(), currentTerm());
+            LOG.info("{}: New Leader {} sent an AppendEntries to Candidate for term {} - will switch to Follower",
+                    logName(), appendEntries.getLeaderId(), currentTerm());
 
             return switchBehavior(new Follower(context));
         }
@@ -92,33 +101,51 @@ public class Candidate extends AbstractRaftActorBehavior {
         return this;
     }
 
-    @Override protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender,
-        AppendEntriesReply appendEntriesReply) {
-
+    @Override
+    protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender, AppendEntriesReply appendEntriesReply) {
         return this;
     }
 
-    @Override protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
-            RequestVoteReply requestVoteReply) {
-
-        LOG.debug("{}: handleRequestVoteReply: {}, current voteCount: {}", logName(), requestVoteReply,
-                voteCount);
+    @Override
+    protected RaftActorBehavior handleRequestVoteReply(ActorRef sender, RequestVoteReply requestVoteReply) {
+        LOG.debug("{}: handleRequestVoteReply: {}, current voteCount: {}", logName(), requestVoteReply, voteCount);
 
         if (requestVoteReply.isVoteGranted()) {
             voteCount++;
         }
 
         if (voteCount >= votesRequired) {
-            return internalSwitchBehavior(RaftState.Leader);
+            if(context.getLastApplied() < context.getReplicatedLog().lastIndex()) {
+                LOG.info("{}: LastApplied index {} is behind last index {} - switching to PreLeader",
+                        logName(), context.getLastApplied(), context.getReplicatedLog().lastIndex());
+                return internalSwitchBehavior(RaftState.PreLeader);
+            } else {
+                return internalSwitchBehavior(RaftState.Leader);
+            }
         }
 
         return this;
     }
 
     @Override
-    public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
+    public RaftActorBehavior handleMessage(ActorRef sender, Object message) {
+        if (message instanceof ElectionTimeout) {
+            LOG.debug("{}: Received ElectionTimeout", logName());
+
+            if (votesRequired == 0) {
+                // If there are no peers then we should be a Leader
+                // We wait for the election timeout to occur before declare
+                // ourselves the leader. This gives enough time for a leader
+                // who we do not know about (as a peer)
+                // to send a message to the candidate
 
-        Object message = fromSerializableMessage(originalMessage);
+                return internalSwitchBehavior(RaftState.Leader);
+            }
+
+            startNewTerm();
+            scheduleElection(electionDuration());
+            return this;
+        }
 
         if (message instanceof RaftRPC) {
 
@@ -133,27 +160,19 @@ public class Candidate extends AbstractRaftActorBehavior {
             // set currentTerm = T, convert to follower (§5.1)
             // This applies to all RPC messages and responses
             if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) {
-                context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
+                LOG.info("{}: Term {} in \"{}\" message is greater than Candidate's term {} - switching to Follower",
+                        logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm());
 
-                return internalSwitchBehavior(RaftState.Follower);
-            }
-        }
+                context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
 
-        if (message instanceof ElectionTimeout) {
-            LOG.debug("{}: Received ElectionTimeout", logName());
+                // The raft paper does not say whether or not a Candidate can/should process a RequestVote in
+                // this case but doing so gains quicker convergence when the sender's log is more up-to-date.
+                if (message instanceof RequestVote) {
+                    super.handleMessage(sender, message);
+                }
 
-            if (votesRequired == 0) {
-                // If there are no peers then we should be a Leader
-                // We wait for the election timeout to occur before declare
-                // ourselves the leader. This gives enough time for a leader
-                // who we do not know about (as a peer)
-                // to send a message to the candidate
-
-                return internalSwitchBehavior(RaftState.Leader);
+                return internalSwitchBehavior(RaftState.Follower);
             }
-            startNewTerm();
-            scheduleElection(electionDuration());
-            return this;
         }
 
         return super.handleMessage(sender, message);
@@ -171,7 +190,7 @@ public class Candidate extends AbstractRaftActorBehavior {
         long newTerm = currentTerm + 1;
         context.getTermInformation().updateAndPersist(newTerm, context.getId());
 
-        LOG.debug("{}: Starting new term {}", logName(), newTerm);
+        LOG.info("{}: Starting new election term {}", logName(), newTerm);
 
         // Request for a vote
         // TODO: Retry request for vote if replies do not arrive in a reasonable
@@ -192,7 +211,8 @@ public class Candidate extends AbstractRaftActorBehavior {
         }
     }
 
-    @Override public void close() throws Exception {
+    @Override
+    public void close() {
         stopElection();
     }
 }