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%2FCandidate.java;h=52ed26758ee26b6f9949fa1202f1a44628b82364;hp=74bede171f1f6e6ad6b33feef6806d3c77321581;hb=bad1f8b8f3c1780cd37ec8a817ef4b0f23901654;hpb=a54ec60368110d22794602343c934902f6833c65

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 74bede171f..52ed26758e 100644
--- 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
@@ -10,7 +10,9 @@ package org.opendaylight.controller.cluster.raft.behaviors;
 
 import akka.actor.ActorRef;
 import akka.actor.ActorSelection;
-import java.util.Set;
+import java.util.ArrayList;
+import java.util.Collection;
+import org.opendaylight.controller.cluster.raft.PeerInfo;
 import org.opendaylight.controller.cluster.raft.RaftActorContext;
 import org.opendaylight.controller.cluster.raft.RaftState;
 import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
@@ -44,67 +46,106 @@ public class Candidate extends AbstractRaftActorBehavior {
 
     private final int votesRequired;
 
-    private final Set<String> peers;
+    private final Collection<String> votingPeers = new ArrayList<>();
 
     public Candidate(RaftActorContext context) {
         super(context, RaftState.Candidate);
 
-        peers = context.getPeerAddresses().keySet();
+        for(PeerInfo peer: context.getPeers()) {
+            if(peer.isVoting()) {
+                votingPeers.add(peer.getId());
+            }
+        }
 
         if(LOG.isDebugEnabled()) {
-            LOG.debug("{}: Election: Candidate has following peers: {}", logName(), peers);
+            LOG.debug("{}: Election: Candidate has following voting peers: {}", logName(), votingPeers);
         }
 
-        votesRequired = getMajorityVoteCount(peers.size());
+        votesRequired = getMajorityVoteCount(votingPeers.size());
 
         startNewTerm();
 
-        if(context.getPeerAddresses().isEmpty()){
-            actor().tell(ELECTION_TIMEOUT, actor());
+        if(votingPeers.isEmpty()){
+            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()) {
             LOG.debug("{}: handleAppendEntries: {}", logName(), appendEntries);
         }
 
-        return this;
-    }
+        // 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());
 
-    @Override protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender,
-        AppendEntriesReply appendEntriesReply) {
+            return switchBehavior(new Follower(context));
+        }
 
         return this;
     }
 
-    @Override protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
-            RequestVoteReply requestVoteReply) {
+    @Override
+    protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender, AppendEntriesReply appendEntriesReply) {
+        return this;
+    }
 
-        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 switchBehavior(new Leader(context));
+            if(context.getCommitIndex() < context.getReplicatedLog().lastIndex()) {
+                LOG.debug("{}: Connmit index {} is behind last index {}", logName(), context.getCommitIndex(),
+                        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
+
+                return internalSwitchBehavior(RaftState.Leader);
+            }
 
-        Object message = fromSerializableMessage(originalMessage);
+            startNewTerm();
+            scheduleElection(electionDuration());
+            return this;
+        }
 
         if (message instanceof RaftRPC) {
 
@@ -121,25 +162,14 @@ public class Candidate extends AbstractRaftActorBehavior {
             if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) {
                 context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
 
-                return switchBehavior(new Follower(context));
-            }
-        }
-
-        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 switchBehavior(new Leader(context));
+                return internalSwitchBehavior(RaftState.Follower);
             }
-            startNewTerm();
-            scheduleElection(electionDuration());
-            return this;
         }
 
         return super.handleMessage(sender, message);
@@ -162,7 +192,7 @@ public class Candidate extends AbstractRaftActorBehavior {
         // Request for a vote
         // TODO: Retry request for vote if replies do not arrive in a reasonable
         // amount of time TBD
-        for (String peerId : peers) {
+        for (String peerId : votingPeers) {
             ActorSelection peerActor = context.getPeerActorSelection(peerId);
             if(peerActor != null) {
                 RequestVote requestVote = new RequestVote(
@@ -178,7 +208,8 @@ public class Candidate extends AbstractRaftActorBehavior {
         }
     }
 
-    @Override public void close() throws Exception {
+    @Override
+    public void close() {
         stopElection();
     }
 }