X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-akka-raft%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fraft%2Fbehaviors%2FCandidate.java;h=0d035dbce747ab258da8200b68e0cf7b71d6dd79;hb=fdab53ef9033fc83c812f7d3d6d3327d3d176f0f;hp=774691154a8ee4782e02532916ebb9c7f29734a5;hpb=583f6075e842a6a37b83bd01e478aebc70c6af73;p=controller.git
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 774691154a..0d035dbce7 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
@@ -9,18 +9,22 @@
package org.opendaylight.controller.cluster.raft.behaviors;
import akka.actor.ActorRef;
+import akka.actor.ActorSelection;
import org.opendaylight.controller.cluster.raft.RaftActorContext;
import org.opendaylight.controller.cluster.raft.RaftState;
+import org.opendaylight.controller.cluster.raft.internal.messages.ElectionTimeout;
import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
import org.opendaylight.controller.cluster.raft.messages.RequestVote;
import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
-import java.util.List;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
/**
* The behavior of a RaftActor when it is in the CandidateState
- *
+ *
* Candidates (§5.2):
*
* - On conversion to candidate, start election:
@@ -37,39 +41,131 @@ import java.util.List;
*
*/
public class Candidate extends AbstractRaftActorBehavior {
- private final List peers;
- public Candidate(RaftActorContext context, List peers) {
+ private final Map peerToActor = new HashMap<>();
+
+ private int voteCount;
+
+ private final int votesRequired;
+
+ public Candidate(RaftActorContext context) {
super(context);
- this.peers = peers;
+
+ Collection peerPaths = context.getPeerAddresses().values();
+
+ for (String peerPath : peerPaths) {
+ peerToActor.put(peerPath,
+ context.actorSelection(peerPath));
+ }
+
+ if(peerPaths.size() > 0) {
+ // Votes are required from a majority of the peers including self.
+ // The votesRequired field therefore stores a calculated value
+ // of the number of votes required for this candidate to win an
+ // election based on it's known peers.
+ // If a peer was added during normal operation and raft replicas
+ // came to know about them then the new peer would also need to be
+ // taken into consideration when calculating this value.
+ // Here are some examples for what the votesRequired would be for n
+ // peers
+ // 0 peers = 1 votesRequired (0 + 1) / 2 + 1 = 1
+ // 2 peers = 2 votesRequired (2 + 1) / 2 + 1 = 2
+ // 4 peers = 3 votesRequired (4 + 1) / 2 + 1 = 3
+ int noOfPeers = peerPaths.size();
+ int self = 1;
+ votesRequired = (noOfPeers + self) / 2 + 1;
+ } else {
+ votesRequired = 0;
+ }
+
+ startNewTerm();
+ scheduleElection(electionDuration());
}
@Override protected RaftState handleAppendEntries(ActorRef sender,
AppendEntries appendEntries, RaftState suggestedState) {
+
+ context.getLogger().error("An unexpected AppendEntries received in state " + state());
+
return suggestedState;
}
@Override protected RaftState handleAppendEntriesReply(ActorRef sender,
AppendEntriesReply appendEntriesReply, RaftState suggestedState) {
- return suggestedState;
- }
- @Override protected RaftState handleRequestVote(ActorRef sender,
- RequestVote requestVote, RaftState suggestedState) {
+ // Some peer thinks I was a leader and sent me a reply
+
return suggestedState;
}
@Override protected RaftState handleRequestVoteReply(ActorRef sender,
RequestVoteReply requestVoteReply, RaftState suggestedState) {
- return suggestedState;
+ if (suggestedState == RaftState.Follower) {
+ // If base class thinks I should be follower then I am
+ return suggestedState;
+ }
+
+ if (requestVoteReply.isVoteGranted()) {
+ voteCount++;
+ }
+
+ if (voteCount >= votesRequired) {
+ return RaftState.Leader;
+ }
+
+ return state();
}
- @Override protected RaftState state() {
+ @Override public RaftState state() {
return RaftState.Candidate;
}
@Override
public RaftState handleMessage(ActorRef sender, Object message) {
+ if (message instanceof ElectionTimeout) {
+ 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 RaftState.Leader;
+ }
+ startNewTerm();
+ scheduleElection(electionDuration());
+ return state();
+ }
return super.handleMessage(sender, message);
}
+
+
+ private void startNewTerm() {
+
+
+ // set voteCount back to 1 (that is voting for self)
+ voteCount = 1;
+
+ // Increment the election term and vote for self
+ long currentTerm = context.getTermInformation().getCurrentTerm();
+ context.getTermInformation().update(currentTerm + 1, context.getId());
+
+ context.getLogger().debug("Starting new term " + (currentTerm+1));
+
+ // Request for a vote
+ for (ActorSelection peerActor : peerToActor.values()) {
+ peerActor.tell(new RequestVote(
+ context.getTermInformation().getCurrentTerm(),
+ context.getId(),
+ context.getReplicatedLog().lastIndex(),
+ context.getReplicatedLog().lastTerm()),
+ context.getActor()
+ );
+ }
+
+
+ }
+
+ @Override public void close() throws Exception {
+ stopElection();
+ }
}