Examples with VoteResponse com.hazelcast.cp.internal.raft.impl.dto.VoteResponse used on opensource projects

Example 1 with VoteResponse

use of com.hazelcast.cp.internal.raft.impl.dto.VoteResponse in project hazelcast by hazelcast.

the class VoteRequestHandlerTask method innerRun.

@Override
@SuppressWarnings({ "checkstyle:npathcomplexity", "checkstyle:cyclomaticcomplexity" })
protected // Justification: It is easier to follow the RequestVoteRPC logic in a single method
void innerRun() {
    RaftState state = raftNode.state();
    RaftEndpoint localMember = localMember();
    // Reply false if last AppendEntries call was received less than election timeout ago (leader stickiness)
    // (Raft thesis - Section 4.2.3) This check conflicts with the leadership transfer mechanism,
    // in which a server legitimately starts an election without waiting an election timeout.
    // Those VoteRequest objects are marked with a special flag ("disruptive") to bypass leader stickiness.
    // Also if request comes from the current leader, then stickiness check is skipped.
    // Since current leader may have restarted by recovering its persistent state.
    long leaderElectionTimeoutDeadline = Clock.currentTimeMillis() - raftNode.getLeaderElectionTimeoutInMillis();
    if (!req.isDisruptive() && raftNode.lastAppendEntriesTimestamp() > leaderElectionTimeoutDeadline && !req.candidate().equals(state.leader())) {
        logger.info("Rejecting " + req + " since received append entries recently.");
        raftNode.send(new VoteResponse(localMember, state.term(), false), req.candidate());
        return;
    }
    // Reply false if term < currentTerm (§5.1)
    if (state.term() > req.term()) {
        logger.info("Rejecting " + req + " since current term: " + state.term() + " is bigger");
        raftNode.send(new VoteResponse(localMember, state.term(), false), req.candidate());
        return;
    }
    if (state.term() < req.term()) {
        // If RPC request or response contains term T > currentTerm: set currentTerm = T, convert to follower (§5.1)
        if (state.role() != FOLLOWER) {
            logger.info("Demoting to FOLLOWER after " + req + " since current term: " + state.term() + " is smaller");
        } else {
            logger.info("Moving to new term: " + req.term() + " from current term: " + state.term() + " after " + req);
        }
        raftNode.toFollower(req.term());
    }
    if (state.leader() != null && !req.candidate().equals(state.leader())) {
        logger.warning("Rejecting " + req + " since we have a leader: " + state.leader());
        raftNode.send(new VoteResponse(localMember, req.term(), false), req.candidate());
        return;
    }
    if (state.votedFor() != null) {
        boolean granted = (req.candidate().equals(state.votedFor()));
        if (granted) {
            logger.info("Vote granted for duplicate" + req);
        } else {
            logger.info("Duplicate " + req + ". currently voted-for: " + state.votedFor());
        }
        raftNode.send(new VoteResponse(localMember, req.term(), granted), req.candidate());
        return;
    }
    RaftLog raftLog = state.log();
    if (raftLog.lastLogOrSnapshotTerm() > req.lastLogTerm()) {
        logger.info("Rejecting " + req + " since our last log term: " + raftLog.lastLogOrSnapshotTerm() + " is greater");
        raftNode.send(new VoteResponse(localMember, req.term(), false), req.candidate());
        return;
    }
    if (raftLog.lastLogOrSnapshotTerm() == req.lastLogTerm() && raftLog.lastLogOrSnapshotIndex() > req.lastLogIndex()) {
        logger.info("Rejecting " + req + " since our last log index: " + raftLog.lastLogOrSnapshotIndex() + " is greater");
        raftNode.send(new VoteResponse(localMember, req.term(), false), req.candidate());
        return;
    }
    logger.info("Granted vote for " + req);
    state.persistVote(req.term(), req.candidate());
    raftNode.send(new VoteResponse(localMember, req.term(), true), req.candidate());
}