Im Raft-Paper ist die RPC Funktion RequestVote folgendermaßen definiert worden:

Im Java Code der Raft-grpc Implementierung ist die Funktion so implementiert worden:

public VoteResponse handleVoteRequest(VoteRequest request) {
        log.info("Received vote request from {} for term {}", request.getCandidateId(), request.getTerm());
        // Deny votes when suspended
        if (suspended) {
            log.info("Denying vote request - node is suspended");
            return VoteResponse.newBuilder()
                .setTerm(currentTerm.get())
                .setVoteGranted(false)
                .build();
        }
        if (request.getTerm() > currentTerm.get()) {
            becomeFollower(request.getTerm());
        }
        boolean voteGranted = false;
        if (request.getTerm() < currentTerm.get()) {
            voteGranted = false;
            logEvent(RaftEvent.EventType.VOTE_DENIED, 
                "Denied vote to " + request.getCandidateId() + " (stale term " + request.getTerm() + ")");
        } else if (votedFor == null || votedFor.equals(request.getCandidateId())) {
            int lastLogIndex = getLastLogIndex();
            int lastLogTerm = getLogTermAt(lastLogIndex);
            boolean logUpToDate = request.getLastLogTerm() > lastLogTerm ||
                (request.getLastLogTerm() == lastLogTerm && request.getLastLogIndex() >= lastLogIndex);
            if (logUpToDate) {
                votedFor = request.getCandidateId();
                voteGranted = true;
                lastHeartbeat = System.currentTimeMillis();
                // Persist vote (CRITICAL for Raft safety - must persist before responding)
                persistenceService.saveState(config.getNodeId(), currentTerm.get(), votedFor);
                startElectionTimer();
                log.info("Voted for {}", request.getCandidateId());
                logEvent(RaftEvent.EventType.VOTE_GRANTED, 
                    "Granted vote to " + request.getCandidateId() + " for term " + request.getTerm());
            } else {
                logEvent(RaftEvent.EventType.VOTE_DENIED, 
                    "Denied vote to " + request.getCandidateId() + " (log not up-to-date)");
            }
        } else {
            logEvent(RaftEvent.EventType.VOTE_DENIED, 
                "Denied vote to " + request.getCandidateId() + " (already voted for " + votedFor + ")");
        }
        return VoteResponse.newBuilder()
            .setTerm(currentTerm.get())
            .setVoteGranted(voteGranted)
            .build();
    }
    private void startElectionTimer() {
        if (electionTask != null) {
            electionTask.cancel(false);
        }
        int timeout = ThreadLocalRandom.current().nextInt(ELECTION_TIMEOUT_MIN, ELECTION_TIMEOUT_MAX);
        electionTask = scheduler.schedule(this::startElection, timeout, TimeUnit.MILLISECONDS);
        log.debug("Election timer started: {}ms", timeout);
    }

Mit den folgenden gRPC Messages:

message VoteRequest {
  int32 term = 1;
  string candidateId = 2;
  int32 lastLogIndex = 3;
  int32 lastLogTerm = 4;
}
message VoteResponse {
  int32 term = 1;
  bool voteGranted = 2;
}

Welche Aussagen treffen dabei zu?