private void BecomeLeader()
{
lock (_lock)
{
CancelScheduledEvents();
_state = RaftServerState.Leader;
_auditLog.LogRecord(new AuditRecord(AuditRecordType.BecomeLeader, Id, _state, _currentTerm));
Task.Run(SendHeartbeat);
}
}
public AuditRecord(AuditRecordType type, string candidate, RaftServerState state, int term, string extraInfo = "")
{
When = DateTime.Now;
Type = type;
Id = candidate;
Term = term;
ExtraInfo = extraInfo;
State = state;
Log.Write(GetLogEventLevel(type), "Raft audit: {@item}", this);
}
public Task BecomeFollower(int term)
{
lock (_lock)
{
CancelScheduledEvents();
UpdateTerm(term);
//Become follower can be called when we already are one (e.g. on receipt of a heartbeat)
if (_state != RaftServerState.Follower)
{
_state = RaftServerState.Follower;
_auditLog.LogRecord(new AuditRecord(AuditRecordType.BecomeFollower, Id, _state, _currentTerm));
}
return(Task.Run(ScheduleFollowerTimeout));
}
}
public async Task BecomeCandidate()
{
_state = RaftServerState.Candidate;
_auditLog.LogRecord(new AuditRecord(AuditRecordType.BecomeCandidate, Id, _state, _currentTerm));
while (_state == RaftServerState.Candidate)
{
lock (_lock)
{
CancelScheduledEvents();
_currentTerm++;
_votesReceived = 0;
_votedFor = null;
_auditLog.LogRecord(new AuditRecord(AuditRecordType.StartElection, Id, _state, _currentTerm));
//vote for self
ReceiveVote(
new RequestVoteResult {
Term = _currentTerm,
VoteGranted = true,
VoterId = Id,
}
);
_votedFor = Id;
var token = _taskCancellation.Token;
//TODO error handling, cancellation
var pendingRequests = new List <Task>(
_servers.Select(
s => RequestAndReceiveVote(s, token)
)
);
}
//wait timeout period
await _planner.ElectionDelay();
//if we are still in candidate state, run another election
//no need to cancel inflight vote requests because increment to term means they will be ignored
}
}
