public AppendEntriesResult AppendEntries(AppendEntriesCommand request)
{
lock (_lock)
{
_auditLog.LogRecord(new AuditRecord(AuditRecordType.RecAppendEntries, Id, _state, _currentTerm));
//this instance considers sender's Term to be stale - reject request and complete.
//NOT IMPLEMENTED return false if log doesn't contain an entry.
//NOT IMPLEMENTED if conflict, delete existing entry
if (_currentTerm > request.Term)
{
_auditLog.LogRecord(new AuditRecord(AuditRecordType.RejectAppendEntries, Id, _state, _currentTerm));
return(new AppendEntriesResult {
Term = _currentTerm,
Success = false
});
}
//we should become a follower, irrespective of current state
BecomeFollower(request.Term);
return(new AppendEntriesResult {
Term = _currentTerm,
Success = true
});
}
}
private async Task SendHeartbeat()
{
List <IServerProxy> servers;
AppendEntriesCommand heartBeatCmd;
lock (_lock)
{
servers = new List <IServerProxy>(_servers);
heartBeatCmd = new AppendEntriesCommand
{
Term = _currentTerm,
LeaderId = Id
};
}
_auditLog.LogRecord(new AuditRecord(AuditRecordType.SendHeartbeat, Id, _state, _currentTerm));
while (_state == RaftServerState.Leader)
{
//TODO error handling, cancellation
var pendingRequests = new List <Task>(
servers.Select(
s => SendAppendEntriesReceiveAck(s, heartBeatCmd)
)
);
await _planner.HeatbeatDelay();
}
}
public async Task <AppendEntriesResult> AppendEntries(AppendEntriesCommand request)
{
if (_config.Reachable(request.LeaderId, _proxy.Id))
{
return(await _proxy.AppendEntries(request));
}
throw new Exception("Network related exception");
}
public async Task <AppendEntriesResult> AppendEntries(AppendEntriesCommand request)
{
if (_rand.NextDouble() < _timeoutPct)
{
await Task.Delay(-1);
}
return(await _proxy.AppendEntries(request));
}
public async Task <AppendEntriesResult> AppendEntries(AppendEntriesCommand request)
{
if (_rand.NextDouble() < _exceptionPct)
{
throw new Exception("Network related exception");
}
return(await _proxy.AppendEntries(request));
}
private async Task SendAppendEntriesReceiveAck(IServerProxy server, AppendEntriesCommand cmd)
{
try
{
var response = await server.AppendEntries(cmd);
BecomeFollowerIfTermIsStale(response.Term);
}
catch (Exception)
{
//TODO exception logging to separate channel
_auditLog.LogRecord(new AuditRecord(AuditRecordType.AppendEntriesRPCFailure, Id, _state, _currentTerm, $"RPC to: {server.Id}"));
}
}
public Task <AppendEntriesResult> AppendEntries(AppendEntriesCommand request)
{
return(Utility.AddLatency(_server.AppendEntries, request, _latency));
}
