private void ConnectCallback(IAsyncResult ar)
{
if (_closed) return;
try
{
var session = (AsyncSession<ServerTimer>) ar.AsyncState;
ServerTimer timer = session.State;
_server = timer.Server;
timer.Elapsed -= destConnectTimer_Elapsed;
timer.Enabled = false;
timer.Dispose();
var remote = session.Remote;
// Complete the connection.
remote.EndConnectDest(ar);
_destConnected = true;
if (_config.isVerboseLogging)
{
Logging.Info($"Socket connected to ss server: {_server.FriendlyName()}");
}
var latency = DateTime.Now - _startConnectTime;
IStrategy strategy = _controller.GetCurrentStrategy();
strategy?.UpdateLatency(_server, latency);
_tcprelay.UpdateLatency(_server, latency);
StartPipe(session);
}
catch (ArgumentException)
{
}
catch (Exception e)
{
if (_server != null)
{
IStrategy strategy = _controller.GetCurrentStrategy();
strategy?.SetFailure(_server);
}
Logging.LogUsefulException(e);
Close();
}
}
private async Task<ICMPResult> ICMPTest(Server server)
{
Logging.Debug("Ping " + server.FriendlyName());
if (server.server == "") return null;
var result = new ICMPResult(server);
try
{
var IP =
Dns.GetHostAddresses(server.server)
.First(
ip =>
ip.AddressFamily == AddressFamily.InterNetwork ||
ip.AddressFamily == AddressFamily.InterNetworkV6);
var ping = new Ping();
foreach (var _ in Enumerable.Range(0, Repeat))
{
try
{
var reply = await ping.SendTaskAsync(IP, TimeoutMilliseconds);
if (reply.Status.Equals(IPStatus.Success))
{
result.RoundtripTime.Add((int?) reply.RoundtripTime);
}
else
{
result.RoundtripTime.Add(null);
}
//Do ICMPTest in a random frequency
Thread.Sleep(TimeoutMilliseconds + new Random().Next()%TimeoutMilliseconds);
}
catch (Exception e)
{
Logging.Error($"An exception occured while eveluating {server.FriendlyName()}");
Logging.LogUsefulException(e);
}
}
}
catch (Exception e)
{
Logging.Error($"An exception occured while eveluating {server.FriendlyName()}");
Logging.LogUsefulException(e);
}
return result;
}
public void SetFailure(Server server)
{
Logging.Debug($"failure: {server.FriendlyName()}");
}
private async Task<List<DataList>> ICMPTest(Server server)
{
Logging.Debug("Ping " + server.FriendlyName());
if (server.server == "") return null;
var IP = Dns.GetHostAddresses(server.server).First(ip => (ip.AddressFamily == AddressFamily.InterNetwork || ip.AddressFamily == AddressFamily.InterNetworkV6));
var ping = new Ping();
var ret = new List<DataList>();
foreach (var timestamp in Enumerable.Range(0, Repeat).Select(_ => DateTime.Now.ToString(DateTimePattern)))
{
//ICMP echo. we can also set options and special bytes
try
{
var reply = await ping.SendTaskAsync(IP, Timeout);
ret.Add(new List<KeyValuePair<string, string>>
{
new KeyValuePair<string, string>("Timestamp", timestamp),
new KeyValuePair<string, string>("Server", server.FriendlyName()),
new KeyValuePair<string, string>("Status", reply?.Status.ToString()),
new KeyValuePair<string, string>("RoundtripTime", reply?.RoundtripTime.ToString())
//new KeyValuePair<string, string>("data", reply.Buffer.ToString()); // The data of reply
});
Thread.Sleep(Timeout + new Random().Next() % Timeout);
//Do ICMPTest in a random frequency
}
catch (Exception e)
{
Logging.Error($"An exception occured while eveluating {server.FriendlyName()}");
Logging.LogUsefulException(e);
}
}
return ret;
}
public void SetFailure(Server server)
{
Logging.Debug(String.Format("failure: {0}", server.FriendlyName()));
}
/**
* once failed, try after 5 min
* and (last write - last read) < 5s
* and (now - last read) < 5s // means not stuck
* and latency < 200ms, try after 30s
*/
public void ChooseNewServer()
{
Server oldServer = _currentServer;
List<ServerStatus> servers = new List<ServerStatus>(_serverStatus.Values);
DateTime now = DateTime.Now;
foreach (var status in servers)
{
// all of failure, latency, (lastread - lastwrite) normalized to 1000, then
// 100 * failure - 2 * latency - 0.5 * (lastread - lastwrite)
status.score =
100 * 1000 * Math.Min(5 * 60, (now - status.lastFailure).TotalSeconds)
-2 * 5 * (Math.Min(2000, status.latency.TotalMilliseconds) / (1 + (now - status.lastTimeDetectLatency).TotalSeconds / 30 / 10) +
-0.5 * 200 * Math.Min(5, (status.lastRead - status.lastWrite).TotalSeconds));
Logging.Debug(String.Format("server: {0} latency:{1} score: {2}", status.server.FriendlyName(), status.latency, status.score));
}
ServerStatus max = null;
foreach (var status in servers)
{
if (max == null)
{
max = status;
}
else
{
if (status.score >= max.score)
{
max = status;
}
}
}
if (max != null)
{
_currentServer = max.server;
if (_currentServer != oldServer)
{
Console.WriteLine("HA switching to server: {0}", _currentServer.FriendlyName());
}
Logging.Debug(String.Format("choosing server: {0}", _currentServer.FriendlyName()));
}
}
