SignlaR不使用負載平衡

Question

我們已經有一個帶信號器集線器的服務器，客戶端使用signalr連接。 我們最近使用負載均衡器將其移動到兩個節點以實現可伸縮性。 但在將其移至負載均衡器后，客戶端無法使用signalr連接到服務器。 客戶端首先嘗試使用Web套接字，它會在信號器跟蹤上出現以下錯誤。

   fae26beb-a806-4957-b52a-39b80856e492 - Auto: Failed to connect to using transport webSockets. System.Net.WebSockets.WebSocketException (0x80004005): Unable to connect to the remote server ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
   at System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult)
   at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
   --- End of inner exception stack trace ---
   at System.Net.Security._SslStream.EndRead(IAsyncResult asyncResult)
   at System.Net.TlsStream.EndRead(IAsyncResult asyncResult)
   at System.Net.PooledStream.EndRead(IAsyncResult asyncResult)
   at System.Net.Connection.ReadCallback(IAsyncResult asyncResult)
   --- End of inner exception stack trace ---
   at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.WebSockets.ClientWebSocket.<ConnectAsyncCore>d__21.MoveNext()
   at System.Net.WebSockets.ClientWebSocket.<ConnectAsyncCore>d__21.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNet.SignalR.Client.Transports.WebSocketTransport.<PerformConnect>d__1.MoveNext()

但經過幾次嘗試連接后，它設法使用SSE（服務器發送事件）進行連接。

   fae26beb-a806-4957-b52a-39b80856e492 - SSE: OnMessage(Data: {"C":"s-0,BA9F","S":1,"M":[]})  
   fae26beb-a806-4957-b52a-39b80856e492 - ChangeState(Connecting, Connected)
   fae26beb-a806-4957-b52a-39b80856e492 - SSE: OnMessage(Data: {"C":"s-0,BAA0","M":[{"H":"PrintConnectorHub","M":"SignalRConnectedSuccessfully","A":[true]}]})  
   fae26beb-a806-4957-b52a-39b80856e492 - OnMessage({"R":false,"I":"3"}) 

但是，當服務器嘗試將消息發送回客戶端時，客戶端不會收到該消息。 我們已經使用SQL Server實現了SignalR擴展，以下是服務器中的日志跟蹤。

TRACE  SignalR.SqlMessageBus  Stream 0 : SqlReceiver last payload ID=47781, new payload ID=47782 (Microsoft.AspNet.SignalR.SqlServer.SqlReceiver.ProcessRecord) 
TRACE  SignalR.SqlMessageBus  Stream 0 : Updated receive reader initial payload ID parameter=47782 (Microsoft.AspNet.SignalR.SqlServer.SqlReceiver.ProcessRecord) 
TRACE  SignalR.SqlMessageBus  Stream 0 : Payload 47782 containing 1 message(s) received (Microsoft.AspNet.SignalR.SqlServer.SqlReceiver.ProcessRecord) 
TRACE  SignalR.SqlMessageBus  Stream 0 : 1 records received (Microsoft.AspNet.SignalR.SqlServer.ObservableDbOperation.ExecuteReaderWithUpdates) 
TRACE  SignalR.SqlMessageBus  Created DbCommand: CommandType=Text, CommandText=SELECT [PayloadId], [Payload], [InsertedOn] FROM [SignalR].[Messages_0] WHERE [PayloadId] > @PayloadId, Parameters= [Name=PayloadId, Value=47782] (Microsoft.AspNet.SignalR.SqlServer.DbOperation.TraceCommand)

客戶端中的信號器初始化

signalrHostUrl = "SignalR_Host"; 

try
{
    hubConnection = new HubConnection(signalrHostUrl);
    hubConnection.Error += ex =>
    {
        signalRlogger.Error(ex, "Exception from hubConnection");
    };

    hubConnection.ConnectionSlow += () => ConnectionSlow();
    hubConnection.Closed += () => SignalrConnectionConnectionClosed();
    hubConnection.StateChanged += signalRConnectionStateController.StateChanged;

    hubConnection.Start().Wait();
}
catch (Exception ex)
{
    signalRlogger.Error(ex, "initialzing hub connection");
}

在轉移到負載均衡器之前，客戶端完全能夠通過Web套接字進行連接並進行通信。 但在轉移到負載均衡器后，它完全無法通過網絡套接字連接。 我們甚至嘗試使用此工具（ https://chrome.google.com/webstore/detail/simple-websocket-client/pfdhoblngboilpfeibdedpjgfnlcodoo?hl=en ）打開網絡套接字連接，該工具也無法打開連接。 雖然它設法通過SSE連接，但它仍然無法與客戶端通信。 在負載均衡中使用Web套接字時出現的復雜情況是什么？在這種情況下，為什么signalr無法與客戶端建立連接？

Answer 1

當另一台機器嘗試解密您在協商連接時獲得的連接令牌時，它無法解決，並且請求失敗。 您需要確保您使用的所有計算機都具有相同的計算機密鑰。 這樣，所有機器都能夠解密由其他機器創建的connectionTokens。

您是否能夠在負載平衡器上啟用粘性？ 例如基於會話的粘性。 這將確保客戶端連接到同一台計算機。 缺點是如果機器出現故障，客戶端將無法重新連接。