TCPListener的辅助角色停止工作

Question

I have this very basic worker role running, listening to a incoming TCP connections and processing them. But for some reason now fails after a while.. seems like it is no longer receiving data... no exception seen in the trace. Now make it synchronous... still the same problem.

The idea is to accept an HTTP request and give a 302 redirection.

When I connect to it via a telnet on port 80 it works.

As soon as I use a browser, it starts failing quickly.

When I try again afterwards on port 80, no response anymore.

public class WorkerRole : RoleEntryPoint
{
    public override void Run()
    {
        TcpListener server = null;
        IPEndPoint ipin = RoleEnvironment.CurrentRoleInstance.InstanceEndpoints["Server"].IPEndpoint;
        server = new TcpListener(ipin);
        server.ExclusiveAddressUse = false;
        server.Start();

        try
        {
            while (true)
            {
                TcpClient client = server.AcceptTcpClient();
                HandleSyncConnection(client);
            }
        }
        catch (Exception ex)
        {
            Trace.WriteLine("Server stopped. Exception:" + ex.Message);
            return;
        }
    }
    private void HandleSyncConnection(TcpClient client)
    {
        try
        {
            // Setup reader/writer 
            NetworkStream netStream = client.GetStream();
            StreamReader reader = new StreamReader(netStream, Encoding.ASCII);
            StreamWriter writer = new StreamWriter(netStream, Encoding.ASCII);
            writer.AutoFlush = true;

            byte[] baBuffer = new byte[10000];
            byte[] baHeader = { 13, 10, 13, 10 };
            Int32 iTotalBytesReceived = 0;
            Int32 iHeaderFound = 0;

            while (iTotalBytesReceived < baBuffer.Length)
            {
              Int32 iBytesReceived = netStream.Read(baBuffer, iTotalBytesReceived, baBuffer.Length - iTotalBytesReceived);
              if (iBytesReceived == 0)
                   break;
              for (int i = 0; i < iBytesReceived; i++)
              {
                  if (baBuffer[iTotalBytesReceived + i] == baHeader[iHeaderFound])
                        iHeaderFound++;
                  else
                      iHeaderFound = 0;
              }
              iTotalBytesReceived += iBytesReceived;
              if (iHeaderFound == baHeader.Length)
                 break;
              Thread.Sleep(50);
            }

            String strResponse;
            Trace.TraceInformation("Request received");
            strResponse = "HTTP/1.1 302 Redirect" + EOL + "Location: http://www.google.com");
            strResponse += EOL + "Content-Type: text/html" + EOL + "Cache-Control: no-cache" + EOL + "Connection: close" + EOL + "Content-Length: 0" + EOL + EOL;
            writer.Write(strResponse);
            writer.Close();
            reader.Close();
            // Done! 
            client.Close();
          }
          catch (Exception e)
          {
            Trace.TraceError("Server stopped in the handling of sync " + e.Message);
          }
    }
    public override bool OnStart()
    {
        return base.OnStart();
    }

Answer 1

I think the problem is not on how your application is implemented.

Have you consider the Azure load balance timeout?

Here is a good blog post detailing it:

Windows Azure Load Balancer Timeout Details

Azure will stop your application after a minute or so independent of your implementation.

Take a look at that and see if that is problem that you are facing.

Regards