最近搞了下ELK，三个工具部署完毕，想再集成上log4net。没想到.net core版Log4net竟然没有直接Tcp发送消息的appender。醉了。

1.RemotingAppender：core已经不支持。

2.RemoteSysLogAppender：只监听 udp的514端口。【：The BSD syslog protocol is used to remotely log to a syslog daemon. The syslogd listens for for messages on UDP port 514.】

3.UdpAppender：udp协议传输数据

4.TelnetAppender：一开始以为肯定是这个可以用了。官网没有examples。。***翻了config。里面竟然只有port配置没有remotingAddress等（黑人问号）？？？。官网解释这个东西怎么玩的【：The TelnetAppender accepts socket connections and streams logging messages back to the client. The output is provided in a telnet-friendly way so that a log can be monitored over a TCP/IP socket. This allows simple remote monitoring of application logging.】

也就是它是开了一个监听。监听别人给他发的日志数据，然后记录数据然后再发回去。。。What？？？。我要的是你发出去。混蛋。下面去反编译看看他的源码。。

namespace log4net.Appender{  public class TelnetAppender : AppenderSkeleton  {    private static readonly Type declaringType = typeof (TelnetAppender);    private int m_listeningPort = 23;    private TelnetAppender.SocketHandler m_handler;    public int Port    {      get      {        return this.m_listeningPort;      }      set      {        if (value < 0 || value > (int) ushort.MaxValue)          throw SystemInfo.CreateArgumentOutOfRangeException("value", (object) value, "The value specified for Port is less than " + 0.ToString((IFormatProvider) NumberFormatInfo.InvariantInfo) + " or greater than " + ((int) ushort.MaxValue).ToString((IFormatProvider) NumberFormatInfo.InvariantInfo) + ".");        this.m_listeningPort = value;      }    }    protected override bool RequiresLayout    {      get      {        return true;      }    }    protected override void OnClose()    {      base.OnClose();      if (this.m_handler == null)        return;      this.m_handler.Dispose();      this.m_handler = (TelnetAppender.SocketHandler) null;    }    public override void ActivateOptions()    {      base.ActivateOptions();      try      {        LogLog.Debug(TelnetAppender.declaringType, "Creating SocketHandler to listen on port [" + (object) this.m_listeningPort + "]");        this.m_handler = new TelnetAppender.SocketHandler(this.m_listeningPort);      }      catch (Exception ex)      {        LogLog.Error(TelnetAppender.declaringType, "Failed to create SocketHandler", ex);        throw;      }    }    protected override void Append(LoggingEvent loggingEvent)    {      if (this.m_handler == null || !this.m_handler.HasConnections)        return;      this.m_handler.Send(this.RenderLoggingEvent(loggingEvent));    }    protected class SocketHandler : IDisposable    {      private ArrayList m_clients = new ArrayList();      private const int MAX_CONNECTIONS = 20;      private Socket m_serverSocket;      public bool HasConnections      {        get        {          ArrayList clients = this.m_clients;          if (clients != null)            return clients.Count > 0;          return false;        }      }      public SocketHandler(int port)      {        this.m_serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);        this.m_serverSocket.Bind((EndPoint) new IPEndPoint(IPAddress.Any, port));        this.m_serverSocket.Listen(5);        this.AcceptConnection();      }      private void AcceptConnection()      {        this.m_serverSocket.AcceptAsync().ContinueWith(new Action
      
       
        >(this.OnConnect), TaskScheduler.Default);      }      public void Send(string message)      {        foreach (TelnetAppender.SocketHandler.SocketClient client in this.m_clients)        {          try          {            client.Send(message);          }          catch (Exception ex)          {            client.Dispose();            this.RemoveClient(client);          }        }      }      private void AddClient(TelnetAppender.SocketHandler.SocketClient client)      {        TelnetAppender.SocketHandler socketHandler = this;        bool lockTaken = false;        try        {          Monitor.Enter((object) socketHandler, ref lockTaken);          ArrayList arrayList = (ArrayList) this.m_clients.Clone();          arrayList.Add((object) client);          this.m_clients = arrayList;        }        finally        {          if (lockTaken)            Monitor.Exit((object) socketHandler);        }      }      private void RemoveClient(TelnetAppender.SocketHandler.SocketClient client)      {        TelnetAppender.SocketHandler socketHandler = this;        bool lockTaken = false;        try        {          Monitor.Enter((object) socketHandler, ref lockTaken);          ArrayList arrayList = (ArrayList) this.m_clients.Clone();          arrayList.Remove((object) client);          this.m_clients = arrayList;        }        finally        {          if (lockTaken)            Monitor.Exit((object) socketHandler);        }      }      private void OnConnect(Task
        
          acceptTask)      {        try        {          Socket result = acceptTask.GetAwaiter().GetResult();          LogLog.Debug(TelnetAppender.declaringType, "Accepting connection from [" + result.RemoteEndPoint.ToString() + "]");          TelnetAppender.SocketHandler.SocketClient client = new TelnetAppender.SocketHandler.SocketClient(result);          int count = this.m_clients.Count;          if (count < 20)          {            try            {              client.Send("TelnetAppender v1.0 (" + (object) (count + 1) + " active connections)\r\n\r\n");              this.AddClient(client);            }            catch            {              client.Dispose();            }          }          else          {            client.Send("Sorry - Too many connections.\r\n");            client.Dispose();          }        }        catch        {        }        finally        {          if (this.m_serverSocket != null)            this.AcceptConnection();        }      }      public void Dispose()      {        foreach (TelnetAppender.SocketHandler.SocketClient client in this.m_clients)          client.Dispose();        this.m_clients.Clear();        Socket serverSocket = this.m_serverSocket;        this.m_serverSocket = (Socket) null;        try        {          serverSocket.Shutdown(SocketShutdown.Both);        }        catch        {        }        try        {          CompatibilityExtensions.Close(serverSocket);        }        catch        {        }      }      protected class SocketClient : IDisposable      {        private Socket m_socket;        private StreamWriter m_writer;        public SocketClient(Socket socket)        {          this.m_socket = socket;          try          {            this.m_writer = new StreamWriter((Stream) new NetworkStream(socket));          }          catch          {            this.Dispose();            throw;          }        }        public void Send(string message)        {          this.m_writer.Write(message);          this.m_writer.Flush();        }        public void Dispose()        {          try          {            if (this.m_writer != null)            {              CompatibilityExtensions.Close(this.m_writer);              this.m_writer = (StreamWriter) null;            }          }          catch          {          }          if (this.m_socket == null)            return;          try          {            this.m_socket.Shutdown(SocketShutdown.Both);          }          catch          {          }          try          {            CompatibilityExtensions.Close(this.m_socket);          }          catch          {          }          this.m_socket = (Socket) null;        }      }    }  }}
        
       
      

那就没办法。。我自己再重写一个直接发送的TcpAppender吧。。写法是完全看udpAppender源码改的。暴露出来的配置和udp基本一致。把local的去除了

internal class TcpAppender : AppenderSkeleton    {        private Encoding _encoding = Encoding.Unicode;        private IPAddress _remoteAddress;        private int _remotePort;        private IPEndPoint _remoteEndPoint;        private TcpClient _client;        public IPAddress RemoteAddress        {            get            {                return this._remoteAddress;            }            set            {                this._remoteAddress = value;            }        }        public int RemotePort        {            get            {                return this._remotePort;            }            set            {                if (value < 0 || value > (int)ushort.MaxValue)                    throw SystemInfo.CreateArgumentOutOfRangeException("value", (object)value, "The value specified is less than " + 0.ToString((IFormatProvider)NumberFormatInfo.InvariantInfo) + " or greater than " + ((int)ushort.MaxValue).ToString((IFormatProvider)NumberFormatInfo.InvariantInfo) + ".");                this._remotePort = value;            }        }        public Encoding Encoding        {            get            {                return this._encoding;            }            set            {                this._encoding = value;            }        }        protected TcpClient Client        {            get            {                return this._client;            }            set            {                this._client = value;            }        }        protected IPEndPoint RemoteEndPoint        {            get            {                return this._remoteEndPoint;            }            set            {                this._remoteEndPoint = value;            }        }        protected override bool RequiresLayout        {            get            {                return true;            }        }        public override void ActivateOptions()        {            base.ActivateOptions();            if (this.RemoteAddress == null)                throw new ArgumentNullException("The required property 'Address' was not specified.");            if (this.RemotePort < 0 || this.RemotePort > (int)ushort.MaxValue)                throw SystemInfo.CreateArgumentOutOfRangeException("this.RemotePort", (object)this.RemotePort, "The RemotePort is less than " + 0.ToString((IFormatProvider)NumberFormatInfo.InvariantInfo) + " or greater than " + ((int)ushort.MaxValue).ToString((IFormatProvider)NumberFormatInfo.InvariantInfo) + ".");            this.RemoteEndPoint = new IPEndPoint(this.RemoteAddress, this.RemotePort);            this.InitializeClientConnection();        }        protected override void Append(LoggingEvent loggingEvent)        {            try            {                NetworkStream ntwStream = this.Client.GetStream();                var aa = this.RenderLoggingEvent(loggingEvent).ToCharArray();                byte[] bytes = this._encoding.GetBytes(this.RenderLoggingEvent(loggingEvent).ToCharArray());                ntwStream.Write(bytes, 0, bytes.Length);            }            catch (Exception ex)            {                this.ErrorHandler.Error("Unable to send logging event to remote host " + this.RemoteAddress.ToString() + " on port " + (object)this.RemotePort + ".", ex, ErrorCode.WriteFailure);            }        }        protected override void OnClose()        {            base.OnClose();            if (this.Client == null)                return;            Client.Dispose();            this.Client = null;        }        protected virtual void InitializeClientConnection()        {            try            {                this.Client = new TcpClient(this.RemoteAddress.ToString(), this.RemotePort);            }            catch (Exception ex)            {                this.ErrorHandler.Error("Could not initialize the UdpClient connection on port " + this.RemotePort.ToString((IFormatProvider)NumberFormatInfo.InvariantInfo) + ".", ex, ErrorCode.GenericFailure);                this.Client = null;            }        }    }

用法代码。里面额外加入了一个consoleAppender 方便查看调试

1         static void Main(string[] args) 2         { 3             Test(); 4             Console.ReadKey(); 5         } 6  7         private static void Test() 8         { 9             var repo = LogManager.CreateRepository("R");10 11             var layout = new PatternLayout()12             {13                 ConversionPattern = "#%date #%level #%message#",14             };15             var tcpAppender = new TcpAppender16             {17                 Encoding = Encoding.UTF8,18                 RemoteAddress = new IPAddress(new byte[] { 192,168,132,128 }),19                 RemotePort = 8001,20                 Layout = layout21             };22             var consoleAppender = new ConsoleAppender23             {24                 Layout = layout25             };26             layout.ActivateOptions();27             tcpAppender.ActivateOptions();28             BasicConfigurator.Configure(repo, consoleAppender,tcpAppender);29 30             ILog log = LogManager.GetLogger(repo.Name, "Debug");31             log.Info("666666666666666666666");32             Console.ReadKey();33         }

 

下面是成功发送到虚拟机上的kibana的后台显示。部分数据和字段没匹配好是logstash的规则和log4net规则没对应好