add speculative more detailed logging of socket exceptions

Author: Paul D'Ambra

Serilog.Sinks.Network.Test/LoggingFailureHandlerTest.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Net.Sockets;
+using FluentAssertions;
+using Serilog.Sinks.Network.Sinks.TCP;
+using Xunit;
+
+namespace Serilog.Sinks.Network.Test
+{
+    public class LoggingFailureHandlerTest
+    {
+        [Fact]
+        public void canHandleAnExceptionWithNoInnerException()
+        {
+            var exception = new Exception("the message");
+            TcpSocketWriter.UnexpectedErrorLogger(
+                exception, 
+                (x, socketError) =>
+                {
+                    x.Should().BeSameAs(exception);
+                    socketError.Should().BeNull();
+                });
+        }
+        
+        [Fact]
+        public void canHandleAnExceptionWithAnInnerException()
+        {
+            var exception = new Exception("the outer", new Exception("the inner"));
+            TcpSocketWriter.UnexpectedErrorLogger(
+                exception, 
+                (x, socketError) =>
+                {
+                    x.Should().BeSameAs(exception);
+                    socketError.Should().BeNull();
+                });
+        }
+        
+        [Fact]
+        public void canHandleASocketExceptionWithNoInnerException()
+        {
+            var exception = new SocketException(997);
+            TcpSocketWriter.UnexpectedErrorLogger(
+                exception, 
+                (x, socketError) =>
+                {
+                    x.Should().BeSameAs(exception);
+                    socketError.Should().Be((SocketError) 997);
+                });
+        }
+        
+        [Fact]
+        public void canHandleASocketExceptionWithAnInnerException()
+        {
+            var exception = new Exception("the outer", new SocketException(10044));
+            TcpSocketWriter.UnexpectedErrorLogger(
+                exception, 
+                (x, socketError) =>
+                {
+                    x.Should().BeSameAs(exception);
+                    socketError.Should().Be((SocketError) 10044);
+                });
+        }
+    }
+}

Serilog.Sinks.Network/Sinks/TCP/TCPSocketWriter.cs

@@ -22,6 +22,7 @@
 using System.Net.Sockets;
 using System.Security.Authentication;
 using System.Text;
+using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -58,9 +59,43 @@ public class TcpSocketWriter : IDisposable
         /// </summary>
         public event Action<Exception> LoggingFailureHandler = ex =>
         {
-            Log.Error(ex, "failure inside TCP socket: {message}", ex.Message);
+            UnexpectedErrorLogger(
+                ex, 
+                (x, socketError) =>
+                {
+                    if (socketError == null)
+                    {
+                        Log.Error(x, "failure inside TCP socket: {message}", x.Message);
+                    }
+                    else
+                    {
+                        Log.Error(
+                            x,
+                            "failure inside TCP socket: {message} - socket error found {socketErrorCode}",
+                            x.Message,
+                            socketError);
+                    }
+                    
+                });
         };
 
+        public static void UnexpectedErrorLogger(Exception ex, Action<Exception, SocketError?> log)
+        {
+            SocketError? socketErrorCode = null;
+            var current = ex;
+            do
+            {
+                if (current is SocketException)
+                {
+                    socketErrorCode = ((SocketException) current).SocketErrorCode;
+                }
+
+                current = current.InnerException;
+            } while (socketErrorCode == null && current != null);
+
+            log(ex, socketErrorCode);
+        }
+
         /// <summary>
         /// Construct a TCP _socket writer that writes to the given endPoint and _port.
         /// </summary>

rakefile.rb

@@ -1,4 +1,4 @@
-semver = '2.0.1'
+semver = '2.0.2'
 
 BUILD_CONFIG = ENV['Configuration'] || 'Release'
 BUILD_NUMBER = ENV['APPVEYOR_BUILD_NUMBER'] || '0'