Better capture error scenarios in TCP managed SNI.

Fix logging bug in SqlClientEventSource.

Author: David-Engel

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ManagedSni/SniTcpHandle.netcore.cs

@@ -444,10 +444,24 @@ private static Socket Connect(string serverName, int port, TimeoutTimer timeout,
 
                                 Socket.Select(checkReadLst, checkWriteLst, checkErrorLst, socketSelectTimeout);
                                 // nothing selected means timeout
+                                SqlClientEventSource.Log.TrySNITraceEvent(nameof(SniTcpHandle), EventType.INFO,
+                                    "Socket.Select results: checkReadLst.Count: {0}, checkWriteLst.Count: {1}, checkErrorLst.Count: {2}",
+                                    checkReadLst.Count, checkWriteLst.Count, checkErrorLst.Count);
                             } while (checkReadLst.Count == 0 && checkWriteLst.Count == 0 && checkErrorLst.Count == 0);
 
                             // workaround: false positive socket.Connected on linux: https://github.com/dotnet/runtime/issues/55538
                             isConnected = socket.Connected && checkErrorLst.Count == 0;
+                            if (!isConnected)
+                            {
+                                // Retrieve the socket error code
+                                int socketErrorCode = (int)socket.GetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Error);
+                                SocketError socketError = (SocketError)socketErrorCode;
+
+                                SqlClientEventSource.Log.TrySNITraceEvent(nameof(SniTcpHandle), EventType.ERR,
+                                "Socket connection failed. SocketError: {0} ({1})", socketError, socketErrorCode);
+
+                                lastSocketException = new SocketException(socketErrorCode);
+                            }
                         }
 
                         if (isConnected)
@@ -465,6 +479,8 @@ private static Socket Connect(string serverName, int port, TimeoutTimer timeout,
                             }
                             pendingDNSInfo = new SQLDNSInfo(cachedFQDN, iPv4String, iPv6String, port.ToString());
                             isSocketSelected = true;
+                            SqlClientEventSource.Log.TrySNITraceEvent(nameof(SniTcpHandle), EventType.INFO,
+                                "Connected to socket: {0}", socket.RemoteEndPoint);
                             return socket;
                         }
                     }
@@ -585,6 +601,20 @@ private static Socket ParallelConnect(IPAddress[] serverAddresses, int port, Tim
                             Socket.Select(checkReadLst, checkWriteLst, checkErrorLst, socketSelectTimeout);
                             // nothing selected means select timed out
                         } while (checkReadLst.Count == 0 && checkWriteLst.Count == 0 && checkErrorLst.Count == 0 && !timeout.IsExpired);
+                        foreach (Socket socket in checkErrorLst)
+                        {
+                            // Retrieve the socket error code
+                            int socketErrorCode = (int)socket.GetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Error);
+                            SocketError socketError = (SocketError)socketErrorCode;
+
+                            // Log any failed sockets
+                            SqlClientEventSource.Log.TrySNITraceEvent(nameof(SniTcpHandle), EventType.INFO,
+                            "Socket connection failed for {0}. SocketError: {1} ({2})",
+                            sockets[socket], socketError, socketErrorCode);
+
+                            lastError = new SocketException(socketErrorCode);
+                        }
+
                     }
                     catch (SocketException e)
                     {
@@ -672,8 +702,13 @@ private static Socket ParallelConnect(IPAddress[] serverAddresses, int port, Tim
                     }
 
                     SqlClientEventSource.Log.TryAdvancedTraceEvent(
-                        "{0}.{1}{2}No socket connections succeeded. Last error: {3}",
+                        "{0}.{1}{2} No socket connections succeeded. Last error: {3}",
                         nameof(SniTcpHandle), nameof(ParallelConnect), EventType.ERR, lastError);
+
+                    if (lastError != null)
+                    {
+                        throw lastError;
+                    }
                 }
 
                 return connectedSocket;

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlClientEventSource.cs

@@ -424,7 +424,7 @@ internal long TryScopeEnterEvent(string className, [System.Runtime.CompilerServi
             {
                 StringBuilder sb = new StringBuilder(className);
                 sb.Append(".").Append(memberName).Append(" | INFO | SCOPE | Entering Scope {0}");
-                return SNIScopeEnter(sb.ToString());
+                return ScopeEnter(sb.ToString());
             }
             return 0;
         }