Fix | Fixing issue for SQL named Instances in Managed SNI using named pipes. (#2142)

Author: arellegue

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SNI/SNINpHandle.cs

@@ -68,7 +68,7 @@ public SNINpHandle(string serverName, string pipeName, TimeoutTimer timeout, boo
                     {
                         int timeoutMilliseconds = timeout.MillisecondsRemainingInt;
                         SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNINpHandle), EventType.INFO,
-                                                                  "Connection Id {0}, Setting server name = {1}, pipe name = {2}. Connecting within the {3} sepecified milliseconds.",
+                                                                  "Connection Id {0}, Setting server name = {1}, pipe name = {2}. Connecting within the {3} specified milliseconds.",
                                                                   args0: _connectionId,
                                                                   args1: serverName,
                                                                   args2: pipeName,

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SNI/SNIProxy.cs

@@ -418,6 +418,8 @@ internal class DataSource
         private const string LocalDbHost_NP = @"np:\\.\pipe\LOCALDB#";
         private const string NamedPipeInstanceNameHeader = "mssql$";
         private const string DefaultPipeName = "sql\\query";
+        private const string InstancePrefix = "MSSQL$";
+        private const string PathSeparator = "\\";
 
         internal enum Protocol { TCP, NP, None, Admin };
 
@@ -683,12 +685,35 @@ private bool InferNamedPipesInformation()
             // If we have a datasource beginning with a pipe or we have already determined that the protocol is Named Pipe
             if (_dataSourceAfterTrimmingProtocol.StartsWith(PipeBeginning, StringComparison.Ordinal) || _connectionProtocol == Protocol.NP)
             {
-                // If the data source is "np:servername"
+                // If the data source starts with "np:servername"
                 if (!_dataSourceAfterTrimmingProtocol.Contains(PipeBeginning))
                 {
-                    PipeHostName = ServerName = _dataSourceAfterTrimmingProtocol;
+                    // Assuming that user did not change default NamedPipe name, if the datasource is in the format servername\instance, 
+                    // separate servername and instance and prepend instance with MSSQL$ and append default pipe path 
+                    // https://learn.microsoft.com/en-us/sql/tools/configuration-manager/named-pipes-properties?view=sql-server-ver16
+                    if (_dataSourceAfterTrimmingProtocol.Contains(PathSeparator) && _connectionProtocol == Protocol.NP)
+                    {
+                        string[] tokensByBackSlash = _dataSourceAfterTrimmingProtocol.Split(BackSlashCharacter);
+                        if (tokensByBackSlash.Length == 2)
+                        {
+                            // NamedPipeClientStream object will create the network path using PipeHostName and PipeName
+                            // and can be seen in its _normalizedPipePath variable in the format \\servername\pipe\MSSQL$<instancename>\sql\query
+                            PipeHostName = ServerName = tokensByBackSlash[0];
+                            PipeName = $"{InstancePrefix}{tokensByBackSlash[1]}{PathSeparator}{DefaultPipeName}";
+                        }
+                        else
+                        {
+                            ReportSNIError(SNIProviders.NP_PROV);
+                            return false;
+                        }
+                    }
+                    else
+                    {
+                        PipeHostName = ServerName = _dataSourceAfterTrimmingProtocol;
+                        PipeName = SNINpHandle.DefaultPipePath;
+                    }
+
                     InferLocalServerName();
-                    PipeName = SNINpHandle.DefaultPipePath;
                     return true;
                 }
 

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/InstanceNameTest/InstanceNameTest.cs

@@ -76,7 +76,7 @@ public static void ConnectManagedWithInstanceNameTest(bool useMultiSubnetFailove
             if (!IsValidInstance(hostname, instanceName))
             {
                 builder.DataSource = hostname + "\\" + instanceName;
-                
+
                 using SqlConnection connection = new(builder.ConnectionString);
                 SqlException ex = Assert.Throws<SqlException>(() => connection.Open());
                 Assert.Contains("Error Locating Server/Instance Specified", ex.Message);

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/SqlCredentialTest/SqlCredentialTest.cs

@@ -12,7 +12,6 @@ namespace Microsoft.Data.SqlClient.ManualTesting.Tests
 {
     public static class SqlCredentialTest
     {
-
         [ConditionalFact(typeof(DataTestUtility), nameof(DataTestUtility.AreConnStringsSetup), nameof(DataTestUtility.IsNotAzureServer))]
         public static void CreateSqlConnectionWithCredential()
         {