Should await result of requestcontext.sendresult in case it errors (#520)

- Refactored to use pattern where we wait on the binding queue action to complete, then send the result / error outside of that.

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.cs

@@ -2405,6 +2405,14 @@ namespace Microsoft.SqlTools.ServiceLayer
             }
         }
 
+        public static string ScriptingUnexpectedError
+        {
+            get
+            {
+                return Keys.GetString(Keys.ScriptingUnexpectedError);
+            }
+        }
+
         public static string unavailable
         {
             get
@@ -4600,6 +4608,9 @@ namespace Microsoft.SqlTools.ServiceLayer
             public const string ScriptingListObjectsCompleteParams_ConnectionString_Property_Invalid = "ScriptingListObjectsCompleteParams_ConnectionString_Property_Invalid";
 
 
+            public const string ScriptingUnexpectedError = "ScriptingUnexpectedError";
+
+
             public const string unavailable = "unavailable";
 
 

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.resx

@@ -1380,6 +1380,10 @@
     <value>Error parsing ScriptingListObjectsCompleteParams.ConnectionString property.</value>
     <comment></comment>
   </data>
+  <data name="ScriptingUnexpectedError" xml:space="preserve">
+    <value>Unexpected error while scripting: no result returned from script operation.</value>
+    <comment></comment>
+  </data>
   <data name="unavailable" xml:space="preserve">
     <value>Unavailable</value>
     <comment></comment>

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.strings

@@ -690,6 +690,8 @@ ScriptingParams_FilePath_Property_Invalid = Invalid directory specified by the S
 
 ScriptingListObjectsCompleteParams_ConnectionString_Property_Invalid = Error parsing ScriptingListObjectsCompleteParams.ConnectionString property.
 
+ScriptingUnexpectedError = Unexpected error while scripting: no result returned from script operation.
+
 
 
 

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.xlf

@@ -2311,6 +2311,11 @@
         <note>.
  Parameters: 0 - value (string), 1 - columnType (string) </note>
       </trans-unit>
+      <trans-unit id="ScriptingUnexpectedError">
+        <source>Unexpected error while scripting: no result returned from script operation.</source>
+        <target state="new">Unexpected error while scripting: no result returned from script operation.</target>
+        <note></note>
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.SqlTools.ServiceLayer/Scripting/ScriptingException.cs

@@ -0,0 +1,28 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+
+namespace Microsoft.SqlTools.ServiceLayer.Scripting
+{
+    public class ScriptingException : Exception
+    {
+        public ScriptingException()
+            : base()
+        {
+        }
+
+        public ScriptingException(string message, Exception exception)
+            : base(message, exception)
+        {
+        }
+
+
+        public ScriptingException(string message)
+            : base(message)
+        {
+        }
+    }
+}

src/Microsoft.SqlTools.ServiceLayer/Scripting/ScriptingService.cs

@@ -23,6 +23,7 @@ using Microsoft.SqlServer.Management.Smo;
 using Microsoft.SqlServer.Management.Common;
 using Microsoft.SqlServer.Management.Sdk.Sfc;
 using Microsoft.SqlTools.ServiceLayer.Utility;
+using Microsoft.SqlTools.ServiceLayer.LanguageServices;
 
 namespace Microsoft.SqlTools.ServiceLayer.Scripting
 {
@@ -228,15 +229,49 @@ namespace Microsoft.SqlTools.ServiceLayer.Scripting
         /// </summary>
         private void RunSelectTask(ConnectionInfo connInfo, ScriptingParams parameters, RequestContext<ScriptingResult> requestContext)
         {
-            ConnectionServiceInstance.ConnectionQueue.QueueBindingOperation(
+            Task.Run(() =>
+            {
+                try
+                {
+                    QueueItem queueItem = ConnectionServiceInstance.ConnectionQueue.QueueBindingOperation(
                         key: ConnectionServiceInstance.ConnectionQueue.AddConnectionContext(connInfo, "Scripting"),
                         bindingTimeout: ScriptingOperationTimeout,
                         bindOperation: (bindingContext, cancelToken) =>
                         {
-                    string script = string.Empty;
+                            return DoScriptSelect(connInfo, parameters, bindingContext);
-                    ScriptingObject scriptingObject = parameters.ScriptingObjects[0];
+                        });
+                        
+                    queueItem.ItemProcessed.WaitOne();
+                    var result = queueItem.GetResultAsT<ScriptingResultWithException>();
+                    if (result == null)
+                    {
+                        result = new ScriptingResultWithException()
+                        { 
+                            Exception = new ScriptingException(SR.ScriptingUnexpectedError)
+                        };
+                    }
+                    if (result.Exception == null)
+                    {
+                        requestContext.SendResult(result).Wait();
+                    }
+                    else
+                    {
+                        requestContext.SendError(result.Exception);
+                    }
+                }
+                catch (Exception e)
+                {
+                    requestContext.SendError(e);
+                }
+            }).ContinueWithOnFaulted(null);
+        }
+
+        private ScriptingResult DoScriptSelect(ConnectionInfo connInfo, ScriptingParams parameters, IBindingContext bindingContext)
+        {
             try
             {
+                string script = string.Empty;
+                ScriptingObject scriptingObject = parameters.ScriptingObjects[0];
                 Server server = new Server(bindingContext.ServerConnection);
                 server.DefaultTextMode = true;
 
@@ -267,15 +302,12 @@ namespace Microsoft.SqlTools.ServiceLayer.Scripting
                 }
 
                 // send script result to client
-                        requestContext.SendResult(new ScriptingResult { Script = script });                          
+                return new ScriptingResult { Script = script };                          
             }
             catch (Exception e)
             {
-                        requestContext.SendError(e);
+                return new ScriptingResultWithException() { Exception = e};
             }
-
-                    return null;
-                });
         }
 
         /// <summary>
@@ -317,5 +349,10 @@ namespace Microsoft.SqlTools.ServiceLayer.Scripting
                 }
             }
         }
+
+        internal class ScriptingResultWithException : ScriptingResult
+        {
+            public Exception Exception { get; set; }
+        }
     }
 }