More error handling in HandleShadowCopy when creating the shadow copy directory fails

Author: absurdlylongusername

src/Servers/IIS/AspNetCoreModuleV2/AspNetCore/applicationinfo.cpp

@@ -331,14 +331,23 @@ APPLICATION_INFO::HandleShadowCopy(const ShimOptions& options, IHttpContext& pHt
     auto shadowCopyBaseDirectory = std::filesystem::directory_entry(shadowCopyPath);
     if (!shadowCopyBaseDirectory.exists())
     {
-        LOG_INFOF(L"Attempting to Create Directory");
-
         auto ret = CreateDirectory(shadowCopyBaseDirectory.path().wstring().c_str(), nullptr);
         if (!ret)
         {
-            LOG_ERRORF(L"Failed to create shadow copy base directory %ls. Error: %d",
-                        shadowCopyBaseDirectory.path().c_str(),
-                        GetLastError());
+            auto pathString = to_multi_byte_string(shadowCopyBaseDirectory.path(), CP_UTF8);
+            auto errorCode = std::error_code(GetLastError(), std::system_category());
+            std::string errorMessage = format("Failed to create shadow copy base directory %s. Error: %s",
+                                              pathString.c_str(),
+                                              errorCode.message().c_str());
+
+            // TODO: Better substatus code
+            error.statusCode = 500i16;
+            error.subStatusCode = 30i16;
+            error.generalErrorType = format("ASP.NET Core app failed to start - Failed to copy to shadow copy directory");
+            error.errorReason = format("Ensure the application pool process model has write permissions for the shadow copy base directory %s",
+                                       pathString.c_str());
+            error.detailedErrorContent = errorMessage;
+            return std::wstring();
         }
     }
 
@@ -373,7 +382,7 @@ APPLICATION_INFO::HandleShadowCopy(const ShimOptions& options, IHttpContext& pHt
     // It could expand to a network drive, or an expanded link folder path
     // We already made it an absolute path relative to the physicalPath above
     try {
-        // CopyToDirectory throws exception on failure, therefore don't need to check return value
+        // CopyToDirectory will succeed or throw exception, so return value can be ignored
         Environment::CopyToDirectory(physicalPath, shadowCopyPath, options.QueryCleanShadowCopyDirectory(), shadowCopyBaseDirectory.path(), copiedFileCount);
     }
     catch (const std::system_error& ex)

src/Servers/IIS/IIS/test/IIS.ShadowCopy.Tests/ShadowCopyTests.cs

@@ -43,7 +43,8 @@ public async Task ShadowCopy_FailsWithUsefulExceptionMessage_WhenNoPermissionsTo
         Assert.Contains(shadowCopyDirectory.DirectoryPath, content, StringComparison.InvariantCultureIgnoreCase);
 
         shadowCopyDirectory.RestoreAllPermissions();
-        Assert.True(IsDirectoryEmpty(shadowCopyDirectory.DirectoryPath), "Expected shadow copy shadowCopyDirectory to be empty");
+        // If failed to copy then the shadowCopyDirectory should be empty
+        Assert.True(IsDirectoryEmpty(shadowCopyDirectory.DirectoryPath), "Expected shadow copy directory to be empty");
     }
 
     [ConditionalFact]
@@ -73,7 +74,7 @@ public async Task ShadowCopy_FailsWithUsefulExceptionMessage_WhenNoWritePermissi
 
         shadowCopyDirectory.RestoreAllPermissions();
         // If failed to copy then the shadowCopyDirectory should be empty
-        Assert.True(IsDirectoryEmpty(shadowCopyDirectory.DirectoryPath), "Expected shadow copy shadowCopyDirectory to be empty");
+        Assert.True(IsDirectoryEmpty(shadowCopyDirectory.DirectoryPath), "Expected shadow copy directory to be empty");
     }
 
     [ConditionalFact]
@@ -241,7 +242,7 @@ public async Task ShadowCopyDeleteFolderDuringShutdownWorks()
         // Act
 
         // Delete folder + file after app is shut down
-        // Testing specific path on startup where we compare the app shadowCopyDirectory contents with the shadow copy shadowCopyDirectory
+        // Testing specific path on startup where we compare the app directory contents with the shadow copy directory
         Directory.Delete(deleteDirPath, recursive: true);
 
         RemoveAppOffline(deploymentResult.ContentRoot);
@@ -313,18 +314,18 @@ public async Task ShadowCopyE2EWorksWithOldFoldersPresent()
 
         // Act & Assert
         response = await deploymentResult.HttpClient.GetAsync("Wow!");
-        Assert.False(Directory.Exists(Path.Combine(directory.DirectoryPath, "0")), "Expected 0 shadow copy shadowCopyDirectory to be skipped");
+        Assert.False(Directory.Exists(Path.Combine(directory.DirectoryPath, "0")), "Expected 0 shadow copy directory to be skipped");
 
         // Depending on timing, this could result in a shutdown failure, but sometimes it succeeds, handle both situations
         if (!response.IsSuccessStatusCode)
         {
             Assert.True(response.ReasonPhrase == "Application Shutting Down" || response.ReasonPhrase == "Server has been shutdown");
         }
 
-        // This shutdown should trigger a copy to the next highest shadowCopyDirectory, which will be 2
+        // This shutdown should trigger a copy to the next highest directory, which will be 2
         await deploymentResult.AssertRecycledAsync();
 
-        Assert.True(Directory.Exists(Path.Combine(directory.DirectoryPath, "2")), "Expected 2 shadow copy shadowCopyDirectory");
+        Assert.True(Directory.Exists(Path.Combine(directory.DirectoryPath, "2")), "Expected 2 shadow copy directory to exist");
 
         // Act & Assert
         response = await deploymentResult.HttpClient.GetAsync("Wow!");
@@ -360,26 +361,26 @@ public async Task ShadowCopyCleansUpOlderFolders()
 
         // Act & Assert
         response = await deploymentResult.HttpClient.GetAsync("Wow!");
-        Assert.False(Directory.Exists(Path.Combine(shadowCopyDirectory.DirectoryPath, "0")), "Expected 0 shadow copy shadowCopyDirectory to be skipped");
+        Assert.False(Directory.Exists(Path.Combine(shadowCopyDirectory.DirectoryPath, "0")), "Expected 0 shadow copy directory to be skipped");
 
         // Depending on timing, this could result in a shutdown failure, but sometimes it succeeds, handle both situations
         if (!response.IsSuccessStatusCode)
         {
             Assert.True(response.ReasonPhrase == "Application Shutting Down" || response.ReasonPhrase == "Server has been shutdown");
         }
 
-        // This shutdown should trigger a copy to the next highest shadowCopyDirectory, which will be 11
+        // This shutdown should trigger a copy to the next highest directory, which will be 11
         await deploymentResult.AssertRecycledAsync();
 
-        Assert.True(Directory.Exists(Path.Combine(shadowCopyDirectory.DirectoryPath, "11")), "Expected 11 shadow copy shadowCopyDirectory");
+        Assert.True(Directory.Exists(Path.Combine(shadowCopyDirectory.DirectoryPath, "11")), "Expected 11 shadow copy directory");
 
         // Act & Assert
         response = await deploymentResult.HttpClient.GetAsync("Wow!");
         Assert.True(response.IsSuccessStatusCode);
 
         // Verify old directories were cleaned up
-        Assert.False(Directory.Exists(Path.Combine(shadowCopyDirectory.DirectoryPath, "1")), "Expected 1 shadow copy shadowCopyDirectory to be deleted");
-        Assert.False(Directory.Exists(Path.Combine(shadowCopyDirectory.DirectoryPath, "3")), "Expected 3 shadow copy shadowCopyDirectory to be deleted");
+        Assert.False(Directory.Exists(Path.Combine(shadowCopyDirectory.DirectoryPath, "1")), "Expected 1 shadow copy directory to be deleted");
+        Assert.False(Directory.Exists(Path.Combine(shadowCopyDirectory.DirectoryPath, "3")), "Expected 3 shadow copy directory to be deleted");
     }
 
     [ConditionalFact]
@@ -539,7 +540,7 @@ private void RestoreAllPermissionsInner()
 
             if (res != 0)
             {
-                Logger.LogError("Failed to restore permissions for shadowCopyDirectory {DirectoryPath}. Takeown result: {TakeownResult}", DirectoryPath, res);
+                Logger.LogError("Failed to restore permissions for directory {DirectoryPath}. Takeown result: {TakeownResult}", DirectoryPath, res);
             }
         }
 
@@ -608,30 +609,30 @@ private static void DeleteDirectory(string directoryPath)
             }
             catch (Exception e)
             {
-                Console.WriteLine($@"Failed to delete shadowCopyDirectory {directoryPath}: {e.Message}");
+                Console.WriteLine($@"Failed to delete directory {directoryPath}: {e.Message}");
             }
         }
     }
 
     // copied from https://learn.microsoft.com/dotnet/standard/io/how-to-copy-directories
     private static void DirectoryCopy(string sourceDirName, string destDirName, bool copySubDirs, string ignoreDirectory = "")
     {
-        // Get the subdirectories for the specified shadowCopyDirectory.
+        // Get the subdirectories for the specified directory.
         DirectoryInfo dir = new DirectoryInfo(sourceDirName);
 
         if (!dir.Exists)
         {
             throw new DirectoryNotFoundException(
-                "Source shadowCopyDirectory does not exist or could not be found: "
+                "Source directory does not exist or could not be found: "
                 + sourceDirName);
         }
 
         DirectoryInfo[] dirs = dir.GetDirectories();
 
-        // If the destination shadowCopyDirectory doesn't exist, create it.
+        // If the destination directory doesn't exist, create it.
         Directory.CreateDirectory(destDirName);
 
-        // Get the files in the shadowCopyDirectory and copy them to the new location.
+        // Get the files in the directory and copy them to the new location.
         FileInfo[] files = dir.GetFiles();
         foreach (FileInfo file in files)
         {