Random Changes and Enhancements (#1819)

* When skipping over folders in a scan, inform the ui

* Try out new backout condition for library watcher.

* Tweaked the code for folder watching to be more intense on killing if stuck in inotify loop.

* Streamlined my implementation of enhanced LibraryWatcher

* Added new extension method to make complex where statements cleaner.

* Added an implementation to flatten series and not show them if they have relationships defined. Only the parent would show. Currently disabled until i figure out how to apply it.

* Added the ability to collapse series that are not the primary entry point to reading. Configurable in library settings, only applies when all libraries in a filter have the property to true.

* Exclude from parsing .@_thumb directories, a QNAP system folder.

Show number of items a JumpKey has

* Refactored some time reading to display in days, months, years or minutes.

API/Services/Tasks/Scanner/LibraryWatcher.cs

@@ -5,6 +5,7 @@ using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
 using API.Data;
+using API.Entities.Enums;
 using Hangfire;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
@@ -55,6 +56,8 @@ public class LibraryWatcher : ILibraryWatcher
     /// Counts within a time frame how many times the buffer became full. Is used to reschedule LibraryWatcher to start monitoring much later rather than instantly
     /// </summary>
     private int _bufferFullCounter;
+    private int _restartCounter;
+    private DateTime _lastErrorTime = DateTime.MinValue;
     /// <summary>
     /// Used to lock buffer Full Counter
     /// </summary>
@@ -180,12 +183,21 @@ public class LibraryWatcher : ILibraryWatcher
         lock (Lock)
         {
             _bufferFullCounter += 1;
-            condition = _bufferFullCounter >= 3;
+            _lastErrorTime = DateTime.Now;
+            condition = _bufferFullCounter >= 3 && (DateTime.Now - _lastErrorTime).TotalMinutes <= 10;
+        }
+
+        if (_restartCounter >= 3)
+        {
+            _logger.LogInformation("[LibraryWatcher] Too many restarts occured, you either have limited inotify or an OS constraint. Kavita will turn off folder watching to prevent high utilization of resources");
+            Task.Run(TurnOffWatching);
+            return;
         }
 
         if (condition)
         {
-            _logger.LogInformation("[LibraryWatcher] Internal buffer has been overflown multiple times in past 10 minutes. Suspending file watching for an hour");
+            _logger.LogInformation("[LibraryWatcher] Internal buffer has been overflown multiple times in past 10 minutes. Suspending file watching for an hour. Restart count: {RestartCount}", _restartCounter);
+            _restartCounter++;
             StopWatching();
             BackgroundJob.Schedule(() => RestartWatching(), TimeSpan.FromHours(1));
             return;
@@ -194,6 +206,16 @@ public class LibraryWatcher : ILibraryWatcher
         BackgroundJob.Schedule(() => UpdateLastBufferOverflow(), TimeSpan.FromMinutes(10));
     }
 
+    private async Task TurnOffWatching()
+    {
+        var setting = await _unitOfWork.SettingsRepository.GetSettingAsync(ServerSettingKey.EnableFolderWatching);
+        setting.Value = "false";
+        _unitOfWork.SettingsRepository.Update(setting);
+        await _unitOfWork.CommitAsync();
+        StopWatching();
+        _logger.LogInformation("[LibraryWatcher] Folder watching has been disabled");
+    }
+
 
     /// <summary>
     /// Processes the file or folder change. If the change is a file change and not from a supported extension, it will be ignored.

API/Services/Tasks/Scanner/ParseScannedFiles.cs

@@ -289,6 +289,8 @@ public class ParseScannedFiles
                 }).ToList();
                 await processSeriesInfos.Invoke(new Tuple<bool, IList<ParserInfo>>(true, parsedInfos));
                 _logger.LogDebug("[ScannerService] Skipped File Scan for {Folder} as it hasn't changed since last scan", folder);
+                await _eventHub.SendMessageAsync(MessageFactory.NotificationProgress,
+                    MessageFactory.FileScanProgressEvent("Skipped " + normalizedFolder, libraryName, ProgressEventType.Updated));
                 return;
             }