rebuild corrupt search index (#770)

CHANGELOG.md

@@ -9,6 +9,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fix health check crash when trash contains a show or a season
 - Fix ability of health check crash to crash home page
 - Remove and ignore Season 0/Specials from Plex shows that have no specials
+- Automatically delete and rebuild the search index on startup if it has become corrupt
 
 ### Changed
 - Update Plex, Jellyfin and Emby movie and show library scanners to share a significant amount of code

ErsatzTV.Application/Search/Commands/RebuildSearchIndexHandler.cs

@@ -35,7 +35,7 @@ public class RebuildSearchIndexHandler : IRequestHandler<RebuildSearchIndex, Uni
     {
         bool indexFolderExists = Directory.Exists(FileSystemLayout.SearchIndexFolder);
 
-        await _searchIndex.Initialize(_localFileSystem);
+        await _searchIndex.Initialize(_localFileSystem, _configElementRepository);
 
         if (!indexFolderExists ||
             await _configElementRepository.GetValue<int>(ConfigElementKey.SearchIndexVersion) <

ErsatzTV.Core/Interfaces/Search/ISearchIndex.cs

@@ -8,7 +8,7 @@ namespace ErsatzTV.Core.Interfaces.Search;
 public interface ISearchIndex : IDisposable
 {
     public int Version { get; }
-    Task<bool> Initialize(ILocalFileSystem localFileSystem);
+    Task<bool> Initialize(ILocalFileSystem localFileSystem, IConfigElementRepository configElementRepository);
     Task<Unit> Rebuild(ISearchRepository searchRepository);
     Task<Unit> RebuildItems(ISearchRepository searchRepository, List<int> itemIds);
     Task<Unit> UpdateItems(ISearchRepository searchRepository, List<MediaItem> items);

ErsatzTV.Infrastructure/Search/SearchIndex.cs

@@ -18,6 +18,7 @@ using Lucene.Net.Search;
 using Lucene.Net.Store;
 using Lucene.Net.Util;
 using Microsoft.Extensions.Logging;
+using Directory = System.IO.Directory;
 using Query = Lucene.Net.Search.Query;
 
 namespace ErsatzTV.Infrastructure.Search;
@@ -86,12 +87,22 @@ public sealed class SearchIndex : ISearchIndex
 
     public int Version => 22;
 
-    public Task<bool> Initialize(ILocalFileSystem localFileSystem)
+    public async Task<bool> Initialize(
+        ILocalFileSystem localFileSystem,
+        IConfigElementRepository configElementRepository)
     {
         if (!_initialized)
         {
             localFileSystem.EnsureFolderExists(FileSystemLayout.SearchIndexFolder);
 
+            if (!ValidateDirectory(FileSystemLayout.SearchIndexFolder))
+            {
+                _logger.LogWarning("Search index failed to initialize; will delete and recreate");
+                await configElementRepository.Upsert(ConfigElementKey.SearchIndexVersion, 0);
+                Directory.Delete(FileSystemLayout.SearchIndexFolder, true);
+                localFileSystem.EnsureFolderExists(FileSystemLayout.SearchIndexFolder);
+            }
+
             _directory = FSDirectory.Open(FileSystemLayout.SearchIndexFolder);
             var analyzer = new StandardAnalyzer(AppLuceneVersion);
             var indexConfig = new IndexWriterConfig(AppLuceneVersion, analyzer)
@@ -100,7 +111,7 @@ public sealed class SearchIndex : ISearchIndex
             _initialized = true;
         }
 
-        return Task.FromResult(_initialized);
+        return _initialized;
     }
 
     public async Task<Unit> UpdateItems(ISearchRepository searchRepository, List<MediaItem> items)
@@ -228,6 +239,24 @@ public sealed class SearchIndex : ISearchIndex
         return Unit.Default;
     }
 
+    private bool ValidateDirectory(string folder)
+    {
+        try
+        {
+            using var d = FSDirectory.Open(folder);
+            var analyzer = new StandardAnalyzer(AppLuceneVersion);
+            var indexConfig = new IndexWriterConfig(AppLuceneVersion, analyzer)
+                { OpenMode = OpenMode.CREATE_OR_APPEND };
+            using var w = new IndexWriter(_directory, indexConfig);
+            using DirectoryReader r = w.GetReader(true);
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
     private async Task RebuildItem(ISearchRepository searchRepository, MediaItem mediaItem)
     {
         switch (mediaItem)