reduce hls segmenter disk use (#806)

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
+### Added
+- Clean transcode cache folder on startup and after `HLS Segmenter` session terminates for any reason
 
 ## [0.5.7-beta] - 2022-05-14
 ### Fixed

ErsatzTV.Application/Streaming/HlsSessionWorker.cs

@@ -21,6 +21,7 @@ public class HlsSessionWorker : IHlsSessionWorker
     private static readonly SemaphoreSlim Slim = new(1, 1);
     private static int _workAheadCount;
     private readonly IHlsPlaylistFilter _hlsPlaylistFilter;
+    private readonly ILocalFileSystem _localFileSystem;
     private readonly ILogger<HlsSessionWorker> _logger;
     private readonly IServiceScopeFactory _serviceScopeFactory;
     private readonly object _sync = new();
@@ -34,10 +35,12 @@ public class HlsSessionWorker : IHlsSessionWorker
     public HlsSessionWorker(
         IHlsPlaylistFilter hlsPlaylistFilter,
         IServiceScopeFactory serviceScopeFactory,
+        ILocalFileSystem localFileSystem,
         ILogger<HlsSessionWorker> logger)
     {
         _hlsPlaylistFilter = hlsPlaylistFilter;
         _serviceScopeFactory = serviceScopeFactory;
+        _localFileSystem = localFileSystem;
         _logger = logger;
     }
 
@@ -153,6 +156,15 @@ public class HlsSessionWorker : IHlsSessionWorker
             {
                 _timer.Elapsed -= Cancel;
             }
+
+            try
+            {
+                _localFileSystem.EmptyFolder(Path.Combine(FileSystemLayout.TranscodeFolder, _channelNumber));
+            }
+            catch
+            {
+                // do nothing
+            }
         }
     }
 

ErsatzTV/Services/RunOnce/CacheCleanerService.cs

@@ -23,8 +23,9 @@ public class CacheCleanerService : IHostedService
     {
         using IServiceScope scope = _serviceScopeFactory.CreateScope();
         await using TvContext dbContext = scope.ServiceProvider.GetRequiredService<TvContext>();
+        ILocalFileSystem localFileSystem = scope.ServiceProvider.GetRequiredService<ILocalFileSystem>();
 
-        if (Directory.Exists(FileSystemLayout.LegacyImageCacheFolder))
+        if (localFileSystem.FolderExists(FileSystemLayout.LegacyImageCacheFolder))
         {
             _logger.LogInformation("Migrating channel logos from legacy image cache folder");
 
@@ -34,13 +35,12 @@ public class CacheCleanerService : IHostedService
                 .Map(a => a.Path)
                 .ToListAsync(cancellationToken);
 
-            ILocalFileSystem localFileSystem = scope.ServiceProvider.GetRequiredService<ILocalFileSystem>();
             foreach (string logo in logos)
             {
                 string legacyPath = Path.Combine(FileSystemLayout.LegacyImageCacheFolder, logo);
-                if (File.Exists(legacyPath))
+                if (localFileSystem.FileExists(legacyPath))
                 {
-                    string subfolder = logo.Substring(0, 2);
+                    string subfolder = logo[..2];
                     string newPath = Path.Combine(FileSystemLayout.LogoCacheFolder, subfolder, logo);
                     await localFileSystem.CopyFile(legacyPath, newPath);
                 }
@@ -49,6 +49,12 @@ public class CacheCleanerService : IHostedService
             _logger.LogInformation("Deleting legacy image cache folder");
             Directory.Delete(FileSystemLayout.LegacyImageCacheFolder, true);
         }
+
+        if (localFileSystem.FolderExists(FileSystemLayout.TranscodeFolder))
+        {
+            _logger.LogInformation("Emptying transcode cache folder");
+            localFileSystem.EmptyFolder(FileSystemLayout.TranscodeFolder);
+        }
     }
 
     public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;