fix transcode folder preparation (#404)

ErsatzTV.Application/Streaming/Commands/StartFFmpegSessionHandler.cs

@@ -8,6 +8,7 @@ using ErsatzTV.Core.Errors;
 using ErsatzTV.Core.Interfaces.FFmpeg;
 using ErsatzTV.Core.Interfaces.Metadata;
 using LanguageExt;
+using Microsoft.Extensions.Logging;
 using static LanguageExt.Prelude;
 
 namespace ErsatzTV.Application.Streaming.Commands
@@ -15,24 +16,29 @@ namespace ErsatzTV.Application.Streaming.Commands
     public class StartFFmpegSessionHandler : MediatR.IRequestHandler<StartFFmpegSession, Either<BaseError, Unit>>
     {
         private readonly ChannelWriter<IFFmpegWorkerRequest> _channel;
+        private readonly ILogger<StartFFmpegSessionHandler> _logger;
         private readonly IFFmpegSegmenterService _ffmpegSegmenterService;
         private readonly ILocalFileSystem _localFileSystem;
 
         public StartFFmpegSessionHandler(
             IFFmpegSegmenterService ffmpegSegmenterService,
             ILocalFileSystem localFileSystem,
-            ChannelWriter<IFFmpegWorkerRequest> channel)
+            ChannelWriter<IFFmpegWorkerRequest> channel,
+            ILogger<StartFFmpegSessionHandler> logger)
         {
             _ffmpegSegmenterService = ffmpegSegmenterService;
             _localFileSystem = localFileSystem;
             _channel = channel;
+            _logger = logger;
         }
 
         public Task<Either<BaseError, Unit>> Handle(StartFFmpegSession request, CancellationToken cancellationToken) =>
             Validate(request)
                 .MapT(_ => StartProcess(request))
                 // this weirdness is needed to maintain the error type (.ToEitherAsync() just gives BaseError)
+#pragma warning disable VSTHRD103
                 .Bind(v => v.ToEither().MapLeft(seq => seq.Head()).MapAsync<BaseError, Task<Unit>, Unit>(identity));
+#pragma warning restore VSTHRD103
 
         private async Task<Unit> StartProcess(StartFFmpegSession request)
         {
@@ -44,13 +50,20 @@ namespace ErsatzTV.Application.Streaming.Commands
             return Unit.Default;
         }
 
-        private Task<Validation<BaseError, Unit>> Validate(StartFFmpegSession request) =>
-            ProcessMustNotExist(request)
-                .BindT(_ => FolderMustBeEmpty(request));
+        private async Task<Validation<BaseError, Unit>> Validate(StartFFmpegSession request)
+        {
+            Validation<BaseError, Unit> existResult = await ProcessMustNotExist(request);
+            if (existResult.IsFail)
+            {
+                return existResult;
+            }
+
+            return await FolderMustBeEmpty(request);
+        }
 
         private Task<Validation<BaseError, Unit>> ProcessMustNotExist(StartFFmpegSession request) =>
             Optional(_ffmpegSegmenterService.ProcessExistsForChannel(request.ChannelNumber))
-                .Filter(containsKey => containsKey == false)
+                .Filter(exists => exists == false)
                 .Map(_ => Unit.Default)
                 .ToValidation<BaseError>(new ChannelHasProcess())
                 .AsTask();
@@ -58,6 +71,8 @@ namespace ErsatzTV.Application.Streaming.Commands
         private Task<Validation<BaseError, Unit>> FolderMustBeEmpty(StartFFmpegSession request)
         {
             string folder = Path.Combine(FileSystemLayout.TranscodeFolder, request.ChannelNumber);
+            _logger.LogInformation("Preparing transcode folder {Folder}", folder);
+
             _localFileSystem.EnsureFolderExists(folder);
             _localFileSystem.EmptyFolder(folder);
 

ErsatzTV.Core.Tests/FFmpeg/TranscodingTests.cs

@@ -146,7 +146,7 @@ namespace ErsatzTV.Core.Tests.FFmpeg
 
             var localStatisticsProvider = new LocalStatisticsProvider(
                 metadataRepository.Object,
-                new LocalFileSystem(),
+                new LocalFileSystem(new Mock<ILogger<LocalFileSystem>>().Object),
                 new Mock<ILogger<LocalStatisticsProvider>>().Object);
 
             await localStatisticsProvider.RefreshStatistics(

ErsatzTV.Core/Metadata/LocalFileSystem.cs

@@ -5,17 +5,32 @@ using System.Threading.Tasks;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.Interfaces.Metadata;
 using LanguageExt;
+using Microsoft.Extensions.Logging;
 using static LanguageExt.Prelude;
 
 namespace ErsatzTV.Core.Metadata
 {
     public class LocalFileSystem : ILocalFileSystem
     {
+        private readonly ILogger<LocalFileSystem> _logger;
+
+        public LocalFileSystem(ILogger<LocalFileSystem> logger)
+        {
+            _logger = logger;
+        }
+
         public Unit EnsureFolderExists(string folder)
         {
-            if (!Directory.Exists(folder))
+            try
+            {
+                if (!Directory.Exists(folder))
+                {
+                    Directory.CreateDirectory(folder);
+                }
+            }
+            catch (Exception ex)
             {
-                Directory.CreateDirectory(folder);
+                _logger.LogWarning(ex, "Failed to ensure folder exists at {Folder}", folder);
             }
 
             return Unit.Default;
@@ -59,14 +74,21 @@ namespace ErsatzTV.Core.Metadata
 
         public Unit EmptyFolder(string folder)
         {
-            foreach (string file in Directory.GetFiles(folder))
+            try
             {
-                File.Delete(file);
-            }
+                foreach (string file in Directory.GetFiles(folder))
+                {
+                    File.Delete(file);
+                }
 
-            foreach (string directory in Directory.GetDirectories(folder))
+                foreach (string directory in Directory.GetDirectories(folder))
+                {
+                    Directory.Delete(directory, true);
+                }
+            }
+            catch (Exception ex)
             {
-                Directory.Delete(directory, true);
+                _logger.LogWarning(ex, "Failed to empty folder at {Folder}", folder);
             }
 
             return Unit.Default;