ffmpeg and ffprobe validation fixes (#63)

* abort building playout if any collection contains a zero-duration item

* surface errors calling ffprobe

* improve ffmpeg/ffprobe path validation

ErsatzTV.Application/FFmpegProfiles/Commands/UpdateFFmpegSettings.cs

@@ -1,6 +1,7 @@
-using MediatR;
+using ErsatzTV.Core;
+using LanguageExt;
 
 namespace ErsatzTV.Application.FFmpegProfiles.Commands
 {
-    public record UpdateFFmpegSettings(FFmpegSettingsViewModel Settings) : IRequest;
+    public record UpdateFFmpegSettings(FFmpegSettingsViewModel Settings) : MediatR.IRequest<Either<BaseError, Unit>>;
 }

ErsatzTV.Application/FFmpegProfiles/Commands/UpdateFFmpegSettingsHandler.cs

@@ -1,21 +1,74 @@
-using System.Threading;
+using System.Diagnostics;
+using System.Threading;
 using System.Threading.Tasks;
+using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Metadata;
 using ErsatzTV.Core.Interfaces.Repositories;
 using LanguageExt;
-using MediatR;
-using Unit = MediatR.Unit;
 
 namespace ErsatzTV.Application.FFmpegProfiles.Commands
 {
-    public class UpdateFFmpegSettingsHandler : IRequestHandler<UpdateFFmpegSettings>
+    public class UpdateFFmpegSettingsHandler : MediatR.IRequestHandler<UpdateFFmpegSettings, Either<BaseError, Unit>>
     {
         private readonly IConfigElementRepository _configElementRepository;
+        private readonly ILocalFileSystem _localFileSystem;
 
-        public UpdateFFmpegSettingsHandler(IConfigElementRepository configElementRepository) =>
+        public UpdateFFmpegSettingsHandler(
+            IConfigElementRepository configElementRepository,
+            ILocalFileSystem localFileSystem)
+        {
             _configElementRepository = configElementRepository;
+            _localFileSystem = localFileSystem;
+        }
+
+        public Task<Either<BaseError, Unit>> Handle(
+            UpdateFFmpegSettings request,
+            CancellationToken cancellationToken) =>
+            Validate(request)
+                .MapT(_ => ApplyUpdate(request))
+                .Bind(v => v.ToEitherAsync());
+
+        private async Task<Validation<BaseError, Unit>> Validate(UpdateFFmpegSettings request) =>
+            (await FFmpegMustExist(request), await FFprobeMustExist(request))
+            .Apply((_, _) => Unit.Default);
+
+        private Task<Validation<BaseError, Unit>> FFmpegMustExist(UpdateFFmpegSettings request) =>
+            ValidateToolPath(request.Settings.FFmpegPath, "ffmpeg");
+
+        private Task<Validation<BaseError, Unit>> FFprobeMustExist(UpdateFFmpegSettings request) =>
+            ValidateToolPath(request.Settings.FFprobePath, "ffprobe");
+
+        private async Task<Validation<BaseError, Unit>> ValidateToolPath(string path, string name)
+        {
+            if (!_localFileSystem.FileExists(path))
+            {
+                return BaseError.New($"{name} path does not exist");
+            }
+
+            var startInfo = new ProcessStartInfo
+            {
+                FileName = path,
+                Arguments = "-version",
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false
+            };
+
+            var test = new Process
+            {
+                StartInfo = startInfo
+            };
+
+            test.Start();
+            string output = await test.StandardOutput.ReadToEndAsync();
+            await test.WaitForExitAsync();
+            return test.ExitCode == 0 && output.Contains($"{name} version")
+                ? Unit.Default
+                : BaseError.New($"Unable to verify {name} version");
+        }
 
-        public async Task<Unit> Handle(UpdateFFmpegSettings request, CancellationToken cancellationToken)
+        private async Task<Unit> ApplyUpdate(UpdateFFmpegSettings request)
         {
             Option<ConfigElement> ffmpegPath = await _configElementRepository.Get(ConfigElementKey.FFmpegPath);
             Option<ConfigElement> ffprobePath = await _configElementRepository.Get(ConfigElementKey.FFprobePath);
@@ -64,7 +117,7 @@ namespace ErsatzTV.Application.FFmpegProfiles.Commands
                     _configElementRepository.Add(ce);
                 });
 
-            return Unit.Value;
+            return Unit.Default;
         }
     }
 }

ErsatzTV.Core.Tests/Scheduling/PlayoutBuilderTests.cs

@@ -37,6 +37,24 @@ namespace ErsatzTV.Core.Tests.Scheduling
             _logger = factory.CreateLogger<PlayoutBuilder>();
         }
 
+        [Test]
+        [Timeout(2000)]
+        public async Task ZeroDurationItem_Should_Abort()
+        {
+            var mediaItems = new List<MediaItem>
+            {
+                TestMovie(1, TimeSpan.Zero, DateTime.Today)
+            };
+
+            (PlayoutBuilder builder, Playout playout) = TestDataFloodForItems(mediaItems, PlaybackOrder.Random);
+            DateTimeOffset start = HoursAfterMidnight(0);
+            DateTimeOffset finish = start + TimeSpan.FromHours(6);
+
+            Playout result = await builder.BuildPlayoutItems(playout, start, finish);
+
+            result.Items.Should().BeNull();
+        }
+
         [Test]
         public async Task InitialFlood_Should_StartAtMidnight()
         {

ErsatzTV.Core/Interfaces/Metadata/ILocalStatisticsProvider.cs

@@ -1,10 +1,11 @@
 using System.Threading.Tasks;
 using ErsatzTV.Core.Domain;
+using LanguageExt;
 
 namespace ErsatzTV.Core.Interfaces.Metadata
 {
     public interface ILocalStatisticsProvider
     {
-        Task<bool> RefreshStatistics(string ffprobePath, MediaItem mediaItem);
+        Task<Either<BaseError, Unit>> RefreshStatistics(string ffprobePath, MediaItem mediaItem);
     }
 }

ErsatzTV.Core/Metadata/LocalFolderScanner.cs

@@ -80,7 +80,15 @@ namespace ErsatzTV.Core.Metadata
                 if (version.DateUpdated < _localFileSystem.GetLastWriteTime(path))
                 {
                     _logger.LogDebug("Refreshing {Attribute} for {Path}", "Statistics", path);
-                    await _localStatisticsProvider.RefreshStatistics(ffprobePath, mediaItem);
+                    Either<BaseError, Unit> refreshResult =
+                        await _localStatisticsProvider.RefreshStatistics(ffprobePath, mediaItem);
+                    refreshResult.IfLeft(
+                        error =>
+                            _logger.LogWarning(
+                                "Unable to refresh {Attribute} for media item {Path}. Error: {Error}",
+                                "Statistics",
+                                path,
+                                error.Value));
                 }
 
                 return mediaItem;

ErsatzTV.Core/Metadata/LocalStatisticsProvider.cs

@@ -29,7 +29,7 @@ namespace ErsatzTV.Core.Metadata
             _logger = logger;
         }
 
-        public async Task<bool> RefreshStatistics(string ffprobePath, MediaItem mediaItem)
+        public async Task<Either<BaseError, Unit>> RefreshStatistics(string ffprobePath, MediaItem mediaItem)
         {
             try
             {
@@ -40,14 +40,20 @@ namespace ErsatzTV.Core.Metadata
                     _ => throw new ArgumentOutOfRangeException(nameof(mediaItem))
                 };
 
-                FFprobe ffprobe = await GetProbeOutput(ffprobePath, filePath);
-                MediaVersion version = ProjectToMediaVersion(ffprobe);
-                return await ApplyVersionUpdate(mediaItem, version, filePath);
+                Either<BaseError, FFprobe> maybeProbe = await GetProbeOutput(ffprobePath, filePath);
+                return await maybeProbe.Match(
+                    async ffprobe =>
+                    {
+                        MediaVersion version = ProjectToMediaVersion(ffprobe);
+                        await ApplyVersionUpdate(mediaItem, version, filePath);
+                        return Right<BaseError, Unit>(Unit.Default);
+                    },
+                    error => Task.FromResult(Left<BaseError, Unit>(error)));
             }
             catch (Exception ex)
             {
                 _logger.LogWarning(ex, "Failed to refresh statistics for media item {Id}", mediaItem.Id);
-                return false;
+                return BaseError.New(ex.Message);
             }
         }
 
@@ -76,7 +82,7 @@ namespace ErsatzTV.Core.Metadata
             return await _mediaItemRepository.Update(mediaItem) && durationChange;
         }
 
-        private Task<FFprobe> GetProbeOutput(string ffprobePath, string filePath)
+        private Task<Either<BaseError, FFprobe>> GetProbeOutput(string ffprobePath, string filePath)
         {
             var startInfo = new ProcessStartInfo
             {
@@ -101,11 +107,13 @@ namespace ErsatzTV.Core.Metadata
             };
 
             probe.Start();
-            return probe.StandardOutput.ReadToEndAsync().MapAsync(
+            return probe.StandardOutput.ReadToEndAsync().MapAsync<string, Either<BaseError, FFprobe>>(
                 async output =>
                 {
                     await probe.WaitForExitAsync();
-                    return JsonConvert.DeserializeObject<FFprobe>(output);
+                    return probe.ExitCode == 0
+                        ? JsonConvert.DeserializeObject<FFprobe>(output)
+                        : BaseError.New($"FFprobe at {ffprobePath} exited with code {probe.ExitCode}");
                 });
         }
 

ErsatzTV.Core/Scheduling/PlayoutBuilder.cs

@@ -88,6 +88,25 @@ namespace ErsatzTV.Core.Scheduling
                 return playout;
             }
 
+            Option<CollectionKey> zeroDurationCollection = collectionMediaItems.Find(
+                c => c.Value.Any(
+                    mi => mi switch
+                    {
+                        Movie m => m.MediaVersions.HeadOrNone().Map(mv => mv.Duration).IfNone(TimeSpan.Zero) ==
+                                   TimeSpan.Zero,
+                        Episode e => e.MediaVersions.HeadOrNone().Map(mv => mv.Duration).IfNone(TimeSpan.Zero) ==
+                                     TimeSpan.Zero,
+                        _ => true
+                    })).Map(c => c.Key);
+            if (zeroDurationCollection.IsSome)
+            {
+                _logger.LogError(
+                    "Unable to rebuild playout; collection {@CollectionKey} contains items with zero duration!",
+                    zeroDurationCollection.ValueUnsafe());
+
+                return playout;
+            }
+
             playout.Items ??= new List<PlayoutItem>();
             playout.ProgramScheduleAnchors ??= new List<PlayoutProgramScheduleAnchor>();
 

ErsatzTV/Pages/FFmpeg.razor

@@ -2,8 +2,11 @@
 @using ErsatzTV.Application.FFmpegProfiles
 @using ErsatzTV.Application.FFmpegProfiles.Commands
 @using ErsatzTV.Application.FFmpegProfiles.Queries
+@using Unit = LanguageExt.Unit
 @inject IDialogService Dialog
 @inject IMediator Mediator
+@inject ILogger<FFmpeg> Logger
+@inject ISnackbar Snackbar
 
 <MudContainer MaxWidth="MaxWidth.ExtraLarge" Class="pt-8">
     <MudCard>
@@ -110,7 +113,17 @@
         await LoadFFmpegProfilesAsync();
     }
 
-    private Task SaveSettings() => Mediator.Send(new UpdateFFmpegSettings(_ffmpegSettings));
+    private async Task SaveSettings()
+    {
+        Either<BaseError, Unit> result = await Mediator.Send(new UpdateFFmpegSettings(_ffmpegSettings));
+        result.Match(
+            Left: error =>
+            {
+                Snackbar.Add(error.Value, Severity.Error);
+                Logger.LogError("Unexpected error saving FFmpeg settings: {Error}", error.Value);
+            },
+            Right: _ => Snackbar.Add("Successfully saved FFmpeg settings", Severity.Success));
+    }
 
     private static string ValidatePathExists(string path) => !File.Exists(path) ? "Path does not exist" : null;
 

ErsatzTV/Services/SchedulerService.cs

@@ -56,7 +56,6 @@ namespace ErsatzTV.Services
             await ScanLocalMediaSources(cancellationToken);
         }
 
-
         private async Task BuildPlayouts(CancellationToken cancellationToken)
         {
             using IServiceScope scope = _serviceScopeFactory.CreateScope();