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.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>();