[backend/drive] Add ImageProcessorConcurrency configuration option, default it to 8 (was: unrestricted)

Iceshrimp.Backend/Core/Configuration/Config.cs

@@ -207,6 +207,8 @@ public sealed class Config
 		public          int                  MaxResolutionMpx { get; init; } = 30;
 		public          bool                 LocalOnly        { get; init; } = false;
 
+		[Range(0, 128)] public int ImageProcessorConcurrency { get; init; } = 8;
+
 		public string MaxFileSize
 		{
 			get => MaxFileSizeBytes.ToString();

Iceshrimp.Backend/Core/Services/DriveService.cs

@@ -343,7 +343,7 @@ public class DriveService(
 	}
 
 	private async Task<ImageVerTriple?> ProcessAndStoreFileVersion(
-		ImageVersion version, Func<Stream>? encode, string fileName
+		ImageVersion version, Func<Task<Stream>>? encode, string fileName
 	)
 	{
 		if (encode == null) return null;
@@ -354,7 +354,7 @@ public class DriveService(
 			try
 			{
 				var sw = Stopwatch.StartNew();
-				stream = encode();
+				stream = await encode();
 				sw.Stop();
 				logger.LogDebug("Encoding {version} image took {ms} ms",
 				                version.Key.ToString().ToLowerInvariant(), sw.ElapsedMilliseconds);
@@ -426,11 +426,7 @@ public class DriveService(
 	private static string GenerateAccessKey(string prefix = "", string extension = "webp")
 	{
 		var guid = Guid.NewGuid().ToStringLower();
-		// @formatter:off
-		return prefix.Length > 0
-			? extension.Length > 0 ? $"{prefix}-{guid}.{extension}" : $"{prefix}-{guid}"
-			: extension.Length > 0 ? $"{guid}.{extension}" : guid;
-		// @formatter:on
+		return extension.Length > 0 ? $"{prefix}-{guid}.{extension}" : $"{prefix}-{guid}";
 	}
 
 	private static string CleanMimeType(string? mimeType)

Iceshrimp.Backend/Core/Services/ImageProcessor.cs

@@ -2,6 +2,7 @@ using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
 using Iceshrimp.Backend.Core.Configuration;
 using Iceshrimp.Backend.Core.Database.Tables;
+using Iceshrimp.Backend.Core.Helpers;
 using Iceshrimp.Backend.Core.Services.ImageProcessing;
 using Microsoft.Extensions.Options;
 using static Iceshrimp.Backend.Core.Services.ImageProcessing.ImageVersion;
@@ -15,6 +16,8 @@ public class ImageProcessor
 
 	private readonly List<IImageProcessor>   _imageProcessors;
 	private readonly ILogger<ImageProcessor> _logger;
+	private readonly SemaphorePlus           _semaphore;
+	private readonly int                     _concurrency;
 
 	public ImageProcessor(
 		ILogger<ImageProcessor> logger, IOptionsMonitor<Config.StorageSection> config,
@@ -24,6 +27,8 @@ public class ImageProcessor
 		_logger          = logger;
 		_config          = config;
 		_imageProcessors = imageProcessors.OrderBy(p => p.Priority).ToList();
+		_concurrency     = config.CurrentValue.MediaProcessing.ImageProcessorConcurrency;
+		_semaphore       = new SemaphorePlus(Math.Max(_concurrency, 1));
 
 		// @formatter:off
 		if (_imageProcessors.Count == 0)
@@ -63,17 +68,31 @@ public class ImageProcessor
 		// @formatter:on
 
 		var results = formats
-		              .ToDictionary<ImageVersion, ImageVersion, Func<Stream>?>(p => p, ProcessImageFormat)
+		              .ToDictionary<ImageVersion, ImageVersion, Func<Task<Stream>>?>(p => p, ProcessImageFormat)
 		              .AsReadOnly();
 
 		return new ProcessedImage(ident) { RequestedFormats = results, Blurhash = blurhash };
 
-		Func<Stream>? ProcessImageFormat(ImageVersion p)
+		Func<Task<Stream>>? ProcessImageFormat(ImageVersion p)
 		{
-			if (p.Format is ImageFormat.Keep) return () => new MemoryStream(buf);
+			if (p.Format is ImageFormat.Keep) return () => Task.FromResult<Stream>(new MemoryStream(buf));
 			var proc = _imageProcessors.FirstOrDefault(i => i.CanEncode(p.Format));
 			if (proc == null) return null;
-			return () => proc.Encode(buf, ident, p.Format);
+			return async () =>
+			{
+				if (_concurrency is 0)
+					return proc.Encode(buf, ident, p.Format);
+
+				await _semaphore.WaitAsync();
+				try
+				{
+					return proc.Encode(buf, ident, p.Format);
+				}
+				finally
+				{
+					_semaphore.Release();
+				}
+			};
 		}
 	}
 
@@ -117,7 +136,7 @@ public class ImageProcessor
 	{
 		public string? Blurhash;
 
-		public required IReadOnlyDictionary<ImageVersion, Func<Stream>?> RequestedFormats;
+		public required IReadOnlyDictionary<ImageVersion, Func<Task<Stream>>?> RequestedFormats;
 
 		public ProcessedImage(IImageInfo info)
 		{
@@ -129,9 +148,9 @@ public class ImageProcessor
 		public ProcessedImage(IImageInfo info, Stream original, DriveFileCreationRequest request) : this(info)
 		{
 			var format = new ImageFormat.Keep(Path.GetExtension(request.Filename), request.MimeType);
-			RequestedFormats = new Dictionary<ImageVersion, Func<Stream>?>
+			RequestedFormats = new Dictionary<ImageVersion, Func<Task<Stream>>?>
 			{
-				{ new ImageVersion(KeyEnum.Original, format), () => original }
+				{ new ImageVersion(KeyEnum.Original, format), () => Task.FromResult(original) }
 			};
 		}
 	}

Iceshrimp.Backend/configuration.ini

@@ -161,10 +161,6 @@ MaxFileSize = 10M
 ;; Caution: metadata (e.g. location data) for locally originating images will *not* be stripped for files larger than this
 MaxResolutionMpx = 30
 
-;; Should you prefer to reject locally originating images that exceed MaxResolutionMpx, set this option to true.
-;; Note that this does not apply to remote images, or to local images in a format not supported by the configured image processor.
-FailIfImageExceedsMaxRes = false
-
 ;; Maxmimum concurrent image encode tasks to run. (0 = no limit)
 ImageProcessorConcurrency = 8