Aws-lambda-dotnet: AWS Lambda 是否支持使用 libgdiplus 进行 System.Drawing 调用？

我听说过在 Linux 上将 libgdiplus 用于 System.Drawing，但我还没有尝试过。 对于 Lambda 中的图像处理，我一直在使用最新版本的Magick.NET-Q16-AnyCPU 。 我没有用它做过任何绘图，我认为你需要验证码，但我看到它确实有一些绘图功能。

我的问题似乎是 libgdiplus 不是 Lambda Linux 实例上的默认安装。 据说，runtime.linux-x64.CoreCompat.System.Drawing 是一个 NuGet 包，它只是在应用程序启动时通过 apt-get 执行脚本来安装这个库； 但是，在通过下面的链接深入研究该项目的代码后，我一直无法确切理解它是如何工作的，或者为什么它可能对我失败。

https://github.com/CoreCompat/CoreCompat/tree/master/native/runtime.linux-x64.CoreCompat.System.Drawing

我现在会继续寻找解决方案； 但是，Magick.NET 链接似乎是生成一些验证码图像的有效方法，所以我一定会保留它作为后备。 我已经考虑使用本机 System.Drawing，因为它似乎是为了更好的跨平台兼容性而开发的，但看起来它们仍然在某种程度上引用了已安装的 GDI+ 库，

你见过在 Lambda 上成功使用的这个 Magick.NET 包吗？

是的，Magick.NET 更新了几个月，可以开箱即用地跨平台工作。 我所要做的就是将它添加到项目中。 下面是我编写的用于创建图像缩略图的 Lambda 函数。

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.0</TargetFramework>
    <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Amazon.Lambda.Core" Version="1.0.0" />
    <PackageReference Include="Amazon.Lambda.Serialization.Json" Version="1.1.0" />
    <PackageReference Include="Amazon.Lambda.S3Events" Version="1.0.2" />
    <PackageReference Include="AWSSDK.S3" Version="3.3.16.2" />
    <PackageReference Include="AWSXRayRecorder.Handlers.AwsSdk" Version="2.1.0-beta" />
    <PackageReference Include="Magick.NET-Q16-AnyCPU" Version="7.4.2" />
  </ItemGroup>

  <ItemGroup>
    <DotNetCliToolReference Include="Amazon.Lambda.Tools" Version="2.1.1" />
  </ItemGroup>

</Project>

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;

using Amazon.Lambda.Core;
using Amazon.Lambda.S3Events;
using Amazon.S3;
using Amazon.S3.Model;
using Amazon.XRay.Recorder.Core;
using ImageMagick;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.Json.JsonSerializer))]

namespace ImageResizer
{
    public class Function
    {
        IAmazonS3 S3Client { get; set; }

        /// <summary>
        /// Default constructor. This constructor is used by Lambda to construct the instance. When invoked in a Lambda environment
        /// the AWS credentials will come from the IAM role associated with the function and the AWS region will be set to the
        /// region the Lambda function is executed in.
        /// </summary>


        public Function()
        {
            Amazon.XRay.Recorder.Handlers.AwsSdk.AWSSDKHandler.RegisterXRayForAllServices();
            S3Client = new AmazonS3Client();
        }

        /// <summary>
        /// Constructs an instance with a preconfigured S3 client. This can be used for testing the outside of the Lambda environment.
        /// </summary>
        /// <param name="s3Client"></param>
        public Function(IAmazonS3 s3Client)
        {
            this.S3Client = s3Client;
        }

        HashSet<string> SupportedImageTypes { get; } = new HashSet<string> { ".png", ".jpg", ".jpeg" };

        /// <summary>
        /// This method is called for every Lambda invocation. This method takes in an S3 event object and can be used 
        /// to respond to S3 notifications.
        /// </summary>
        /// <param name="evnt"></param>
        /// <param name="context"></param>
        /// <returns></returns>
        public async Task FunctionHandlerAsync(S3Event evnt, ILambdaContext context)
        {
            foreach (var record in evnt.Records)
            {
                var bucket = record.S3.Bucket.Name;
                var key = record.S3.Object.Key;

                if (key.StartsWith("thumbnails"))
                {
                    context.Logger.LogLine($"Object s3://{bucket}/{key} is already a thumbnail");
                    continue;
                }
                if (!SupportedImageTypes.Contains(Path.GetExtension(key.ToLower())))
                {
                    context.Logger.LogLine($"Object s3://{bucket}/{key} is not a supported image type");
                    continue;
                }

                context.Logger.LogLine($"Processing s3://{bucket}/{key}");

                MemoryStream resizedImageStream;
                using (var response = await this.S3Client.GetObjectAsync(bucket, key))
                {
                    AWSXRayRecorder.Instance.BeginSubsegment("Magick Image Resize");
                    try
                    {
                        using (MagickImageCollection collection = new MagickImageCollection(response.ResponseStream))
                        {
                            foreach (MagickImage image in collection)
                            {
                                image.Resize(200, 200);
                            }
                            context.Logger.LogLine($"   Image resized");

                            resizedImageStream = new MemoryStream();
                            collection.Write(resizedImageStream);
                            resizedImageStream.Position = 0;
                        }
                    }
                    catch(Exception e)
                    {
                        AWSXRayRecorder.Instance.AddException(e);
                        throw;
                    }
                    finally
                    {
                        AWSXRayRecorder.Instance.EndSubsegment();
                    }
                }

                var index = key.LastIndexOf('/');
                var thumbnailKey = "thumbnails/" + (index != -1 ? key.Substring(index + 1) : key);
                await this.S3Client.PutObjectAsync(new PutObjectRequest
                {
                    BucketName = bucket,
                    Key = thumbnailKey,
                    InputStream = resizedImageStream
                });

                context.Logger.LogLine($"   Thumbnail saved to s3://{bucket}/{thumbnailKey}");
            }
        }
    }
}

我刚刚进入 Magick，我认为它会很好地工作。 您不仅可以访问相对多样化的图像处理 API，而且它似乎得到了很好的跨平台支持。 非常感谢您的建议，多做一点开发工作，我应该能够毫无问题地清除这个障碍！

我仍然很好奇有些人似乎能够启动并运行 GDI+ 实现。 我看不出有什么方法可以在运行时执行之前将适当的 libgdiplus 库安装到 Lambda 中。

从我所见，ImageMagick Drawables API 似乎与 AWS Lambda 的跨平台兼容可能不正确。 在实现库并执行 Draw() 函数后，我引发了以下错误：

ImageMagick.MagickDrawErrorException: NonconformingDrawingPrimitiveDefinition `text' @ error/draw.c/DrawImage/3402
   at ImageMagick.MagickExceptionHelper.Check(IntPtr exception)
   at ImageMagick.DrawingWand.NativeDrawingWand.Render()
   at ImageMagick.MagickImage.Draw(IEnumerable`1 drawables)
   at Ivy.Captcha.Magick.Services.MagickCaptchaGenerationService.GenerateCaptchaImage(Int32 captchaCharLength, Int32 width, Int32 height)
   at IAGE.Api.Data.Services.CaptchaApiService.GenerateCaptcha() in D:\Workspaces\iam-global-education\src\Api\IAGE.Api.Data\Services\CaptchaApiService.cs:line 63
   at lambda_method.lambda_method(Closure , Object , Object[] )
   at Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(Object target, Object[] parameters)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.d__12.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.d__10.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.d__14.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.d__17.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.d__15.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Elmah.Io.AspNetCore.ElmahIoMiddleware.d__6.MoveNext()

无论我做什么，我似乎都无法在 Lambda 中使用任何绘图功能。 我曾尝试使用 System.Drawing (Microsoft)、CoreCompat.System.Drawing (Mono) 和 ImageMagick (3rd Party)，但似乎都无济于事。 每个图像生成库似乎都有一些主要的系统依赖项，我很难用 AWS Lambda 解决这些依赖项。 如果成功，我会继续尝试并报告。

将来我们有没有可能像自定义 Docker 容器一样自定义我们的 Lambda 运行时？ 所有这些都可以通过将 libgdiplus 安装到我的 Lambda 实例中的简单执行来解决。

我是个白痴，当我可以简单地使用 Google ReCaptcha 时，我不应该在我的 AWS Lambda 服务器上生成 Captcha 图像。 这样我的 AWS Lambda 只处理验证码，而不必引用任何形式的绘图功能。

我仍然希望看到未来在 AWS Lambda 上实现某种形式的绘图功能的方法； 但是，我将把这个问题搁置一旁，并暂时将其归结为我的一个糟糕的设计决定。

也许 Lambda 的部署层可以解决这个问题，直到 .Net Core 在某个时候提供适当的支持。

https://docs.aws.amazon.com/lambda/latest/dg/configuration-layers.html