具有本机 AOT 编译功能的 .NET 函数

要初始化和部署本机 AOT 编译的 Lambda 函数

1. 使用本机 AOT 模板初始化新项目，然后导航到包含已创建的 .cs 和 .csproj 文件的目录。在此示例中，我们将函数命名为 NativeAotSample。

   dotnet new lambda.NativeAOT -n NativeAotSample
   cd ./NativeAotSample/src/NativeAotSample

   由本机 AOT 模板创建的 Function.cs 文件包含以下函数代码。

   using Amazon.Lambda.Core;
   using Amazon.Lambda.RuntimeSupport;
   using Amazon.Lambda.Serialization.SystemTextJson;
   using System.Text.Json.Serialization;
   
   namespace NativeAotSample;
   
   public class Function
   {
       /// <summary>
       /// The main entry point for the Lambda function. The main function is called once during the Lambda init phase. It
       /// initializes the .NET Lambda runtime client passing in the function handler to invoke for each Lambda event and
       /// the JSON serializer to use for converting Lambda JSON format to the .NET types.
       /// </summary>
       private static async Task Main()
       {
           Func<string, ILambdaContext, string> handler = FunctionHandler;
           await LambdaBootstrapBuilder.Create(handler, new SourceGeneratorLambdaJsonSerializer<LambdaFunctionJsonSerializerContext>())
               .Build()
               .RunAsync();
       }
   
       /// <summary>
       /// A simple function that takes a string and does a ToUpper.
       ///
       /// To use this handler to respond to an AWS event, reference the appropriate package from
       /// https://github.com/aws/aws-lambda-dotnet#events
       /// and change the string input parameter to the desired event type. When the event type
       /// is changed, the handler type registered in the main method needs to be updated and the LambdaFunctionJsonSerializerContext
       /// defined below will need the JsonSerializable updated. If the return type and event type are different then the
       /// LambdaFunctionJsonSerializerContext must have two JsonSerializable attributes, one for each type.
       ///
       // When using Native AOT extra testing with the deployed Lambda functions is required to ensure
       // the libraries used in the Lambda function work correctly with Native AOT. If a runtime
       // error occurs about missing types or methods the most likely solution will be to remove references to trim-unsafe
       // code or configure trimming options. This sample defaults to partial TrimMode because currently the AWS
       // SDK for .NET does not support trimming. This will result in a larger executable size, and still does not
       // guarantee runtime trimming errors won't be hit.
       /// </summary>
       /// <param name="input"></param>
       /// <param name="context"></param>
       /// <returns></returns>
       public static string FunctionHandler(string input, ILambdaContext context)
       {
           return input.ToUpper();
       }
   }
   
   /// <summary>
   /// This class is used to register the input event and return type for the FunctionHandler method with the System.Text.Json source generator.
   /// There must be a JsonSerializable attribute for each type used as the input and return type or a runtime error will occur
   /// from the JSON serializer unable to find the serialization information for unknown types.
   /// </summary>
   [JsonSerializable(typeof(string))]
   public partial class LambdaFunctionJsonSerializerContext : JsonSerializerContext
   {
       // By using this partial class derived from JsonSerializerContext, we can generate reflection free JSON Serializer code at compile time
       // which can deserialize our class and properties. However, we must attribute this class to tell it what types to generate serialization code for.
       // See https://docs.microsoft.com/en-us/dotnet/standard/serialization/system-text-json-source-generation

   本机 AOT 将您的应用程序编译成单个本机二进制文件。该二进制文件的入口点是 static Main 方法。在 static Main 内，引导 Lambda 运行时系统并设置 FunctionHandler 方法。作为运行时系统引导程序的一部分，使用 new SourceGeneratorLambdaJsonSerializer<LambdaFunctionJsonSerializerContext>() 配置源代码生成的序列化器

2. 要将您的应用程序部署到 Lambda，请确保 Docker 在您的本地环境中运行，并运行以下命令。

   dotnet lambda deploy-function

   在后台，.NET 全局 CLI 会下载 AL2023 Docker 映像，并在正在运行的容器中编译您的应用程序代码。在部署到 Lambda 之前，编译后的二进制文件会输出回您的本地文件系统。

3. 通过运行以下命令来测试您的函数。将 <FUNCTION_NAME> 替换为您在部署向导中为函数选择的名称。

   dotnet lambda invoke-function <FUNCTION_NAME> --payload "hello world"

   来自 CLI 的响应包括冷启动的性能详细信息（初始化持续时间）以及函数调用的总运行时间。

4. 要删除按照上述步骤创建的 Amazon 资源，请运行以下命令。将 <FUNCTION_NAME> 替换为您在部署向导中为函数选择的名称。通过删除您不再使用的 Amazon 资源，可防止您的 Amazon Web Services 账户 产生不必要的费用。

   dotnet lambda delete-function <FUNCTION_NAME>