將 .NET Lambda 函數代碼編譯為本機運行時格式

初始化和部署原生 AOT 編譯的 Lambda 函數

1. 使用原生 AOT 範本初始化新專案，然後瀏覽至包含所建立 .cs 和 .csproj 檔案的目錄。在此範例中，我們將函數命名為 NativeAotSample。

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

   原生 AOT 範本建立的 Function.cs 檔案包含以下函數程式碼。

   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

   原生 AOT 會將應用程式編譯成單一原生二進位檔。該二進位檔的進入點是 static Main 方法。在 static Main 中，系統會引導 Lambda 執行期並設定 FunctionHandler 方法。在執行期引導程序中，原始碼產生的序列化程式是使用 new SourceGeneratorLambdaJsonSerializer<LambdaFunctionJsonSerializerContext>() 加以設定

2. 若要將應用程式部署到 Lambda，請確定本機環境中的 Docker 正在執行，並執行下列命令。

   dotnet lambda deploy-function

   在幕後，.NET 全域 CLI 會下載 AL2023 Docker 映像檔，並在執行中的容器中編譯您的應用程式程式碼。編譯後的二進位檔會輸出回本機檔案系統，然後再部署至 Lambda。

3. 執行以下命令來測試函數。以您在部署精靈中為函數選擇的名稱取代 <FUNCTION_NAME>。

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

   CLI 的回應包括冷啟動 (初始化持續時間) 的效能詳細資訊，以及函數調用的總執行時間。

4. 若要依照上述步驟刪除您建立的 AWS 資源，請執行下列命令。以您在部署精靈中為函數選擇的名稱取代 <FUNCTION_NAME>。刪除不再使用的 AWS 資源後，您就可以避免向您收取不必要的費用 AWS 帳戶。

   dotnet lambda delete-function <FUNCTION_NAME>