.NET 8 AOT Minimal API部署AWS Lambda启动失败求助

问题详情 #

AWS新手部署.NET 8 AOT编译的Minimal API到Lambda，使用x86_64架构的.NET 8运行时，通过dotnet lambda package打包上传ZIP后，测试触发初始化错误，提示/var/task目录缺少.deps.json文件，错误日志如下：

INIT_REPORT Init Duration: 20.68 ms Phase: init Status: error   Error Type: Runtime.ExitError
Error: .NET binaries for Lambda function are not correctly installed in the /var/task directory of the image when the image was built. The /var/task directory is missing the required .deps.json file.
Error: .NET binaries for Lambda function are not correctly installed in the /var/task directory of the image when the image was built. The /var/task directory is missing the required .deps.json file.
INIT_REPORT Init Duration: 21.40 ms Phase: invoke   Status: error   Error Type: Runtime.ExitError
START RequestId: <redacted UUID> Version: $LATEST
RequestId: <redacted UUID> Error: Runtime exited with error: exit status 105

项目及Lambda名称为BasicRules，相关文件如下：

Program.cs #

using Amazon.Lambda.Serialization.SystemTextJson;
using BasicRules;
using Microsoft.Extensions.Options;

var builder = WebApplication.CreateSlimBuilder(args);

builder.Services.ConfigureHttpJsonOptions(options =>
{
    options.SerializerOptions.TypeInfoResolver = CustomSerializationContext.Default;
});

builder.Services.AddAWSLambdaHosting(LambdaEventSource.RestApi, options =>
{
    options.Serializer = new SourceGeneratorLambdaJsonSerializer<CustomSerializationContext>();
});

var app = builder.Build();

app.MapGet("/", () => "Welcome to running AOT compiled ASP.NET Core Minimal API on AWS Lambda");

app.MapGet("/_health", () => "We are healthy");

app.MapGet("/test", () => "Test endpoint");

app.Run();

BasicRules.csproj #

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

    <PropertyGroup>
        <TargetFramework>net8.0</TargetFramework>
        <ImplicitUsings>enable</ImplicitUsings>
        <Nullable>enable</Nullable>
        <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
        <AWSProjectType>Lambda</AWSProjectType>
        <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
        <PublishReadyToRun>true</PublishReadyToRun>
        <PublishAot>true</PublishAot>
        <OutputType>exe</OutputType>
        <StripSymbols>true</StripSymbols>
    </PropertyGroup>
    
    <ItemGroup>
        <PackageReference Include="Amazon.Lambda.AspNetCoreServer.Hosting" Version="1.7.0" />
        <PackageReference Include="Amazon.Lambda.Serialization.SystemTextJson" Version="2.4.1" />
        <PackageReference Include="AWS.Lambda.Powertools.Logging" Version="1.5.0" />
        <PackageReference Include="AWS.Lambda.Powertools.Metrics" Version="1.6.0" />
        <PackageReference Include="AWS.Lambda.Powertools.Tracing" Version="1.4.0" />
        <PackageReference Include="Amazon.Lambda.APIGatewayEvents" Version="2.7.0" />
<!--        <PackageReference Include="Amazon.Lambda.Core" Version="2.2.0" />-->
<!--        <PackageReference Include="Amazon.Lambda.Annotations" Version="1.2.0" />-->
<!--        <PackageReference Include="Amazon.Lambda.RuntimeSupport" Version="1.10.0" />-->
<!--        <PackageReference Include="AWSXRayRecorder.Core" Version="2.14.0" />-->
<!--        <PackageReference Include="AWSXRayRecorder.Handlers.AwsSdk" Version="2.12.0" />-->
    </ItemGroup>

    <ItemGroup>
        <TrimmerRootAssembly Include="Amazon.Lambda.AspNetCoreServer.Hosting"/>
        <TrimmerRootAssembly Include="BasicRules" />
        <TrimmerRootAssembly Include="AWS.Lambda.Powertools.Logging" />
        <TrimmerRootAssembly Include="AWS.Lambda.Powertools.Tracing" />
        <TrimmerRootAssembly Include="AWS.Lambda.Powertools.Metrics" />
        <TrimmerRootAssembly Include="Amazon.Lambda.APIGatewayEvents" />
<!--        <TrimmerRootAssembly Include="Amazon.Lambda.RuntimeSupport"/>
<!--        <TrimmerRootAssembly Include="AWSSDK.Core" />
<!--        <TrimmerRootAssembly Include="AWSXRayRecorder.Core" />
<!--        <TrimmerRootAssembly Include="AWSXRayRecorder.Handlers.AwsSdk" />
    </ItemGroup>
    
</Project>

注：注释内容为之前尝试添加的其他包。

aws-lambda-tools-defaults.json #

{
  "function-memory-size" : 1024,
  "configuration": "Release",
  "function-runtime" : "dotnet8",
  "function-architecture": "x86_64"
}

CustomSerializerContext.cs #

using System.Text.Json.Serialization;
using Amazon.Lambda.APIGatewayEvents;

namespace BasicRules;

[JsonSerializable(typeof(APIGatewayProxyRequest))]
[JsonSerializable(typeof(APIGatewayProxyResponse))]
[JsonSerializable(typeof(Dictionary<string, object>))]
public partial class CustomSerializationContext : JsonSerializerContext
{
}

解决步骤 #

1. 修正.csproj配置 #

• 跳过.deps.json检查：AOT编译的Lambda函数不需要.deps.json，但默认运行时会检查该文件。在<PropertyGroup>中添加以下属性跳过检查：

  <_LambdaSkipDepsFileCheck>true</_LambdaSkipDepsFileCheck>
  

• 禁用PublishReadyToRun：AOT与ReadyToRun不兼容，将<PublishReadyToRun>true</PublishReadyToRun>改为<PublishReadyToRun>false</PublishReadyToRun>，或者直接删除该行。
• 移除不必要的属性：CopyLocalLockFileAssemblies和GenerateRuntimeConfigurationFiles对AOT编译无用，可以删除这两行，避免混淆。

修改后的<PropertyGroup>示例：

<PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <AWSProjectType>Lambda</AWSProjectType>
    <PublishReadyToRun>false</PublishReadyToRun>
    <PublishAot>true</PublishAot>
    <OutputType>exe</OutputType>
    <StripSymbols>true</StripSymbols>
    <_LambdaSkipDepsFileCheck>true</_LambdaSkipDepsFileCheck>
</PropertyGroup>

2. 正确打包AOT程序 #

使用dotnet publish直接生成符合要求的输出，替代dotnet lambda package：

dotnet publish -c Release -r linux-x64 --self-contained true /p:PublishAot=true

进入发布目录（默认路径：bin/Release/net8.0/linux-x64/publish），将目录内所有文件直接压缩为ZIP包，确保ZIP根目录包含可执行文件（BasicRules），不要将文件嵌套在子文件夹中。

3. 配置Lambda处理程序 #

在Lambda控制台的函数配置中，将处理程序设置为可执行文件的名称BasicRules，而非传统的命名空间.类::方法格式。

验证 #

解压打包后的ZIP文件，确认根目录下存在BasicRules可执行文件，无需.deps.json文件（AOT已将所有依赖编译到可执行文件中）。重新上传ZIP包并测试函数，初始化错误即可解决。

内容的提问来源于stack exchange，提问作者Hallisloak