.NET 6.0+Azure Functions v4下Swagger CLI生成OpenAPI文件遇重载错误

编辑 - 已定位问题并在Github提交了Issue

经过多日调研，未找到可靠解决方案，但发现有博客实现了类似Azure Functions配置，因此认为该需求可实现。

问题 #

当前尝试通过Swagger CLI和MSBuild生成openapiv3.json文件，作为CI/CD流程的构建产物导入Azure API管理（APIM），而非部署后依赖运行中的函数获取。现有配置可生成swagger.json和openapi/v3.json端点并成功导入APIM，但生成构建产物时始终报错：

C:\MyApiFolder [t/238123_OpenApiGen ≡ +1 ~2 -0 !]> dotnet tool run swagger tofile --output openapi.json MyApi/bin/Debug/net6.0/MyApi.dll v1

Unhandled exception. System.InvalidOperationException: Having multiple overloads of method 'Configure' is not supported.
   at Microsoft.AspNetCore.Hosting.StartupLoader.FindMethod(Type startupType, String methodName, String environmentName, Type returnType, Boolean required)
   at Microsoft.AspNetCore.Hosting.StartupLoader.FindConfigureDelegate(Type startupType, String environmentName)
   at Microsoft.AspNetCore.Hosting.StartupLoader.LoadMethods(IServiceProvider hostingServiceProvider, Type startupType, String environmentName, Object instance)
   at Microsoft.AspNetCore.Hosting.WebHostBuilder.<>c__DisplayClass14_1.<BuildCommonServices>b__4(IServiceProvider sp)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.CreateServiceAccessor(Type serviceType)
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService[T](IServiceProvider provider)
   at Microsoft.AspNetCore.Hosting.WebHost.EnsureStartup()
   at Microsoft.AspNetCore.Hosting.WebHost.EnsureApplicationServices()
   at Microsoft.AspNetCore.Hosting.WebHost.Initialize()
   at Microsoft.AspNetCore.Hosting.WebHostBuilder.Build()
   at Swashbuckle.AspNetCore.Cli.Program.GetServiceProvider(Assembly startupAssembly) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\Program.cs:line 145
   at Swashbuckle.AspNetCore.Cli.Program.<>c.<Main>b__0_4(IDictionary`2 namedArgs) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\Program.cs:line 82
   at Swashbuckle.AspNetCore.Cli.CommandRunner.Run(IEnumerable`1 args) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\CommandRunner.cs:line 68
   at Swashbuckle.AspNetCore.Cli.CommandRunner.Run(IEnumerable`1 args) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\CommandRunner.cs:line 59
   at Swashbuckle.AspNetCore.Cli.Program.Main(String[] args) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\Program.cs:line 121

环境配置 #

使用的环境如下：

• .NET 6.0
• Azure Functions v4
• Microsoft.Azure.WebJobs.Extensions.OpenApi 版本1.5.1（用于生成OpenApi文档）
• Swashbuckle.AspNetCore 版本6.5.0

上述OpenApi扩展为Azure官方提供的Functions OpenApi扩展。尝试使用Swashbuckle.AspNetCore NuGet包中的Swagger CLI（版本6.5.0，由AzureExtensions.Swashbuckle版本3.3.2提供），并已按照Swashbuckle官方文档添加Swashbuckle到项目中。

示例函数代码：

[FunctionName("CreateClient")]
[OpenApiOperation(operationId: "CreateClient", tags: new[] { "client", "create" })]
[OpenApiSecurity("function_key", SecuritySchemeType.ApiKey, Name = "code", In = OpenApiSecurityLocationType.Query)]
[OpenApiRequestBody("application/json", typeof(CreateClient))]
[OpenApiResponseWithBody(statusCode: HttpStatusCode.Created, contentType: "application/json", bodyType: typeof(string), Description = "Success Response")]
[OpenApiResponseWithBody(statusCode: HttpStatusCode.Conflict, contentType: "application/json", bodyType: typeof(string), Description = "Returned when item exists")]
[OpenApiResponseWithBody(statusCode: HttpStatusCode.InternalServerError, contentType: "application/json", bodyType: typeof(string), Description = "Returned for unhandled errors")]

Startup.cs中Swashbuckle/Swagger配置（尝试过多种组合，仅AddSwaggerGen始终保留）：

public override void Configure(IFunctionsHostBuilder builder)
{
   // 其他服务注册

    builder.Services.AddSingleton<IOpenApiConfigurationOptions, OpenApiConfiguration>()
                        .AddSwashBuckle(Assembly.GetExecutingAssembly())
                        .AddSwaggerGen(c => c.SwaggerDoc("v1", new OpenApiConfiguration().Info))
                        .AddSwaggerGenNewtonsoftSupport();
}

同时在csproj中添加配置以输出runtimeconfig.json：

<PropertyGroup>
  <TargetFramework>net6.0</TargetFramework>
  <AzureFunctionsVersion>v4</AzureFunctionsVersion>
  <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
</PropertyGroup>

补充说明 #

使用了一些外部NuGet包添加函数绑定，这些扩展包含使用IWebJobsBuilder的Configure方法，尝试移除后问题仍存在。示例：

public void Configure(IWebJobsBuilder builder)
    => builder.AddExtension<StartupTriggerExtensionConfigProvider>();

已尝试方案 #

• 更换AzureExtensions.Swashbuckle版本：Swashbuckle.AspNetCore6.5.0面向.NET7.0，通过global.json设置RollForward解决版本兼容，但仍报错。
  global.json配置：

  {
    "sdk": {
      "rollForward": "latestMinor",
      "version": "6.0.114"
    }
  }
  

• 使用注入IFunctionsHostBuilder实现SwashbuckleStartup：无效且已标记为[Obsolete]，尽量避免。
• 按照Swashbuckle官方文档配置自定义Host：未解决问题。

寻求可行的解决方案或规避方法。

内容的提问来源于stack exchange，提问作者Matthew Alltop