依赖关系注入无法解析在 Azure 中运行的 .NET Core 函数应用中类型的服务

Question

我一直遵循微软指南使用依赖注入。NET Azure Functions将一些依赖注入(DI)引入到我们团队正在创建的Azure函数中。当我在Visual Studio 2017中本地运行并使用Fiddler或Postman调用函数时，一切都正常——我可以调试命中断点，并且通过DI设置提供的服务正常工作。然而，当我们将相同的功能部署到Azure中时，我们会得到以下异常:

无法解析“MyLibrary”类型的服务。ITelemetryClient '在尝试激活' MyFunctionApp时'。GetRemoteSystemsByFeature。

我有一个库程序集（.NET Standard 2.0），它公开了一个接口ITelemetryClient和一个默认实现AppplicationInsightsTelemetryClient。它们是非常简单的代码 - 我不认为这些的实现对这个问题很重要，所以我现在跳过它们。

在定义函数应用（.NET Core 2.2）的解决方案中，我已确保安装了正确的 NuGet 包：

• Microsoft.Azure.Functions.Extensions v1.0.0
• Microsoft.Azure.WebJobs.Script.ExtensionsMetadataGenerator v1.1.1
• Microsoft.NET.Sdk.Functions v1.0.28

我创建了从FunctionsStartup继承的Startup：

using System;
using System.Runtime.CompilerServices;
using MyLibrary;
using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;

[assembly: FunctionsStartup(typeof(MyFunctionApp.Startup))]
[assembly: InternalsVisibleTo("MyFunctionApp.Tests")]

namespace MyFunctionApp
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddSingleton<MyLibrary.ITelemetryClient, MyLibrary.ApplicationInsightsTelemetryClient>();
        }
    }
}

然后，我给我的函数一个构造函数，它要求MyLibrary.ITelemetryClient：

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Extensions.Logging;
using System;
using System.Threading.Tasks;
using MyLibrary;
using MyRepository;
using MyService;

namespace MyFunctionApp
{
    public class GetRemoteSystemsByFeature
    {
        private readonly MyLibrary.ITelemetryClient _telemetryClient;

        public GetRemoteSystemsByFeature(MyLibrary.ITelemetryClient telemetryClient)
        {
            _telemetryClient = telemetryClient;
        }

        // snip - the rest shouldn't matter for this question
    }
}

所以我认为我做对了一切。正如我所说，当我在本地调试时，整个事情都可以工作，并且使用了正确的ITelemetryClient实现并成功地完成了它的事情。

但是，当它被部署到Azure中时，我们会得到上面引用的错误。该异常的堆栈跟踪没有提到我们的任何代码:

System.InvalidOperationException:
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService (Microsoft.Extensions.DependencyInjection.Abstractions, Version=2.2.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60)
   at lambda_method (Anonymously Hosted DynamicMethods Assembly, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null)
   at Microsoft.Azure.WebJobs.Host.Executors.DefaultJobActivator.CreateInstance (Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\DefaultJobActivator.csMicrosoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 42)
   at Microsoft.Azure.WebJobs.Host.Executors.DefaultJobActivator.CreateInstance (Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\DefaultJobActivator.csMicrosoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 32)
   at Microsoft.Azure.WebJobs.Host.Executors.ActivatorInstanceFactory`1+<>c__DisplayClass1_1.<.ctor>b__0 (Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\ActivatorInstanceFactory.csMicrosoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 20)
   at Microsoft.Azure.WebJobs.Host.Executors.ActivatorInstanceFactory`1.Create (Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\ActivatorInstanceFactory.csMicrosoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 26)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionInvoker`2.CreateInstance (Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionInvoker.csMicrosoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 44)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+ParameterHelper.Initialize (Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 845)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<TryExecuteAsyncCore>d__16.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.9.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 116)

有什么想法吗？

有人要求我共享扩展的内容。json文件：

{
  "extensions":[
    { "name": "Startup", "typeName":"MyFunctionApp.Startup, MyFunctionApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"}
  ]
}

Answer 1

您需要添加＜code＞Microsoft.ApplicationInsights。AspNetCore添加到您的项目中，并将其添加到＜code＞启动中。csclass：

public void ConfigureServices(IServiceCollection services)
{
    services.AddApplicationInsightsTelemetry(Configuration);
    ...
}

Answer 2

在我的情况下，我缺少[assembly:functions startup(type of(MyFunctionApp。启动))]

Answer 3

卸载Microsoft.Azure.WebJobs.Script后。MyFunctionApp中的ExtensionsMetadataGeneratorpackage和重新部署依赖注入错误停止，一切开始正常工作。感谢所有提出见解的人，尤其是Katy Shimizu。