如何使用新的 DI 通过 IWebJobsStartup 将 ILogger 注入 Azure 函数？

Question

我正在使用< code>Azure Function v2。下面是我使用构造函数注入的函数:

public sealed class FindAccountFunction
{
    private readonly IAccountWorkflow m_accountWorkflow;

    private readonly IMapper m_mapper;

    private readonly ILogger m_logger;

    public FindAccountFunction(ILogger logger, IMapper mapper, IAccountWorkflow accountWorkflow)
    {
        m_logger = logger;
        m_mapper = mapper;
        m_accountWorkflow = accountWorkflow;
    }

    [FunctionName("FindAccount")]
    public async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, Verbs.Get, Route = "v1/accounts/")] HttpRequest httpRequest, ILogger logger)
    {
        // Do stuff.
    }
}

我在从IWebJobsStartup派生的Startup类中声明了我要注入Azure函数的所有依赖项：

    public sealed class Startup : IWebJobsStartup
    {
        public void Configure(IWebJobsBuilder webJobsBuilder)
        {
            //  Registers the application settings' class.
            webJobsBuilder.Services.AddSingleton<IApplicationSettings, ApplicationSettings>();

            //  ** Registers the ILogger instance **
            //  ** ?? **

            //  Registers the IMapper instance for the contracts.
            var mapperConfiguration = new MapperConfiguration(cfg => cfg.AddProfile(new MyProfile()));

     webJobsBuilder.Services.AddSingleton(mapperConfiguration.CreateMapper());

            // Registers custom services.
            webJobsBuilder.Services.AddTransient<IStorageService, StorageService>();

            webJobsBuilder.Services.AddTransient<IAccountWorkflow, AccountWorkflow>();
        }
   }

Azure函数调用其他依赖于ILogger的注入服务，例如< code > iaccountworf :

public sealed class AccountWorkflow : IAccountWorkflow
{  
    public AccountWorkflow(ILogger logger, IStorageService storageService)
    {
        if(logger is null)
            throw new ArgumentNullException();
    }
}

问题在于DI找不到任何＜code＞ILogger

问题

如何在< code>IWebJobsStartup中设置< code>ILogger的注入？

Answer 1

您应该从启动类中删除AddLogging方法的调用。默认记录器已经由azure函数主机设置。

[assembly: WebJobsStartup(typeof(StartUp))]
public class StartUp : IWebJobsStartup
{
    public void Configure(IWebJobsBuilder builder)
    {
        builder.Services.AddSingleton<AppSettings>();

        builder.Services.AddTransient<IMyService, MyService>();
    }
}

public MyFunction(IMyService service, ILogger<IMyService> logger)
{
    this.service = service;
    this.logger = logger;
}

自azure函数运行时2.0.12265以来，azure函数现在支持实例方法

Answer 2

我设法解决了这个问题：

注入我的类如下：MyClass.cs：

public class MyClass
{
    private readonly ILogger<MyClass> _logger;

    public MyClass(ILogger<MyClass> logger)
    {
        _logger = logger;
    }
}

Startup.cs：

[assembly: FunctionsStartup(typeof(Namespace.Startup))]   

namespace Namespace {    
public class Startup : FunctionsStartup 
{
    public override void Configure(IFunctionsHostBuilder builder) 
    {
        builder.Services.AddLogging(); 
    }
  }
}

Answer 3

引用使用依赖注入。NET Azure函数

要注册服务，您可以创建一个configure方法，并将组件添加到IFunctionsHostBuilder实例中。Azure函数主机创建一个IFunctionsHostBuilder，并将其直接传递到您配置的方法中。

若要注册configure方法，必须添加一个assembly属性，该属性使用< code>FunctionsStartup属性指定configure方法的类型。

所以在这种情况下

[assembly: FunctionsStartup(typeof(MyNamespace.Startup))]    
namespace MyNamespace {
    public class Startup : FunctionsStartup {
        public override void Configure(IFunctionsHostBuilder builder) {
            //  ** Registers the ILogger instance **
            builder.Services.AddLogging();

            //  Registers the application settings' class.
            //...

            //...omitted for brevity    
        }
    }
}

我相信，既然您有权访问服务集合，那么您应该能够向其添加日志记录

public void Configure(IWebJobsBuilder webJobsBuilder) {       

    //  ** Registers the ILogger instance **
    webJobsBuilder.Services.AddLogging();

    //OR
    //webJobsBuilder.Services.AddLogging(builder => {
    //    //...
    //});

    //  Registers the application settings' class.
    //...

    //...removed for brevity
}

并且在函数的构造函数中有一个< code>ILoggerFactory。

//...

//Ctor
public FindAccountFunction(ILoggerFactory loggerFactory, IMapper mapper, IAccountWorkflow accountWorkflow) {
    m_logger = loggerFactory.CreateLogger<FindAccountFunction>();
    m_mapper = mapper;
    m_accountWorkflow = accountWorkflow;
}

//...