ILogger 通过 Azure Function 2.x 的 Http 触发函数的构造函数注入

问题描述

ILogger 可以注入到函数参数中，比如下面的Token方法.

ILogger can be injected to function parameter, like Token method below.

但是，注入到构造函数参数log时，出现如下错误.

However, the error below occurred when it is injected to constructor parameter log.

[07/03/2019 17:15:17] 执行令牌"(失败，id=4e22b21f-97f0-4ab4-8f51-8651b 09aedc8) [07/03/2019 17:15:17]Microsoft.Extensions.DependencyInjection.Abstractions:无法解析Microsoft.Extensions.Logging.ILogger"类型的服务，而尝试激活功能".

ILogger 可以注入到下面的Token 函数参数中.但是上面的错误是注入到构造函数参数log的时候出现的.

ILogger can be injected to Token function parameter below. But the error above occurred when it is injected to constructor parameter log.

public class Functions
{
    private HttpClient _httpClient;
    private IAppSettings _appSettings;
    private ILogger _log;

    public Functions(HttpClient httpClient, IAppSettings appSettings  //working for these two
      , ILogger log  //not working, errors
    )
    {

        _log = log;
    }

    [FunctionName("Token")]
    public async Task<IActionResult> Token(
        [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "Token")]
        HttpRequest httpRequest,
        ILogger log)
    {

    }
}

下面的依赖注入

[assembly: WebJobsStartup(typeof(Startup))]
namespace MyApp
{
    public class Startup : IWebJobsStartup
    {
        public void Configure(IWebJobsBuilder builder)
        {
            builder.Services.AddHttpClient();
            builder.Services.AddTransient<IAppSettings, AppSettings>();     
             //builder.Services.AddLogging();  //not working
           //builder.Services.AddSingleton<ILogger>() //not working
        }
}

视觉工作室 2017

Visual studio 2017

推荐答案

我也遇到了这个问题.我可以通过调用 AddLogging():

I had this problem as well. I was able to fix it by calling AddLogging():

[assembly: WebJobsStartup(typeof(Startup))]
namespace MyApp
{
    public class Startup : IWebJobsStartup
    {
        public void Configure(IWebJobsBuilder builder)
        {
            builder.Services.AddHttpClient();
            builder.Services.AddTransient<IAppSettings, AppSettings>();     
            builder.Services.AddLogging();
        }
}

然后，在 Azure 函数中，我必须传递 ILoggerFactory 而不是 ILogger 并从loggerFactory:

And then, in the Azure Function, I had to do pass a ILoggerFactory instead of an ILogger and get the ILogger instance from the loggerFactory:

public class Functions
{
    private HttpClient _httpClient;
    private IAppSettings _appSettings;
    private ILogger _log;

    public Functions(HttpClient httpClient, IAppSettings appSettings, ILoggerFactory loggerFactory)
    {
        _log = loggerFactory.CreateLogger<Functions>();
    }

    [FunctionName("Token")]
    public async Task<IActionResult> Token(
        [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "Token")]
        HttpRequest httpRequest)
    {
           // No need to keep getting the ILogger from the Run method anymore :)
    }
}

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