如何使用第三方日志记录提供程序替代.NET Core中的内置程序

.NET Core 支持适用于各种内置和第三方日志记录提供程序的日志记录 API。先来看下如何将日志记录 API 与内置提供程序一起使用。

调用 CreateDefaultBuilder，这将添加以下日志记录提供程序：.

控制台
调试
EventSource
EventLog：仅限 Windows

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }
    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

若要替代Host.CreateDefaultBuilder 添加的默认日志记录提供程序集，请调用 ClearProviders 并添加所需的日志记录提供程序。例如，以下代码：

调用 ClearProviders 以从生成器中删除所有 ILoggerProvider 实例。
添加控制台日志记录提供程序。


public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureLogging(logging =>
        {
            logging.ClearProviders();
            logging.AddConsole();
        })
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        });

使用第三方替代，以Nlog为例

修改 program.cs

using System;
using NLog.Web;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Hosting;
public static void Main(string[] args)
{
    var logger = NLog.Web.NLogBuilder.ConfigureNLog("nlog.config").GetCurrentClassLogger();
    try
    {
        logger.Debug("init main");
        CreateHostBuilder(args).Build().Run();
    }
    catch (Exception exception)
    {
        //NLog: catch setup errors
        logger.Error(exception, "Stopped program because of exception");
        throw;
    }
    finally
    {
        // Ensure to flush and stop internal timers/threads before application-exit (Avoid segmentation fault on Linux)
        NLog.LogManager.Shutdown();
    }
}

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
      .ConfigureWebHostDefaults(webBuilder =>
      {
          webBuilder.UseStartup<Startup>();
      })
      .ConfigureLogging(logging =>
      {
          logging.ClearProviders();
          logging.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace);
      })
      .UseNLog();  // NLog: Setup NLog for Dependency injection

写日志

using Microsoft.Extensions.Logging;
public class HomeController : Controller
{
    private readonly ILogger<HomeController> _logger;
    public HomeController(ILogger<HomeController> logger)
    {
        _logger = logger;
        _logger.LogDebug(1, "NLog injected into HomeController");
    }
    public IActionResult Index()
    {
        _logger.LogInformation("Hello, this is the index!");
        return View();
    }

董川民