ASP.NET Core 5 配置NLog

一、下载NuGet包

1. NLog.Web.AspNetCore
2. NLog

二、创建一个 nlog.config 文件

1. 在项目的根目录中创建 nlog.config（全部小写）文件
2. 例子如下：

3. <?xml version="1.0" encoding="utf-8" ?>
   <nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         autoReload="true"
         internalLogLevel="Info"
         internalLogFile="c:\temp\internal-nlog-AspNetCore.txt">
   
     <!-- enable asp.net core layout renderers -->
     <extensions>
       <add assembly="NLog.Web.AspNetCore"/>
     </extensions>
   
     <!-- the targets to write to -->
     <targets>
       <!-- File Target for all log messages with basic details -->
       <target xsi:type="File" name="allfile" fileName="c:\temp\nlog-AspNetCore-all-${shortdate}.log"
               layout="${longdate}|${event-properties:item=EventId_Id:whenEmpty=0}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />
   
       <!-- File Target for own log messages with extra web details using some ASP.NET core renderers -->
       <target xsi:type="File" name="ownFile-web" fileName="c:\temp\nlog-AspNetCore-own-${shortdate}.log"
               layout="${longdate}|${event-properties:item=EventId_Id:whenEmpty=0}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}|url: ${aspnet-request-url}|action: ${aspnet-mvc-action}|${callsite}| body: ${aspnet-request-posted-body}" />
   
       <!--Console Target for hosting lifetime messages to improve Docker / Visual Studio startup detection -->
       <target xsi:type="Console" name="lifetimeConsole" layout="${level:truncate=4:lowercase=true}: ${logger}[0]${newline}      ${message}${exception:format=tostring}" />
     </targets>
   
     <!-- rules to map from logger name to target -->
     <rules>
       <!--All logs, including from Microsoft-->
       <logger name="*" minlevel="Trace" writeTo="allfile" />
   
       <!--Output hosting lifetime messages to console target for faster startup detection -->
       <logger name="Microsoft.Hosting.Lifetime" minlevel="Info" writeTo="lifetimeConsole, ownFile-web" final="true" />
   
       <!--Skip non-critical Microsoft logs and so log only own logs (BlackHole) -->
       <logger name="Microsoft.*" maxlevel="Info" final="true" />
       <logger name="System.Net.Http.*" maxlevel="Info" final="true" />
       
       <logger name="*" minlevel="Trace" writeTo="ownFile-web" />
     </rules>
   </nlog>
   

   　　

三、更新program.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using System;
using NLog.Web;

namespace ASP.NET_Core_5_NLog_Example
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var logger = 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(LogLevel.Trace);
                })
                .UseNLog();  // NLog: Setup NLog for Dependency injection
    }
}

四、配置appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Trace",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*"
}

五、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();
    }

六、根据地址找到输出位置

fileName="c:\temp\nlog-AspNetCore-all-${shortdate}.log"