Microsoft.Framework.Logging.NLog 已替换为 NLog.Extensions.Logging on NuGet，由 NLog 团队维护。
对于 ASP.NET Core，您需要 NLog.Web.AspNetCore（它依赖于
NLog.Extensions.Logging)。
使用方法：
设置
需要启用 NLog，以便将其集成到 ASP.NET Core 的 DI 和日志 API 中。
这将导致所有由外部（例如 Microsoft）写入的日志也将发送到 NLog - 您可以在 NLog 的配置中将其过滤掉（不会影响性能）。
ASP.NET Core 1
在 ASP.NET Core 中的 Configure 和可选的 ConfigureServices 需要更新。
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
//add NLog to .NET Core
loggerFactory.AddNLog();
//Enable ASP.NET Core features (NLog.web) - only needed for ASP.NET Core users
app.AddNLogWeb();
//configure nlog.config in your project root.
env.ConfigureNLog("nlog.config");
...
//you could use LogManager.Configuration from here
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
// e.g. services.AddMvc();
//needed for NLog.Web
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
}
ASP.NET Core 2
对于 ASP.NET Core 2，设置不同于 ASP.NET Core 1
在 program.cs 中设置 NLog：
using NLog.Web;
using Microsoft.Extensions.Logging;
public static void Main(string[] args)
{
// NLog: setup the logger first to catch all errors
var logger = NLog.Web.NLogBuilder.ConfigureNLog("nlog.config").GetCurrentClassLogger();
try
{
logger.Debug("init main");
CreateWebHostBuilder(args).Build().Run();
}
catch (Exception ex)
{
//NLog: catch setup errors
logger.Error(ex, "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 IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>()
.ConfigureLogging(logging =>
{
logging.ClearProviders();
logging.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace);
})
.UseNLog(); // NLog: setup NLog for Dependency injection
ASP.NET Core 3 & 5
与 ASP.NET Core 2 相比，有一些小的变化，例如有一个IHostBuilder 而不是IWebHostBuilder。
对于 ASP.NET Core 5，步骤相同。
在 program.cs 中设置 NLog：
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
使用类类型作为泛型参数注入ILogger。
public class HomeController : Controller
{
public HomeController(ILogger<HomeController> logger)
{
logger.LogInformation("created homeController");
}
ASP.NET Core 6
对于 ASP.NET Core 6，您可以在没有 Startup 类的情况下对其进行配置。更新Program.cs如下：
using NLog;
using NLog.Web;
var logger = NLog.LogManager.Setup().LoadConfigurationFromAppSettings().GetCurrentClassLogger();
logger.Debug("init main");
try
{
var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllersWithViews();
// NLog: Setup NLog for Dependency injection
builder.Logging.ClearProviders();
builder.Logging.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace);
builder.Host.UseNLog();
var app = builder.Build();
// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
app.UseExceptionHandler("/Home/Error");
// The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
app.UseHsts();
}
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthorization();
app.MapControllerRoute(
name: "default",
pattern: "{controller=Home}/{action=Index}/{id?}");
app.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();
}
配置 NLog 规则
有关如何配置、记录和过滤的示例。
创建一个 nlog.config（有关 nlog.config 的更多信息，请参阅docs）。
此示例将创建 2 个文件，一个包含所有日志（包括 Microsoft 的），一个文件仅包含您的日志。
<?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="Warn"
internalLogFile="c:\temp\internal.txt">
<extensions>
<!--enable NLog.Web for ASP.NET Core-->
<add assembly="NLog.Web.AspNetCore"/>
</extensions>
<!-- define various log targets -->
<targets>
<!-- write logs to file -->
<target xsi:type="File" name="allfile" fileName="c:\temp\nlog-all-${shortdate}.log"
layout="${longdate}|${logger}|${uppercase:${level}}|${message} ${exception}" />
<target xsi:type="File" name="ownFile" fileName="c:\temp\nlog-own-${shortdate}.log"
layout="${longdate}|${logger}|${uppercase:${level}}|${message} ${exception}" />
</targets>
<rules>
<!--All logs, including from Microsoft-->
<logger name="*" minlevel="Trace" writeTo="allfile" />
<!--Skip Microsoft logs - no writeTo attribute-->
<logger name="Microsoft.*" minlevel="Trace" final="true" />
<logger name="*" minlevel="Trace" writeTo="ownFile" />
</rules>
</nlog>
发布 nlog.config
这不是 ASP.NET Core 5 的必需步骤
确保 nlog.config 将被发布，例如在您的 csproj 文件中：
<ItemGroup>
<Content Update="nlog.config" CopyToOutputDirectory="PreserveNewest" />
</ItemGroup>
输出
“nlog-own-2018-02-14.log”包含：
2018-02-14 16:27:04.0547|aspnetCoreApplication.Controllers|INFO|创建的 homeController
2018-02-14 16:27:04.0547|aspnetCoreApplication.Controllers|INFO|创建的 homeController
疑难解答
在 ASP.NET Core 2 中缺少调试日志消息？虽然我们在 program.cs 中使用 SetMinimumLevel，但 appsettings.json 也可以将其融合。
你可以改变如下：
更改 appsettings.json：
{
"Logging": {
"LogLevel": {
"Default": "Trace"
}
}
}
你也可以在这里过滤微软的日志，例如
{
"Logging": {
"LogLevel": {
"Default": "Trace",
"Microsoft": "Information"
}
}
}
其他问题，看这个步骤计划查找原因：
Logging-troubleshooting in NLog
干杯，
朱利安 (NLog)
编辑：为 NLog.Web.AspNetCore 4.3 更新
编辑 2：针对 ASP.NET Core 2 和最新建议进行了更新
编辑 3：针对 ASP.NET Core 3 更新
编辑 4：针对 ASP.NET Core 5 更新
编辑 5：针对 ASP.NET Core 6 更新