0. Create a new ASP.NET Core project

1. Add dependency in csproj manually or using NuGet

<ItemGroup>  <PackageReferenceInclude="NLog.Web.AspNetCore"Version="4.*" />  <PackageReferenceInclude="NLog"Version="4.*" /></ItemGroup>

2. Create a nlog.config file.

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

3. Update program.cs

usingMicrosoft.AspNetCore.Hosting;usingMicrosoft.Extensions.Hosting;usingMicrosoft.Extensions.Logging;usingSystem;usingNLog.Web;namespaceASP.NET_Core_5_NLog_Example{publicclassProgram{publicstaticvoidMain(string[]args){// Early init of NLog to allow startup and exception logging, before host is builtvarlogger=NLog.LogManager.Setup().LoadConfigurationFromAppSettings().GetCurrentClassLogger();try{logger.Debug("init main");CreateHostBuilder(args).Build().Run();}catch(Exceptionexception){//NLog: catch setup errorslogger.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();}}publicstaticIHostBuilderCreateHostBuilder(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}}

4. Configure appsettings.json

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

5. Write logs

usingMicrosoft.Extensions.Logging;publicclassHomeController:Controller{privatereadonlyILogger<HomeController>_logger;publicHomeController(ILogger<HomeController>logger){_logger=logger;_logger.LogDebug(1,"NLog injected into HomeController");}publicIActionResultIndex(){_logger.LogInformation("Hello, this is the index!");returnView();}

6. Example Output

nlog-own-2020-12-29.log

2020-12-29 16:47:02.5291||DEBUG|ASP.NET_Core_5_NLog_Example.Program|init main |url: |action: 2020-12-29 16:47:03.5943|1|DEBUG|ASP.NET_Core_5_NLog_Example.Controllers.HomeController|NLog injected into HomeController |url: https://localhost/|action: Index2020-12-29 16:47:03.5943||INFO|ASP.NET_Core_5_NLog_Example.Controllers.HomeController|Hello, this is the index! |url: https://localhost/|action: Index

nlog-all-2020-12-29.log

2020-12-29 16:47:02.5291||DEBUG|ASP.NET_Core_5_NLog_Example.Program|init main 2020-12-29 16:47:03.5260||INFO|Microsoft.Hosting.Lifetime|Application started. Press Ctrl+C to shut down. 2020-12-29 16:47:03.5260||INFO|Microsoft.Hosting.Lifetime|Hosting environment: Development 2020-12-29 16:47:03.5260||INFO|Microsoft.Hosting.Lifetime|Content root path: D:\nlog\NLog.Web\examples\ASP.NET Core 5\ASP.NET Core 5 NLog Example 2020-12-29 16:47:03.5943|1|DEBUG|ASP.NET_Core_5_NLog_Example.Controllers.HomeController|NLog injected into HomeController 2020-12-29 16:47:03.5943||INFO|ASP.NET_Core_5_NLog_Example.Controllers.HomeController|Hello, this is the index!

Configure NLog Targets for output