How to use Nlog for ASP.NET Core with csproj
1. Add dependency in csproj manually or using NuGet
Install the latest:
- NLog.Web.AspNetCore 4.5+
- Update the NLog package if possible
in csproj:
<PackageReference Include="NLog.Web.AspNetCore" Version="4.5.1" />
<PackageReference Include="NLog" Version="4.5.1" />
2. Create a nlog.config file.
Create nlog.config (lowercase all) file in the root of your project.
We use this example:
1 <?xml version="1.0" encoding="utf-8" ?> 2 <nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 autoReload="true" 5 internalLogLevel="info" 6 internalLogFile="c:\temp\internal-nlog.txt"> 7 8 <!-- enable asp.net core layout renderers --> 9 <extensions> 10 <add assembly="NLog.Web.AspNetCore"/> 11 </extensions> 12 13 <!-- the targets to write to --> 14 <targets> 15 <!-- write logs to file --> 16 <target xsi:type="File" name="allfile" fileName="c:\temp\nlog-all-${shortdate}.log" 17 layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" /> 18 19 <!-- another file log, only own logs. Uses some ASP.NET core renderers --> 20 <target xsi:type="File" name="ownFile-web" fileName="c:\temp\nlog-own-${shortdate}.log" 21 layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}|url: ${aspnet-request-url}|action: ${aspnet-mvc-action}" /> 22 </targets> 23 24 <!-- rules to map from logger name to target --> 25 <rules> 26 <!--All logs, including from Microsoft--> 27 <logger name="*" minlevel="Trace" writeTo="allfile" /> 28 29 <!--Skip non-critical Microsoft logs and so log only own logs--> 30 <logger name="Microsoft.*" maxLevel="Info" final="true" /> <!-- BlackHole without writeTo --> 31 <logger name="*" minlevel="Trace" writeTo="ownFile-web" /> 32 </rules> 33 </nlog>
More details of the config file are here.
If you like to include other targets or layout renderers, check the Platform support table, as there is a limited set implemented. Check the column NetStandard
. To read more about NetStandard, see the docs from Microsoft
3. Enable copy to bin folder
Enable copy to bin folder for nlog.config
or edit .csproj
file manually and add:
<ItemGroup>
<Content Update="nlog.config" CopyToOutputDirectory="PreserveNewest" />
</ItemGroup>
4. Update program.cs
Update the program.cs
add using NLog.Web;
and using Microsoft.Extensions.Logging;
1 public static void Main(string[] args) 2 { 3 // NLog: setup the logger first to catch all errors 4 var logger = NLog.Web.NLogBuilder.ConfigureNLog("nlog.config").GetCurrentClassLogger(); 5 try 6 { 7 logger.Debug("init main"); 8 BuildWebHost(args).Run(); 9 } 10 catch (Exception ex) 11 { 12 //NLog: catch setup errors 13 logger.Error(ex, "Stopped program because of exception"); 14 throw; 15 } 16 finally 17 { 18 // Ensure to flush and stop internal timers/threads before application-exit (Avoid segmentation fault on Linux) 19 NLog.LogManager.Shutdown(); 20 } 21 } 22 23 public static IWebHost BuildWebHost(string[] args) => 24 WebHost.CreateDefaultBuilder(args) 25 .UseStartup<Startup>() 26 .ConfigureLogging(logging => 27 { 28 logging.ClearProviders(); 29 logging.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace); 30 }) 31 .UseNLog() // NLog: setup NLog for Dependency injection 32 .Build();
5. Configure appsettings.json
The Logging configuration specified in appsettings.json
overrides any call to SetMinimumLevel
. So either remove "Default":
or adjust it correctly to your needs.
1 { 2 "Logging": { 3 "LogLevel": { 4 "Default": "Trace", 5 "Microsoft": "Information" 6 } 7 } 8 }
Remember to also update any environment specific configuration to avoid any surprises. Ex appsettings.Development.json
6. Write logs
Inject the ILogger in your controller:
1 using Microsoft.Extensions.Logging; 2 3 public class HomeController : Controller 4 { 5 private readonly ILogger<HomeController> _logger; 6 7 public HomeController(ILogger<HomeController> logger) 8 { 9 _logger = logger; 10 } 11 12 public IActionResult Index() 13 { 14 _logger.LogInformation("Index page says hello"); 15 return View(); 16 }
7. Example Output
When starting the ASP.NET Core website, we get two files:
nlog-own-2017-10-10.log
2017-10-10 23:40:29.5143||DEBUG|ASP.NET_Core_2___VS2017.Program|init main |url: |action:
2017-10-10 23:40:32.1326|0|INFO|ASP.NET_Core_2___VS2017.Controllers.HomeController|Hello, this is the index! |url: http://localhost/|action: Index
nlog-all-2017-10-10.log
2017-10-10 23:40:29.5143||DEBUG|ASP.NET_Core_2___VS2017.Program|init main
2017-10-10 23:40:30.9739|0|INFO|Microsoft.AspNetCore.DataProtection.KeyManagement.XmlKeyManager|User profile is available. Using 'C:\Users\j.verdurmen\AppData\Local\ASP.NET\DataProtection-Keys' as key repository and Windows DPAPI to encrypt keys at rest.
2017-10-10 23:40:30.9897|37|DEBUG|Microsoft.AspNetCore.DataProtection.Repositories.FileSystemXmlRepository|Reading data from file 'C:\Users\j.verdurmen\AppData\Local\ASP.NET\DataProtection-Keys\key-bfd1ce07-8dc6-4eef-a51a-d21ddb547109.xml'.
2017-10-10 23:40:31.0004|18|DEBUG|Microsoft.AspNetCore.DataProtection.KeyManagement.XmlKeyManager|Found key {bfd1ce07-8dc6-4eef-a51a-d21ddb547109}.
2017-10-10 23:40:31.0124|13|DEBUG|Microsoft.AspNetCore.DataProtection.KeyManagement.DefaultKeyResolver|Considering key {bfd1ce07-8dc6-4eef-a51a-d21ddb547109} with expiration date 2017-12-28 19:01:07Z as default key.
2017-10-10 23:40:31.0422|0|DEBUG|Microsoft.AspNetCore.DataProtection.TypeForwardingActivator|Forwarded activator type request from Microsoft.AspNetCore.DataProtection.XmlEncryption.DpapiXmlDecryptor, Microsoft.AspNetCore.DataProtection, Version=2.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60 to Microsoft.AspNetCore.DataProtection.XmlEncryption.DpapiXmlDecryptor, Microsoft.AspNetCore.DataProtection, Culture=neutral, PublicKeyToken=adb9793829ddae60
2017-10-10 23:40:31.0422|51|DEBUG|Microsoft.AspNetCore.DataProtection.XmlEncryption.DpapiXmlDecryptor|Decrypting secret element using Windows DPAPI.
2017-10-10 23:40:31.0422|0|DEBUG|Microsoft.AspNetCore.DataProtection.TypeForwardingActivator|Forwarded activator type request from Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.ConfigurationModel.AuthenticatedEncryptorDescriptorDeserializer, Microsoft.AspNetCore.DataProtection, Version=2.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60 to Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.ConfigurationModel.AuthenticatedEncryptorDescriptorDeserializer, Microsoft.AspNetCore.DataProtection, Culture=neutral, PublicKeyToken=adb9793829ddae60
2017-10-10 23:40:31.0422|4|DEBUG|Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.CngCbcAuthenticatedEncryptorFactory|Opening CNG algorithm 'AES' from provider '(null)' with chaining mode CBC.
2017-10-10 23:40:31.0543|3|DEBUG|Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.CngCbcAuthenticatedEncryptorFactory|Opening CNG algorithm 'SHA256' from provider '(null)' with HMAC.
2017-10-10 23:40:31.0543|2|DEBUG|Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingProvider|Using key {bfd1ce07-8dc6-4eef-a51a-d21ddb547109} as the default key.
2017-10-10 23:40:31.0543|0|DEBUG|Microsoft.AspNetCore.DataProtection.Internal.DataProtectionStartupFilter|Key ring with default key {bfd1ce07-8dc6-4eef-a51a-d21ddb547109} was loaded during application startup.
2017-10-10 23:40:31.4080|3|DEBUG|Microsoft.AspNetCore.Hosting.Internal.WebHost|Hosting starting
2017-10-10 23:40:31.5508|4|DEBUG|Microsoft.AspNetCore.Hosting.Internal.WebHost|Hosting started
2017-10-10 23:40:31.5508|0|DEBUG|Microsoft.AspNetCore.Hosting.Internal.WebHost|Loaded hosting startup assembly ASP.NET Core 2 - VS2017
2017-10-10 23:40:31.5526|0|DEBUG|Microsoft.AspNetCore.Hosting.Internal.WebHost|Loaded hosting startup assembly Microsoft.AspNetCore.ApplicationInsights.HostingStartup
2017-10-10 23:40:31.5526|0|DEBUG|Microsoft.AspNetCore.Hosting.Internal.WebHost|Loaded hosting startup assembly Microsoft.AspNetCore.Server.IISIntegration
2017-10-10 23:40:31.6909|1|DEBUG|Microsoft.AspNetCore.Server.Kestrel|Connection id "0HL8G4U42CK64" started.
2017-10-10 23:40:31.6909|1|DEBUG|Microsoft.AspNetCore.Server.Kestrel|Connection id "0HL8G4U42CK65" started.
2017-10-10 23:40:31.7418|19|DEBUG|Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv|Connection id "0HL8G4U42CK65" reset.
2017-10-10 23:40:31.7418|10|DEBUG|Microsoft.AspNetCore.Server.Kestrel|Connection id "0HL8G4U42CK65" disconnecting.
2017-10-10 23:40:31.7418|7|DEBUG|Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv|Connection id "0HL8G4U42CK65" sending FIN.
2017-10-10 23:40:31.7591|2|DEBUG|Microsoft.AspNetCore.Server.Kestrel|Connection id "0HL8G4U42CK65" stopped.
2017-10-10 23:40:31.8153|1|INFO|Microsoft.AspNetCore.Hosting.Internal.WebHost|Request starting HTTP/1.1 GET http://localhost:56152/
2017-10-10 23:40:31.8607|4|DEBUG|Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware|The request path / does not match a supported file type
2017-10-10 23:40:32.0160|1|DEBUG|Microsoft.AspNetCore.Routing.RouteBase|Request successfully matched the route with name 'default' and template '{controller=Home}/{action=Index}/{id?}'.
2017-10-10 23:40:32.1120|1|DEBUG|Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker|Executing action ASP.NET_Core_2___VS2017.Controllers.HomeController.Index (ASP.NET Core 2 - VS2017)
2017-10-10 23:40:32.1326|1|INFO|Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker|Executing action method ASP.NET_Core_2___VS2017.Controllers.HomeController.Index (ASP.NET Core 2 - VS2017) with arguments ((null)) - ModelState is Valid
2017-10-10 23:40:32.1326|0|INFO|ASP.NET_Core_2___VS2017.Controllers.HomeController|Hello, this is the index!
2017-10-10 23:40:32.1620|2|DEBUG|Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker|Executed action method ASP.NET_Core_2___VS2017.Controllers.HomeController.Index (ASP.NET Core 2 - VS2017), returned result Microsoft.AspNetCore.Mvc.ViewResult.
2017-10-10 23:40:32.1620|1|DEBUG|Microsoft.AspNetCore.Mvc.Razor.RazorViewEngine|View lookup cache miss for view 'Index' in controller 'Home'.
2017-10-10 23:40:33.6906|1|DEBUG|Microsoft.AspNetCore.Mvc.Razor.Internal.RazorViewCompiler|Compilation of the generated code for the Razor file at 'X:\nlog\NLog.Web\examples\ASP.NET Core 2\Visual Studio 2017\ASP.NET Core 2 - VS2017\Views\Home\Index.cshtml' started.
2017-10-10 23:40:35.7180|2|DEBUG|Microsoft.AspNetCore.Mvc.Razor.Internal.RazorViewCompiler|Compilation of the generated code for the Razor file at 'X:\nlog\NLog.Web\examples\ASP.NET Core 2\Visual Studio 2017\ASP.NET Core 2 - VS2017\Views\Home\Index.cshtml' completed in 2024.1338ms.
2017-10-10 23:40:35.7988|1|DEBUG|Microsoft.AspNetCore.Mvc.Razor.Internal.RazorViewCompiler|Compilation of the generated code for the Razor file at 'X:\nlog\NLog.Web\examples\ASP.NET Core 2\Visual Studio 2017\ASP.NET Core 2 - VS2017\Views\_ViewStart.cshtml' started.