NLog 记录日志是微软官方推荐使用。
接下来，通过配置日志记录到文件和Sql Server数据库。
第一步：首先添加包NLog.Config （可通过微软添加包命令Install-Package 包名进行添加，也可以通过管理NuGet程序包进行添加），添加成功后会生成NLog.config配置文件。并对该配置文件进行配置。详细配置可参考Git上 NLog说明。
一下是我个人配置。
<?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" xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd" autoReload="true" throwExceptions="false" internalLogLevel="Warn" internalLogFile="Logs/nlog-internal.log"> <!--internalLogLevel="Off"--> <!-- optional, add some variables https://github.com/nlog/NLog/wiki/Configuration-file#variables --> <variable value="myvalue"/> <!-- See https://github.com/nlog/nlog/wiki/Configuration-file for information on customizing logging rules and outputs. --> <targets> <!-- add your targets here See https://github.com/nlog/NLog/wiki/Targets for possible targets. See https://github.com/nlog/NLog/wiki/Layout-Renderers for the possible layout renderers. --> <!-- Write events to a file with the date in the filename. <target xsi:type="File" fileName="${basedir}/logs/${shortdate}.log" layout="${longdate} ${uppercase:${level}} ${message}" /> --> <!-- write logs to file --> <target xsi:type="File" fileName="Logs/${date:format=yyyyMM}/nlog-all-${shortdate}.log" layout="${longdate}|${event-properties:item=EventId.Id}|${uppercase:${level}}|${logger} ${newline}${message} ${exception} ${newline}" /> <target xsi:type="File" fileName="Logs/${date:format=yyyyMM}/nlog-own-${shortdate}.log" layout="${longdate}|${event-properties:item=EventId.Id}|${uppercase:${level}}|${logger} ${newline}${message} ${exception} ${newline} --- |url: ${aspnet-request-url}|action: ${aspnet-mvc-action}" /> <target xsi:type="Null" /> <target xsi:type="Database"> <connectionString>${var:connectionString}</connectionString> <commandText> insert into syslogs (Application,Levels,Operatingtime,Operatingaddress,Userid,Logger,Callsite,Requesturl,Referrerurl,Action,Message,Exception) values (@application,@levels,@operatingtime,@operatingaddress,@userid,@logger,@callSite,@requesturl,@referrerurl,@action,@message,@exception); </commandText> <parameter layout="WebApi" /> <parameter layout="${level}" /> <parameter layout="${date}" /> <parameter layout="${aspnet-Request-IP}" /> <parameter layout="1" /> <parameter layout="${logger}" /> <parameter layout="${callsite}" /> <parameter layout="${aspnet-request-url}" /> <parameter layout="${aspnet-request}" /> <parameter layout="${aspnet-mvc-action}" /> <parameter layout="${message}" /> <parameter layout="${exception:tostring}" /> </target> </targets> <rules> <!-- add your logging rules here --> <!-- Write all events with minimal level of Debug (So Debug, Info, Warn, Error and Fatal, but not Trace) to "f" <logger minlevel="Debug" writeTo="f" /> --> <!--All logs, including from Microsoft--> <!--minlevel 改为Trace 跟踪全部 Error 只捕获异常--> <logger minlevel="Error" writeTo="allfile" /> <!--Skip Microsoft logs and so log only own logs--> <logger minlevel="Trace" writeTo="blackhole" final="true" /> <logger minlevel="Trace" writeTo="ownFile-web" /> <logger minlevel="Trace" writeTo="database" /> </rules> </nlog> <!--增加引用 <PackageReference Include="NLog.Extensions.Logging" Version="1.2.1" /> <PackageReference Include="NLog.Web.AspNetCore" Version="4.6.0" />-->
说明：targets 中有一节点为Database，是配置将日志写入数据库中，注意需要在数据库中添加该记录日志表。
{ "ConnectionStrings": { "DefaultConnection": "Data Source=192.168.30.133;Initial Catalog=Test;User ID=sa;Password=123456;Trusted_Connection=True;MultipleActiveResultSets=true;Integrated Security=false;" }, "Logging": { "LogLevel": { "Default": "Warning" } }, "AllowedHosts": "*" }
第二步：添加包NLog.Web.AspNetCore，在Program.cs中的WebHost加入".UseNLog()"（该属于程序集NLog.Web，需要添加引用using NLog.Web;）,即为添加nlog.
using Microsoft.AspNetCore; using Microsoft.AspNetCore.Hosting; using NLog.Web; namespace WebApi { public class Program { public static void Main(string[] args) { CreateWebHostBuilder(args).Build().Run(); } public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args) .UseStartup<Startup>() .UseNLog(); //加入nlog日志 } }
第三步：在Startup.cs中的Configure方法中添加记日志代码，即需要加载的配置文件和配置日志写入数据库连接字符串代码。注意：为避免中文乱码问题需要添加System.Text.Encoding.CodePages包。