.NET Core使用Nlog记录日志

1.引入Nuget包

Nlog

Nlog.Web.AspNetCore

2.添加nlog配置文件

 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="Warn"
 6        internalLogFile="internal-nlog.txt">
 7      <!--define various log targets-->
 8      <targets>
 9         <!--write logs to file-->
10          <target xsi:type="File" name="allfile" fileName="nlog-all-${shortdate}.log"
11                   layout="${longdate}|${logger}|${uppercase:${level}}|${message} ${exception}" />
12
13          <target xsi:type="File" name="ownFile-web" fileName="nlog-my-${shortdate}.log"
14                   layout="${longdate}|${logger}|${uppercase:${level}}|${message} ${exception}" />
15         <target xsi:type="Null" name="blackhole" />
16   </targets>
17      <rules>
18          <!--All logs, including from Microsoft-->
19          <logger name="*" minlevel="Trace" writeTo="allfile" />
20
21        <!--Skip Microsoft logs and so log only own logs-->
22          <logger name="Microsoft.*" minlevel="Trace" writeTo="blackhole" final="true" />
23          <logger name="*" minlevel="Trace" writeTo="ownFile-web" />
24   </rules>
25 </nlog>

3.使用nlog

在StartUp.cs中配置配置日志中间件

 1   public void Configure(IApplicationBuilder app, IHostingEnvironment env,ILoggerFactory loggerFactory)
 2         {
 3             app.UseStaticFiles();
 4             //使用NLog作为日志记录工具
 5             loggerFactory.AddNLog();
 6             //引入Nlog配置文件
 7             env.ConfigureNLog("nlog.config");
 8             if (env.IsDevelopment())
 9             {
10                 app.UseDeveloperExceptionPage();
11             }
12             app.UseMvc();
13         }

4.在程序中中使用nlog写日志

下面是注入到控制器中的示例

 1  public class ValuesController : Controller
 2     {
 3
 4         private ILogger<ValuesController> logger;
 5         public ValuesController(ILogger<ValuesController> _logger)
 6         {
 7             logger = _logger;
 8         }
 9         // GET api/values
10         [HttpGet]
11         public string Get()
12         {
13             logger.LogError("123");
14             return "value";
15         }

调用该api,然后查看文件目录

5.日志文件生成在指定目录下

大家会发现文件是生成在项目目录下的，日志多的时候，会导致文件目录太乱

此时，只需更改nlog.config中的内容如下即可生成在logs目录里

 <targets>
        <!--write logs to file-->
         <target xsi:type="File" name="allfile" fileName="logs/all/nlog-all-${shortdate}.log"
                  layout="${longdate}|${logger}|${uppercase:${level}}|${message} ${exception}" />

         <target xsi:type="File" name="ownFile-web" fileName="logs/my/nlog-my-${shortdate}.log"
                  layout="${longdate}|${logger}|${uppercase:${level}}|${message} ${exception}" />
        <target xsi:type="Null" name="blackhole" />
  </targets>

原文地址：https://www.cnblogs.com/qmhuang/p/8305915.html