.net core 2.1 Nlog.Web.AspNetCore Nlog日志

1、先创建 .net core Web 应用程序,选择API

2、安装 Nuget 包：Nlog.Web.AspNetCore

install-package Nlog
install-package Nlog.Web.AspNetCore

或者打开Nuget管理界面搜索Nlog.Web.AspNetCore(我安装的版本是V4.9.0)

3、添加配置文件： nlog.config  

注意，此处nlog.config最好是小写的，需修改属性使其始终复制

<?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="Info"
      internalLogFile="c:\temp\internal-nlog.txt">

  <!-- enable asp.net core layout renderers -->
  <extensions>
    <add assembly="NLog.Web.AspNetCore"/>
  </extensions>

  <!-- the targets to write to -->
  <targets>
    <!-- write logs to file  -->
    <target xsi:type="File" name="allfile" fileName="c:\temp\nlog-all-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />

    <!-- another file log, only own logs. Uses some ASP.NET core renderers -->
    <target xsi:type="File" name="ownFile-web" fileName="c:\temp\nlog-own-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}|url: ${aspnet-request-url}|action: ${aspnet-mvc-action}" />
  </targets>

  <!-- rules to map from logger name to target -->
  <rules>
    <!--All logs, including from Microsoft-->
    <logger name="*" minlevel="Trace" writeTo="allfile" />

    <!--Skip non-critical Microsoft logs and so log only own logs-->
    <logger name="Microsoft.*" maxlevel="Info" final="true" /> <!-- BlackHole without writeTo -->
    <logger name="*" minlevel="Trace" writeTo="ownFile-web" />
  </rules>
</nlog>

nlog.config(来源：官方文档)

配置appsettings.json

 "Logging": {
    "LogLevel": {
      "Default": "Trace",
      "Microsoft": "Information"
    }
  }

4、注册日志依赖

方法一：通过修改Program.cs

//需引用
//using Microsoft.Extensions.Logging;
//using NLog.Web;

public class Program
    {
        public static void Main(string[] args)
        {
            NLog.Web.NLogBuilder.ConfigureNLog("nlog.config");
            CreateWebHostBuilder(args).Build().Run();
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>()
                .ConfigureLogging(logging =>
                 {
                     logging.ClearProviders(); //移除已经注册的其他日志处理程序
                     logging.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace); //设置最小的日志级别
                 })
                 .UseNLog();
    }

Program.cs

方法二：通过修改Startup.cs里的Configure函数

//需引用
//using NLog.Extensions.Logging;
//using NLog.Web;

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseHsts();
            }

            app.UseHttpsRedirection();

            loggerFactory.AddNLog();//添加NLog
            env.ConfigureNLog("nlog.config");//读取Nlog配置文件

            app.UseMvc();
        }

Configure

5、修改 Controller, 输出日志：

  [Route("api/")]
    public class LoginController : Controller
    {
        private ILogger<LoginController> logger;
         public LoginController(ILogger<LoginController> _logger)
        {
             logger = _logger;
          }

        [Route("Login")]
        [HttpGet]
        public stringLogin()
        {
            logger.LogInformation("Info日志");
            logger.LogError("Error日志");
            logger.LogWarning("Warning日志");
            logger.LogCritical("Critical日志");
            logger.LogWarning("Warning日志");
            logger.LogTrace("Trace日志");
            logger.Log(LogLevel.Warning, "LogWarn日志");
            logger.Log(LogLevel.Debug, "LogDebug日志");
            logger.Log(LogLevel.Error, "LogError日志");
            return "";
        }
}     

控制器

打印日志的时候有两种方式

logger.Log(LogLevel.Warning, "LogWarning日志:"); //标红的地方可以选择日志的级别

logger.LogWarning("Warning日志");//直接调内置的级别函数

6、结果

程序跑起来之后会出现前两个文件~访问完接口后会出现最后那个文件

internal-nlog 记录了NLog的启动及加载config的信息。
nlog-all 记录了所有日志
nlog-own 记录了我们自定义的日志

 7、修改配置

打开官方提供的nlog.config  配置参考 https://github.com/NLog/NLog/wiki/Configuration-file

子节点<target>  配置参考 https://nlog-project.org/config/?tab=targets

属性Layout表示输出文本格式 配置参考 https://nlog-project.org/config/?tab=layouts

子节点<rule>  日志的路由表  顺序是从上往下 一个<logger>就是一个路由信息

日志级别：Trace >Debug> Information >Warn> Error> Fatal
<logger>属性:
name - 日志源/记录者的名字 (允许使用通配符*)
minlevel ： 匹配日志范围的最低级别
maxlevel ： 匹配日志范围的最高级别
level ： 单一日志级别
levels ： 一系列日志级别，由逗号分隔
writeTo ： 日志应该被写入的目标，由逗号分隔，与target的你name对应
final ： 为true标记当前规则为最后一个规则。其后的logger不会运行

附最后的配置文档

<?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"
    >

  <!-- the targets to write to -->
  <targets>
    <!-- write logs to file  -->
    <target xsi:type="File" name="allfile" fileName="log\${shortdate}-All.log"
            layout="${longdate} | ${event-properties:item=EventId_Id:whenEmpty=0} | ${uppercase:${level}}|${logger} |${message} ${exception:format=tostring}" />

    <!-- another file log, only own logs.Uses some ASP.NET core renderers -->
    <target xsi:type="File" name="errorfile" fileName="log\${shortdate}-Error.log"
            layout="${longdate} | ${event-properties:item=EventId_Id:whenEmpty=0} | ${uppercase:${level}} | ${logger} | ${message} ${exception:format=tostring} | url: ${aspnet-request-url} | action: ${aspnet-mvc-action} | ${callsite}" />

    <target xsi:type="File" name="taskfile" fileName="log\${shortdate}-Warn.log"
            layout="${longdate} | ${event-properties:item=EventId_Id:whenEmpty=0} | ${uppercase:${level}} | ${logger} | ${message} ${exception:format=tostring} | url: ${aspnet-request-url} | action: ${aspnet-mvc-action} | ${callsite}" />

    <target xsi:type="File" name="runfile" fileName="log\${shortdate}-Info.log"
            layout="${longdate} | ${event-properties:item=EventId_Id:whenEmpty=0} | ${uppercase:${level}} | ${logger} | ${message} ${exception:format=tostring} | url: ${aspnet-request-url} | action: ${aspnet-mvc-action} | ${callsite}" />

  </targets>

  <!-- rules to map from logger name to target -->
  <rules>
    <!--All logs, including from Microsoft-->
    <logger name = "*" minlevel="Trace" writeTo="allfile" />
    <!--Skip non-critical Microsoft logs and so log only own logs-->
    <logger name = "*" levels="Error,Warn,Critical" writeTo="errorfile" />
    <logger name = "*" level="Info" writeTo="taskfile" />
    <logger name = "*" level="Warn" writeTo="runfile" final="true"/>

  </rules>
</nlog>

nlog.config

参考github: https://github.com/nlog/nlog/wiki