Core使用NLog记录日志

一、新建日志表

CREATE TABLE [dbo].[Sys_Log](
	[Id] [varchar](50) NOT NULL CONSTRAINT [DF_Sys_Log_Id]  DEFAULT (newid()),
	[Application] [varchar](200) NULL,
	[Logger] [varchar](200) NULL,
	[Level] [varchar](50) NULL,
	[Message] [varchar](max) NULL,
	[Exception] [varchar](max) NULL,
	[Callsite] [varchar](200) NULL,
	[CreateDate] [datetime] NULL,
 CONSTRAINT [PK_SYS_LOG] PRIMARY KEY CLUSTERED 
(
	[Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'主键（默认值是newid()）' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log', @level2type=N'COLUMN',@level2name=N'Id'
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'日志所属应用' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log', @level2type=N'COLUMN',@level2name=N'Application'
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'日志所属类' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log', @level2type=N'COLUMN',@level2name=N'Logger'
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'日志级别' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log', @level2type=N'COLUMN',@level2name=N'Level'
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'日志信息' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log', @level2type=N'COLUMN',@level2name=N'Message'
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'异常信息' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log', @level2type=N'COLUMN',@level2name=N'Exception'
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'日志所属方法' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log', @level2type=N'COLUMN',@level2name=N'Callsite'
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'创建时间' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log', @level2type=N'COLUMN',@level2name=N'CreateDate'
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'系统异常日志表' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Sys_Log'
GO

二、准备配置文件

设置<parameter>节点中的layout="${event-properties:item=callsite}" ，可以自定义日志表中某列的值。
如果设置了layout="${event-properties:item=callsite}"，但是没有通过LogEventInfo.Properties[""]对参数赋值，那数据库中本条数据对应的字段值就为空。

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

  <!-- 加载ASP.NET Core插件 -->
  <extensions>
    <add assembly="NLog.Web.AspNetCore"/>
  </extensions>

  <!-- 输出目的地 -->
  <targets>
    <!-- 输出到文件,这个文件记录所有日志 -->
    <target xsi:type="File" name="allfile" fileName="d:\temp\nlog-all-${shortdate}.log"
                layout="${longdate} | ${event-properties:item=EventId.Id} | ${logger} | ${uppercase:${level}} | ${message} ${exception}" />

    <!-- 另外一个日志记录文件,户口也跳过Microsoft开头相关日志信息 -->
    <target xsi:type="File" name="ownFile-web" fileName="d:\temp\nlog-own-${shortdate}.log"
                layout="${longdate} | ${event-properties:item=EventId.Id} | ${logger} | ${uppercase:${level}} | ${message} ${exception} | ${aspnet-mvc-controller} | ${aspnet-mvc-action}" />

    <!-- write to the void aka just remove -->
    <target xsi:type="Null" name="blackhole" />

    <target name="database" xsi:type="Database">
      <connectionString>${var:connectionString}</connectionString>

      <commandText>
        insert into dbo.Sys_Log (
        Application, CreateDate, Level, Message,Logger, Callsite, Exception
        ) values (
        @Application, @CreateDate, @Level, @Message,@Logger, @Callsite, @Exception
        );
      </commandText>

      <parameter name="@application" layout="${event-properties:item=application}" />
      <parameter name="@createDate" layout="${date}" />
      <parameter name="@level" layout="${level}" />
      <parameter name="@message" layout="${message}" />
      <parameter name="@logger" layout="${logger}" />
      <parameter name="@callSite" layout="${event-properties:item=callsite}" />
      <parameter name="@exception" layout="${exception:format=toString,Data}" />

    </target>
  </targets>

  <!-- 写入目的地的规则 -->
  <rules>
    <!--全部记录,包括Microsoft开头的相关日志信息-->
    <!--<logger name="*" minlevel="Trace" writeTo="allfile" />-->

    <!--跳过Microsoft开头的相关日志信息-->
    <logger name="Microsoft.*" minlevel="Trace" writeTo="blackhole" final="true" />
    <logger name="*" minlevel="Trace" writeTo="database" />
    <!--<logger name="*" minlevel="Trace" writeTo="ownFile-web" />-->
  </rules>
</nlog>

三、设置Core启用NLog

1、方法一

步骤一：

public class Program
{
    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
        .UseNLog()//配置NLog（1）
        .UseStartup<Startup>();
}

步骤二：

public class Startup
{
    public Startup(IConfiguration configuration, IHostingEnvironment env)
    {
        Configuration = configuration;

        //配置NLog（2）
        env.ConfigureNLog("nlog.config");
        LogManager.Configuration.Variables["connectionString"] = Configuration["ConnectionString:SqlServer:Value"];
        LogManager.Configuration.Variables["configDir"] = Configuration.GetSection("LogFilesDir").Value;
    }
}

2、方法二

步骤一：

public class Startup
{
    public Startup(IConfiguration configuration, IHostingEnvironment env)
    {
        Configuration = configuration;

        //配置NLog（1）
        env.ConfigureNLog("nlog.config");
        LogManager.Configuration.Variables["connectionString"] = Configuration["ConnectionString:SqlServer:Value"];
        LogManager.Configuration.Variables["configDir"] = Configuration.GetSection("LogFilesDir").Value;
    }
}

步骤二：

public class Startup
{
	public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
	{
		if (env.IsDevelopment())
		{
			app.UseDeveloperExceptionPage();
		}
		else
		{
			app.UseExceptionHandler("/Home/Error");
		}
	
		//配置NLog（2）
		loggerFactory.AddNLog();
		app.AddNLogWeb();
	}
}

四、记录日志

public IActionResult Index()
{
    ViewData["Err"] = string.Empty;

    try
    {
        LogEventInfo ei = new LogEventInfo(NLog.LogLevel.Info, System.Reflection.MethodBase.GetCurrentMethod().DeclaringType.FullName, "获取PersonalAccount_Apply成功");
        ei.Properties["application"] = "myApplication";
        Logger logger = LogManager.GetCurrentClassLogger();
        logger.Log(ei);

        int a = 1 - 1;
        int result = 5 / a;
    }
    catch (Exception ex)
    {
        LogEventInfo ei = LogEventInfo.Create(NLog.LogLevel.Error, System.Reflection.MethodBase.GetCurrentMethod().DeclaringType.FullName, ex, null, "获取PersonalAccount_Apply失败");
        ei.Properties["application"] = "myApplication";
        ei.Properties["callsite"] = "callsite";
        Logger logger = LogManager.GetCurrentClassLogger();
        logger.Log(ei);
        string message = ex.Message;
    }
    return View();
}