asp.net core之NLog | 易学教程

NuGet添加 NLog.Web.AspNetCore。

<PackageReference Include="Microsoft.AspNetCore.App" />

添加配置文件

新建一个文件nlog.config(建议全部小写，linux系统中要注意)，并右键点击其属性，将其“复制到输出目录”设置为“始终复制”。文件内容如下

<?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">

  <targets>
    
    <target xsi:type="File" 
            name="allfile" 
            keepFileOpen="false" 
            encoding="utf-8"
            fileName="${basedir}/logs/${shortdate}-${level}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />
    
    
    <target xsi:type="Null" name="blackhole" />
    
    <!--需要安装下mysql驱动-->
    <target name="database" xsi:type="Database" dbProvider="MySql.Data.MySqlClient.MySqlConnection, MySql.Data" 
            connectionString="server=127.0.0.1;Database=example;user id=root;password=qwe123;SslMode=none" >
      <commandText>
        insert into log (
           Application, Logged, Level, Message,Username,ServerName, Url,RemoteAddress,Logger, CallSite, Exception
        ) values (
           @Application, @Logged, @Level, @Message,@Username,@ServerName, @Url,@RemoteAddress,@Logger, @Callsite, @Exception
        );
      </commandText>
      <parameter name="@application" layout="yourappname" />
      <parameter name="@logged" layout="${date}" />
      <parameter name="@level" layout="${level}" />
      <parameter name="@message" layout="${message}" />
      <parameter name="@username" layout="${identity}" />
      <parameter name="@serverName" layout="${aspnet-request-host}" />
      <parameter name="@url" layout="${aspnet-request-url:IncludeQueryString=true}" />
      <parameter name="@remoteAddress" layout="${aspnet-Request-ip}" />
      <parameter name="@logger" layout="${logger}" />
      <parameter name="@callSite" layout="${callsite}" />
      <parameter name="@exception" layout="${exception:tostring}" />
    </target>
    
  </targets>
  <rules>
    <logger name="*" minlevel="Trace" writeTo="allfile" />
    <logger name="Microsoft.*" minlevel="Trace" writeTo="blackhole" final="true" />
    <logger name="dblog" minlevel="Trace" writeTo="database" />
  </rules>
</nlog>

<!--
 CREATE TABLE `log` (
  `Id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `Application` varchar(50) DEFAULT NULL,
  `Logged` datetime DEFAULT NULL,
  `Level` varchar(50) DEFAULT NULL,
  `Message` text DEFAULT NULL,
  `UserName` varchar(512) Default Null,
  `ServerName` text Default Null,
  `Url` text NULL,
  `RemoteAddress` nvarchar(100) NULL,
  `Logger` text DEFAULT NULL,
  `Callsite` text DEFAULT NULL,
  `Exception` text DEFAULT NULL,
  PRIMARY KEY (`Id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
-->

    <Content Update="nlog.config">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>

修改Program.cs文件

添加引用 NLog.Web 和 Microsoft.Extensions.Logging。
在 .UseStartup() 后添加一句 .UseNLog() 。

如果要禁用默认的输出框日志，可以调用logging.ClearProviders()

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
    WebHost.CreateDefaultBuilder(args)
        .UseStartup<Startup>()
        .ConfigureLogging(logging =>
        {
            logging.ClearProviders();
            logging.SetMinimumLevel(LogLevel.Trace);
        })
        .UseNLog();

输出到数据库

除了把日志输出到文件之外，也可以保存到SQL Server， PostgreSQL， MySQL， Elasticsearch等。下面是保存到SQL Server的一个示例配置：

<?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"
      autoReload="true"
      internalLogLevel="info"
      internalLogFile="d:\temp\logs\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="d:\temp\logs\all-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />

    <target name="blackhole" xsi:type="Null" />

    <target name="database" xsi:type="Database" dbProvider="System.Data.SqlClient">
      <connectionString>
        Server=.;Database=Log;Trusted_Connection=True
      </connectionString>
      <commandText>
              insert into dbo.Log (
              Application, Logged, Level, Message,
              Logger, CallSite, Exception
              ) values (
              @Application, @Logged, @Level, @Message,
              @Logger, @Callsite, @Exception
              );
          </commandText>
 
          <parameter name="@application" layout="Application" />
          <parameter name="@logged" layout="${date}" />
          <parameter name="@level" layout="${level}" />
          <parameter name="@message" layout="url: ${aspnet-request-url} | action: ${aspnet-mvc-action} | ${message}" />
 
          <parameter name="@logger" layout="${logger}" />
          <parameter name="@callSite" layout="${callsite:filename=true}" />
          <parameter name="@exception" layout="${exception:tostring}" />
    </target>
  </targets>

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

配置简要说明

targets：用于配置输出相关内容，比如 type 属性可选项为File、Mail、Console等，用于设置输出目标，layout属性用于设置输出信息的组成元素及格式。
rules：其实是一个“路由表”，日志是从上到下匹配的。 logger name="Microsoft." maxlevel="Info" final="true" 一句话的 final="true" 过滤掉了"Microsoft." Info级别以下的日志。

全局异常中间件

除了输出日志外，可以写一个中间件来处理全局的异常。

public class GlobalErrorHandlingMiddleware
{
    private readonly RequestDelegate next;
    private readonly ILogger<GlobalErrorHandlingMiddleware> _logger;

    public GlobalErrorHandlingMiddleware(RequestDelegate next, ILogger<GlobalErrorHandlingMiddleware> logger)
    {
        this.next = next;
        this._logger = logger;
    }

    public async Task Invoke(HttpContext context)
    {
        try
        {
            await next(context);
        }
        catch (Exception ex)
        {

            var Request = context.Request;
            ///访问路径
            string visit_url = Request.Path;
            ///URL 请求方法
            string method = Request.Method.ToUpper();
            ///URL 请求的参数
            string url_paramters = string.Empty;

            if (method == "GET") url_paramters = Request.QueryString.Value;


            if (method == "POST")
            {
                foreach (var item in Request.Form)
                    url_paramters = url_paramters + item.Key + "=" + item.Value + "&";
            }

            ///错识信息
            string err_msg = ex.Message;//ex.StackTrace;

            ///日志格式内容
            var logs_msg = $"{visit_url}#{method}#{url_paramters}#{err_msg}";

            _logger.LogError(logs_msg);

            var statusCode = context.Response.StatusCode;

            var msg = $"Status Code: {statusCode}, Message: {ex.Message}";

            await HandleExceptionAsync(context, msg);
        }
    }

    private static Task HandleExceptionAsync(HttpContext context, string msg)
    {
        //var data = new Result { Title = "异常中间件返回", Msg = msg };
        //var result = JsonConvert.SerializeObject(data);
        //context.Response.ContentType = "application/json;charset=utf-8";
        return context.Response.WriteAsync(msg);
    }
}

public static class GlobalErrorHandlingMiddlewareExtensions
{
    public static IApplicationBuilder UseGlobalErrorHandlingMiddleware(
        this IApplicationBuilder builder)
    {
        return builder.UseMiddleware<GlobalErrorHandlingMiddleware>();
    }
}

来源：oschina

链接：https://my.oschina.net/it110/blog/4358825

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ASP.NET Core

nlog

SQL Server

ElasticSearch