NLog在asp.net core中的应用

2024-12-15 技术教程

Asp.net core中，自带的Log是在当selfhost运行时，在控制台中输出，不便于查阅，如果用一个log架框，把日志持久化，便于查询．

NLog是一个免费的日志记录框架，专门为.net平台下的框架提供日志功能，本文主要说明asp.net core下怎么使用NLog。

首先用Nuget安装NLog.Extensions.Logging和NLog.Web.AspNetCore两个类库。

修改project.json，在publishOptions中添加”nlog.config节点”

"publishOptions":{

"include":[

"wwwroot",

"**/*.cshtml",

"appsettings.json",

"web.config",

"nlog.config"

]

}

在StartUp.cs中添加

publicvoidConfigureServices(IServiceCollectionservices){//Addframeworkservices.services.AddMvc();//为NLog.web注入HttpContextAccessorservices.AddSingleton<IHttpContextAccessor,HttpContextAccessor>();……}publicvoidConfigure(IApplicationBuilderapp,IHostingEnvironmentenv,ILoggerFactoryloggerFactory){//添加NLog到.netcore框架中loggerFactory.AddNLog();//添加NLog的中间件app.AddNLogWeb();//指定NLog的配置文件env.ConfigureNLog("nlog.config");……}

HomeController.cs中是自定义日志

staticLoggerLogger=LogManager.GetCurrentClassLogger();publicIActionResultIndex(){Logger.Info("普通信息日志");Logger.Debug("调试日志");Logger.Error("错误日志");Logger.Fatal("异常日志");Logger.Warn("警告日志");Logger.Trace("跟踪日志");Logger.Log(NLog.LogLevel.Warn,"Log日志");try{inti=0;vara=10/i;}catch(Exceptionexc){//异常日志Logger.Fatal(exc,exc.Message);}returnView();}

NLog.config，有两种日志，记录在C:\temp下，一种是全部日志，一种是自己通过NLog函数记录的日志。如果日志库异常，会产生在c:\temp\internal-nlog.txt下，

<?xmlversion="1.0"encoding="utf-8"?><nlogxmlns="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"><extensions><addassembly="NLog.Web.AspNetCore"/></extensions><targets><targetxsi:type="File"name="allfile"fileName="c:\temp\nlog-all-${shortdate}.log"layout="${longdate}|${event-properties:item=EventId.Id}|${logger}|${uppercase:${level}}|${message}${exception}"/><targetxsi:type="File"name="ownFile-web"fileName="c:\temp\nlog-own-${shortdate}.log"layout="${longdate}|${event-properties:item=EventId.Id}|${logger}|${uppercase:${level}}|${message}${exception}|url:${aspnet-request-url}|action:${aspnet-mvc-action}"/><targetxsi:type="Null"name="blackhole"/></targets><rules><loggername="*"minlevel="Trace"writeTo="allfile"/><loggername="Microsoft.*"minlevel="Trace"writeTo="blackhole"final="true"/><loggername="*"minlevel="Trace"writeTo="ownFile-web"/></rules></nlog>

Layout中$后的数据就是要写日志的内容，关于这些数据可参考https://github.com/nlog/nlog/wiki/Layout-Renderers，可以根据自己的需要，选择要保存的日志数据，如下图是web中的日志数据：

如果想把日志保存到数据库中，可以把NLog.config修改如下：

<?xmlversion="1.0"encoding="utf-8"?><nlogxmlns="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"><extensions><addassembly="NLog.Web.AspNetCore"/></extensions><targets><targetname="database"xsi:type="Database"connectionString="server=.;database=nglogdb;uid=SQL用户名;pwd=SQL密码;"><commandText>INSERTINTO[dbo].[NLog]([MachineName],[SiteName],[Logged],[Level],[UserName],[Message],[Logger],[Properties],[Host],[Controller],[Action],[Url],[CallSite],[Exception])VALUES(@machineName,@siteName,@logged,@level,@userName,@message,@logger,@properties,@host,@controller,@action,@url,@callSite,@exception);</commandText><parametername="@machineName"layout="${machinename}"/><parametername="@siteName"layout="${iis-site-name}"/><parametername="@logged"layout="${date}"/><parametername="@level"layout="${level}"/><parametername="@username"layout="${aspnet-user-identity}"/><parametername="@message"layout="${message}"/><parametername="@logger"layout="${logger}"/><parametername="@properties"layout="${all-event-properties:separator=|}"/><parametername="@host"layout="${aspnet-request-host}"/><parametername="@controller"layout="${aspnet-MVC-Controller}"/><parametername="@action"layout="${aspnet-MVC-Action}"/><parametername="@url"layout="${aspnet-request-url}"/><parametername="@callSite"layout="${callsite}"/><parametername="@exception"layout="${exception:tostring}"/></target></targets><rules><loggername="*"minlevel="Trace"writeTo="database"/></rules></nlog>

数据库数据如下：