NLog是一个简单灵活的.NET日志记录类库,NLog的API非常类似于log4net,且配置方式非常简单。通过使用NLog,我们可以在任何一种.NET语言中输出带有上下文的调试信息,根据项目需求配置署出格式和输出目标的规则。
NLog使用路由进行配置,但log4net却使用层次性的appender配置,这样就让NLog的配置文件非常容易阅读,并便于今后维护。
支持多种形式输出日志:文本文件 系统日志 数据库 控制台 邮箱 等
下载
通过Nuget安装NLog,你也可以同时安装NLog.Config,它会在项目目录下帮你建立一个配置文件NLog.config,不过不需要,我们直接手动建立一个,你也可以将配置的信息写入到 App.config/Web.config,我比较喜欢独立出来,不与其它配置掺和在一起。
配置
在项目根目录下新建一个NLog.config,基本目录结构:targets下面配置日志输出目标及相关参数,rules下面配置目标输出规则。
1 2 3 4 5 6 7 8 9 10 11 | <?xml version="1.0" ?> <nlog> <targets> <target></target> <target></target> </targets> <rules> <logger></logger> <logger></logger> </rules> </nlog> |
记得在NLog.config的属性中设置 Copy to Output Directory: Copy always
现在我们要将日志输出到文本文件,数据库,VS调试窗口,完整配置文件如下:
</>code
- <?xml version="1.0" ?><!--<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- autoReload="true"
- internalLogLevel="Trace"
- internalLogFile="D:\work\log.txt">--><nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- autoReload="true">
- <targets>
- <!-- Log in a separate thread, possibly queueing up to
- 5000 messages. When the queue overflows, discard any
- extra messages-->
- <!-- write logs to file -->
- <target name="file" xsi:type="AsyncWrapper" queueLimit="5000" overflowAction="Discard">
- <target xsi:type="File" fileName="${basedir}/logs/${shortdate}.log" layout="${longdate} ${level:uppercase=true} ${event-context:item=Action} ${message} ${event-context:item=Amount} ${stacktrace}" />
- </target>
- <!-- write log message to database -->
- <target name="db" xsi:type="AsyncWrapper" queueLimit="5000" overflowAction="Discard">
- <target type="Database" dbProvider="mssql" connectionString="Data Source=.\SQLEXPRESS;Initial Catalog=EFinance;Persist Security Info=True;User ID=sa;Password=123456;">
- <commandText>
- INSERT INTO Log(Timestamp,Level,Message,Action,Amount,StackTrace) VALUES(@time_stamp, @level, @message, @action, @amount, @stacktrace); </commandText>
- <!-- database connection parameters -->
- <parameter name="@time_stamp" layout="${date}" />
- <parameter name="@level" layout="${level:uppercase=true}" />
- <parameter name="@message" layout="${message}" />
- <parameter name="@action" layout="${event-context:item=Action}" />
- <parameter name="@amount" layout="${event-context:item=Amount}" />
- <parameter name="@stacktrace" layout="${stacktrace}" />
- </target>
- </target>
- <!--write log message to Visual Studio Output-->
- <target name="debugger" xsi:type="Debugger" layout="NLog: ${date:format=HH\:mm\:ss} | ${level:uppercase=true:padding=-5} | ${message}" />
- </targets>
- <rules>
- <!--TRACE,DEBUG,INFO,WARN,ERROR,FATAL-->
- <logger name="*" minlevel="Trace" writeTo="debugger" />
- <!--INFO,WARN,ERROR,FATAL-->
- <logger name="*" minlevel="Info" writeTo="db" />
- <!--DEBUG,INFO,WARN,ERROR,FATAL-->
- <logger name="*" minlevel="Debug" writeTo="file" />
- </rules></nlog>
如在根节点(nlog)配置 internalLogLevel, internalLogFile,可以查看NLog输出日志时的内部信息,比如你配置文件有错误,很有帮助,不过项目发布后还是关闭比较好,以免影响效率;
在target外面罩了一个 <target>并且xsi:type为 AsyncWrapper,即表示这条 target 将异步输出,这里我将文件和数据库日志异步输出;
db target内指定了数据库连接字符串 connectionString,SQL语句,SQL参数,还可以指定数据库/表创建和删除的脚本(推荐看NLog源码示例,这里不介绍),同时我们自定义了2个参数 action和amount;
target参数里有些是NLog内置参数,比如message,level,date,longdate,exception,stacktrace等,NLog在输出时会自动赋值;
layout设置了每条日志的格式;
在rules节点,我们分别指定了三个target输出日志的级别,NLog用于输出日志的级别包括:Trace,Debug,Info,Warn,Error,Fatal,可以设置 minlevel设置最小级别,也可以用 levels定义你所有需要的级别(多个用逗号分隔)。
封装
简单两句就可以使用NLog了:
NLog.Logger logger = Nlog.LogManager.GetCurrentClassLogger();
logger.Fatal("发生致命错误");
logger.Warn("警告信息");
但是这样只能记录了NLog的内置字段,我们定义的 Amount, Action都不能写入,接下来我们来封装一个Logger:
</>code
- public class Logger
- {
- NLog.Logger _logger; private Logger(NLog.Logger logger)
- {
- _logger = logger;
- } public Logger(string name) : this(LogManager.GetLogger(name))
- {
- } public static Logger Default { get; private set; } static Logger()
- {
- Default = new Logger(NLog.LogManager.GetCurrentClassLogger());
- } #region Debug public void Debug(string msg, params object[] args)
- {
- _logger.Debug(msg, args);
- }
- public void Debug(string msg, Exception err)
- {
- _logger.Debug(err, msg);
- }
- #endregion
- #region Info public void Info(string msg, params object[] args)
- {
- _logger.Info(msg, args);
- } public void Info(string msg, Exception err)
- {
- _logger.Info(err, msg);
- } #endregion
- #region Warn public void Warn(string msg, params object[] args)
- {
- _logger.Warn(msg, args);
- } public void Warn(string msg, Exception err)
- {
- _logger.Warn(err, msg);
- } #endregion
- #region Trace public void Trace(string msg, params object[] args)
- {
- _logger.Trace(msg, args);
- } public void Trace(string msg, Exception err)
- {
- _logger.Trace(err, msg);
- } #endregion
- #region Error public void Error(string msg, params object[] args)
- {
- _logger.Error(msg, args);
- } public void Error(string msg, Exception err)
- {
- _logger.Error(err, msg);
- } #endregion
- #region Fatal public void Fatal(string msg, params object[] args)
- {
- _logger.Fatal(msg, args);
- } public void Fatal(string msg, Exception err)
- {
- _logger.Fatal(err, msg);
- } #endregion
- #region Custom public void Process(Models.Log log)
- { var level = LogLevel.Info; if (log.Level == Models.EFLogLevel.Trace)
- level = LogLevel.Trace; else if (log.Level == Models.EFLogLevel.Debug)
- level = LogLevel.Debug; else if (log.Level == Models.EFLogLevel.Info)
- level = LogLevel.Info; else if (log.Level == Models.EFLogLevel.Warn)
- level = LogLevel.Warn; else if (log.Level == Models.EFLogLevel.Error)
- level = LogLevel.Error; else if (log.Level == Models.EFLogLevel.Fatal)
- level = LogLevel.Fatal; var ei = new MyLogEventInfo(level, _logger.Name, log.Message);
- ei.TimeStamp = log.Timestamp;
- ei.Properties["Action"] = log.Action;
- ei.Properties["Amount"] = log.Amount;
- _logger.Log(level, ei);
- } #endregion
- /// <summary>
- /// Flush any pending log messages (in case of asynchronous targets). /// </summary>
- /// <param name="timeoutMilliseconds">Maximum time to allow for the flush. Any messages after that time will be discarded.</param>
- public void Flush(int? timeoutMilliseconds = null)
- { if (timeoutMilliseconds != null)
- NLog.LogManager.Flush(timeoutMilliseconds.Value);
- NLog.LogManager.Flush();
- }
- } public class MyLogEventInfo : LogEventInfo
- { public MyLogEventInfo() { } public MyLogEventInfo(LogLevel level, string loggerName, string message) : base(level, loggerName, message)
- { } public override string ToString()
- { //Message format //Log Event: Logger='XXX' Level=Info Message='XXX' SequenceID=5
- return FormattedMessage;
- }
- }
</>code
- public class Log : IEntityBase<long>
- { public long Id { get; set; } /// <summary>
- /// 日志级别 Trace|Debug|Info|Warn|Error|Fatal /// </summary>
- public string Level { get; set; }
- public string Message { get; set; }
- public string Action { get; set; }
- public string Amount { get; set; } public string StackTrace { get; set; }
- public DateTime Timestamp { get; set; } private Log() { } public Log(string level, string message, string action = null, string amount = null)
- { this.Level = level; this.Message = message; this.Action = action;
- this.Amount = amount;
- }
- }
Models.Log是我们项目里的日志对象,它对应一个数据表Log,NLog将日志数据写入到这个表;
Process(Models.Log)是我们处理自定义对象的日志方法,用LogEventInfo来写入;
重写 LogEventInfo.ToString() 是因为 LogEventInfo的Message格式是“Log Event: Logger='XXX' Level=Info Message='XXX' SequenceID=5”,不便于查阅,我们只需要我们设置的Message。
使用:
下面是测试方法,我们一共输出9条日志,这9条日志将输出到哪个目标,由配置文件中的Rules/logger决定
</>code
- Logger.Default.Trace("Hello World! Trace");
- Logger.Default.Info("Hello World! Info");
- Logger.Default.Warn("Hello World! Warn");
- Logger.Default.Debug("Hello World! Debug");
- Logger.Default.Error("Hello World! Error");
- Logger.Default.Fatal("Hello World! Fatal");
- Logger.Default.Process(new Models.Log(Models.EFLogLevel.Info, "Hello World! Info", "TEST", "100.00"));
- Logger.Default.Process(new Models.Log(Models.EFLogLevel.Debug, "Hello World! Debug", "TEST", "100.00"));
- Logger.Default.Process(new Models.Log(Models.EFLogLevel.Error, "Hello World! Error", "TEST", "100.00"));
</>code
- Logger.Default.Flush();
因为我们在Target中设置了异步,所以如果我们想当场看到输出结果,就需要使用Flush()方法,实际输出日志时就不需要了。
结果:
查看日志记录:
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