包装 NLog 时如何保留调用点信息
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【中文标题】包装 NLog 时如何保留调用点信息【英文标题】:How to retain callsite information when wrapping NLog 【发布时间】:2011-11-16 18:00:03 【问题描述】:我有一个包装 NLog 的类(称为 NLogger)。我的日志被保存到我的数据库中。 我遇到的问题是如何显示日志记录发生的位置。 我有这个
<parameter name="@Logger" layout="$callsite"/>
但这只是显示 Core.Logging.Loggers.NLogLogger.Log 这是我的 NlogWrapper 而不是调用我的包装器的类。
这是我的包装方法
public void Log(LogType messageType, Type context, string message, Exception exception)
NLog.Logger logger = NLog.LogManager.GetLogger(context.Name);
LogLevel logLevel = LogLevel.Info; // Default level to info
switch (messageType)
case LogType.Debug:
logLevel = LogLevel.Debug;
break;
case LogType.Info:
logLevel = LogLevel.Info;
break;
case LogType.Warning:
logLevel = LogLevel.Warn;
break;
case LogType.Error:
logLevel = LogLevel.Error;
break;
case LogType.Fatal:
logLevel = LogLevel.Fatal;
break;
default:
throw new ArgumentException("Log message type is not supported");
logger.Log(logLevel, message, exception);
【问题讨论】:
【参考方案1】:现在修复呼叫站点的一种更简单的方法是使用LogManager.AddHiddenAssembly(Assembly)
例如
LogManager.AddHiddenAssembly(yourAssembly);
这将修复调用站点,无需进行手动堆栈遍历等。
【讨论】:
这是否涵盖了整个程序集,或者如果从 Func有一种简单的方法可以实现这一点。只需将这些属性添加到您的日志包装方法签名中:
void Log(LogSeverity severity, string message, [CallerFilePath] string fileName = null, [CallerMemberName] string member = null, [CallerLineNumber] int? lineNumber = null);
并将这些传递给包装好的 NLog 方法。
有关 .NET 中 System.Runtime.CompilerServices 属性的更多信息,请参阅 https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.callerfilepathattribute?view=netframework-4.7.2。
【讨论】:
【参考方案3】:要跳过几帧并深入到包装调用者上下文中,请在 App.config 或程序中设置著名的修饰符:
skipFrames=1
示例:
见this page$callsite:skipFrames=Integer
和this page 为$callsite-linenumber:skipFrames=Integer
我建议您在包装器中使用这种格式:
$callsite:fileName=true:includeSourcePath=false:skipFrames=1
此设置的输出如下:
... LicenseServer.LSCore.MainThreadFunction(LSCore.cs:220) ...
【讨论】:
不确定哪个是 NLog 上支持 skipFrames=Integer 功能的最低版本。必须检查他们的文档。 查看此链接以获取布局渲染器列表:github.com/nlog/nlog/wiki/Layout-Renderers 赢家鸡肉晚餐,这对我来说非常适合。 截至今天,这是泛型类唯一可行的解决方案。我试过接受的答案无济于事,但这就像一个魅力。【参考方案4】:伙计们 经过几天的努力和搜索。最后,我只使用一个简单的类构建了 Nlog Wrapper,它可以保留 $callsite 并在创建 Nlog Wrapper 实例时获取正确的记录器名称。我将把代码放在后面加上简单的注释。如您所见,我使用 Stacktrace 来获取正确的记录器名称。使用write和writewithex注册logevnet,这样就可以保留callsite了。
public class NlogWrapper
private readonly NLog.Logger _logger; //NLog logger
/// <summary>
/// This is the construtor, which get the correct logger name when instance created
/// </summary>
public NlogWrapper()
StackTrace trace = new StackTrace();
if (trace.FrameCount > 1)
_logger = LogManager.GetLogger(trace.GetFrame(1).GetMethod().ReflectedType.FullName);
else //This would go back to the stated problem
_logger = LogManager.GetCurrentClassLogger();
/// <summary>
/// These two method are used to retain the $callsite for all the Nlog method
/// </summary>
/// <param name="level">LogLevel.</param>
/// <param name="format">Passed message.</param>
/// <param name="ex">Exception.</param>
private void Write(LogLevel level, string format, params object[] args)
LogEventInfo le = new LogEventInfo(level, _logger.Name, null, format, args);
_logger.Log(typeof(NlogWrapper), le);
private void WriteWithEx(LogLevel level, string format,Exception ex, params object[] args)
LogEventInfo le = new LogEventInfo(level, _logger.Name, null, format, args);
le.Exception = ex;
_logger.Log(typeof(NlogWrapper), le);
#region Methods
/// <summary>
/// This method writes the Debug information to trace file
/// </summary>
/// <param name="message">The message.</param>
public void Debug(String message)
if (!_logger.IsDebugEnabled) return;
Write(LogLevel.Debug, message);
public void Debug(string message, Exception exception, params object[] args)
if (!_logger.IsFatalEnabled) return;
WriteWithEx(LogLevel.Debug, message, exception);
/// <summary>
/// This method writes the Information to trace file
/// </summary>
/// <param name="message">The message.</param>
public void Info(String message)
if (!_logger.IsInfoEnabled) return;
Write(LogLevel.Info, message);
public void Info(string message, Exception exception, params object[] args)
if (!_logger.IsFatalEnabled) return;
WriteWithEx(LogLevel.Info, message, exception);
/// <summary>
/// This method writes the Warning information to trace file
/// </summary>
/// <param name="message">The message.</param>
public void Warn(String message)
if (!_logger.IsWarnEnabled) return;
Write(LogLevel.Warn, message);
public void Warn(string message, Exception exception, params object[] args)
if (!_logger.IsFatalEnabled) return;
WriteWithEx(LogLevel.Warn, message, exception);
/// <summary>
/// This method writes the Error Information to trace file
/// </summary>
/// <param name="error">The error.</param>
/// <param name="exception">The exception.</param>
// public static void Error( string message)
//
// if (!_logger.IsErrorEnabled) return;
// _logger.Error(message);
//
public void Error(String message)
if (!_logger.IsWarnEnabled) return;
//_logger.Warn(message);
Write(LogLevel.Error, message);
public void Error(string message, Exception exception, params object[] args)
if (!_logger.IsFatalEnabled) return;
WriteWithEx(LogLevel.Error, message, exception);
/// <summary>
/// This method writes the Fatal exception information to trace target
/// </summary>
/// <param name="message">The message.</param>
public void Fatal(String message)
if (!_logger.IsFatalEnabled) return;
Write(LogLevel.Fatal, message);
public void Fatal(string message, Exception exception, params object[] args)
if (!_logger.IsFatalEnabled) return;
WriteWithEx(LogLevel.Fatal, message, exception);
/// <summary>
/// This method writes the trace information to trace target
/// </summary>
/// <param name="message">The message.</param>
///
public void Trace(string message, Exception exception, params object[] args)
if (!_logger.IsFatalEnabled) return;
WriteWithEx(LogLevel.Trace, message, exception);
public void Trace(String message)
if (!_logger.IsTraceEnabled) return;
Write(LogLevel.Trace, message);
#endregion
【讨论】:
当你在你的项目中使用它时。只需这样做: NlogWrapper mylog= new NlogWrapper( ); mylog.Error("这是关于:", ex).然后包装类将处理记录器名称和调用站点信息。当您使用 $logger $callsite。您将获得正确的信息,而不是 logwrapper 类调用站点的信息【参考方案5】:或者,您可以从 NLog 设置中避免本机解决方案,并检索文件 |方法 |包装代码中的行信息:
using System.Diagnostics;
...
static private string GetCallsite()
StackFrame sf = new StackTrace(2/*Skip two frames - dive to the callers context*/, true/*Yes I want the file info !*/).GetFrame(0);
return "" + sf.GetFileName() + " | " + sf.GetMethod().Name + "-" + sf.GetFileLineNumber() + " ";
然后你只需调用你的静态方法并在消息之前添加调用站点:
LogManager.GetCurrentClassLogger().Trace(GetCallsite() + "My Trace Message.");
【讨论】:
注意:如果您使用 GetCallsite() 方法,则需要跳过 2 帧,因为这将比包装器本身中的调用方法高一个堆栈级别。然后注意不要从较低级别调用它。 此代码无法很好地扩展。从性能方面来看,使用 StackFrame 的成本很高【参考方案6】:问题是您的包装器没有正确包装。这是一个如何正确包装 NLog 的示例,直接取自source tree of NLog:
using System;
using System.Text;
using NLog;
namespace LoggerWrapper
/// <summary>
/// Provides methods to write messages with event IDs - useful for the Event Log target.
/// Wraps a Logger instance.
/// </summary>
class MyLogger
private Logger _logger;
public MyLogger(string name)
_logger = LogManager.GetLogger(name);
public void WriteMessage(string eventID, string message)
///
/// create log event from the passed message
///
LogEventInfo logEvent = new LogEventInfo(LogLevel.Info, _logger.Name, message);
//
// set event-specific context parameter
// this context parameter can be retrieved using $event-context:EventID
//
logEvent.Context["EventID"] = eventID;
//
// Call the Log() method. It is important to pass typeof(MyLogger) as the
// first parameter. If you don't, $callsite and other callstack-related
// layout renderers will not work properly.
//
_logger.Log(typeof(MyLogger), logEvent);
关键是将记录器包装器的类型传递给对 Log 的调用。当 NLog 试图找到调用点时,它会向上堆栈,直到第一个调用方法的声明类型不是传递给 Log 调用的类型。这将是实际调用包装器的代码。
在您的情况下,您的记录器看起来像这样:
public void Log(LogType messageType, Type context, string message, Exception exception)
NLog.Logger logger = NLog.LogManager.GetLogger(context.Name);
LogLevel logLevel = LogLevel.Info; // Default level to info
switch (messageType)
case LogType.Debug:
logLevel = LogLevel.Debug;
break;
case LogType.Info:
logLevel = LogLevel.Info;
break;
case LogType.Warning:
logLevel = LogLevel.Warn;
break;
case LogType.Error:
logLevel = LogLevel.Error;
break;
case LogType.Fatal:
logLevel = LogLevel.Fatal;
break;
default:
throw new ArgumentException("Log message type is not supported");
//
// Build LogEvent here...
//
LogEventInfo logEvent = new LogEventInfo(logLevel, context.Name, message);
logEvent.Exception = exception;
//
// Pass the type of your wrapper class here...
//
logger.Log(typeof(YourWrapperClass), logEvent);
【讨论】:
我已经根据 github.com/NLog/NLog/tree/master/examples/ExtendingLoggers 的 LoggerWrapper 示例扩展了 NLog,以便我可以填充自定义事件属性,例如logEvent.Properties["EventID"] = eventID;
,如示例中所示。我想将调用站点添加为属性之一 - 即logEvent.Properties["callsite"] = *caller_method_name*
。如何以编程方式获取呼叫站点信息?【参考方案7】:
我一直在努力解决这个问题。
真正重要的是日志文件中的调用站点(FullyQualified Namespace)。
首先,我尝试从 Stacktrace 中获取正确的记录器:
[MethodImpl(MethodImplOptions.NoInlining)]
private static NLog.Logger GetLogger()
var stackTrace = new StackTrace(false);
StackFrame[] frames = stackTrace.GetFrames();
if (null == frames) throw new ArgumentException("Stack frame array is null.");
StackFrame stackFrame;
switch (frames.Length)
case 0:
throw new ArgumentException("Length of stack frames is 0.");
case 1:
case 2:
stackFrame = frames[frames.Length - 1];
break;
default:
stackFrame = stackTrace.GetFrame(2);
break;
Type declaringType = stackFrame.GetMethod()
.DeclaringType;
return declaringType == null ? LogManager.GetCurrentClassLogger() : LogManager.GetLogger(declaringType.FullName);
但遗憾的是,带有 MEF 的 Stacktrace 非常长,我无法清楚地识别 ILogger 请求者的正确调用者。
所以,我没有通过构造函数注入注入 ILogger 接口,而是创建了一个 ILogFactory 接口,它可以通过构造函数注入注入,然后调用工厂上的创建方法
public interface ILogFactory
#region Public Methods and Operators
/// <summary>
/// Creates a logger with the Callsite of the given Type
/// </summary>
/// <example>
/// factory.Create(GetType());
/// </example>
/// <param name="type">The type.</param>
/// <returns></returns>
ILogger Create(Type type);
#endregion
并实现它:
using System;
using System.ComponentModel.Composition;
[Export(typeof(ILogFactory))]
[PartCreationPolicy(CreationPolicy.Shared)]
public class LogFactory : ILogFactory
#region Public Methods and Operators
public ILogger Create(Type type)
var logger = new Logger().CreateLogger(type);
return logger;
#endregion
使用 ILogger:
public interface ILogger
#region Public Properties
bool IsDebugEnabled get;
bool IsErrorEnabled get;
bool IsFatalEnabled get;
bool IsInfoEnabled get;
bool IsTraceEnabled get;
bool IsWarnEnabled get;
#endregion
#region Public Methods and Operators
void Debug(Exception exception);
void Debug(string format, params object[] args);
void Debug(Exception exception, string format, params object[] args);
void Error(Exception exception);
void Error(string format, params object[] args);
void Error(Exception exception, string format, params object[] args);
void Fatal(Exception exception);
void Fatal(string format, params object[] args);
void Fatal(Exception exception, string format, params object[] args);
void Info(Exception exception);
void Info(string format, params object[] args);
void Info(Exception exception, string format, params object[] args);
void Trace(Exception exception);
void Trace(string format, params object[] args);
void Trace(Exception exception, string format, params object[] args);
void Warn(Exception exception);
void Warn(string format, params object[] args);
void Warn(Exception exception, string format, params object[] args);
#endregion
和实现:
using System;
using NLog;
using NLog.Config;
/// <summary>
/// The logging service.
/// </summary>
public class Logger : NLog.Logger, ILogger
#region Fields
private string _loggerName;
#endregion
#region Public Methods and Operators
/// <summary>
/// The get logging service.
/// </summary>
/// <returns>
/// The <see cref="ILogger" />.
/// </returns>
public ILogger CreateLogger(Type type)
if (type == null) throw new ArgumentNullException("type");
_loggerName = type.FullName;
var logger = (ILogger)LogManager.GetLogger(_loggerName, typeof(Logger));
return logger;
要使用它...只需注入 ILogFactory 并在 Mefed 导入构造函数中调用 Create 方法:
[ImportingConstructor]
public MyConstructor(
ILogFactory logFactory)
_logger = logFactory.Create(GetType());
希望对你有帮助
【讨论】:
【参考方案8】:internal string GetCallingMethodName()
string result = "unknown";
StackTrace trace = new StackTrace(false);
for (int i = 0; i < trace.FrameCount; i++)
StackFrame frame = trace.GetFrame(i);
MethodBase method = frame.GetMethod();
Type dt = method.DeclaringType;
if (!typeof(ILogger).IsAssignableFrom(dt) && method.DeclaringType.Namespace != "DiagnosticsLibrary")
result = string.Concat(method.DeclaringType.FullName, ".", method.Name);
break;
return result;
来源:http://slf.codeplex.com/discussions/210075
我使用上面发布的代码来简单地提取调用方法名称并将其作为“消息”参数的一部分传递给布局。这让我可以将调用日志包装器的原始方法名称写入日志文件(而不是日志包装器的类名)。
【讨论】:
此代码无法很好地扩展。从性能方面来看,使用 StackFrame 的成本很高。以上是关于包装 NLog 时如何保留调用点信息的主要内容,如果未能解决你的问题,请参考以下文章
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