Questions tagged [log4net]

The Apache log4net library is a tool to help the programmer output log statements to a variety of output targets. log4net is a port of the excellent Apache log4j™ framework to the Microsoft® .NET runtime. We have kept the framework similar in spirit to the original log4j while taking advantage of new features in the .NET runtime.

Apache log4net is a tool to help the programmer output log statements to a variety of output targets. In case of problems with an application, it is helpful to enable logging so that the problem can be located. With log4net it is possible to enable logging at runtime without modifying the application binary. The log4net package is designed so that log statements can remain in shipped code without incurring a high performance cost. It follows that the speed of logging (or rather not logging) is crucial.

At the same time, log output can be so voluminous that it quickly becomes overwhelming. One of the distinctive features of log4net is the notion of hierarchical loggers. Using these loggers it is possible to selectively control which log statements are output at arbitrary granularity.

log4net is designed with two distinct goals in mind: speed and flexibility.

Features:

  • Support for multiple frameworks
  • Output to multiple logging targets
  • Hierarchical logging architecture
  • XML Configuration
  • Dynamic Configuration
  • Logging Context
  • Proven architecture
  • Modular and extensible design
  • High performance with flexibility

Support for multiple frameworks:

log4net runs on all ECMA CLI 1.0 compatible runtimes. log4net has specific builds for the following frameworks:

  • Microsoft® .NET Framework 1.0
  • Microsoft .NET Framework 1.1
  • Microsoft .NET Framework 2.0
  • Microsoft .NET Framework 3.5
  • Microsoft .NET Framework 4.0
  • Microsoft .NET Framework 3.5 Client Profile
  • Microsoft .NET Framework 4.0 Client Profile
  • Microsoft .NET Compact Framework 1.0*
  • Microsoft .NET Compact Framework 2.0
  • Mono 1.0
  • Mono 2.0
  • Microsoft Shared Source CLI 1.0*
  • CLI 1.0 Compatible
  • Microsoft .NET Core 1.0 providing .NET Standard 1.3

The "Client Profile" builds are stripped down versions of the "normal" builds that don't contain any ASP.NET releated code - which for example means the %aspnet-* patterns and the AspNetTraceAppender are not available.

* Not supported by the binary release but can be built from the source release.

Official Website: http://logging.apache.org/log4net/

Useful Links:

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How i can use the connectionString of the current website for log4Net instead of configuring

I use log4Net for my system's log. The connectionString node is mandatory if the appender type is the AdoNetAppender in Log4Net. However, I already have a connectionString in my website where I use Log4Net. How can I use the connStr of the website…
Aiping He
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log4Net config transform

I am able to transform my log4net.config but I am not getting this one. How do I change the following connectionString?
Jack Smit
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How to auto log every request in .NET Core WebAPI?

I'd like to have every request logged automatically. In previous .Net Framwork WebAPI project, I used to register a delegateHandler to do so. WebApiConfig.cs public static void Register(HttpConfiguration config) { config.MessageHandlers.Add(new…
wtf512
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log4net will not read from app.config

I have two projects configured identically for log4net. One project logs fine; however, the other does not log at all. The Logger in the project that is not logging returns IsFatalEnabled = false, IsErrorEnabled = false, IsWarnEnabled = false,…
Even Mien
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Add a custom property to include in all log4net messages

I have a unique identifier which goes through the whole application. I want this 'ID' to be logged as a separate property, so that it's easy to find out in log files or from the database.
Miral
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log4net - LogicalThreadContext - and unit test cases

I am starting to write a unit test (MS Test, with Resharper as the test runner). When I set the LogicalThreadContext (see below), my test cases get 'aborted'. Anybody know why? Is this related to the unit test being on a different thread? How do I…
Raymond
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log4net initialisation

I've looked hard for duplicates but have to ask the following, no matter how basic it may seem, to get it clear once and for all! In a fresh Console app using log4net version 1.2.10.0 on VS28KSP1 on 64 bit W7, I have the following code:- using…
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log4net BufferingForwardingAppender performance issue

EDIT 2 : I have solved the problem (see answer below) Please note that the problem potentially affects all appenders decorated with BufferingForwardingAppender as well as all appenders inheriting from BufferingAppenderSkeleton (respectively :…
darkey
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How do I stop the Visual Studio Output window displaying the logger name of log4net output?

I am using log4net DebugAppender (or TraceAppender). I have configured the appender like this:
James World
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What is the difference between log4net.ThreadContext and log4net.LogicalThreadContext?

UPDATED on 11/18/2014 - While browsing the log4net source repository, I found that the implementation of LogicalThreadContext was modified in November 2011 to that it stores its properties using CallContext.LogicalSetData (and gets them using…
wageoghe
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log4net with .NET 4.0

I've thrown together some code to tinker with the new .Net 4.0/VS 2010 pieces, but I can't seem to find a build of my logging framework of choice (log4net) for 4.0, and I'm getting reference errors with the 2.0 version. Is there a 4.0 version…
Jonathan Rupp
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log4net only works when XmlConfigurator.Configure() is called

I understand that this question has been asked several times, but unfortunately, I haven't been able to get my logging configuration working. I have to be making some very small mistake somewhere. I have a .NET 4.5 MVC 4/EF 5 web application and…
Brad
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Log4Net with AdoNetAppender - nothing happens

Description I have a config file as a resource in my assembly and want to change the ConnectionString programmatically in my application. I load the configuration using log4net.Config.XmlConfigurator.Configure. I have some breakpoints and see that…
dknaack
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Log4net/Logging - What have you found to be useful?

I just started using Log4Net and was looking to see what you have found to be useful in your logging experiences. What types of things have you found to be useful to log; what ended up being just noise; when do you use the different logging levels…
Chris Burgess
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log4net with ASP.NET MVC: nothing happens

I am trying to use log4net with ASP.NET MVC and I cannot get anything to happen with it. I've created a config that is in my web project root:
twal
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