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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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Log4Net config in external file does not work

We are using log4net and want to specify it's configuration in an external config file (as we have done with other sections). To do this we have changed the log4net section in the App.config to: ...
Robert Wagner
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Where will log4net create this log file?

When I set the file value to logs\log-file.txt, where exactly will it create this folder? In the /bin directory? My web.config looks like this:
Blankman
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Why do loggers recommend using a logger per class?

As per NLog's documentation: Most applications will use one logger per class, where the name of the logger is the same as the name of the class. This is the same way that log4net operates. Why is this a good practice?
Daniel T.
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How to configure log4net programmatically from scratch (no config)

This is a Bad Idea, I know, but... I want to configure log4net programmatically from scratch with no config file. I'm working on a simple logging application for me and my team to use for a bunch of relatively small departmental applications we're…
John M Gant
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Correct way of using log4net (logger naming)

There are two ways of configuring and using log4net. First one is when I can configure my own appender and associated logger:
Sly
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Log4Net Logging of two different levels to two different appenders for the same logger

We have two different asp.net applications with Log4net logging enabled. They both have the same version of Log4Net, 1.2.10.0. We have added the log4net.Appender.AdoNetAppender logger to both of them and want to log Info level to it for the root…
graney
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Referencing 2 different versions of log4net in the same solution

I'm using NHibernate 2.1.2.400 that is referencing log4net 1.2.10.0. In the same project, I also use the simply accounting SDK, sadly it is still using log4net 1.2.9.0. So I can get NHibernate to work if I reference log4net 1.2.10.0 but the…
Joel Gauvreau
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Log4Net: set Max backup files on RollingFileAppender with rolling Date

I have the following configuration, but I have not able to find any documentation on how to set a maximum backup files on date rolling style. I know that you can do this with size rolling style by using the maxSizeRollBackups.
Ricky Supit
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How to use log4net with Dependency Injection

I'm trying to figure out what the right patter and usage of log4net is with a dependency injection framework. Log4Net uses the ILog interface but requires me to call LogManager.GetLogger(Reflection.MethodBase.GetCurrentMethod().DeclaringType) in…
Micah
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Dependency injection and named loggers

I am interested in learning more about how people inject logging with dependency injection platforms. Although the links below and my examples refer to log4net and Unity, I am not necessarily going to use either of those. For dependency…
wageoghe
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How can I change the file location programmatically?

I am totally new to Log4net. I have managed to get something going by adding a config file and simple logging. I have hardcoded the value to be "C:\temp\log.txt" but this is not good enough. The logs must go to the special folders path =…
user186134
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How to log Trace messages with log4net?

I'm using log4net to log write log message to a rolling log file. Now I would also redirect all trace messages from System.Diagnostics.Trace to that log file. How can I configure that? I tried to find anything about that in the log4net…
Dirk Vollmar
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Setting a log file name to include current date in Log4j

I would like to set the log file name for a log4j and log4net appender to have the current date. We are doing Daily rollovers but the current log file does not have a date. The log file name format would be logname.2008-10-10.log Anyone know the…
Tim
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Get log4net log file in C#

This is my configuration for log4net: …
Carlo
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Log4Net: Rolling File appender, define extension

I want my logfile to look something like this: 2009-02-13.log but the problem is that I can't seem to find any way to add the .log extension. I've tried a lot of things but nothing helps. This is what I have this far:
user29964
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