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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 vs. Nlog

Anyone have experience for both? How do they stack up against each other? We are planning on using one of them for logging in an enterprise application. References: log4net nlog EDIT: We have no existing dependencies to either nlog or log4net.
Greg Dean
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How to track down log4net problems

I use log4net all the time, but one thing I've never figured out is how to tell what's going on on the inside. For example, I've got a console appender and a database appender in my project. I made a few changes to the database and the code, and now…
John M Gant
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Log4net does not write the log in the log file

I have created a simple scenario using Log4net, but it seems that my log appenders do not work because the messages are not added to the log file. I added the following to the web.config file:
john84
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log4net hierarchy and logging levels

This site says Loggers may be assigned levels. Levels are instances of the log4net.Core.Level class. The following levels are defined in order of increasing priority: ALL DEBUG INFO WARN ERROR FATAL OFF DEBUG seems to have lowest priority and…
Siva
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Can you configure log4net in code instead of using a config file?

I understand why log4net uses app.config files for setting up logging - so you can easily change how information is logged without needing to recompile your code. But in my case I do not want to pack a app.config file with my executable. And I have…
Michael Mankus
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Configure Log4net to write to multiple files

I'd like to write log to 2 different log files from the same process. is that possible thing to do using log4net? I'll need to write separate messages to each log file. how can I write a message to a specific appender?
ofer
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Log4net rolling daily filename with date in the file name

I would like to have files named for example: dd.mm.yyyy.log How is this possible with log4net?
JL.
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log4net not working

Hey I have this configuration in my web.config
Jakob
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Intermittent log4net RollingFileAppender locked file issue

We are seeing an intermittent issue on development and production machines whereby our log files are not getting logged to. When running in development and debugging using Visual Studio we get the following log4net error messages in the VS output…
Richard Ev
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What is the difference between log4net and ELMAH?

Some people are using ELMAH instead of log4net. What makes it better? I found out about ELMAH in an answer to Stack Overflow question How do I do logging in C#?
IAdapter
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How do I resolve configuration errors with Nant 0.91?

After downloading Nant 0.91, I'm getting some rather cryptic configuration errors relating to configuration or security (see below). I'm trying to simply upgrade my Nant executables from 0.86 to 0.91. How can I resolve the issues below when…
Peter Bernier
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Log4Net, how to add a custom field to my logging

I use the log4net.Appender.AdoNetAppender appender. My log4net table are the following fields [Date],[Thread],[Level],[Logger],[Message],[Exception] I would need to add another field to the log4net table (e.g SalesId), but how would I specify in my…
Eminem
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how do I work around log4net keeping changing publickeytoken

We have an asp.net 4.0 project which uses a couple of frameworks which is dependent on log4net version 1.2.10.0. Today I tried to include a new framework which is dependent on log4net version 1.2.11.0, I've been stuck ever since: log4net 1.2.10.0…
AndreasKnudsen
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log4net argument to LogManager.GetLogger

Why do most log4net examples get the logger for a class by doing this: private static ILog logger = LogManager.GetLogger( System.Reflection.MethodBase.GetCurrentMethod().DeclaringType); Rather than just passing typeof(MyClass): private…
Andy White
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app.config for a class library

I cannot see a app.config file generated for a class library by the VS2008 wizard. In my research I found that in an application only one app.config exists. Is it a bad thing to add an app.config manually to a class library or are there any other…
logeeks
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