Correct way of using log4net logger naming

Question

There are two ways of configuring and using log4net  First one is when I can configure my own appender and associated logger    lt  -- language  xml -- gt    lt appender name  myLogAppender  type  log4net Appender RollingFileAppender   gt       lt file value  Logs myLog log    gt       lt layout type  log4net Layout PatternLayout  gt           lt conversionPattern value   date  level -  message n    gt       lt  layout gt   lt  appender gt    lt logger name  myLog  gt       lt level value  All  gt  lt  level gt       lt appender-ref ref  myLogAppender    gt   lt  logger gt    And then when I want to write something in log  I can do the following   ILog log   LogManager GetLogger  myLog    log Info  message      Another way to use it is to configure root to be as detailed as I want    lt  -- language  xml -- gt    lt root gt       lt level value  Error    gt       lt appender-ref ref  myLogAppender    gt   lt  root gt    And in this case I can log messages like this   ILog log   LogManager GetLogger typeof Bar    log Info  message      The benefits of second approach is that you can enable or disable some messages on the fly  But the problem is that I m developing in EPiServer CMS and it has its own logging system that uses log4net and if I enable info logging at root level  then a lot of system logs will be written    How do you use log4net  Each part of a system writes in its own logger  or everything is written in default logger  and configuration decides what to do next

User · Accepted Answer

Regarding how you log messages within code, I would opt for the second approach:

ILog log = LogManager.GetLogger(typeof(Bar));
log.Info("message");

Where messages sent to the log above will be 'named' using the fully-qualifed type Bar, e.g.

MyNamespace.Foo.Bar [INFO] message

The advantage of this approach is that it is the de-facto standard for organising logging, it also allows you to filter your log messages by namespace. For example, you can specify that you want to log INFO level message, but raise the logging level for Bar specifically to DEBUG:

<log4net>
    <!-- appenders go here -->
    <root>
        <level value="INFO" />
        <appender-ref ref="myLogAppender" />
    </root>

    <logger name="MyNamespace.Foo.Bar">
        <level value="DEBUG" />
    </logger>
</log4net>

The ability to filter your logging via name is a powerful feature of log4net, if you simply log all your messages to "myLog", you loose much of this power!

Regarding the EPiServer CMS, you should be able to use the above approach to specify a different logging level for the CMS and your own code.

For further reading, here is a codeproject article I wrote on logging:

The Art Of Logging

User · Answer

My Answer might be coming late  but I think it can help newbie  You shall not see logs executed unless the changes are made as below   2 Files have to be changes when you implement Log4net      Add Reference of log4net dll in the project  app config Class file where you will implement Logs    Inside  app config     First  under  configSections   you need to add below piece of code    lt section name  log4net  type  log4net Config Log4NetConfigurationSectionHandler  log4net    gt    Then  under  configuration  block  you need to write below piece of code  This piece of code is customised as per my need   but it works like charm     lt log4net debug  true  gt       lt logger name  log  gt         lt level value  All  gt  lt  level gt         lt appender-ref ref  RollingLogFileAppender    gt       lt  logger gt        lt appender name  RollingLogFileAppender  type  log4net Appender RollingFileAppender  gt         lt file value  log txt    gt         lt appendToFile value  true    gt         lt rollingStyle value  Composite    gt         lt maxSizeRollBackups value  1    gt         lt maximumFileSize value  1MB    gt         lt staticLogFileName value  true    gt          lt layout type  log4net Layout PatternLayout  gt           lt conversionPattern value   date  C  M   line   -5level -  message  newline  exception  newline    gt         lt  layout gt       lt  appender gt   lt  log4net gt    Inside Calling Class    Inside the class where you are going to use this log4net  you need to declare below piece of code    ILog log   LogManager GetLogger  log      Now  you are ready call log wherever you want in that same class  Below is one of the method you can call while doing operations   log Error  message

User · Answer

Instead of naming my invoking class  I started using the following   private static readonly ILog log   LogManager GetLogger System Reflection MethodBase GetCurrentMethod   DeclaringType     In this way  I can use the same line of code in every class that uses log4net without having to remember to change code when I copy and paste  Alternatively  i could create a logging class  and have every other class inherit from my logging class

User · Answer

Disadvantage of second approach is big repository with created loggers  This loggers do the same if root is defined and class loggers are not defined  Standard scenario on production system is using few loggers dedicated to group of class  Sorry for my English

[c#] Correct way of using log4net (logger naming)

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