Query and modify log4net logger levels from code

Question

I would like to create an area in my application that will let sysadmins modify logger levels directly.

This answer from 2009 implies that I can do it with

foreach (ILog logger in log4net.LogManager.GetCurrentLoggers())
{
  ((log4net.Repository.Hierarchy.Logger)logger).Level = 
      log4net.Core.Level.Error;
}

My application uses log4net 2.0.3 (1.2.13) and this seems to not be available as no implementation of ILog inherits that class.

Instead I can grab each ILog's Logger property for an instance of ILogger. This gives me the name but will not let me query or set the Level. While this is an ability that IS available on the implementation I cannot simply do a cast as the implementation is an internal class.

How do I do this in recent versions?

score 1 · Answer 1 · answered Dec 04 '13 at 21:06

You're right that you have to get each ILog's Logger property: then you need to cast it to log4net.Repository.Hierarchy.Logger.

ILog.Logger returns an ILogger, which as you've seen doesn't expose the writeable Level property, which I guess is considered to be an internal implementation detail. But casting it to the concrete log4net.Repository.Hierarchy.Logger type gives you access to what you need.

From the sample in the question whose answer you linked to:

foreach (log4net.ILog log in log4net.LogManager.GetCurrentLoggers())
{
    log4net.Repository.Hierarchy.Logger logger = 
         (log4net.Repository.Hierarchy.Logger)log.Logger;
    Debug.WriteLine(
        String.Format("{0} Parent {1} Level {2} EffectiveLevel {3}<br>",
        logger.Name,
        logger.Parent.Name,
        logger.Level == null ? "<null>" : logger.Level.Name,
        logger.EffectiveLevel
        )
        );
}

Thanks for the full answer, this clarifies it – George Mauer Dec 04 '13 at 21:41 — George Mauer, Dec 04 '13 at 21:41

score 1 · Accepted Answer · answered Dec 04 '13 at 21:15

You'll have to grab the Logger property off of each logger and cast it as a log4net.Repository.Hierarchy.Logger.

foreach (ILog logger in log4net.LogManager.GetCurrentLoggers())
{
    var log = logger.Logger as log4net.Repository.Hierarchy.Logger;
    Console.WriteLine("Name: {0}, Level: {1}", log.Name, log.Level);
    log.Level = log4net.Core.Level.Error;
}

Query and modify log4net logger levels from code

2 Answers2