Log4net

How to Configure Log4Net to Log Only Info Level Messages

Logging is an essential part of software development, helping developers debug and troubleshoot applications efficiently. However, controlling what gets logged can be a tricky task. If you’re looking for a way to configure Log4Net to log only messages at the Info level, you’re in the right place! In this blog post, we will walk you through the steps required to achieve that using Log4Net’s capabilities.

The Problem: Wanting Only Info Logs

You may have configured Log4Net to log at the Info level, but still notice that messages at different levels (like Debug or Warn) are being logged as well. This raises the question: Is it possible to limit Log4Net to only log Info level logs? The answer is yes! With the right configuration, you can filter out any unnecessary logging and maintain a clean logging output.

Understanding Log4Net Configuration

To configure Log4Net effectively, it’s important to understand its structure. The logging configuration is typically outlined in an XML format. Here’s an example setup you might have:

<logger name="BrokerCollection.Model.XmlDocumentCreationTask">
  <appender-ref ref="SubmissionAppender"/>
  <level value="Info" />
</logger>

In this snippet, you can see the logger is set to the Info level, but this alone does not filter out logs that are below this level. To achieve your goal of logging only Info, we must introduce a filter inside an appender.

The Solution: Using Level Range Filter

To restrict Log4Net to log only Info level messages, you can implement a LevelRangeFilter inside the appender configuration. Here’s how you can set that up:

Example Configuration

You can modify your appender definition as follows:

<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
    <filter type="log4net.Filter.LevelRangeFilter">
        <param name="LevelMin" value="INFO"/>
        <param name="LevelMax" value="INFO"/>
    </filter>
    ...
</appender>

In this configuration:

  • LevelMin: Specifies the minimum level of messages you want to log (INFO in our case).
  • LevelMax: Specifies the maximum level of messages you want to log (also set to INFO to ensure only these logs are recorded).

Implementation Steps

  1. Locate your Log4Net configuration file: This is usually an XML file where appenders and loggers are defined.
  2. Identify the appender you are using: Make sure to modify the correct appender.
  3. Add the filter: Use the LevelRangeFilter as shown above to restrict logging to only Info level messages.
  4. Test the configuration: Generate logs at various levels to confirm that only Info logs are captured.

Conclusion

By utilizing the LevelRangeFilter in your Log4Net configuration, you can effectively limit your logging output to only show messages that are relevant and informative. This makes it easier to manage logs, especially in large applications where excessive logging can lead to clutter and confusion.

Now, you can implement this configuration in your Log4Net setup. Happy logging!