Best practices for using Markers in SLF4J/Logback

Question

We are using SLF4J+Logback combination at our project for a while now and are quite happy with it, but our logging strategy is fairly simple, using straightforward class bas

Answer 1

Markers can be used to color or mark a single log statement. What you do with these colors, i.e. markers, is entirely up to you. However, two patterns seem to be common (the first more common than the second) for marker usage.

1. Triggering: Some appender could be instructed to take an action in the presence of a certain marker. For example, SMTPAppender can be configured to send an email whenever a logging event is marked with the NOTIFY_ADMIN marker regardless of the log level. See marker-based triggering in the logback documentation. You may also combine log levels and markers for triggering.

2. Filtering: You could for example color/mark all your persistence related logs (in various and multiple class files) with the color "DB". You could then filter for "DB": disable logging except for log statements marked with DB. See the chapter on filters in the logback documentation for more information (search for MarkerFilter).