Python Module logging Concepts
Internal
Logging Levels
The logging system can be configured to filter out log messages whose logging level is under a certain threshold. The logging levels, and the corresponding logging functions are, listed from the most important to the least important, are provided below. By default, the logging system is configured to allow log messages of level WARNING and above, INFO and below are discarded.
CRITICAL
Has numeric value 50. Generated with logging.critical().
ERROR
Has numeric value 40. Generated with logging.error().
WARNING
Has numeric value 30. Generated with logging.warning().
INFO
Has numeric value 20. Generated with logging.info().
DEBUG
Has numeric value 10. Generated with logging.debug().
NOTSET
Has numeric value 0.
Logger
Logger Hierarchy
If the logger name contains dot characters, they separate levels of a hierarchy. Closer to the left, the higher the logger in the logger hierarchy: a has a higher level than a.b . Each level in the hierarchy can be given different properties. At the top of the hierarchy there's a root logger.
The root Logger
At the top of the logger hierarchy, there is a special root logger, called .
Format
The default format, without any customization is <LOGGING_LEVEL>:<logger_name>:<message>.