Python

Initialisation

Class "static" member

Logger should be defined as Logger is a static  member of a class. Suggested name is "logger" . An example:

import logging
 
class B:
        # class logger 
        logger = logging.getLogger(__name__ + "." +__qualname__)

A global variable

Logger can be defined as a global variable  (i.e. out of a class scope).  This is not recommended way , because names may clash, if two or more modules will use the same name of variable. 

import logging

# global variable 
logger = logging.getLogger(__name__)

class B:
		# class content
		pass     

Printing information

The recommended way to access logger from within a class is   is __class__.logger 

__class__.logger.debug('This is a debug message')
__class__.logger.info('This is an info message')
__class__.logger.warning('This is a warning message')
__class__.logger.error('This is an error message')
__class__.logging.critical('This is a critical message')

...

User can configure logging level for:

• all classes of and modules  of given application (via root logger)

  Code Block
  import logging # setting ALL loggers logging.basicConfig(level=logging.ERROR)

  
  

• given particular class  (via via class logger )

  Code Block
  import logging #setting particular logger logging.getLogger('fully.qualified.class.name').setLevel(logging.INFO)

  
  

• module (via logger defined as global variable)

  Code Block
  import logging #setting particular logger logging.getLogger(A.B.__qualname__'fully.qualified.module.name').setLevel(logging.INFO)

  
  

  Info
  title Fully Qualified Name
  A name is fully qualified when it "is complete in the sense that it includes     (a) all names in the hierarchic sequence above the given element and     (b) the name of the given element itself." https://en.wikipedia.org/wiki/Fully_qualified_name