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pythonloggingpython-logging

Avoid `logger=logging.getLogger(__name__)`


We set up logging like the django docs told us:

https://docs.djangoproject.com/en/2.1/topics/logging/#using-logging

# import the logging library
import logging

# Get an instance of a logger
logger = logging.getLogger(__name__)

def my_view(request, arg1, arg):
    ...
    if bad_mojo:
        # Log an error message
        logger.error('Something went wrong!')

I want to avoid this line in every Python file which wants to log:

logger = logging.getLogger(__name__)

I want it simple:

logging.error('Something went wrong!')

But we want to keep one feature: We want to see the Python file name in the logging output.

Up to now we use this format:

'%(asctime)s %(name)s.%(funcName)s +%(lineno)s: %(levelname)-8s [%(process)d] %(message)s'

Example output:

2016-01-11 12:12:31 myapp.foo +68: ERROR Something went wrong

How to avoid logger = logging.getLogger(__name__)?


Solution

  • You can use logging.basicConfig to define the default interface available through logging as follows:

    import logging
    logging.basicConfig(level=logging.DEBUG,
                        format='%(asctime)s %(name)s.%(funcName)s +%(lineno)s: %(levelname)-8s [%(process)d] %(message)s',
                        )
    

    This definition will now be used whenever you do the following anywhere in your application:

    import logging
    logging.error(...)
    

    While __name__ is not available, the equivalent (and other options) are available through the default LogRecord attributes that can be used for error string formatting - including module, filename and pathname. The following is a two-script demonstration of this in action:

    scripta.py

    import logging
    logging.basicConfig(level=logging.DEBUG,
                        format='%(asctime)s %(module)s %(name)s.%(funcName)s +%(lineno)s: %(levelname)-8s [%(process)d] %(message)s',
                        )
    
    from scriptb import my_view
    
    my_view()
    

    scriptb.py

    import logging
    
    def my_view():
        # Log an error message
        logging.error('Something went wrong!')
    

    The logging definition is defined in scripta.py, with the added module parameter. In scriptb.py we simply need to import logging to get access to this defined default. When running scripta.py the following output is generated:

    2016-01-14 13:22:24,640 scriptb root.my_view +9: ERROR    [14144] Something went wrong!
    

    Which shows the module (scriptb) where the logging of the error occurs.

    According to this answer you can continue to use any per-module configuration of logging from Django, by turning off Django handling and setting up the root handler as follows:

    # settings.py - django config
    LOGGING_CONFIG = None # disables Django handling of logging
    LOGGING = {...}  # your standard Django logging configuration
    
    import logging.config
    logging.config.dictConfig(LOGGING)