verboselogs 1.1

Verbose logging level for Python's logging module

The verboselogs.VerboseLogger class extends logging.Logger to add the log levels VERBOSE and SPAM. The VERBOSE level sits between the predefined INFO and DEBUG levels and SPAM sits between DEBUG and NOTSET. The code to do this is simple and short, but I still don’t want to copy/paste it to every project I’m working on, hence this package. The table below shows the names, numeric values and descriptions of the predefined log levels and the VERBOSE and SPAM levels defined by this module. I’ve added some notes to the other levels, these are marked in bold:

Level	Numeric value	Description
NOTSET	0	When a logger is created, the level is set to NOTSET (note that the root logger is created with level WARNING). In practice this level is never explicitly used; it’s mentioned here only for completeness.
SPAM	5	Way to verbose for regular debugging, but nice to have when someone is getting desperate in a late night debugging session and decides that they want as much instrumentation as possible! :-)
DEBUG	10	Detailed information, typically of interest only when diagnosing problems. Usually at this level the logging output is so low level that it’s not useful to users who are not familiar with the software’s internals.
VERBOSE	15	Detailed information that should be understandable to experienced users to provide insight in the software’s behavior; a sort of high level debugging information.
INFO	20	Confirmation that things are working as expected.
WARNING	30	An indication that something unexpected happened, or indicative of some problem in the near future (e.g. ‘disk space low’). The software is still working as expected.
ERROR	40	Due to a more serious problem, the software has not been able to perform some function.
CRITICAL	50	A serious error, indicating that the program itself may be unable to continue running.

Usage

It’s very simple to start using the verboselogs package:

>>> import logging, verboselogs
>>> logger = verboselogs.VerboseLogger('verbose-demo')
>>> logger.addHandler(logging.StreamHandler())
>>> logger.setLevel(logging.VERBOSE)
>>> logger.verbose("Can we have verbose logging? %s", "Yes we can!")

Here’s a skeleton of a very simple Python program with a command line interface and configurable logging:

"""
Usage: demo.py [OPTIONS]

This is the usage message of demo.py. Usually
this text explains how to use the program.

Supported options:
  -v, --verbose  make more noise
  -h, --help     show this message and exit
"""

import getopt
import logging
import sys
import verboselogs

logger = verboselogs.VerboseLogger('demo')
logger.addHandler(logging.StreamHandler())
logger.setLevel(logging.INFO)

# Command line option defaults.
verbosity = 0

# Parse command line options.
opts, args = getopt.getopt(sys.argv[1:], 'vqh', ['verbose', 'quiet', 'help'])

# Map command line options to variables.
for option, argument in opts:
    if option in ('-v', '--verbose'):
        verbosity += 1
    elif option in ('-q', '--quiet'):
        verbosity -= 1
    elif option in ('-h', '--help'):
        print __doc__.strip()
        sys.exit(0)
    else:
        assert False, "Unhandled option!"

# Configure logger for requested verbosity.
if verbosity >= 3:
    logger.setLevel(logging.SPAM)
elif verbosity >= 2:
    logger.setLevel(logging.DEBUG)
elif verbosity >= 1:
    logger.setLevel(logging.VERBOSE)
elif verbosity < 0:
    logger.setLevel(logging.WARNING)

# Your code goes here.
...

Contact

The latest version of verboselogs is available on PyPI and GitHub. For bug reports please create an issue on GitHub. If you have questions, suggestions, etc. feel free to send me an e-mail at [e-mail].

License

This software is licensed under the MIT license.

© 2016 Peter Odding.