verboselogs: Verbose logging level for Python’s logging module¶
- The VERBOSE level sits between the predefined INFO and DEBUG levels.
- The NOTICE level sits between the predefined WARNING and INFO levels.
- The SPAM level sits between the predefined DEBUG and NOTSET levels.
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. It’s currently tested on Python 2.6, 2.7, 3.4, 3.5, 3.6 and PyPy.
The verboselogs package is available on PyPI which means installation should be as simple as:
$ pip install verboselogs
There’s actually a multitude of ways to install Python packages (e.g. the per user site-packages directory, virtual environments or just installing system wide) and I have no intention of getting into that discussion here, so if this intimidates you then read up on your options before returning to these instructions ;-).
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 >= 4: logger.setLevel(logging.SPAM) elif verbosity >= 3: logger.setLevel(logging.DEBUG) elif verbosity >= 2: logger.setLevel(logging.VERBOSE) elif verbosity >= 1: logger.setLevel(logging.NOTICE) elif verbosity < 0: logger.setLevel(logging.WARNING) # Your code goes here. ...
import logging import verboselogs verboselogs.install() logger = logging.getLogger(__name__) # will be a VerboseLogger instance
E:285,24: Module 'logging' has no 'VERBOSE' member (no-member) E:375,12: Instance of 'RootLogger' has no 'verbose' member (no-member)
To fix this, verboselogs provides a Pylint plugin verboselogs.pylint which,
when loaded with
pylint --load-plugins verboselogs.pylint, adds the
verboselogs methods and constants to Pylint’s understanding of the logging
|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 too 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.|
|NOTICE||25||Auditing information about things that have multiple success paths or may need to be reverted.|
|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.|
The latest version of verboselogs is available on PyPI and GitHub. The documentation is hosted on Read the Docs. For bug reports please create an issue on GitHub. If you have questions, suggestions, etc. feel free to send me an e-mail at email@example.com.