logmuse

A small Python package that makes it easy to add CLI-controllable logging to your command-line tools. It provides a simple interface for standard logging arguments (--verbosity, --silent, --logdev) that can be passed directly to a logger.

Installation

pip install logmuse

Quick start

Add logging options to your CLI and create a logger in three lines:

import argparse
import logmuse

parser = argparse.ArgumentParser()
# your arguments here...
parser = logmuse.add_logging_options(parser)
args = parser.parse_args()
logger = logmuse.logger_via_cli(args)

logger.info("Hello, world!")

This adds --silent, --verbosity, and --logdev options to your CLI automatically.

Setup for a CLI package

1. Add CLI args to your argparser

parser = logmuse.add_logging_options(parser)

This gives you --verbosity, --silent, and --logdev options.

2. Activate in your main function

import logmuse

def main():
    # ... parse args ...
    logger = logmuse.logger_via_cli(args, make_root=True)

That's it. Call logger_via_cli once in your CLI entry point, and all loggers in your package (and its dependencies) will respect the CLI options.

For imported packages

Imported packages don't need logmuse at all. Just use the standard logging module:

import logging
_LOGGER = logging.getLogger(__name__)

The CLI arguments passed to logmuse will control these loggers too.

Avoid calling init_logger at import time

Do not put logmuse.init_logger() in your package's __init__.py. This replaces the logger's handlers at import time, which prevents it from inheriting configuration from a root logger. This causes problems when your package is used as a library (not via its own CLI).

Using logmuse interactively

To set logging to DEBUG in an interactive session:

logmuse.init_logger("my_package", "DEBUG", devmode=True)

Usage reference

CLI options

add_logging_options(parser) adds three arguments to an argparse.ArgumentParser:

Option	Effect
--silent	Silence all logging output
--verbosity V	Set logging level (1=CRITICAL, 2=ERROR, 3=WARN, 4=INFO, 5=DEBUG, or a level name)
--logdev	Use a detailed developer log format with timestamps, module, and line numbers

init_logger parameters

Parameter	Default	Description
name	"logmuse"	Logger name
level	None	Logging level (int or string)
verbosity	None	Verbosity level (1-5); alternative to level
silent	False	Silence all output
devmode	False	Use detailed developer format
stream	stderr	Output stream ("OUT" for stdout, "ERR" for stderr)
logfile	None	Path to log file (mutes stream output)
make_root	None	Use as root logger
propagate	False	Allow messages to reach parent loggers
fmt	None	Custom format string
datefmt	"%H:%M:%S"	Time format
plain_format	False	Force plain format even in devmode
style	None	Format style (%, {, or $)
use_full_names	False	Don't truncate level names

Verbosity levels

Verbosity	Logging Level
1	CRITICAL
2	ERROR
3	WARN
4	INFO
5	DEBUG