multilevelformatter 0.4.1

logger.Formatter to simplify setting formatting for multiple logging levels

MultiLevelFormatter

MultiLevelFormatter is a Python logging.Formatter that simplifies setting log formats for different log levels. Log records with level logging.ERROR or higher are printed to STDERR if using defaults with MultilevelFormatter.setDefaults().

Motivation for the class has been the use of logging package for CLI verbosity control (--verbose, --debug):

1. Define shortcuts for printing different level information instead of using print() :

logger = logging.getLogger(__name__)
error = logger.error
message = logger.warning
verbose = logger.info
debug = logger.debug

2. Set logging level based on CLI option given. Mapping of logging levels:

CLI option	logging level
--debug	logging.DEBUG
--verbose	logging.INFO
default	logging.WARNING
--silent	logging.ERROR

# Not complete, does not run
def main() -> None:
    
    ...

    # assumes command line arguments have been parsed into 
    # boolean flags: arg_verbose, arg_debug, arg_silent
    
    LOG_LEVEL: int = logging.WARNING
    if arg_verbose: 
        LOG_LEVEL = logging.INFO
    elif arg_debug:
        LOG_LEVEL = logging.DEBUG
    elif arg_silent:
        LOG_LEVEL = logging.ERROR
    MultilevelFormatter.setDefaults(logger, log_file=log)
    logger.setLevel(LOG_LEVEL)

See the example below for more details.

Install

Python 3.11 or later is required.

pip install multilevelformatter

Example

Full runnable example below. It can be found in demos/ folder.

import logging
from typer import Typer, Option
from typing import Annotated, Optional
from pathlib import Path
from multilevelformatter import MultilevelFormatter

logger = logging.getLogger(__name__)
error = logger.error
message =  logger.warning 
verbose = logger.info
debug = logger.debug

# the demo uses typer for CLI parsing. 
# Typer has nothing to do with MultiLevelFormatter
app = Typer()

@app.callback(invoke_without_command=True)
def cli(
    print_verbose: Annotated[
        bool,
        Option(
            "--verbose",
            "-v",
            show_default=False,
            help="verbose logging",
        ),
    ] = False,
    print_debug: Annotated[
        bool,
        Option(
            "--debug",
            show_default=False,
            help="debug logging",
        ),
    ] = False,
    print_silent: Annotated[
        bool,
        Option(
            "--silent",
            show_default=False,
            help="silent logging",
        ),
    ] = False,
    log: Annotated[Optional[Path], Option(help="log to FILE", metavar="FILE")] = None,
) -> None:
    """MultilevelFormatter demo"""
    global logger

    try:
        LOG_LEVEL: int = logging.WARNING
        if print_verbose:
            LOG_LEVEL = logging.INFO
        elif print_debug:
            LOG_LEVEL = logging.DEBUG
        elif print_silent:
            LOG_LEVEL = logging.ERROR
        MultilevelFormatter.setDefaults(logger, log_file=log, level=LOG_LEVEL)        
    except Exception as err:
        error(f"{err}")
    message("standard")
    verbose("verbose")
    error("error")
    debug("debug")


if __name__ == "__main__":
    app()