chromaformatter 5.0.1

Wrapper for the Python logging module to add color.

Chroma Formatter

An extended Python logging formatter that adds color.

Installation

Chroma Formatter is on PyPI and can be installed with:

pip install chromaformatter

Usage

Chroma Formatter adds two features to the default logging formatter, colors can be added to the log format string, and formatted arguments in a log message can be colored. Colors can be inserted info the format string as such:

log_format = (
    f'{Colors.Fore.GREEN}%(asctime)-s '
    f'{Colors.LEVEL_COLOR}%(levelname).1s '
    f'{Colors.Fore.MAGENTA}%(filename)-s:%(lineno)03d '
    f'{Colors.LEVEL_COLOR}- %(message)s'
)

Then, use chromaformatter.ChromaFormatter rather than logging.Formatter.

import sys
import logging
from chromaformatter import ChromaFormatter, Colors

log = logging.getLogger()
log_format = (
    f'{Colors.Fore.GREEN}%(asctime)-s '
    f'{Colors.LEVEL_COLOR}%(levelname).1s '
    f'{Colors.Fore.MAGENTA}%(filename)-s:%(lineno)03d '
    f'{Colors.LEVEL_COLOR}- %(message)s'
)
formatter = ChromaFormatter(
    fmt=log_format,
    arg_start_color=Colors.Fore.WHITE,
    arg_end_color=Colors.LEVEL_COLOR
)
handler = logging.StreamHandler(stream=sys.stdout)
handler.setFormatter(formatter)
log.addHandler(handler)

Formatted Arguments in a Log

By setting arg_start_color for argument colors and arg_end_color for the rest of the string that comes after the argument, those colors will be applied to arguments.

log.info('This %s will be colored.', 'variable')

Additional Configuration

ChromaFormatter has a dict called color_map to determine the colors of each logging level.

By default, the colors are:

Category	Color
DEBUG	Fore.BLUE
INFO	Fore.Cyan
WARNING	Fore.YELLOW
ERROR	Fore.LIGHTRED_EX
CRITICAL	Fore.RED
ARGS	Fore.White

Color map can be changed as such:

formatter.color_map[logging.INFO] = Colors.Fore.WHITE
formatter.color_map[logging.DEBUG] = Colors.Fore.MAGENTA

Applying to Existing Loggers

If you are using a third party module that uses the standard python logging module you can apply a ChromaFormatter as such:

import sys
import logging

from chromaformatter import ChromaFormatter, Colors

log_format = (
    f'{Colors.Fore.GREEN}%(asctime)-s '
    f'{Colors.LEVEL_COLOR}%(levelname).1s '
    f'{Colors.Fore.MAGENTA}%(filename)-s:%(lineno)03d '
    f'{Colors.LEVEL_COLOR}- %(message)s'
)
stream_formatter = ChromaFormatter(log_format)
stream_handler = logging.StreamHandler(stream=sys.stdout)

flask_logger = logging.getLogger('werkzeug')
while flask_logger.handlers:
    flask_logger.removeHandler(flask_logger.handlers.pop())
flask_logger.addHandler(stream_handler)