chromaformatter 4.0.0

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. The syntax to add colors in the format string is $COLOR_NAME_HERE to add a color. $LEVEL refers to the color of the logging level for a log.

log_format = ('$GREEN[%(asctime)-s]'
              '$LEVEL[%(levelname)-s]'
              '$MAGENTA[%(filename)-s:%(lineno)-d]'
              '$LEVEL: %(message)s')

To use, we use a chromaformatter.ChromaFormatter rather than the logging.Formatter.

import sys
import logging
from chromaformatter import ChromaFormatter

log = logging.getLogger()
log_format = ('$GREEN[%(asctime)-s]'
              '$LEVEL[%(levelname)-s]'
              '$MAGENTA[%(filename)-s:%(lineno)-d]'
              '$LEVEL: %(message)s')
formatter = ChromaFormatter(log_format)
handler = logging.StreamHandler(stream=sys.stdout)
handler.setFormatter(formatter)
log.addHandler(handler)

All supported colors:

Regular	Light
$BLACK	$LI_BLACK
$RED	$LI_RED
$GREEN	$LI_GREEN
$YELLOW	$LI_YELLOW
$BLUE	$LI_BLUE
$MAGENTA	$LI_MAGENTA
$CYAN	$LI_CYAN
$WHITE	$LI_WHITE

Additionally $BOLD applies bold text and $RESET resets back to no colors unless use_bold is True, then it resets to bold text.

Formatted Arguments in a Log

By inserting a %s placeholder in your log message and passing the value in as a parameter, colors will be added.

log.info('Format %s.', 10)

Additional Configuration

ChromaFormatter has a dict called color_map to determine the colors of parts of the log msg that can't be configured from the format string passed into ChromaFormatter. Logging levels, and the color of formatted arguments are set in color_map.

By default, the colors are:

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

To change color_map colors use colorama:

formatter.color_map[chromaformatter.INFO] = colorama.Fore.WHITE
formatter.color_map[chromaformatter.ARGS] = colorama.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

log_format = ('$GREEN[%(asctime)-0s]'
              '$LEVEL[%(levelname)-5s]'
              '$MAGENTA[%(filename)-21s:'
              '%(lineno)-3d]'
              '$LEVEL: %(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)