Logger Module

foo.py

import logging
import os
import sys

import colorama
import sh

colorama.init(autoreset=True)

SUCCESS = 100
OUT = 101


class LogFilter(object):
    """
    A custom log filter which excludes log messages above the logged
    level.
    """

    def __init__(self, level):
        self.__level = level

    def filter(self, logRecord):  # pragma: no cover
        # https://docs.python.org/3/library/logging.html#logrecord-attributes
        return logRecord.levelno <= self.__level


class CustomLogger(logging.getLoggerClass()):
    """
    A custom logging class which adds additional methods to the logger.  These
    methods serve as syntactic sugar for formatting log messages.
    """

    def __init__(self, name, level=logging.NOTSET):
        super(logging.getLoggerClass(), self).__init__(name, level)
        logging.addLevelName(SUCCESS, 'SUCCESS')
        logging.addLevelName(OUT, 'OUT')

    def success(self, msg, *args, **kwargs):
        if self.isEnabledFor(SUCCESS):
            self._log(SUCCESS, msg, args, **kwargs)

    def out(self, msg, *args, **kwargs):
        if self.isEnabledFor(OUT):
            self._log(OUT, msg, args, **kwargs)


class TrailingNewlineFormatter(logging.Formatter):
    """
    A custom logging formatter which removes additional newlines from messages.
    """

    def format(self, record):
        if record.msg:
            record.msg = record.msg.rstrip()
        return super(TrailingNewlineFormatter, self).format(record)


def get_logger(name=None):
    """
    Build a logger with the given name and returns the logger.

    :param name: The name for the logger. This is usually the module
                 name, ``__name__``.
    :return: logger object
    """
    logging.setLoggerClass(CustomLogger)

    logger = logging.getLogger(name)
    logger.setLevel(logging.DEBUG)

    logger.addHandler(_get_info_handler())
    logger.addHandler(_get_out_handler())
    logger.addHandler(_get_warn_handler())
    logger.addHandler(_get_error_handler())
    logger.addHandler(_get_critical_handler())
    logger.addHandler(_get_success_handler())
    logger.propagate = False

    return logger


def _get_info_handler():
    color = colorama.Fore.CYAN
    handler = logging.StreamHandler(sys.stdout)
    handler.setLevel(logging.INFO)
    handler.addFilter(LogFilter(logging.INFO))
    handler.setFormatter(
        TrailingNewlineFormatter('--> {}%(message)s'.format(color)))

    return handler


def _get_out_handler():
    handler = logging.StreamHandler(sys.stdout)
    handler.setLevel(OUT)
    handler.addFilter(LogFilter(OUT))
    handler.setFormatter(TrailingNewlineFormatter('    %(message)s'))

    return handler


def _get_warn_handler():
    color = colorama.Fore.YELLOW
    handler = logging.StreamHandler(sys.stdout)
    handler.setLevel(logging.WARN)
    handler.addFilter(LogFilter(logging.WARN))
    handler.setFormatter(
        TrailingNewlineFormatter('{}%(message)s'.format(color)))

    return handler


def _get_error_handler():
    color = colorama.Fore.RED
    handler = logging.StreamHandler(sys.stderr)
    handler.setLevel(logging.ERROR)
    handler.addFilter(LogFilter(logging.ERROR))
    handler.setFormatter(
        TrailingNewlineFormatter('{}%(message)s'.format(color)))

    return handler


def _get_critical_handler():
    color = colorama.Fore.RED
    handler = logging.StreamHandler(sys.stderr)
    handler.setLevel(logging.CRITICAL)
    handler.addFilter(LogFilter(logging.CRITICAL))
    handler.setFormatter(
        TrailingNewlineFormatter('{}ERROR: %(message)s'.format(color)))

    return handler


def _get_success_handler():
    color = colorama.Fore.GREEN
    handler = logging.StreamHandler(sys.stdout)
    handler.setLevel(SUCCESS)
    handler.addFilter(LogFilter(SUCCESS))
    handler.setFormatter(
        TrailingNewlineFormatter('{}%(message)s'.format(color)))

    return handler


log = get_logger(name=__name__)
command = sh.tester.bake(_out=log.out, _err=log.error, _env=os.environ.copy())
command()

tester.bash

#!/usr/bin/env bash

while true; do
  echo 'hi'
  sleep 1
done