mycroft-core/mycroft/util/log.py

# Copyright 2016 Mycroft AI, Inc.
#
# This file is part of Mycroft Core.
#
# Mycroft Core is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Mycroft Core is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Mycroft Core.  If not, see <http://www.gnu.org/licenses/>.
import inspect
import logging
import sys
from traceback import format_exception

from os.path import isfile

from mycroft.util.json_helper import load_commented_json


def getLogger(name="MYCROFT"):
    """Depreciated. Use LOG instead"""
    return logging.getLogger(name)


class LOG:
    """
    Custom logger class that acts like logging.Logger
    The logger name is automatically generated by the module of the caller

    Usage:
        LOG.debug('My message: %s', debug_str)
        LOG('custom_name').debug('Another message')
    """

    _custom_name = None

    @classmethod
    def init(cls):
        sys_config = '/etc/mycroft/mycroft.conf'
        cls.level = logging.getLevelName(load_commented_json(sys_config)['log_level']
                                         if isfile(sys_config) else 'DEBUG')

        fmt = '%(asctime)s.%(msecs)03d - %(name)s - %(levelname)s - %(message)s'
        datefmt = '%H:%M:%S'
        formatter = logging.Formatter(fmt, datefmt)
        cls.ch = logging.StreamHandler(sys.stdout)
        cls.ch.setFormatter(formatter)
        cls.create_logger('')  # Enables logging in external modules

    @classmethod
    def create_logger(cls, name):
        l = logging.getLogger(name)
        l.propagate = False
        if not hasattr(cls, 'level'):
            cls.init()

        l.addHandler(cls.ch)
        l.setLevel(cls.level)
        return l

    def __init__(self, name):
        LOG._custom_name = name

    @classmethod
    def _log(cls, func, args, kwargs):
        if cls._custom_name is not None:
            name = cls._custom_name
            cls._custom_name = None
        else:
            # Stack:
            # [0] - _log()
            # [1] - debug(), info(), warning(), or error()
            # [2] - caller
            stack = inspect.stack()

            # Record:
            # [0] - frame object
            # [1] - filename
            # [2] - line number
            # [3] - function
            # ...
            record = stack[2]
            name = inspect.getmodule(record[0]).__name__ + ':' + record[3] + ':' + str(record[2])
        func(cls.create_logger(name), *args, **kwargs)

    @classmethod
    def debug(cls, *args, **kwargs):
        cls._log(logging.Logger.debug, args, kwargs)

    @classmethod
    def info(cls, *args, **kwargs):
        cls._log(logging.Logger.info, args, kwargs)

    @classmethod
    def warning(cls, *args, **kwargs):
        cls._log(logging.Logger.warning, args, kwargs)

    @classmethod
    def error(cls, *args, **kwargs):
        cls._log(logging.Logger.error, args, kwargs)

    @classmethod
    def exception(cls, *args, **kwargs):
        cls._log(logging.Logger.exception, args, kwargs)

    @classmethod
    def print_trace(cls, location='', warn=False, *args):
        trace_lines = format_exception(*sys.exc_info())
        if warn:
            intro = 'Warning' + ('in ' + location + ': ' if location else ': ')
            trace_str = intro + trace_lines[-1].strip()
            t = logging.Logger.info
        else:
            trace_str = '\n' + ''.join(trace_lines)
            if location:
                trace_str = '\n=== ' + location + ' ===' + trace_str
            trace_str = '\n' + trace_str
            t = logging.Logger.error
        cls._log(t, trace_str, args)