glances/logger.py

#
# This file is part of Glances.
#
# SPDX-FileCopyrightText: 2022 Nicolas Hennion <nicolas@nicolargo.com>
#
# SPDX-License-Identifier: LGPL-3.0-only
#

"""Custom logger class."""

import getpass
import json
import logging
import logging.config
import os
import tempfile

from glances.globals import safe_makedirs

# Choose the good place for the log file (see issue #1575)
# Default root path
if 'HOME' in os.environ:
    _XDG_CACHE_HOME = os.path.join(os.environ['HOME'], '.local', 'share')
else:
    _XDG_CACHE_HOME = ''
# Define the glances log file
if (
    'XDG_CACHE_HOME' in os.environ
    and os.path.isdir(os.environ['XDG_CACHE_HOME'])
    and os.access(os.environ['XDG_CACHE_HOME'], os.W_OK)
):
    safe_makedirs(os.path.join(os.environ['XDG_CACHE_HOME'], 'glances'))
    LOG_FILENAME = os.path.join(os.environ['XDG_CACHE_HOME'], 'glances', 'glances.log')
elif os.path.isdir(_XDG_CACHE_HOME) and os.access(_XDG_CACHE_HOME, os.W_OK):
    safe_makedirs(os.path.join(_XDG_CACHE_HOME, 'glances'))
    LOG_FILENAME = os.path.join(_XDG_CACHE_HOME, 'glances', 'glances.log')
else:
    LOG_FILENAME = os.path.join(tempfile.gettempdir(), f'glances-{getpass.getuser()}.log')

# Define the logging configuration
LOGGING_CFG = {
    "version": 1,
    "disable_existing_loggers": "False",
    "root": {"level": "INFO", "handlers": ["file", "console"]},
    "formatters": {
        "standard": {"format": "%(asctime)s -- %(levelname)s -- %(message)s"},
        "short": {"format": "%(levelname)s -- %(message)s"},
        "long": {"format": "%(asctime)s -- %(levelname)s -- %(message)s (%(funcName)s in %(filename)s)"},
        "free": {"format": "%(message)s"},
    },
    "handlers": {
        "file": {
            "level": "DEBUG",
            "class": "logging.handlers.RotatingFileHandler",
            "maxBytes": 1000000,
            "backupCount": 3,
            "formatter": "standard",
            "filename": LOG_FILENAME,
        },
        "console": {"level": "CRITICAL", "class": "logging.StreamHandler", "formatter": "free"},
    },
    "loggers": {
        "debug": {"handlers": ["file", "console"], "level": "DEBUG"},
        "verbose": {"handlers": ["file", "console"], "level": "INFO"},
        "standard": {"handlers": ["file"], "level": "INFO"},
        "requests": {"handlers": ["file", "console"], "level": "ERROR"},
        "elasticsearch": {"handlers": ["file", "console"], "level": "ERROR"},
        "elasticsearch.trace": {"handlers": ["file", "console"], "level": "ERROR"},
    },
}


def glances_logger(env_key='LOG_CFG'):
    """Build and return the logger.

    env_key define the env var where a path to a specific JSON logger
            could be defined

    :return: logger -- Logger instance
    """
    _logger = logging.getLogger()

    # By default, use the LOGGING_CFG logger configuration
    config = LOGGING_CFG

    # Check if a specific configuration is available
    user_file = os.getenv(env_key, None)
    if user_file and os.path.exists(user_file):
        # A user file as been defined. Use it...
        with open(user_file) as f:
            config = json.load(f)

    # Load the configuration
    logging.config.dictConfig(config)

    return _logger


logger = glances_logger()