Python logging example from dictionary (or loaded JSON) featuring formatting that includes the local timezone, custom log format, logging to both console AND file, and automatically rotating log files.

Python.Logging.Dictionary-or-JSON.py

import logging.config
import time

TZ_NAME = time.tzname[0] if not time.localtime().tm_isdst else time.tzname[1]
# Alternatively, convert the localtime to UTC/GMT but if you use this then update
# the logging formatter because this example is using the local timezone.
#   logging_handler.formatter.converter = time.gmtime

# This is kept separate as it can be used to apply a default log level to your
# loggers otherwise you can use a method to change this to debug and apply the
# logging config dictionary but I will create another gist to show an example
# of that.
LOGGER_DEFAULT = {
    'level': 'INFO'
}

# List concatenation makes long strings easier to digest so I include each of
# my log format components here and concatenate later.
FORMATTER_PARTS = [
    '%(asctime)s',
    '%(levelname)s',
    'PID:%(process)d - PROC:%(processName)s - THREAD:%(thread)s:',
    '%(name)s.%(funcName)s',
    '%(message)s'
]

# Now for the nitty-gritty.
LOG_CONFIG = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'default': {
            'format': ' | '.join(FORMATTER_PARTS),
            'datefmt': '%Y-%m-%d %H:%M:%S {}'.format(TZ_NAME)
        }
    },
    'handlers': {
        'console': {
            'class': 'logging.StreamHandler',
            'formatter': 'default'
        },
        'file': {
            'backupCount': 10,
            'class': 'logging.handlers.RotatingFileHandler',
            'encoding': 'utf-8',
            'formatter': 'default',
            'filename': 'recentmetadata.log',
            'maxBytes': 10485760  # 10MB
        }
    },
    'loggers': {
        'main': LOGGER_DEFAULT,
        'elasticsearch': LOGGER_DEFAULT
    },
    'root': {
        'handlers': ['console', 'file']
    }
}

# Finally apply the logging config dictionary.
logging.config.dictConfig(LOG_CONFIG)

# The only thing left to do is setup your loggers and enjoy!
logger = logging.getLogger('main')