Where is a complete example of logging.config.dictConfig?

How about here! The corresponding documentation reference is configuration-dictionary-schema.

LOGGING_CONFIG = { 
    'version': 1,
    'disable_existing_loggers': True,
    'formatters': { 
        'standard': { 
            'format': '%(asctime)s [%(levelname)s] %(name)s: %(message)s'
        },
    },
    'handlers': { 
        'default': { 
            'level': 'INFO',
            'formatter': 'standard',
            'class': 'logging.StreamHandler',
            'stream': 'ext://sys.stdout',  # Default is stderr
        },
    },
    'loggers': { 
        '': {  # root logger
            'handlers': ['default'],
            'level': 'WARNING',
            'propagate': False
        },
        'my.packg': { 
            'handlers': ['default'],
            'level': 'INFO',
            'propagate': False
        },
        '__main__': {  # if __name__ == '__main__'
            'handlers': ['default'],
            'level': 'DEBUG',
            'propagate': False
        },
    } 
}

Usage:

import logging.config

# Run once at startup:
logging.config.dictConfig(LOGGING_CONFIG)

# Include in each module:
log = logging.getLogger(__name__)
log.debug("Logging is configured.")

In case you see too many logs from third-party packages, be sure to run this config using logging.config.dictConfig(LOGGING_CONFIG) before the third-party packages are imported.

To add additional custom info to each log message using a logging filter, consider this answer.

Example with Stream Handler, File Handler, Rotating File Handler and SMTP Handler

from logging.config import dictConfig

LOGGING_CONFIG = {
    'version': 1,
    'loggers': {
        '': {  # root logger
            'level': 'NOTSET',
            'handlers': ['debug_console_handler', 'info_rotating_file_handler', 'error_file_handler', 'critical_mail_handler'],
        },
        'my.package': { 
            'level': 'WARNING',
            'propagate': False,
            'handlers': ['info_rotating_file_handler', 'error_file_handler' ],
        },
    },
    'handlers': {
        'debug_console_handler': {
            'level': 'DEBUG',
            'formatter': 'info',
            'class': 'logging.StreamHandler',
            'stream': 'ext://sys.stdout',
        },
        'info_rotating_file_handler': {
            'level': 'INFO',
            'formatter': 'info',
            'class': 'logging.handlers.RotatingFileHandler',
            'filename': 'info.log',
            'mode': 'a',
            'maxBytes': 1048576,
            'backupCount': 10
        },
        'error_file_handler': {
            'level': 'WARNING',
            'formatter': 'error',
            'class': 'logging.FileHandler',
            'filename': 'error.log',
            'mode': 'a',
        },
        'critical_mail_handler': {
            'level': 'CRITICAL',
            'formatter': 'error',
            'class': 'logging.handlers.SMTPHandler',
            'mailhost' : 'localhost',
            'fromaddr': '[email protected]',
            'toaddrs': ['[email protected]', '[email protected]'],
            'subject': 'Critical error with application name'
        }
    },
    'formatters': {
        'info': {
            'format': '%(asctime)s-%(levelname)s-%(name)s::%(module)s|%(lineno)s:: %(message)s'
        },
        'error': {
            'format': '%(asctime)s-%(levelname)s-%(name)s-%(process)d::%(module)s|%(lineno)s:: %(message)s'
        },
    },

}

dictConfig(LOGGING_CONFIG)

The accepted answer is nice! But what if one could begin with something less complex? The logging module is very powerful thing and the documentation is kind of a little bit overwhelming especially for novice. But for the beginning you don't need to configure formatters and handlers. You can add it when you figure out what you want.

For example:

import logging.config

DEFAULT_LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'loggers': {
        '': {
            'level': 'INFO',
        },
        'another.module': {
            'level': 'DEBUG',
        },
    }
}

logging.config.dictConfig(DEFAULT_LOGGING)

logging.info('Hello, log')