dev-notes/docs/languages/python/modules/logging.md

Logging Module

Configuration

# basic configuration for the logging system
logging.basicConfig(filename="relpath", level=logging.LOG_LEVEL, format=f"message format", **kwargs)  
# DATEFMT: Use the specified date/time format, as accepted by time.strftime().

# create a logger with a name (useful for having multiple loggers)
logger = logging.getLogger(name="logger name")  
logger.level  # LOG_LEVEL for this logger

# disable all logging calls of severity level and below
# alternative to basicConfig(level=logging.LOG_LEVEL)
logging.disable(level=LOG_LEVEL)  

Format (basicConfig(format=""))

Attribute name	Format	Description
asctime	%(asctime)s	Human-readable time when the LogRecord was created. Modified by basicConfig(datefmt="")
created	%(created)f	Time when the LogRecord was created (as returned by time.time()).
filename	%(filename)s	Filename portion of pathname.
funcName	%(funcName)s	Name of function containing the logging call.
levelname	%(levelname)s	Text logging level for the message.
levelno	%(levelno)s	Numeric logging level for the message.
lineno	%(lineno)d	Source line number where the logging call was issued (if available).
message	%(message)s	The logged message, computed as msg % args.
module	%(module)s	Module (name portion of filename).
msecs	%(msecs)d	Millisecond portion of the time when the LogRecord was created.
name	%(name)s	Name of the logger used to log the call.
pathname	%(pathname)s	Full pathname of the source file where the logging call was issued (if available).
process	%(process)d	Process ID (if available).
processName	%(processName)s	Process name (if available).
thread	%(thread)d	Thread ID (if available).
threadName	%(threadName)s	Thread name (if available).

Datefmt (basicConfig(datefmt=""))

Directive	Meaning
%a	Locale's abbreviated weekday name.
%A	Locale's full weekday name.
%b	Locale's abbreviated month name.
%B	Locale's full month name.
%c	Locale's appropriate date and time representation.
%d	Day of the month as a decimal number [01,31].
%H	Hour (24-hour clock) as a decimal number [00,23].
%I	Hour (12-hour clock) as a decimal number [01,12].
%j	Day of the year as a decimal number [001,366].
%m	Month as a decimal number [01,12].
%M	Minute as a decimal number [00,59].
%p	Locale's equivalent of either AM or PM.
%S	Second as a decimal number [00,61].
%U	Week number of the year (Sunday as the first day of the week) as a decimal number [00,53].
%w	Weekday as a decimal number [0(Sunday),6].
%W	Week number of the year (Monday as the first day of the week) as a decimal number [00,53].
%x	Locale's appropriate date representation.
%X	Locale's appropriate time representation.
%y	Year without century as a decimal number [00,99].
%Y	Year with century as a decimal number.
%z	Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM [-23:59, +23:59].
%Z	Time zone name (no characters if no time zone exists).
%%	A literal '%' character.

Logs

Log Levels (Low To High):

• default: 0
• debug: 10
• info: 20
• warning: 30
• error: 40
• critical: 50

logging.debug(msg)  # Logs a message with level DEBUG on the root logger
logging.info(msg)  # Logs a message with level INFO on the root logger
logging.warning(msg)  # Logs a message with level WARNING on the root logger
logging.error(msg)  # Logs a message with level ERROR on the root logger
logging.critical(msg)  # Logs a message with level CRITICAL on the root logger