2. Logowanie zdarzeń

2.1. Korzystanie z logging

2.1.1. Poziomy logowania

  • Critical
  • Error
  • Warning
  • Info
  • Debug
import logging

logging.critical('Błąd krytyczny, kończę.')
logging.error('Błąd, ale kontynuuję.')
logging.warning('Uwaga będę coś robił')
logging.info('Będę coś robił')
logging.debug('Robię to tak')

2.1.2. Konfiguracja logowania

import logging

logging.basicConfig(
    level=logging.INFO,
    filename='/tmp/logging.csv',
    format='"%(asctime).19s", "%(levelname)s", "%(message)s"'
)

log = logging.getLogger(__name__)

log.warning('warning!')  # zostanie zapisana do pliku
log.debug('wiadomosc debuggingowa')  # nie zostanie zapisana, bo level jest INFO, czyli powyżej DEBUG

2.1.3. Logowanie zdarzeń

import logging
log = logging.getLogger(__name__)

def sum(a, b):
    log.debug('Function `sum()` executed with: %s', locals())
    value = a + b
    log.debug(f'Will produce "{value}" as result')
    return value

sum(1, 2)
# Function `sum()` executed with: {'b': 2, 'a': 1}
# Will produce "3" as result
# 3

2.1.4. Wyciszanie logowania

import logging

logging.basicConfig(
    level=logging.DEBUG,
    format='[%(asctime).19s] [%(levelname)s] %(message)s')

logging.getLogger('requests').setLevel(logging.WARNING)
log = logging.getLogger(__name__)

log.debug('to jest moja debugowa wiadomosc')

2.2. Konfiguracja formatowania logów

Todo

convert table to CSV

Format Description
args The tuple of arguments merged into msg to produce message, or a dict whose values are used for the merge (when there is only one argument, and it is a dictionary). You shouldn’t need to format this yourself.
%(asctime)s Human-readable time when the LogRecord was created. By default this is of the form ‘2003-07-08 16:49:45,896’ (the numbers after the comma are millisecond portion of the time).
%(created)f Time when the LogRecord was created (as returned by time.time).
exc_info Exception tuple (à la sys.exc_info) or, if no exception has occurred, None. You shouldn’t need to format this yourself.
%(filename)s Filename portion of pathname.
%(funcName)s Name of function containing the logging call.
%(levelname)s Text logging level for the message ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL').
%(levelno)s Numeric logging level for the message (DEBUG, INFO, WARNING, ERROR, CRITICAL).
%(lineno)d Source line number where the logging call was issued (if available).
%(module)s Module (name portion of filename).
%(msecs)d Millisecond portion of the time when the LogRecord was created.
%(message)s The logged message, computed as msg % args. This is set when Formatter.format is invoked.
msg The format string passed in the original logging call. Merged with args to produce message, or an arbitrary object (see arbitrary-object-messages). You shouldn’t need to format this yourself.
%(name)s Name of the logger used to log the call.
%(pathname)s Full pathname of the source file where the logging call was issued (if available).
%(process)d Process ID (if available).
%(processName)s Process name (if available).
%(relativeCreated)d Time in milliseconds when the LogRecord was created, relative to the time the logging module was loaded.
stack_info Stack frame information (where available) from the bottom of the stack in the current thread, up to and including the stack frame of the logging call which resulted in the creation of this record. You shouldn’t need to format this yourself.
%(thread)d Thread ID (if available).
%(threadName)s Thread name (if available).

2.2.1. DictConfig

{
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'standard': {
            'format': '%(asctime)s [%(levelname)s] %(name)s: %(message)s'
        },
    },
    'handlers': {
        'default': {
            'level': 'INFO',
            'formatter': 'standard',
            'class': 'logging.StreamHandler',
        },
    },
    'loggers': {
        '': {
            'handlers': ['default'],
            'level': 'INFO',
            'propagate': True
        },
        'django.request': {
            'handlers': ['default'],
            'level': 'WARN',
            'propagate': False
        },
    }
}
Tab. 2.3. DictConfig
Format Description
filename Specifies that a FileHandler be created, using the specified filename, rather than a StreamHandler
filemode If filename is specified, open the file in this mode. Defaults to ‘a’
format Use the specified format string for the handler
datefmt Use the specified date/time format, as accepted by time.strftime()
style If format is specified, use this style for the format string. One of ‘%’, ‘{‘ or ‘$’ for printf-style, str.format() or string.Template respectively. Defaults to ‘%’
level Set the root logger level to the specified level
stream Use the specified stream to initialize the StreamHandler. Note that this argument is incompatible with filename - if both are present, a ValueError is raised
handlers If specified, this should be an iterable of already created handlers to add to the root logger. Any handlers which don’t already have a formatter set will be assigned the default formatter created in this function. Note that this argument is incompatible with filename or stream - if both are present, a ValueError is raised

2.3. warnings

import warnings

warnings.warn('Wersja API jest już nieaktualna', PendingDeprecationWarning)
import warnings

def sumuj(a, b):
    warnings.warn('You should english name ``sum()``.', PendingDeprecationWarning)
    return a + b

def sum(a, b):
    return a + b


sumuj(1, 2)
sum(1, 2)