"logging" — Fonctionnalités de journalisation pour Python
*********************************************************

**Code source :** Lib/logging/__init__.py


Important
^^^^^^^^^

Cette page contient les informations de référence de l’API. Pour des
tutoriels et des discussions sur des sujets plus avancés, voir

* Tutoriel de découverte

* Tutoriel avancé

* Recettes pour la journalisation

======================================================================

Ce module définit les fonctions et les classes qui mettent en œuvre un
système flexible d’enregistrement des événements pour les applications
et les bibliothèques.

L'intérêt principal d'utiliser une API de journalisation fournie par
un module de bibliothèque standard réside dans le fait que tous les
modules Python peuvent participer à la journalisation, de sorte que le
journal de votre application peut inclure vos propres messages et ceux
de modules tiers.

Here's a simple example of idiomatic usage:

   # myapp.py
   import logging
   import mylib
   logger = logging.getLogger(__name__)

   def main():
       logging.basicConfig(filename='myapp.log', level=logging.INFO)
       logger.info('Started')
       mylib.do_something()
       logger.info('Finished')

   if __name__ == '__main__':
       main()

   # mylib.py
   import logging
   logger = logging.getLogger(__name__)

   def do_something():
       logger.info('Doing something')

If you run *myapp.py*, you should see this in *myapp.log*:

   INFO:__main__:Started
   INFO:mylib:Doing something
   INFO:__main__:Finished

The key features of this idiomatic usage is that the majority of code
is simply creating a module level logger with "getLogger(__name__)",
and using that logger to do any needed logging. This is concise while
allowing downstream code fine grained control if needed. Logged
messages to the module-level logger get forwarded up to handlers of
loggers in higher-level modules, all the way up to the root logger;
for this reason this approach is known as hierarchical logging.

For logging to be useful, it needs to be configured: setting the
levels and destinations for each logger, potentially changing how
specific modules log, often based on command-line arguments or
application configuration. In most cases, like the one above, only the
root logger needs to be so configured, since all the lower level
loggers at module level eventually forward their messages to its
handlers.  "basicConfig()" provides a quick way to configure the root
logger that handles many use cases.

Ce module offre de nombreuses fonctionnalités et une grande
flexibilité. Si vous n'êtes pas familier avec la journalisation, la
meilleure façon de l’appréhender est de consulter les tutoriels
(**voir les liens ci-dessus et à droite**).

Les classes élémentaires définies par le module, ainsi que leurs
fonctions, sont énumérées ci-dessous.

* les enregistreurs (*loggers* en anglais) exposent l'interface que le
  code de l'application utilise directement ;

* les gestionnaires (*handlers*) envoient les entrées de journal
  (créées par les *loggers*) vers les destinations voulues ;

* les filtres (*filters*) fournissent un moyen de choisir plus
  finement quelles entrées de journal doivent être sorties ;

* les formateurs (*formatters*) définissent la structure de l'entrée
  de journal dans la sortie finale.


Enregistreurs
=============

Les enregistreurs ont les attributs et les méthodes suivants. Notez
que les enregistreurs ne doivent *JAMAIS* être instanciés directement,
mais toujours par la fonction au niveau du module
"logging.getLogger(nom)". Les appels à "getLogger()" avec le même nom
renvoient toujours une référence au même objet enregistreur.

"nom" est une valeur avec un ou plusieurs niveaux de hiérarchie,
séparés par des points, comme "truc.machin.bidule" (bien qu’elle
puisse aussi valoir simplement "truc", par exemple). Les enregistreurs
à droite dans la liste hiérarchique sont les enfants des enregistreurs
plus à gauche dans cette liste. Par exemple, pour un enregistreur
nommé "truc", les enregistreurs portant les noms "truc.machin",
"truc.machin.bidule" et "truc.chose" sont tous des enfants de "truc".
La hiérarchie des noms d’enregistreurs est analogue à la hiérarchie
des paquets Python et est même identique à celle-ci si vous organisez
vos enregistreurs par module en utilisant la construction recommandée
"logging.getLogger(__name__)". C’est ainsi parce que dans un module,
"__name__" est le nom du module dans l’espace de noms des paquets
Python.

class logging.Logger

   name

      This is the logger's name, and is the value that was passed to
      "getLogger()" to obtain the logger.

      Note:

        This attribute should be treated as read-only.

   level

      The threshold of this logger, as set by the "setLevel()" method.

      Note:

        Do not set this attribute directly - always use "setLevel()",
        which has checks for the level passed to it.

   parent

      The parent logger of this logger. It may change based on later
      instantiation of loggers which are higher up in the namespace
      hierarchy.

      Note:

        This value should be treated as read-only.

   propagate

      Si cet attribut est évalué comme vrai, les événements
      enregistrés dans cet enregistreur seront transmis aux
      gestionnaires des enregistreurs de niveau supérieur (parents),
      en plus des gestionnaires attachés à l'enregistreur. Les
      messages sont transmis directement aux gestionnaires des
      enregistreurs parents — ni le niveau ni les filtres des
      enregistreurs parentaux en question ne sont pris en compte.

      S’il s’évalue comme faux, les messages de journalisation ne sont
      pas transmis aux gestionnaires des enregistreurs parents.

      Spelling it out with an example: If the propagate attribute of
      the logger named "A.B.C" evaluates to true, any event logged to
      "A.B.C" via a method call such as
      "logging.getLogger('A.B.C').error(...)" will [subject to passing
      that logger's level and filter settings] be passed in turn to
      any handlers attached to loggers named "A.B", "A" and the root
      logger, after first being passed to any handlers attached to
      "A.B.C". If any logger in the chain "A.B.C", "A.B", "A" has its
      "propagate" attribute set to false, then that is the last logger
      whose handlers are offered the event to handle, and propagation
      stops at that point.

      Le constructeur fixe cet attribut à "True".

      Note:

        si vous associez un gestionnaire à un enregistreur *et* à un
        ou plusieurs de ses parents, il peut émettre le même
        enregistrement plusieurs fois. En général, il est rare d'avoir
        besoin d'attacher un gestionnaire à plus d'un enregistreur —
        si vous l'attachez simplement à l'enregistreur approprié le
        plus haut possible dans la hiérarchie des enregistreurs, alors
        il voit tous les événements enregistrés par tous les
        enregistreurs descendants, à condition que leur paramètre de
        propagation soit laissé à "True". La pratique la plus courante
        est de n'attacher les gestionnaires qu'à l'enregistreur racine
        et à laisser la propagation s'occuper du reste.

   handlers

      The list of handlers directly attached to this logger instance.

      Note:

        This attribute should be treated as read-only; it is normally
        changed via the "addHandler()" and "removeHandler()" methods,
        which use locks to ensure thread-safe operation.

   disabled

      This attribute disables handling of any events. It is set to
      "False" in the initializer, and only changed by logging
      configuration code.

      Note:

        This attribute should be treated as read-only.

   setLevel(level)

      Fixe le seuil de l'enregistreur au niveau *level*. Les messages
      de journalisation qui sont moins graves que *level* sont ignorés
      ; les messages qui ont une gravité égale à *level* ou plus
      élevée sont traités par le ou les gestionnaires de
      l'enregistreur, à moins que le niveau d'un gestionnaire n'ait
      été fixé à un niveau de gravité plus élevé que *level*.

      Lorsqu'un enregistreur est créé, son niveau est fixé à "NOTSET"
      (ce qui entraîne le traitement de tous les messages lorsque
      l'enregistreur est l'enregistreur racine, ou la délégation au
      parent lorsque l'enregistreur est un enregistreur non racine).
      Notez que l'enregistreur racine est créé avec le niveau
      "WARNING".

      Le terme « délégation au parent » signifie que si un
      enregistreur a un niveau de "NOTSET", sa chaîne d’enregistreurs
      parents est parcourue jusqu'à ce qu'un parent ayant un niveau
      autre que "NOTSET" soit trouvé, ou que la racine soit atteinte.

      Si un parent est trouvé avec un niveau autre que NOTSET, alors
      le niveau de ce parent est utilisé comme le niveau effectif de
      l'enregistreur d'où la recherche du parent a commencé. Ce niveau
      est utilisé pour déterminer comment un événement
      d'enregistrement est traité.

      Si la racine est atteinte, et qu'elle a un niveau de NOTSET,
      alors tous les messages sont traités. Sinon, le niveau de la
      racine est utilisé comme niveau effectif.

      Voir Niveaux de journalisation pour la liste des niveaux.

      Modifié dans la version 3.2: le paramètre *level* peut désormais
      être une chaîne de caractères représentant le niveau de gravité
      (comme "'INFO'") en plus des constantes entières (comme "INFO").
      Notez cependant que les niveaux sont stockés en interne sous
      forme d'entiers, et que des méthodes telles que
      "getEffectiveLevel()" et "isEnabledFor()" renvoient et
      s'attendent à recevoir des entiers.

   isEnabledFor(level)

      Indique si un message de gravité *level* est traitable par cet
      enregistreur. Cette méthode vérifie d'abord le niveau de gravité
      du module défini par "logging.disable(level)" et ensuite le
      niveau effectif de l'enregistreur, déterminé par
      "getEffectiveLevel()".

   getEffectiveLevel()

      Indique le niveau effectif de l'enregistreur. Si une valeur
      autre que "NOTSET" a été définie en utilisant "setLevel()", elle
      est renvoyée. Sinon, la hiérarchie est parcourue vers la racine
      jusqu'à ce qu'une valeur autre que "NOTSET" soit trouvée, et
      cette valeur est renvoyée. La valeur renvoyée est un entier, par
      exemple "logging.DEBUG", "logging.INFO", etc.

   getChild(suffix)

      Renvoie un enregistreur enfant de l'enregistreur, déterminé par
      *suffix*. Ainsi, "logging.getLogger('abc').getChild('def.ghi')"
      renvoie le même enregistreur que
      "logging.getLogger('abc.def.ghi')". C'est une méthode destinée à
      simplifier la vie du développeur. Elle est très utile quand
      l’enregistreur parent est nommé en utilisant, par exemple,
      "__name__" plutôt qu'une chaîne de caractères littérale.

      Nouveau dans la version 3.2.

   debug(msg, *args, **kwargs)

      Enregistre un message de niveau "DEBUG" dans cet enregistreur.
      *msg* est la chaîne du message qui sera formatée avec *args* en
      utilisant l'opérateur de formatage. Cela signifie qu'il est
      possible de mettre des mots-clé dans la chaîne et de passer un
      dictionnaire en argument. Si *args* n'est pas fourni, aucun
      formatage « à la % » n'est appliqué.

      Quatre mots-clés de *kwargs* sont analysés : *exc_info*,
      *stack_info*, *stacklevel* et *extra*.

      Si la valeur booléenne de *exc_info* est vraie, les informations
      des exceptions sont ajoutées au message. Si *exc_info* est un
      *n*-uplet d'exception (au format identique aux valeurs renvoyées
      par "sys.exc_info()") ou une instance d'exception, sa valeur est
      utilisée. Dans le cas contraire, les informations sur
      l'exception sont déterminées par un appel à "sys.exc_info()".

      Le deuxième argument par mot-clé optionnel est *stack_info*,
      valant "False" par défaut. S'il est vrai, les informations de la
      pile d'appels sont ajoutées à l'entrée de journal, en incluant
      aussi l'appel à la fonction de journalisation. Ce ne sont pas
      les mêmes informations que celles affichées en définissant
      *exc_info* : les premières représentent les appels de fonctions
      successifs, du bas de la pile jusqu'à l'appel de la fonction de
      journalisation dans le fil d'exécution actuel, alors que les
      secondes portent des informations sur les appels successifs
      déclenchés par la levée d'une exception et la recherche de
      gestionnaires pour cette exception.

      Il est possible de définir *stack_info* indépendamment de
      *exc_info*, p. ex. pour s'assurer que l'exécution a atteint un
      certain point dans le code, même si aucune exception n'a été
      levée. La pile d'appels est alors affichée après la ligne d'en-
      tête suivante :

         Stack (most recent call last):

      Elle imite la ligne "Traceback (most recent call last):"
      affichée avec la pile d'appels d'une exception.

      Le troisième argument par mot-clé optionnel est *stacklevel*,
      valant "1" par défaut. S'il est supérieur à 1, il correspond au
      nombre d'entrées dans la pile qui sont ignorées en déterminant
      le numéro de ligne et le nom de la fonction dans la classe
      "LogRecord" créée pour l'évènement de journalisation. C'est
      utile pour les utilitaires de journalisation car cela permet
      d'ignorer les informations (nom de fonction, fichier source et
      ligne) de l'utilitaire et de ne traiter que celles de
      l'appelant. Le nom de ce paramètre est le même que son
      équivalent dans le module "warnings".

      Le quatrième argument par mot-clé est *extra* qui permet de
      remplir le dictionnaire *__dict__* du "LogRecord" créé pour
      l'évènement de journalisation, avec des attributs personnalisés.
      Ces attributs peuvent être utilisés comme bon vous semble. Ils
      peuvent ainsi être incorporés aux entrées de journalisation. Par
      exemple :

         FORMAT = '%(asctime)s %(clientip)-15s %(user)-8s %(message)s'
         logging.basicConfig(format=FORMAT)
         d = {'clientip': '192.168.0.1', 'user': 'fbloggs'}
         logger = logging.getLogger('tcpserver')
         logger.warning('Protocol problem: %s', 'connection reset', extra=d)

      affiche

         2006-02-08 22:20:02,165 192.168.0.1 fbloggs  Protocol problem: connection reset

      Les clés du dictionnaire passé dans *extra* ne doivent pas être
      les mêmes que les clés utilisées par le système de
      journalisation. Voir la documentation de la classe "Formatter"
      pour plus de précisions sur les clés utilisées par le système de
      journalisation.

      Si vous choisissez d'utiliser des attributs dans les messages à
      journaliser, il faut être prudent. Ainsi, dans l'exemple
      précédent, le "Formatter" a été configuré avec une chaîne qui
      attend *clientip* et *user* dans le dictionnaire d'attributs du
      "LogRecord". S'ils sont manquants, le message n'est pas
      enregistré car une exception de formatage de chaîne est levée.
      Il faut alors toujours passer un dictionnaire *extra* avec ces
      clés.

      Même si elle peut sembler gênante, cette fonctionnalité est
      nécessaire dans certains cas, comme sur des serveurs à fils
      d'exécution multiples, où le même code s'exécute dans des
      contextes différents et où les évènements significatifs
      dépendent du contexte (comme l'adresse IP du client et le nom
      d'utilisateur dans l'exemple précédent). Dans ces circonstances,
      il est clair que les classes "Formatter"s spécialisées doivent
      être utilisées avec des "Handler"s particuliers.

      If no handler is attached to this logger (or any of its
      ancestors, taking into account the relevant "Logger.propagate"
      attributes), the message will be sent to the handler set on
      "lastResort".

      Modifié dans la version 3.2: ajout du paramètre *stack_info*.

      Modifié dans la version 3.5: le paramètre *exc_info* peut être
      une instance d'exception.

      Modifié dans la version 3.8: ajout du paramètre *stacklevel*.

   info(msg, *args, **kwargs)

      Enregistre un message avec le niveau de gravité "INFO". Les
      arguments ont la même signification que pour "debug()".

   warning(msg, *args, **kwargs)

      Enregistre un message avec le niveau de gravité "WARNING". Les
      arguments ont la même signification que pour "debug()".

      Note:

        Il existe une méthode obsolète "warn" qui est identique à
        "warning". "warn" n'est plus maintenue, prière de ne plus
        l'utiliser et de la remplacer par "warning".

   error(msg, *args, **kwargs)

      Enregistre un message avec le niveau de gravité "ERROR". Les
      arguments ont la même signification que pour "debug()".

   critical(msg, *args, **kwargs)

      Enregistre un message avec le niveau de gravité "CRITICAL". Les
      arguments ont la même signification que pour "debug()".

   log(level, msg, *args, **kwargs)

      Enregistre un message avec le niveau de gravité *level*. Les
      arguments ont la même signification que pour "debug()".

   exception(msg, *args, **kwargs)

      Enregistre un message avec le niveau de gravité "ERROR". Les
      arguments ont la même signification que pour "debug()". Des
      informations sur l'exception sont ajoutées au message. Cette
      méthode doit être appelée depuis un gestionnaire d'exceptions.

   addFilter(filter)

      Ajoute le filtre *filter* à l'enregistreur.

   removeFilter(filter)

      Retire le filtre *filter* de cet enregistreur.

   filter(record)

      Applique les filtres associés à l'enregistreur et renvoie "True"
      si l'entrée doit être traitée. Les filtres sont appliqués les
      uns après les autres, jusqu'à ce que l'un renvoie faux. Si ce
      n'est pas le cas, le traitement de l'entrée se poursuit (elle
      est alors passée aux gestionnaires). Si l'un d'entre eux renvoie
      faux, le traitement de l'entrée s'arrête.

   addHandler(hdlr)

      Ajoute le gestionnaire *hdlr* à l'enregistreur.

   removeHandler(hdlr)

      Retire le gestionnaire *hdlr* de l'enregistreur.

   findCaller(stack_info=False, stacklevel=1)

      Détermine le fichier source et la ligne de l'appelant. Renvoie
      un quadruplet contenant le nom du fichier source, le numéro de
      ligne, le nom de la fonction et la pile d'appels. La pile vaut
      "None" si *stack_info* n'est pas "True".

      Le paramètre *stacklevel* est passé par le code appelant
      "debug()" (entre autres). S'il est supérieur à 1, *n*-1 entrées
      de la pile sont supprimées avant de renvoyer la pile. C'est
      pratique quand on appelle des APIs de journalisation à travers
      du code d'encapsulation car cela permet de retirer les
      informations sur ce code de l'entrée, tout en conservant celles
      sur le code au-dessus du code d'encapsulation.

   handle(record)

      Traite une entrée en la passant à tous les gestionnaires de
      l'enregistreur et à tous ses parents (jusqu'à ce qu'un
      *propagate* soit faux). C'est pratique pour désérialiser les
      entrées reçues d'un connecteur et celles créées localement. Du
      filtrage au niveau de l'enregistreur est appliqué en appelant
      "filter()".

   makeRecord(name, level, fn, lno, msg, args, exc_info, func=None, extra=None, sinfo=None)

      Fabrique qui peut être redéfinie pour créer des instances de
      "LogRecord".

   hasHandlers()

      Vérifie si l'enregistreur a des gestionnaires associés. Elle
      recherche les gestionnaires de l'enregistreur et ceux de ses
      parents. Renvoie "True" si au moins un gestionnaire a été trouvé
      et "False" sinon. Cette méthode arrête de remonter la hiérarchie
      dès qu'un enregistreur avec l'attribut *propagate* à faux est
      rencontré ­— cet enregistreur est alors le dernier dans lequel
      la méthode cherche des gestionnaires.

      Nouveau dans la version 3.2.

   Modifié dans la version 3.7: les enregistreurs peuvent être
   sérialisés et désérialisés.


Niveaux de journalisation
=========================

Les valeurs numériques des niveaux de journalisation sont données dans
le tableau suivant. Celles-ci n'ont d'intérêt que si vous voulez
définir vos propres niveaux, avec des valeurs spécifiques par rapport
aux niveaux prédéfinis. Si vous définissez un niveau avec la même
valeur numérique, il écrase la valeur prédéfinie ; le nom prédéfini
est perdu.

+-------------------------+-----------------+---------------------------------------+
| Niveau                  | Valeur          | What it means / When to use it        |
|                         | numérique       |                                       |
|=========================|=================|=======================================|
| logging.NOTSET          | 0               | When set on a logger, indicates that  |
|                         |                 | ancestor loggers are to be consulted  |
|                         |                 | to determine the effective level. If  |
|                         |                 | that still resolves to "NOTSET", then |
|                         |                 | all events are logged. When set on a  |
|                         |                 | handler, all events are handled.      |
+-------------------------+-----------------+---------------------------------------+
| logging.DEBUG           | 10              | Detailed information, typically only  |
|                         |                 | of interest to a developer trying to  |
|                         |                 | diagnose a problem.                   |
+-------------------------+-----------------+---------------------------------------+
| logging.INFO            | 20              | Confirmation that things are working  |
|                         |                 | as expected.                          |
+-------------------------+-----------------+---------------------------------------+
| logging.WARNING         | 30              | An indication that something          |
|                         |                 | unexpected happened, or that a        |
|                         |                 | problem might occur in the near       |
|                         |                 | future (e.g. 'disk space low'). The   |
|                         |                 | software is still working as          |
|                         |                 | expected.                             |
+-------------------------+-----------------+---------------------------------------+
| logging.ERROR           | 40              | Due to a more serious problem, the    |
|                         |                 | software has not been able to perform |
|                         |                 | some function.                        |
+-------------------------+-----------------+---------------------------------------+
| logging.CRITICAL        | 50              | A serious error, indicating that the  |
|                         |                 | program itself may be unable to       |
|                         |                 | continue running.                     |
+-------------------------+-----------------+---------------------------------------+


Gestionnaires
=============

Handlers have the following attributes and methods. Note that
"Handler" is never instantiated directly; this class acts as a base
for more useful subclasses. However, the "__init__()" method in
subclasses needs to call "Handler.__init__()".

class logging.Handler

   __init__(level=NOTSET)

      Initialise l'objet "Handler" en définissant le niveau de
      gravité, en initialisant la liste des filtres avec une liste
      vide et en créant un verrou (avec "createLock()") pour
      sérialiser l'accès au mécanisme d'E-S.

   createLock()

      Instancie un verrou qui peut être utilisé pour sérialiser
      l'accès au système d'E-S sous-jacent (qui peut ne pas être à fil
      d'exécution sécurisé).

   acquire()

      Acquiert le verrou créé par "createLock()".

   release()

      Relâche le verrou acquis par "acquire()".

   setLevel(level)

      Ajuste le seuil déclenchement du gestionnaire au niveau *level*.
      Les messages de gravité moindre que *level* sont alors ignorés.
      Ce seuil est fixé à "NOTSET" lors de la création d'un
      gestionnaire (ce qui signifie que tous les messages seront
      traités).

      Voir Niveaux de journalisation pour la liste des niveaux.

      Modifié dans la version 3.2: le paramètre *level* peut être une
      chaîne de caractères, comme "'INFO'", en plus d'une constante
      entière comme "INFO".

   setFormatter(fmt)

      Définit le "Formatter" du gestionnaire à *fmt*.

   addFilter(filter)

      Ajoute le filtre *filter* au gestionnaire.

   removeFilter(filter)

      Retire le filtre *filter* du gestionnaire.

   filter(record)

      Applique les filtres du gestionnaire à *record* et renvoie
      "True" si l'entrée doit être traitée. Les filtres sont appliqués
      l'un après l'autre, jusqu'à ce que l'un renvoie faux. Si aucun
      d'entre eux ne renvoie faux, l'entrée est enregistrée, sinon le
      gestionnaire ne traitera pas l'entrée.

   flush()

      Oblige toutes les entrées à être traitées. Cette fonction ne
      fait rien de spécial et doit être redéfinie par les sous-
      classes.

   close()

      Recycle toutes les ressources utilisées par le gestionnaire.
      Cette version ne fait rien de particulier mais elle retire le
      gestionnaire de la liste interne des gestionnaires à recycler à
      l'appel de "shutdown()". Les sous-classes doivent appeler cette
      méthode depuis leur surcharge de "close()".

   handle(record)

      Traite ou non *record* selon les filtres ajoutés au
      gestionnaire. Un verrou sur l'E-S. est mis en place durant
      l'écriture effective.

   handleError(record)

      This method should be called from handlers when an exception is
      encountered during an "emit()" call. If the module-level
      attribute "raiseExceptions" is "False", exceptions get silently
      ignored. This is what is mostly wanted for a logging system -
      most users will not care about errors in the logging system,
      they are more interested in application errors. You could,
      however, replace this with a custom handler if you wish. The
      specified record is the one which was being processed when the
      exception occurred. (The default value of "raiseExceptions" is
      "True", as that is more useful during development).

   format(record)

      Formate *record* avec le formateur défini. S'il n'y en a pas, le
      formateur par défaut du module est utilisé.

   emit(record)

      Journalise *record* « pour de bon ». Cette version doit être
      redéfinie par les sous-classes et lève donc une
      "NotImplementedError".

      Avertissement:

        This method is called after a handler-level lock is acquired,
        which is released after this method returns. When you override
        this method, note that you should be careful when calling
        anything that invokes other parts of the logging API which
        might do locking, because that might result in a deadlock.
        Specifically:

        * Logging configuration APIs acquire the module-level lock,
          and then individual handler-level locks as those handlers
          are configured.

        * Many logging APIs lock the module-level lock. If such an API
          is called from this method, it could cause a deadlock if a
          configuration call is made on another thread, because that
          thread will try to acquire the module-level lock *before*
          the handler-level lock, whereas this thread tries to acquire
          the module-level lock *after* the handler-level lock
          (because in this method, the handler-level lock has already
          been acquired).

Les gestionnaires de la bibliothèque standard sont répertoriés dans
"logging.handlers".


Formateurs
==========

"Formatter" objects have the following attributes and methods. They
are responsible for converting a "LogRecord" to (usually) a string
which can be interpreted by either a human or an external system. The
base "Formatter" allows a formatting string to be specified. If none
is supplied, the default value of "'%(message)s'" is used, which just
includes the message in the logging call. To have additional items of
information in the formatted output (such as a timestamp), keep
reading.

A Formatter can be initialized with a format string which makes use of
knowledge of the "LogRecord" attributes - such as the default value
mentioned above making use of the fact that the user's message and
arguments are pre-formatted into a "LogRecord"'s *message* attribute.
This format string contains standard Python %-style mapping keys. See
section Formatage de chaines à la printf for more information on
string formatting.

The useful mapping keys in a "LogRecord" are given in the section on
LogRecord attributes.

class logging.Formatter(fmt=None, datefmt=None, style='%', validate=True, *, defaults=None)

   Returns a new instance of the "Formatter" class.  The instance is
   initialized with a format string for the message as a whole, as
   well as a format string for the date/time portion of a message.  If
   no *fmt* is specified, "'%(message)s'" is used.  If no *datefmt* is
   specified, a format is used which is described in the
   "formatTime()" documentation.

   The *style* parameter can be one of '%', '{' or '$' and determines
   how the format string will be merged with its data: using one of
   %-formatting, "str.format()" or "string.Template". This only
   applies to the format string *fmt* (e.g. "'%(message)s'" or
   "{message}"), not to the actual log messages passed to
   "Logger.debug" etc; see Using particular formatting styles
   throughout your application for more information on using {- and
   $-formatting for log messages.

   The *defaults* parameter can be a dictionary with default values to
   use in custom fields. For example: "logging.Formatter('%(ip)s
   %(message)s', defaults={"ip": None})"

   Modifié dans la version 3.2: The *style* parameter was added.

   Modifié dans la version 3.8: The *validate* parameter was added.
   Incorrect or mismatched style and fmt will raise a "ValueError".
   For example: "logging.Formatter('%(asctime)s - %(message)s',
   style='{')".

   Modifié dans la version 3.10: The *defaults* parameter was added.

   format(record)

      The record's attribute dictionary is used as the operand to a
      string formatting operation. Returns the resulting string.
      Before formatting the dictionary, a couple of preparatory steps
      are carried out. The *message* attribute of the record is
      computed using *msg* % *args*. If the formatting string contains
      "'(asctime)'", "formatTime()" is called to format the event
      time. If there is exception information, it is formatted using
      "formatException()" and appended to the message. Note that the
      formatted exception information is cached in attribute
      *exc_text*. This is useful because the exception information can
      be pickled and sent across the wire, but you should be careful
      if you have more than one "Formatter" subclass which customizes
      the formatting of exception information. In this case, you will
      have to clear the cached value (by setting the *exc_text*
      attribute to "None") after a formatter has done its formatting,
      so that the next formatter to handle the event doesn't use the
      cached value, but recalculates it afresh.

      If stack information is available, it's appended after the
      exception information, using "formatStack()" to transform it if
      necessary.

   formatTime(record, datefmt=None)

      This method should be called from "format()" by a formatter
      which wants to make use of a formatted time. This method can be
      overridden in formatters to provide for any specific
      requirement, but the basic behavior is as follows: if *datefmt*
      (a string) is specified, it is used with "time.strftime()" to
      format the creation time of the record. Otherwise, the format
      '%Y-%m-%d %H:%M:%S,uuu' is used, where the uuu part is a
      millisecond value and the other letters are as per the
      "time.strftime()" documentation.  An example time in this format
      is "2003-01-23 00:29:50,411".  The resulting string is returned.

      This function uses a user-configurable function to convert the
      creation time to a tuple. By default, "time.localtime()" is
      used; to change this for a particular formatter instance, set
      the "converter" attribute to a function with the same signature
      as "time.localtime()" or "time.gmtime()". To change it for all
      formatters, for example if you want all logging times to be
      shown in GMT, set the "converter" attribute in the "Formatter"
      class.

      Modifié dans la version 3.3: Previously, the default format was
      hard-coded as in this example: "2010-09-06 22:38:15,292" where
      the part before the comma is handled by a strptime format string
      ("'%Y-%m-%d %H:%M:%S'"), and the part after the comma is a
      millisecond value. Because strptime does not have a format
      placeholder for milliseconds, the millisecond value is appended
      using another format string, "'%s,%03d'" --- and both of these
      format strings have been hardcoded into this method. With the
      change, these strings are defined as class-level attributes
      which can be overridden at the instance level when desired. The
      names of the attributes are "default_time_format" (for the
      strptime format string) and "default_msec_format" (for appending
      the millisecond value).

      Modifié dans la version 3.9: The "default_msec_format" can be
      "None".

   formatException(exc_info)

      Formats the specified exception information (a standard
      exception tuple as returned by "sys.exc_info()") as a string.
      This default implementation just uses
      "traceback.print_exception()". The resulting string is returned.

   formatStack(stack_info)

      Formats the specified stack information (a string as returned by
      "traceback.print_stack()", but with the last newline removed) as
      a string. This default implementation just returns the input
      value.

class logging.BufferingFormatter(linefmt=None)

   A base formatter class suitable for subclassing when you want to
   format a number of records. You can pass a "Formatter" instance
   which you want to use to format each line (that corresponds to a
   single record). If not specified, the default formatter (which just
   outputs the event message) is used as the line formatter.

   formatHeader(records)

      Return a header for a list of *records*. The base implementation
      just returns the empty string. You will need to override this
      method if you want specific behaviour, e.g. to show the count of
      records, a title or a separator line.

   formatFooter(records)

      Return a footer for a list of *records*. The base implementation
      just returns the empty string. You will need to override this
      method if you want specific behaviour, e.g. to show the count of
      records or a separator line.

   format(records)

      Return formatted text for a list of *records*. The base
      implementation just returns the empty string if there are no
      records; otherwise, it returns the concatenation of the header,
      each record formatted with the line formatter, and the footer.


Filtres
=======

"Filters" can be used by "Handlers" and "Loggers" for more
sophisticated filtering than is provided by levels. The base filter
class only allows events which are below a certain point in the logger
hierarchy. For example, a filter initialized with 'A.B' will allow
events logged by loggers 'A.B', 'A.B.C', 'A.B.C.D', 'A.B.D' etc. but
not 'A.BB', 'B.A.B' etc. If initialized with the empty string, all
events are passed.

class logging.Filter(name='')

   Returns an instance of the "Filter" class. If *name* is specified,
   it names a logger which, together with its children, will have its
   events allowed through the filter. If *name* is the empty string,
   allows every event.

   filter(record)

      Is the specified record to be logged? Returns zero for no,
      nonzero for yes. If deemed appropriate, the record may be
      modified in-place by this method.

Note that filters attached to handlers are consulted before an event
is emitted by the handler, whereas filters attached to loggers are
consulted whenever an event is logged (using "debug()", "info()",
etc.), before sending an event to handlers. This means that events
which have been generated by descendant loggers will not be filtered
by a logger's filter setting, unless the filter has also been applied
to those descendant loggers.

You don't actually need to subclass "Filter": you can pass any
instance which has a "filter" method with the same semantics.

Modifié dans la version 3.2: You don't need to create specialized
"Filter" classes, or use other classes with a "filter" method: you can
use a function (or other callable) as a filter. The filtering logic
will check to see if the filter object has a "filter" attribute: if it
does, it's assumed to be a "Filter" and its "filter()" method is
called. Otherwise, it's assumed to be a callable and called with the
record as the single parameter. The returned value should conform to
that returned by "filter()".

Although filters are used primarily to filter records based on more
sophisticated criteria than levels, they get to see every record which
is processed by the handler or logger they're attached to: this can be
useful if you want to do things like counting how many records were
processed by a particular logger or handler, or adding, changing or
removing attributes in the "LogRecord" being processed. Obviously
changing the LogRecord needs to be done with some care, but it does
allow the injection of contextual information into logs (see
Utilisation de filtres pour transmettre des informations
contextuelles).


Objets LogRecord
================

"LogRecord" instances are created automatically by the "Logger" every
time something is logged, and can be created manually via
"makeLogRecord()" (for example, from a pickled event received over the
wire).

class logging.LogRecord(name, level, pathname, lineno, msg, args, exc_info, func=None, sinfo=None)

   Contains all the information pertinent to the event being logged.

   The primary information is passed in *msg* and *args*, which are
   combined using "msg % args" to create the "message" attribute of
   the record.

   Paramètres:
      * **name** (*str*) -- The name of the logger used to log the
        event represented by this "LogRecord". Note that the logger
        name in the "LogRecord" will always have this value, even
        though it may be emitted by a handler attached to a different
        (ancestor) logger.

      * **level** (*int*) -- The numeric level of the logging event
        (such as "10" for "DEBUG", "20" for "INFO", etc). Note that
        this is converted to *two* attributes of the LogRecord:
        "levelno" for the numeric value and "levelname" for the
        corresponding level name.

      * **pathname** (*str*) -- The full string path of the source
        file where the logging call was made.

      * **lineno** (*int*) -- The line number in the source file where
        the logging call was made.

      * **msg** (*Any*) -- The event description message, which can be
        a %-format string with placeholders for variable data, or an
        arbitrary object (see Utilisation d'objets arbitraires comme
        messages).

      * **args** (*tuple** | **dict**[**str**, **Any**]*) -- Variable
        data to merge into the *msg* argument to obtain the event
        description.

      * **exc_info** (*tuple**[**type**[**BaseException**]**,
        **BaseException**, **types.TracebackType**] **| **None*) -- An
        exception tuple with the current exception information, as
        returned by "sys.exc_info()", or "None" if no exception
        information is available.

      * **func** (*str** | **None*) -- The name of the function or
        method from which the logging call was invoked.

      * **sinfo** (*str** | **None*) -- A text string representing
        stack information from the base of the stack in the current
        thread, up to the logging call.

   getMessage()

      Returns the message for this "LogRecord" instance after merging
      any user-supplied arguments with the message. If the user-
      supplied message argument to the logging call is not a string,
      "str()" is called on it to convert it to a string. This allows
      use of user-defined classes as messages, whose "__str__" method
      can return the actual format string to be used.

   Modifié dans la version 3.2: The creation of a "LogRecord" has been
   made more configurable by providing a factory which is used to
   create the record. The factory can be set using
   "getLogRecordFactory()" and "setLogRecordFactory()" (see this for
   the factory's signature).

   This functionality can be used to inject your own values into a
   "LogRecord" at creation time. You can use the following pattern:

      old_factory = logging.getLogRecordFactory()

      def record_factory(*args, **kwargs):
          record = old_factory(*args, **kwargs)
          record.custom_attribute = 0xdecafbad
          return record

      logging.setLogRecordFactory(record_factory)

   With this pattern, multiple factories could be chained, and as long
   as they don't overwrite each other's attributes or unintentionally
   overwrite the standard attributes listed above, there should be no
   surprises.


LogRecord attributes
====================

The LogRecord has a number of attributes, most of which are derived
from the parameters to the constructor. (Note that the names do not
always correspond exactly between the LogRecord constructor parameters
and the LogRecord attributes.) These attributes can be used to merge
data from the record into the format string. The following table lists
(in alphabetical order) the attribute names, their meanings and the
corresponding placeholder in a %-style format string.

If you are using {}-formatting ("str.format()"), you can use
"{attrname}" as the placeholder in the format string. If you are using
$-formatting ("string.Template"), use the form "${attrname}". In both
cases, of course, replace "attrname" with the actual attribute name
you want to use.

In the case of {}-formatting, you can specify formatting flags by
placing them after the attribute name, separated from it with a colon.
For example: a placeholder of "{msecs:03.0f}" would format a
millisecond value of "4" as "004". Refer to the "str.format()"
documentation for full details on the options available to you.

+------------------+---------------------------+-------------------------------------------------+
| Attribute name   | Format                    | Description                                     |
|==================|===========================|=================================================|
| args             | You shouldn't need to     | The tuple of arguments merged into "msg" to     |
|                  | format this yourself.     | produce "message", or a dict whose values are   |
|                  |                           | used for the merge (when there is only one      |
|                  |                           | argument, and it is a dictionary).              |
+------------------+---------------------------+-------------------------------------------------+
| asctime          | "%(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          | "%(created)f"             | Time when the "LogRecord" was created (as       |
|                  |                           | returned by "time.time()").                     |
+------------------+---------------------------+-------------------------------------------------+
| exc_info         | You shouldn't need to     | Exception tuple (à la "sys.exc_info") or, if no |
|                  | format this yourself.     | exception has occurred, "None".                 |
+------------------+---------------------------+-------------------------------------------------+
| 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 ("'DEBUG'",  |
|                  |                           | "'INFO'", "'WARNING'", "'ERROR'",               |
|                  |                           | "'CRITICAL'").                                  |
+------------------+---------------------------+-------------------------------------------------+
| levelno          | "%(levelno)s"             | Numeric logging level for the message ("DEBUG", |
|                  |                           | "INFO", "WARNING", "ERROR", "CRITICAL").        |
+------------------+---------------------------+-------------------------------------------------+
| lineno           | "%(lineno)d"              | Source line number where the logging call was   |
|                  |                           | issued (if available).                          |
+------------------+---------------------------+-------------------------------------------------+
| message          | "%(message)s"             | The logged message, computed as "msg % args".   |
|                  |                           | This is set when "Formatter.format()" is        |
|                  |                           | invoked.                                        |
+------------------+---------------------------+-------------------------------------------------+
| module           | "%(module)s"              | Module (name portion of "filename").            |
+------------------+---------------------------+-------------------------------------------------+
| msecs            | "%(msecs)d"               | Millisecond portion of the time when the        |
|                  |                           | "LogRecord" was created.                        |
+------------------+---------------------------+-------------------------------------------------+
| msg              | You shouldn't need to     | The format string passed in the original        |
|                  | format this yourself.     | logging call. Merged with "args" to produce     |
|                  |                           | "message", or an arbitrary object (see          |
|                  |                           | Utilisation d'objets arbitraires comme          |
|                  |                           | messages).                                      |
+------------------+---------------------------+-------------------------------------------------+
| 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).                    |
+------------------+---------------------------+-------------------------------------------------+
| relativeCreated  | "%(relativeCreated)d"     | Time in milliseconds when the LogRecord was     |
|                  |                           | created, relative to the time the logging       |
|                  |                           | module was loaded.                              |
+------------------+---------------------------+-------------------------------------------------+
| stack_info       | You shouldn't need to     | Stack frame information (where available) from  |
|                  | format this yourself.     | 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.                                    |
+------------------+---------------------------+-------------------------------------------------+
| thread           | "%(thread)d"              | Thread ID (if available).                       |
+------------------+---------------------------+-------------------------------------------------+
| threadName       | "%(threadName)s"          | Thread name (if available).                     |
+------------------+---------------------------+-------------------------------------------------+

Modifié dans la version 3.1: *processName* was added.


LoggerAdapter Objects
=====================

"LoggerAdapter" instances are used to conveniently pass contextual
information into logging calls. For a usage example, see the section
on adding contextual information to your logging output.

class logging.LoggerAdapter(logger, extra)

   Returns an instance of "LoggerAdapter" initialized with an
   underlying "Logger" instance and a dict-like object.

   process(msg, kwargs)

      Modifies the message and/or keyword arguments passed to a
      logging call in order to insert contextual information. This
      implementation takes the object passed as *extra* to the
      constructor and adds it to *kwargs* using key 'extra'. The
      return value is a (*msg*, *kwargs*) tuple which has the
      (possibly modified) versions of the arguments passed in.

   manager

      Delegates to the underlying "manager`" on *logger*.

   _log

      Delegates to the underlying "_log`()" method on *logger*.

   In addition to the above, "LoggerAdapter" supports the following
   methods of "Logger": "debug()", "info()", "warning()", "error()",
   "exception()", "critical()", "log()", "isEnabledFor()",
   "getEffectiveLevel()", "setLevel()" and "hasHandlers()". These
   methods have the same signatures as their counterparts in "Logger",
   so you can use the two types of instances interchangeably.

   Modifié dans la version 3.2: The "isEnabledFor()",
   "getEffectiveLevel()", "setLevel()" and "hasHandlers()" methods
   were added to "LoggerAdapter".  These methods delegate to the
   underlying logger.

   Modifié dans la version 3.6: Attribute "manager" and method
   "_log()" were added, which delegate to the underlying logger and
   allow adapters to be nested.


Thread Safety
=============

The logging module is intended to be thread-safe without any special
work needing to be done by its clients. It achieves this though using
threading locks; there is one lock to serialize access to the module's
shared data, and each handler also creates a lock to serialize access
to its underlying I/O.

If you are implementing asynchronous signal handlers using the
"signal" module, you may not be able to use logging from within such
handlers. This is because lock implementations in the "threading"
module are not always re-entrant, and so cannot be invoked from such
signal handlers.


Fonctions de niveau module
==========================

In addition to the classes described above, there are a number of
module-level functions.

logging.getLogger(name=None)

   Return a logger with the specified name or, if name is "None",
   return a logger which is the root logger of the hierarchy. If
   specified, the name is typically a dot-separated hierarchical name
   like *'a'*, *'a.b'* or *'a.b.c.d'*. Choice of these names is
   entirely up to the developer who is using logging.

   All calls to this function with a given name return the same logger
   instance. This means that logger instances never need to be passed
   between different parts of an application.

logging.getLoggerClass()

   Return either the standard "Logger" class, or the last class passed
   to "setLoggerClass()". This function may be called from within a
   new class definition, to ensure that installing a customized
   "Logger" class will not undo customizations already applied by
   other code. For example:

      class MyLogger(logging.getLoggerClass()):
          # ... override behaviour here

logging.getLogRecordFactory()

   Return a callable which is used to create a "LogRecord".

   Nouveau dans la version 3.2: This function has been provided, along
   with "setLogRecordFactory()", to allow developers more control over
   how the "LogRecord" representing a logging event is constructed.

   See "setLogRecordFactory()" for more information about the how the
   factory is called.

logging.debug(msg, *args, **kwargs)

   This is a convenience function that calls "Logger.debug()", on the
   root logger. The handling of the arguments is in every way
   identical to what is described in that method.

   The only difference is that if the root logger has no handlers,
   then "basicConfig()" is called, prior to calling "debug" on the
   root logger.

   For very short scripts or quick demonstrations of "logging"
   facilities, "debug" and the other module-level functions may be
   convenient. However, most programs will want to carefully and
   explicitly control the logging configuration, and should therefore
   prefer creating a module-level logger and calling "Logger.debug()"
   (or other level-specific methods) on it, as described at the
   beginnning of this documentation.

logging.info(msg, *args, **kwargs)

   Logs a message with level "INFO" on the root logger. The arguments
   and behavior are otherwise the same as for "debug()".

logging.warning(msg, *args, **kwargs)

   Logs a message with level "WARNING" on the root logger. The
   arguments and behavior are otherwise the same as for "debug()".

   Note:

     There is an obsolete function "warn" which is functionally
     identical to "warning". As "warn" is deprecated, please do not
     use it - use "warning" instead.

logging.error(msg, *args, **kwargs)

   Logs a message with level "ERROR" on the root logger. The arguments
   and behavior are otherwise the same as for "debug()".

logging.critical(msg, *args, **kwargs)

   Logs a message with level "CRITICAL" on the root logger. The
   arguments and behavior are otherwise the same as for "debug()".

logging.exception(msg, *args, **kwargs)

   Logs a message with level "ERROR" on the root logger. The arguments
   and behavior are otherwise the same as for "debug()". Exception
   info is added to the logging message. This function should only be
   called from an exception handler.

logging.log(level, msg, *args, **kwargs)

   Logs a message with level *level* on the root logger. The arguments
   and behavior are otherwise the same as for "debug()".

logging.disable(level=CRITICAL)

   Provides an overriding level *level* for all loggers which takes
   precedence over the logger's own level. When the need arises to
   temporarily throttle logging output down across the whole
   application, this function can be useful. Its effect is to disable
   all logging calls of severity *level* and below, so that if you
   call it with a value of INFO, then all INFO and DEBUG events would
   be discarded, whereas those of severity WARNING and above would be
   processed according to the logger's effective level. If
   "logging.disable(logging.NOTSET)" is called, it effectively removes
   this overriding level, so that logging output again depends on the
   effective levels of individual loggers.

   Note that if you have defined any custom logging level higher than
   "CRITICAL" (this is not recommended), you won't be able to rely on
   the default value for the *level* parameter, but will have to
   explicitly supply a suitable value.

   Modifié dans la version 3.7: The *level* parameter was defaulted to
   level "CRITICAL". See bpo-28524 for more information about this
   change.

logging.addLevelName(level, levelName)

   Associates level *level* with text *levelName* in an internal
   dictionary, which is used to map numeric levels to a textual
   representation, for example when a "Formatter" formats a message.
   This function can also be used to define your own levels. The only
   constraints are that all levels used must be registered using this
   function, levels should be positive integers and they should
   increase in increasing order of severity.

   Note:

     If you are thinking of defining your own levels, please see the
     section on Niveaux personnalisés.

logging.getLevelNamesMapping()

   Returns a mapping from level names to their corresponding logging
   levels. For example, the string "CRITICAL" maps to "CRITICAL". The
   returned mapping is copied from an internal mapping on each call to
   this function.

   Nouveau dans la version 3.11.

logging.getLevelName(level)

   Returns the textual or numeric representation of logging level
   *level*.

   If *level* is one of the predefined levels "CRITICAL", "ERROR",
   "WARNING", "INFO" or "DEBUG" then you get the corresponding string.
   If you have associated levels with names using "addLevelName()"
   then the name you have associated with *level* is returned. If a
   numeric value corresponding to one of the defined levels is passed
   in, the corresponding string representation is returned.

   The *level* parameter also accepts a string representation of the
   level such as 'INFO'. In such cases, this functions returns the
   corresponding numeric value of the level.

   If no matching numeric or string value is passed in, the string
   'Level %s' % level is returned.

   Note:

     Levels are internally integers (as they need to be compared in
     the logging logic). This function is used to convert between an
     integer level and the level name displayed in the formatted log
     output by means of the "%(levelname)s" format specifier (see
     LogRecord attributes), and vice versa.

   Modifié dans la version 3.4: In Python versions earlier than 3.4,
   this function could also be passed a text level, and would return
   the corresponding numeric value of the level. This undocumented
   behaviour was considered a mistake, and was removed in Python 3.4,
   but reinstated in 3.4.2 due to retain backward compatibility.

logging.makeLogRecord(attrdict)

   Creates and returns a new "LogRecord" instance whose attributes are
   defined by *attrdict*. This function is useful for taking a pickled
   "LogRecord" attribute dictionary, sent over a socket, and
   reconstituting it as a "LogRecord" instance at the receiving end.

logging.basicConfig(**kwargs)

   Does basic configuration for the logging system by creating a
   "StreamHandler" with a default "Formatter" and adding it to the
   root logger. The functions "debug()", "info()", "warning()",
   "error()" and "critical()" will call "basicConfig()" automatically
   if no handlers are defined for the root logger.

   This function does nothing if the root logger already has handlers
   configured, unless the keyword argument *force* is set to "True".

   Note:

     This function should be called from the main thread before other
     threads are started. In versions of Python prior to 2.7.1 and
     3.2, if this function is called from multiple threads, it is
     possible (in rare circumstances) that a handler will be added to
     the root logger more than once, leading to unexpected results
     such as messages being duplicated in the log.

   The following keyword arguments are supported.

   +----------------+-----------------------------------------------+
   | 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. Defaults to attributes "levelname",  |
   |                | "name" and "message" separated by colons.     |
   +----------------+-----------------------------------------------+
   | *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.                       |
   +----------------+-----------------------------------------------+
   | *force*        | If this keyword argument is specified as      |
   |                | true, any existing handlers attached to the   |
   |                | root logger are removed and closed, before    |
   |                | carrying out the configuration as specified   |
   |                | by the other arguments.                       |
   +----------------+-----------------------------------------------+
   | *encoding*     | If this keyword argument is specified along   |
   |                | with *filename*, its value is used when the   |
   |                | "FileHandler" is created, and thus used when  |
   |                | opening the output file.                      |
   +----------------+-----------------------------------------------+
   | *errors*       | If this keyword argument is specified along   |
   |                | with *filename*, its value is used when the   |
   |                | "FileHandler" is created, and thus used when  |
   |                | opening the output file. If not specified,    |
   |                | the value 'backslashreplace' is used. Note    |
   |                | that if "None" is specified, it will be       |
   |                | passed as such to "open()", which means that  |
   |                | it will be treated the same as passing        |
   |                | 'errors'.                                     |
   +----------------+-----------------------------------------------+

   Modifié dans la version 3.2: The *style* argument was added.

   Modifié dans la version 3.3: The *handlers* argument was added.
   Additional checks were added to catch situations where incompatible
   arguments are specified (e.g. *handlers* together with *stream* or
   *filename*, or *stream* together with *filename*).

   Modifié dans la version 3.8: The *force* argument was added.

   Modifié dans la version 3.9: The *encoding* and *errors* arguments
   were added.

logging.shutdown()

   Informs the logging system to perform an orderly shutdown by
   flushing and closing all handlers. This should be called at
   application exit and no further use of the logging system should be
   made after this call.

   When the logging module is imported, it registers this function as
   an exit handler (see "atexit"), so normally there's no need to do
   that manually.

logging.setLoggerClass(klass)

   Tells the logging system to use the class *klass* when
   instantiating a logger. The class should define "__init__()" such
   that only a name argument is required, and the "__init__()" should
   call "Logger.__init__()". This function is typically called before
   any loggers are instantiated by applications which need to use
   custom logger behavior. After this call, as at any other time, do
   not instantiate loggers directly using the subclass: continue to
   use the "logging.getLogger()" API to get your loggers.

logging.setLogRecordFactory(factory)

   Set a callable which is used to create a "LogRecord".

   Paramètres:
      **factory** -- The factory callable to be used to instantiate a
      log record.

   Nouveau dans la version 3.2: This function has been provided, along
   with "getLogRecordFactory()", to allow developers more control over
   how the "LogRecord" representing a logging event is constructed.

   The factory has the following signature:

   "factory(name, level, fn, lno, msg, args, exc_info, func=None,
   sinfo=None, **kwargs)"

      name:
         The logger name.

      level:
         The logging level (numeric).

      fn:
         The full pathname of the file where the logging call was
         made.

      lno:
         The line number in the file where the logging call was made.

      msg:
         The logging message.

      args:
         The arguments for the logging message.

      exc_info:
         An exception tuple, or "None".

      func:
         The name of the function or method which invoked the logging
         call.

      sinfo:
         A stack traceback such as is provided by
         "traceback.print_stack()", showing the call hierarchy.

      kwargs:
         Additional keyword arguments.


Module-Level Attributes
=======================

logging.lastResort

   A "handler of last resort" is available through this attribute.
   This is a "StreamHandler" writing to "sys.stderr" with a level of
   "WARNING", and is used to handle logging events in the absence of
   any logging configuration. The end result is to just print the
   message to "sys.stderr". This replaces the earlier error message
   saying that "no handlers could be found for logger XYZ". If you
   need the earlier behaviour for some reason, "lastResort" can be set
   to "None".

   Nouveau dans la version 3.2.

logging.raiseExceptions

   Used to see if exceptions during handling should be propagated.

   Default: "True".

   If "raiseExceptions" is "False", exceptions get silently ignored.
   This is what is mostly wanted for a logging system - most users
   will not care about errors in the logging system, they are more
   interested in application errors.


Integration with the warnings module
====================================

The "captureWarnings()" function can be used to integrate "logging"
with the "warnings" module.

logging.captureWarnings(capture)

   This function is used to turn the capture of warnings by logging on
   and off.

   If *capture* is "True", warnings issued by the "warnings" module
   will be redirected to the logging system. Specifically, a warning
   will be formatted using "warnings.formatwarning()" and the
   resulting string logged to a logger named "'py.warnings'" with a
   severity of "WARNING".

   If *capture* is "False", the redirection of warnings to the logging
   system will stop, and warnings will be redirected to their original
   destinations (i.e. those in effect before "captureWarnings(True)"
   was called).

Voir aussi:

  Module "logging.config"
     API de configuration pour le module de journalisation.

  Module "logging.handlers"
     Gestionnaires utiles inclus avec le module de journalisation.

  **PEP 282** - A Logging System
     The proposal which described this feature for inclusion in the
     Python standard library.

  Original Python logging package
     This is the original source for the "logging" package.  The
     version of the package available from this site is suitable for
     use with Python 1.5.2, 2.1.x and 2.2.x, which do not include the
     "logging" package in the standard library.
