125 lines
4.0 KiB
Python
125 lines
4.0 KiB
Python
"""
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Extra functionality for Flask logging
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Flask-Logging-Extras is a Flask extension that plugs into the logging
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mechanism of Flask applications.
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"""
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import logging
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__version_info__ = ('0', '0', '1')
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__version__ = '.'.join(__version_info__)
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__author__ = 'Gergely Polonkai'
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__license__ = 'BSD'
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__copyright__ = '(c) 2015 GT2'
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class FlaskExtraLogger(logging.getLoggerClass()):
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"""
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A logger class that is capable of adding extra keywords to log formatters
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Usage:
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.. code-block:: python
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import logging
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from flask_logging_extras import register_logger_class
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# This must be done before the app is initialized!
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register_logger_class(cls=FlaskExtraLogger)
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app = Flask(__name__)
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app.config['FLASK_LOGGING_EXTRAS_KEYWORDS'] = ['category']
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app.logger.init_app()
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formatter = logging.Formatter(
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'[%(asctime)s] [%(levelname)s] [%(category)s] %(message)s')
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handler = logging.FileHandler('app.log', mode='a')
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handler.setFormatter(formatter)
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handler.setLevel(logging.INFO)
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app.logger.addHandler(handler)
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app.logger.info('The message', category='my category')
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# This will produce something like this in app.log:
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# [TIMESTAMP2017-01-16 08:44:48.944] [INFO] [my category] The message
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"""
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def __init__(self, *args, **kwargs):
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if 'app' in kwargs and kwargs['app'] is not None:
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raise TypeError(
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"Cannot initialise {classname} with an app. "
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"See the documentation of Flask-Logging-Extras for more info."
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.format(classname=self.__class__.__name__))
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super(FlaskExtraLogger, self).__init__(*args, **kwargs)
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def _log(self, *args, **kwargs):
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if 'extra' not in kwargs:
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kwargs['extra'] = {}
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for kw in self._valid_keywords:
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if kw in kwargs:
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kwargs['extra'][kw] = kwargs[kw]
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super(FlaskExtraLogger, self)._log(*args, **kwargs)
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def init_app(self, app):
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"""
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Intialize the logger class with a Flask application
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The class reads its necessary configuration from the config of this
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application.
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If the application doesn’t call this, or doesn’t have the
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`FLASK_LOGGING_EXTRAS_KEYWORDS` in its config, no extra
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functionality will be added.
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:param app: a Flask application
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:type app: Flask
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:raises ValueError: if the app tries to register a keyword that is
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reserved for internal use
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"""
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app.config.setdefault('FLASK_LOGGING_EXTRAS_KEYWORDS', [])
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for kw in app.config['FLASK_LOGGING_EXTRAS_KEYWORDS']:
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if kw in ['exc_info', 'extra', 'stack_info']:
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raise ValueError(
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'"{keyword}" member of FLASK_LOGGING_EXTRAS_KEYWORDS is '
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'reserved for internal use.')
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def register_logger_class(cls=FlaskExtraLogger):
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"""
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Register a new logger class
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It is effectively a wrapper around `logging.setLoggerClass()`, with an
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added check to make sure the class can be used as a logger.
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To use the extra features of the logger class in a Flask app, you must
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call it before the app is instantiated.
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This function returns the logger class that was the default before
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calling. This might be useful if you only want to use `cls` in the
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Flask app object, but not anywhere else in your code. In this case,
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simply call `register_logger_class()` again with the return value from
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the first invocation.
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:param cls: a logger class to register as the default one
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:type cls: class(logging.Logger)
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:returns: the old default logger class
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:rtype: class
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:raises TypeError: if the class is not a subclass of `logging.Logger`
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"""
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if not issubclass(cls, logging.Logger):
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raise TypeError(
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"The logger class must be a subclass of logging.Logger!")
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old_class = logging.get_logger_class()
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logging.setLoggerClass(cls)
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return old_class
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