oslo.i18n/oslo_i18n/log.py
Doug Hellmann ba05e9a9b9 Move out of the oslo namespace package
Move the public API out of oslo.i18n to oslo_i18n. Retain the ability to
import from the old namespace package for backwards compatibility for
this release cycle.

bp/drop-namespace-packages

Change-Id: I800f121c271d8e69f6e776c4aef509bbb8008170
2014-12-18 16:35:03 -05:00

98 lines
3.5 KiB
Python

# Copyright 2012 Red Hat, Inc.
# Copyright 2013 IBM Corp.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""logging utilities for translation
"""
from logging import handlers
from oslo_i18n import _translate
class TranslationHandler(handlers.MemoryHandler):
"""Handler that translates records before logging them.
When lazy translation is enabled in the application (see
:func:`~oslo_i18n.enable_lazy`), the :class:`TranslationHandler`
uses its locale configuration setting to determine how to
translate LogRecord objects before forwarding them to the
logging.Handler.
When lazy translation is disabled, the message in the LogRecord is
converted to unicode without any changes and then forwarded to the
logging.Handler.
The handler can be configured declaratively in the
``logging.conf`` as follows::
[handlers]
keys = translatedlog, translator
[handler_translatedlog]
class = handlers.WatchedFileHandler
args = ('/var/log/api-localized.log',)
formatter = context
[handler_translator]
class = oslo_i18n.log.TranslationHandler
target = translatedlog
args = ('zh_CN',)
If the specified locale is not available in the system, the handler will
log in the default locale.
"""
def __init__(self, locale=None, target=None):
"""Initialize a TranslationHandler
:param locale: locale to use for translating messages
:param target: logging.Handler object to forward
LogRecord objects to after translation
"""
# NOTE(luisg): In order to allow this handler to be a wrapper for
# other handlers, such as a FileHandler, and still be able to
# configure it using logging.conf, this handler has to extend
# MemoryHandler because only the MemoryHandlers' logging.conf
# parsing is implemented such that it accepts a target handler.
handlers.MemoryHandler.__init__(self, capacity=0, target=target)
self.locale = locale
def setFormatter(self, fmt):
self.target.setFormatter(fmt)
def emit(self, record):
# We save the message from the original record to restore it
# after translation, so other handlers are not affected by this
original_msg = record.msg
original_args = record.args
try:
self._translate_and_log_record(record)
finally:
record.msg = original_msg
record.args = original_args
def _translate_and_log_record(self, record):
record.msg = _translate.translate(record.msg, self.locale)
# In addition to translating the message, we also need to translate
# arguments that were passed to the log method that were not part
# of the main message e.g., log.info(_('Some message %s'), this_one))
record.args = _translate.translate_args(record.args, self.locale)
self.target.emit(record)