vmware-nsx/neutron/openstack/common/gettextutils.py
Luis A. Garcia 37d1c58b57 Sync gettextutils from oslo
Some Messages, such as those created from Invalid exceptions, use a
Message within a Message, and we were only translating the base Message
but not the Message substitution within.

Fixes bug: #1221808

Change-Id: Ic3119df23a090cfaa160c1461e955f0af55fe1cf
2013-09-18 23:11:06 +00:00

352 lines
12 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# 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.
"""
gettext for openstack-common modules.
Usual usage in an openstack.common module:
from neutron.openstack.common.gettextutils import _
"""
import copy
import gettext
import logging
import os
import re
try:
import UserString as _userString
except ImportError:
import collections as _userString
from babel import localedata
import six
_localedir = os.environ.get('neutron'.upper() + '_LOCALEDIR')
_t = gettext.translation('neutron', localedir=_localedir, fallback=True)
_AVAILABLE_LANGUAGES = {}
USE_LAZY = False
def enable_lazy():
"""Convenience function for configuring _() to use lazy gettext
Call this at the start of execution to enable the gettextutils._
function to use lazy gettext functionality. This is useful if
your project is importing _ directly instead of using the
gettextutils.install() way of importing the _ function.
"""
global USE_LAZY
USE_LAZY = True
def _(msg):
if USE_LAZY:
return Message(msg, 'neutron')
else:
return _t.ugettext(msg)
def install(domain, lazy=False):
"""Install a _() function using the given translation domain.
Given a translation domain, install a _() function using gettext's
install() function.
The main difference from gettext.install() is that we allow
overriding the default localedir (e.g. /usr/share/locale) using
a translation-domain-specific environment variable (e.g.
NOVA_LOCALEDIR).
:param domain: the translation domain
:param lazy: indicates whether or not to install the lazy _() function.
The lazy _() introduces a way to do deferred translation
of messages by installing a _ that builds Message objects,
instead of strings, which can then be lazily translated into
any available locale.
"""
if lazy:
# NOTE(mrodden): Lazy gettext functionality.
#
# The following introduces a deferred way to do translations on
# messages in OpenStack. We override the standard _() function
# and % (format string) operation to build Message objects that can
# later be translated when we have more information.
#
# Also included below is an example LocaleHandler that translates
# Messages to an associated locale, effectively allowing many logs,
# each with their own locale.
def _lazy_gettext(msg):
"""Create and return a Message object.
Lazy gettext function for a given domain, it is a factory method
for a project/module to get a lazy gettext function for its own
translation domain (i.e. nova, glance, cinder, etc.)
Message encapsulates a string so that we can translate
it later when needed.
"""
return Message(msg, domain)
import __builtin__
__builtin__.__dict__['_'] = _lazy_gettext
else:
localedir = '%s_LOCALEDIR' % domain.upper()
gettext.install(domain,
localedir=os.environ.get(localedir),
unicode=True)
class Message(_userString.UserString, object):
"""Class used to encapsulate translatable messages."""
def __init__(self, msg, domain):
# _msg is the gettext msgid and should never change
self._msg = msg
self._left_extra_msg = ''
self._right_extra_msg = ''
self._locale = None
self.params = None
self.domain = domain
@property
def data(self):
# NOTE(mrodden): this should always resolve to a unicode string
# that best represents the state of the message currently
localedir = os.environ.get(self.domain.upper() + '_LOCALEDIR')
if self.locale:
lang = gettext.translation(self.domain,
localedir=localedir,
languages=[self.locale],
fallback=True)
else:
# use system locale for translations
lang = gettext.translation(self.domain,
localedir=localedir,
fallback=True)
full_msg = (self._left_extra_msg +
lang.ugettext(self._msg) +
self._right_extra_msg)
if self.params is not None:
full_msg = full_msg % self.params
return six.text_type(full_msg)
@property
def locale(self):
return self._locale
@locale.setter
def locale(self, value):
self._locale = value
if not self.params:
return
# This Message object may have been constructed with one or more
# Message objects as substitution parameters, given as a single
# Message, or a tuple or Map containing some, so when setting the
# locale for this Message we need to set it for those Messages too.
if isinstance(self.params, Message):
self.params.locale = value
return
if isinstance(self.params, tuple):
for param in self.params:
if isinstance(param, Message):
param.locale = value
return
for param in self.params.values():
if isinstance(param, Message):
param.locale = value
def _save_dictionary_parameter(self, dict_param):
full_msg = self.data
# look for %(blah) fields in string;
# ignore %% and deal with the
# case where % is first character on the line
keys = re.findall('(?:[^%]|^)?%\((\w*)\)[a-z]', full_msg)
# if we don't find any %(blah) blocks but have a %s
if not keys and re.findall('(?:[^%]|^)%[a-z]', full_msg):
# apparently the full dictionary is the parameter
params = copy.deepcopy(dict_param)
else:
params = {}
for key in keys:
try:
params[key] = copy.deepcopy(dict_param[key])
except TypeError:
# cast uncopyable thing to unicode string
params[key] = unicode(dict_param[key])
return params
def _save_parameters(self, other):
# we check for None later to see if
# we actually have parameters to inject,
# so encapsulate if our parameter is actually None
if other is None:
self.params = (other, )
elif isinstance(other, dict):
self.params = self._save_dictionary_parameter(other)
else:
# fallback to casting to unicode,
# this will handle the problematic python code-like
# objects that cannot be deep-copied
try:
self.params = copy.deepcopy(other)
except TypeError:
self.params = unicode(other)
return self
# overrides to be more string-like
def __unicode__(self):
return self.data
def __str__(self):
return self.data.encode('utf-8')
def __getstate__(self):
to_copy = ['_msg', '_right_extra_msg', '_left_extra_msg',
'domain', 'params', '_locale']
new_dict = self.__dict__.fromkeys(to_copy)
for attr in to_copy:
new_dict[attr] = copy.deepcopy(self.__dict__[attr])
return new_dict
def __setstate__(self, state):
for (k, v) in state.items():
setattr(self, k, v)
# operator overloads
def __add__(self, other):
copied = copy.deepcopy(self)
copied._right_extra_msg += other.__str__()
return copied
def __radd__(self, other):
copied = copy.deepcopy(self)
copied._left_extra_msg += other.__str__()
return copied
def __mod__(self, other):
# do a format string to catch and raise
# any possible KeyErrors from missing parameters
self.data % other
copied = copy.deepcopy(self)
return copied._save_parameters(other)
def __mul__(self, other):
return self.data * other
def __rmul__(self, other):
return other * self.data
def __getitem__(self, key):
return self.data[key]
def __getslice__(self, start, end):
return self.data.__getslice__(start, end)
def __getattribute__(self, name):
# NOTE(mrodden): handle lossy operations that we can't deal with yet
# These override the UserString implementation, since UserString
# uses our __class__ attribute to try and build a new message
# after running the inner data string through the operation.
# At that point, we have lost the gettext message id and can just
# safely resolve to a string instead.
ops = ['capitalize', 'center', 'decode', 'encode',
'expandtabs', 'ljust', 'lstrip', 'replace', 'rjust', 'rstrip',
'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']
if name in ops:
return getattr(self.data, name)
else:
return _userString.UserString.__getattribute__(self, name)
def get_available_languages(domain):
"""Lists the available languages for the given translation domain.
:param domain: the domain to get languages for
"""
if domain in _AVAILABLE_LANGUAGES:
return copy.copy(_AVAILABLE_LANGUAGES[domain])
localedir = '%s_LOCALEDIR' % domain.upper()
find = lambda x: gettext.find(domain,
localedir=os.environ.get(localedir),
languages=[x])
# NOTE(mrodden): en_US should always be available (and first in case
# order matters) since our in-line message strings are en_US
language_list = ['en_US']
# NOTE(luisg): Babel <1.0 used a function called list(), which was
# renamed to locale_identifiers() in >=1.0, the requirements master list
# requires >=0.9.6, uncapped, so defensively work with both. We can remove
# this check when the master list updates to >=1.0, and all projects udpate
list_identifiers = (getattr(localedata, 'list', None) or
getattr(localedata, 'locale_identifiers'))
locale_identifiers = list_identifiers()
for i in locale_identifiers:
if find(i) is not None:
language_list.append(i)
_AVAILABLE_LANGUAGES[domain] = language_list
return copy.copy(language_list)
def get_localized_message(message, user_locale):
"""Gets a localized version of the given message in the given locale."""
if isinstance(message, Message):
if user_locale:
message.locale = user_locale
return unicode(message)
else:
return message
class LocaleHandler(logging.Handler):
"""Handler that can have a locale associated to translate Messages.
A quick example of how to utilize the Message class above.
LocaleHandler takes a locale and a target logging.Handler object
to forward LogRecord objects to after translating the internal Message.
"""
def __init__(self, locale, target):
"""Initialize a LocaleHandler
:param locale: locale to use for translating messages
:param target: logging.Handler object to forward
LogRecord objects to after translation
"""
logging.Handler.__init__(self)
self.locale = locale
self.target = target
def emit(self, record):
if isinstance(record.msg, Message):
# set the locale and resolve to a string
record.msg.locale = self.locale
self.target.emit(record)