50 lines
1.8 KiB
ReStructuredText
50 lines
1.8 KiB
ReStructuredText
Internationalization
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====================
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Nova uses the `oslo.i18n library
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<http://docs.openstack.org/developer/oslo.i18n/index.html>`_ to support
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internationalization. The oslo.i18n library is built on top of `gettext
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<http://docs.python.org/library/gettext.html>`_ and provides functions that are
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used to enable user-facing strings such as log messages to appear in the
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appropriate language in different locales.
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Nova exposes the oslo.i18n library support via the ``nova/i18n.py`` integration
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module. This module provides the functions needed to wrap translatable strings.
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It provides the ``_()`` wrapper for general user-facing messages and specific
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wrappers for messages used only for logging. DEBUG level messages do not need
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translation but CRITICAL, ERROR, WARNING and INFO messages should be wrapped
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with ``_LC()``, ``_LE()``, ``_LW()`` or ``_LI()`` respectively.
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For example::
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LOG.debug("block_device_mapping %(mapping)s",
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{'mapping': block_device_mapping})
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or::
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LOG.warn(_LW('Unknown base file %(img)s'), {'img': img})
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You should use the basic wrapper ``_()`` for strings which are not log
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messages::
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raise nova.SomeException(_('Invalid service catalogue'))
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Do not use ``locals()`` for formatting messages because:
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1. It is not as clear as using explicit dicts.
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2. It could produce hidden errors during refactoring.
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3. Changing the name of a variable causes a change in the message.
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4. It creates a lot of otherwise unused variables.
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If you do not follow the project conventions, your code may cause hacking
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checks to fail.
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The ``_()``, ``_LC()``, ``_LE()``, ``_LW()`` and ``_LI()`` functions can be
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imported with::
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from nova.i18n import _
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from nova.i18n import _LC
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from nova.i18n import _LE
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from nova.i18n import _LW
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from nova.i18n import _LI
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