809a71822c
Added a page to the RST documentation about gettext usage for internationalization. Change-Id: I2b3b25ad3ab5f3d41b5298f6bad18b216644eeed
35 lines
1.3 KiB
ReStructuredText
35 lines
1.3 KiB
ReStructuredText
Internationalization
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====================
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nova uses `gettext <http://docs.python.org/library/gettext.html>`_ so that
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user-facing strings such as log messages appear in the appropriate
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language in different locales.
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To use gettext, make sure that the strings passed to the logger are wrapped
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in a ``_()`` function call. For example::
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LOG.debug(_("block_device_mapping %s"), block_device_mapping)
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If you have multiple arguments, the convention is to use named parameters.
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It's common to use the ``locals()`` dict (which contains the names and values
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of the local variables in the current scope) to do the string interpolation.
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For example::
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label = ...
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sr_ref = ...
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LOG.debug(_('Introduced %(label)s as %(sr_ref)s.') % locals())
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If you do not follow the project conventions, your code may cause the
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LocalizationTestCase.test_multiple_positional_format_placeholders test to fail
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in nova/tests/test_localization.py.
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The ``_()`` function is brought into the global scope by doing::
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import gettext
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gettext.install("nova", unicode=1)
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In general, you shouldn't need to add these to any nova files, since the lines
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are present in ``nova/__init__.py``. However, if this code is missing, it may
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result in an error that looks like like::
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NameError: name '_' is not defined
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