For internationalization guidelines, see the oslo.i18n documentation. The information below can be used to get started.

Cinder uses gettext so that user-facing strings such as log messages appear in the appropriate language in different locales.

To use gettext, make sure that the strings passed to the logger are wrapped in a _Lx() function call. For example:"block_device_mapping %s"), block_device_mapping)

There are a few different _() translation markers, depending on the logging level of the text:

  • _LI() - Used for INFO level log messages

  • _LW() - Used for WARNING level log messages

  • _LE() - Used for ERROR level log messages (this includes LOG.exception)

  • _() - Used for any exception messages, including strings used for both logging and exceptions.


Starting with the Pike series, OpenStack no longer supports log translation markers like _Lx(), only _() should still be used for exceptions that could be user facing. It is not necessary to add _Lx() translation instructions to new code, and the instructions can be removed from old code. Refer to the email thread understanding log domain change on the openstack-dev mailing list for more details.

Do not use locals() for formatting messages because:

  1. It is not as clear as using explicit dicts.

  2. It could produce hidden errors during refactoring.

  3. Changing the name of a variable causes a change in the message.

  4. It creates a lot of otherwise unused variables.

If you do not follow the project conventions, your code may cause pep8 hacking check failures.

For translation to work properly, the top level scripts for Cinder need to first do the following before any Cinder modules are imported:

from cinder import i18n

Note: this should only be called from top level scripts - no library code or common modules should call this method.

Any files that use the _() for translation then must have the following lines:

from cinder.i18n import _

If the above code is missing, it may result in an error that looks like:

NameError: name '_' is not defined