nova/doc/source/i18n.rst
Joe Gordon a1e8fc6dd9 Update docs layout
* Explain these docs are for trunk (copied from ironic)
* All the docs in this repo are meant to be developer docs, so having a
  devref inside of the docs is redundant and just makes the docs more
  complicated to navigate. Move everything out of the devref folder and
  link to everything from main index.
* Move man pages into separate section. The man pages are pretty sparse
* right now, we should either make them useful or just delete them
* Remove dead docs from unused_docs list in doc/source/conf.py
* Shuffle docs landing page, move common referees to the top (API,
  hypervisor support matrix), Add a introduction section and more. The
  hope is the updated layout makes this document easier to navigate.
* Use maxdepth of 1
* Rename a few sections with what are hopefully better names

The next step is to prune out outdated documents and further cleanup
this page.

Change-Id: Iff453e47ccc902a0e72b1a5f6ce1ee939ff3a1a0
2015-05-15 10:47:18 -07:00

1.8 KiB

Internationalization

Nova uses the oslo.i18n library to support internationalization. The oslo.i18n library is built on top of gettext and provides functions that are used to enable user-facing strings such as log messages to appear in the appropriate language in different locales.

Nova exposes the oslo.i18n library support via the nova/i18n.py integration module. This module provides the functions needed to wrap translatable strings. It provides the _() wrapper for general user-facing messages and specific wrappers for messages used only for logging. DEBUG level messages do not need translation but CRITICAL, ERROR, WARNING and INFO messages should be wrapped with _LC(), _LE(), _LW() or _LI() respectively.

For example:

LOG.debug("block_device_mapping %(mapping)s",
          {'mapping': block_device_mapping})

or:

LOG.warn(_LW('Unknown base file %(img)s'), {'img': img})

You should use the basic wrapper _() for strings which are not log messages:

raise nova.SomeException(_('Invalid service catalogue'))

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 hacking checks to fail.

The _(), _LC(), _LE(), _LW() and _LI() functions can be imported with:

from nova.i18n import _
from nova.i18n import _LC
from nova.i18n import _LE
from nova.i18n import _LW
from nova.i18n import _LI