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This page covers various operations around i18n activities.

Zanata CLI

OpenStack uses Zanata as a translation platform. While most operations around the translation platform are automated, if you want to communicate with the translation platform manually, you can use Zanata CLI.

User configuration

You need to create a configuration file in $HOME/.config/zanata.ini that contains user-specific configuration. For information on how to create a configuration file, see Zanata CLI configuration.

Project configuration

To communicate with the translation platform, you need to prepare a project configuration file named zanata.xml in the top directory of a project you are interested in. OpenStack projects does not contain zanata.xml in their git repositories, so you need to create it manually.

The following is an example of zanata.xml. In most cases, what you need to edit are project and project-version.

<config xmlns="">
    <rule pattern="**/*.pot">{path}/{locale_with_underscore}/LC_MESSAGES/{filename}.po</rule>

Pull translations from Zanata

To download translations from Zanata, run the following command after going into a project directory. You are usually interested in only a few of languages, so --locales option would be useful. For more options, see the output of zanata pull --help.

$ zanata-cli pull --locales ja,ko-KR,zh-CN

Handling documentation projects


This is written about openstack-manuals project. As of the end of Pike development cycle, the document migration community-wide effort is being done. The process documented here might be changed in near future.

OpenStack documents are using RST format. The steps to translate RST documents include:

  • Slicing: generate PO templates from RST documents
  • Uploading: Upload the translation resources to Zanata
  • Translating: manage the translation in Zanata, including the translation memory and glossary management
  • Downloading: Download the translated results by automation scripts.
  • Building: Build HTML from RST documents and the translated results.

Sphinx is a tool to translate RST source files to various output formats, including POT and HTML. You need to install Sphinx before you go to below steps. Almost all projects have test-requirements.txt in their repositories and you can check the required version of Sphinx by checking this file.

$ pip install Sphinx

Or, more convenient way would be:

$ pip install -r test-requirements.txt


We use sphinx-build to translate RST files to POT files. Because we want to have a single POT file per document, we use msgcat to merge those POTs after sphinx-build.

$ sphinx-build -b gettext doc/[docname]/source/ doc/[docname]/source/locale/
$ msgcat doc/[docname]/source/locale/*.pot > doc/[docname]/source/locale/[docname].pot


We use Zanata CLI to upload the POT file to the translate platform.


We use Zanata CLI to download the translated PO files from the translation platform.


Before use sphinx-build to build HTML file, we need to feed the translations from the single PO file into those small PO files. For example:

$ msgmerge -o doc/[docname]/source/locale/zh_CN/LC_MESSAGES/A.po \
    doc/[docname]/source/locale/zh_CN/LC_MESSAGES/[docname].po \

Then, for every PO file, we should execute the following command to build into MO file:

$ msgfmt doc/[docname]/source/locale/zh_CN/LC_MESSAGES/A.po \
   -o doc/[docname]/source/locale/zh_CN/LC_MESSAGES/

Finally, we could generate HTML files by

$ sphinx-build -D "language='zh_CN' doc/[docname]/source/ \

Handling python projects

For most of the Python projects, the preferred tools for I18N are gettext and babel. The gettext module provides internationalization (I18N) and localization (L10N) services for your Python modules and applications. Babel are a collection of tools for internationalizing Python applications.


You can extract the messages in code to PO template (POT) with pybabel, where PROJECT is a project name like nova and VERSION is a version number. Note that you can omit --project and --version options if you just use them locally as they are just used in the POT file header.

$ pybabel extract \
    --add-comments Translators: \
    -k "_C:1c,2" -k "_P:1,2" \
    --project=${PROJECT} --version=${VERSION} \
    -o ${modulename}/locale/${modulename}.pot \

For example, in case of nova,

$ pybabel extract \
    --add-comments Translators: \
    -k "_C:1c,2" -k "_P:1,2" \
    --project=nova --version=${VERSION} \
    -o nova/locale/nova.pot nova/


For each Python project in OpenStack, there is an automation job to extract the messages , generate PO template and upload to Zanata, which is triggered by the “commit” event. See here.


For each Python project in OpenStack, there is an automation job daily to download the translations in PO file to the “locale” folder under the source folder of each project. See here. It will generate a review request in Gerrit. After review, the translation in PO file will be merged.

Using translations

To display translated messages in python server projects, you need to compile message catalogs and also need to configure your server services following instructions described at oslo.i18n documentation.

Handling horizon projects

(Some contribution would be appreciated.)

Project maintenance


The scripts below depend on several python modules. To install these dependencies, run pip install -e requirements.txt.

More convenient way is to use tox like tox -e venv -- python <script-name>.

tox is available on PyPI and also available in various Linux distribution. pip install tox or apt-get install python-tox (in case of Ubuntu) installs tox.

Sync the translator list with Zanata

The I18n project maintains a list of language teams and their members. The list is used by Stackalytics to gather translation statistics (See Stackalytics for detail). It is also used by the scripts below.

The filename of the list is tools/translation_team.yaml.

This list is a cache of information on Zanata, and we need to keep it synced with Zanata.

To sync the translator list, run the following command:

tox -e zanata-users-sync

The above run the following internally:

python tools/zanata/ --output-file tools/zanata/translation_team.yaml

Retrieve translation statistics

ATC status in I18n project is determined based on translation statistics in a specific period.

The script tools/zanata/ helps retrieving translation statistics from Zanata.

To run the script:

tox -e venv -- python ./tools/zanata/ <options>

--help option shows the detail usage.

Extract Zanata user information

At the moment, the I18n PTL needs to maintain the ATC list of the I18n project manually around the end of each release cycle. This requires name and e-mail address of individual translators.

The script tools/zanata/ helps this. It generates a CSV file by reading a YAML file which contains the list of translators (e.g., translation_team.yaml) with user name and e-mail addresses by interacting with Zanata API.


This script requires Zanata admin privilege.

Creative Commons Attribution 3.0 License

Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.