Internationalization

Added in version 1.1.

Complementary to translations provided for Sphinx-generated messages such as navigation bars, Sphinx provides mechanisms facilitating the translation of documents. See the Options for internationalization for details on configuration.

../../_images/translation.svg

Workflow visualization of translations in Sphinx. (The figure is created by plantuml.)

Sphinx internationalization details

gettext [1] is an established standard for internationalization and localization. It naively maps messages in a program to a translated string. Sphinx uses these facilities to translate whole documents.

Initially project maintainers have to collect all translatable strings (also referred to as messages) to make them known to translators. Sphinx extracts these through invocation of sphinx-build -M gettext.

Every single element in the doctree will end up in a single message which results in lists being equally split into different chunks while large paragraphs will remain as coarsely-grained as they were in the original document. This grants seamless document updates while still providing a little bit of context for translators in free-text passages. It is the maintainer’s task to split up paragraphs which are too large as there is no sane automated way to do that.

After Sphinx successfully ran the MessageCatalogBuilder you will find a collection of .pot files in your output directory. These are catalog templates and contain messages in your original language only.

They can be delivered to translators which will transform them to .po files — so called message catalogs — containing a mapping from the original messages to foreign-language strings.

gettext compiles them into a binary format known as binary catalogs through msgfmt for efficiency reasons. If you make these files discoverable with locale_dirs for your language, Sphinx will pick them up automatically.

An example: you have a document usage.rst in your Sphinx project. The gettext builder will put its messages into usage.pot. Imagine you have Spanish translations [2] stored in usage.po — for your builds to be translated you need to follow these instructions:

  • Compile your message catalog to a locale directory, say locale, so it ends up in ./locale/es/LC_MESSAGES/usage.mo in your source directory (where es is the language code for Spanish.)

    msgfmt "usage.po" -o "locale/es/LC_MESSAGES/usage.mo"
    
  • Set locale_dirs to ["locale/"].

  • Set language to es (also possible via -D).

  • Run your desired build.

In order to protect against mistakes, a warning is emitted if cross-references in the translated paragraph do not match those from the original. This can be turned off globally using the suppress_warnings configuration variable. Alternatively, to turn it off for one message only, end the message with #noqa like this:

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse
risus tortor, luctus id ultrices at. #noqa

(Write \#noqa in case you want to have “#noqa” literally in the text. This does not apply to code blocks, where #noqa is ignored because code blocks do not contain references anyway.)

Added in version 4.5: The #noqa mechanism.

Translating with sphinx-intl

Quick guide

sphinx-intl is a useful tool to work with Sphinx translation flow. This section describe an easy way to translate with sphinx-intl.

  1. Install sphinx-intl.

    $ pip install sphinx-intl
    
  2. Add configurations to conf.py.

    locale_dirs = ['locale/']   # path is example but recommended.
    gettext_compact = False     # optional.
    

    This case-study assumes that BUILDDIR is set to _build, locale_dirs is set to locale/ and gettext_compact is set to False (the Sphinx document is already configured as such).

  3. Extract translatable messages into pot files.

    $ make gettext
    

    The generated pot files will be placed in the _build/gettext directory.

  4. Generate po files.

    We’ll use the pot files generated in the above step.

    $ sphinx-intl update -p _build/gettext -l de -l ja
    

    Once completed, the generated po files will be placed in the below directories:

    • ./locale/de/LC_MESSAGES/

    • ./locale/ja/LC_MESSAGES/

  5. Translate po files.

    As noted above, these are located in the ./locale/<lang>/LC_MESSAGES directory. An example of one such file, from Sphinx, builders.po, is given below.

    # a5600c3d2e3d48fc8c261ea0284db79b
    #: ../../builders.rst:4
    msgid "Available builders"
    msgstr "<FILL HERE BY TARGET LANGUAGE>"
    

    Another case, msgid is multi-line text and contains reStructuredText syntax:

    # 302558364e1d41c69b3277277e34b184
    #: ../../builders.rst:9
    msgid ""
    "These are the built-in Sphinx builders. More builders can be added by "
    ":ref:`extensions <extensions>`."
    msgstr ""
    "FILL HERE BY TARGET LANGUAGE FILL HERE BY TARGET LANGUAGE FILL HERE "
    "BY TARGET LANGUAGE :ref:`EXTENSIONS <extensions>` FILL HERE."
    

    Please be careful not to break reST notation. Most po-editors will help you with that.

  6. Build translated document.

    You need a language parameter in conf.py or you may also specify the parameter on the command line.

    For BSD/GNU make, run:

    $ make -e SPHINXOPTS="-D language='de'" html
    

    For Windows cmd.exe, run:

    > set SPHINXOPTS=-D language=de
    > .\make.bat html
    

    For PowerShell, run:

    > Set-Item env:SPHINXOPTS "-D language=de"
    > .\make.bat html
    

Congratulations! You got the translated documentation in the _build/html directory.

Added in version 1.3: sphinx-build that is invoked by make command will build po files into mo files.

If you are using 1.2.x or earlier, please invoke sphinx-intl build command before make command.

Translating

Update your po files by new pot files

If a document is updated, it is necessary to generate updated pot files and to apply differences to translated po files. In order to apply the updates from a pot file to the po file, use the sphinx-intl update command.

$ sphinx-intl update -p _build/gettext

Using Transifex service for team translation

Transifex is one of several services that allow collaborative translation via a web interface. It has a nifty Go-based command line client that makes it easy to fetch and push translations.

  1. Install the Transifex CLI tool.

    You need the tx command line tool for uploading resources (pot files). The official installation process place the tx binary file in the current directory along with a README and a LICENSE file, and adds the current directory to $PATH.

    $ curl -o- https://raw.githubusercontent.com/transifex/cli/master/install.sh | bash
    
  2. Create your Transifex account and create a new project and an organization for your document.

    Currently, Transifex does not allow for a translation project to have more than one version of the document, so you’d better include a version number in your project name.

    For example:

    Organization ID:

    sphinx-document

    Project ID:

    sphinx-document-test_1_0

    Project URL:

    https://www.transifex.com/projects/p/sphinx-document-test_1_0/

  3. Create an API token to be used in the command-line.

    Go to your Transifex API token page and generate a token. Copy the generated token now, as you will not be able to see it again later.

  4. Set your Transifex API token in the user configuration file $HOME/.transifexrc.

    [https://app.transifex.com]
    rest_hostname = https://rest.api.transifex.com
    token         = paste_your_api_token_here
    
  5. Alternatively, you can store your Transifex API token as the environment variable TX_TOKEN, which is recognized and used by tx.

    $ export TX_TOKEN=paste_your_api_token_here
    
  6. Create the project’s config file for tx command.

    This process will create .tx/config in the current directory.

    $ cd /your/document/root
    $ tx init
    
    Successful creation of '.tx/config' file
    
  7. Upload pot files to Transifex service.

    Register pot files to .tx/config file using sphinx-intl update-txconfig-resources, adjusting --pot-dir value to your project’s pot files’ directory:

    $ cd /your/document/root
    $ sphinx-intl update-txconfig-resources --pot-dir _build/locale \
      --transifex-organization-name=sphinx-document \
      --transifex-project-name=sphinx-document-test_1_0
    

    You can use the SPHINXINTL_TRANSIFEX_ORGANIZATION_NAME and SPHINXINTL_TRANSIFEX_PROJECT_NAME environment variables instead of the respective command line arguments.

    and upload pot files:

    $ tx push -s
    # Getting info about resources
    
    sphinx-document-test_1_0.builders - Getting info
    sphinx-document-test_1_0.builders - Done
    
    # Pushing source files
    
    sphinx-document-test_1_0.builders - Uploading file
    sphinx-document-test_1_0.builders - Done
    
  8. Forward the translation on Transifex.

  9. Pull translated po files and make translated HTML.

    Get translated catalogs and build mo files. For example, to build mo files for German (de):

    $ cd /your/document/root
    $ tx pull -l de
    # Getting info about resources
    
    sphinx-document-test_1_0.builders - Getting info
    sphinx-document-test_1_0.builders - Done
    
    # Pulling files
    
    sphinx-document-test_1_0.builders [de] - Pulling file
    sphinx-document-test_1_0.builders [de] - Creating download job
    sphinx-document-test_1_0.builders [de] - Done
    

    Invoke make html (for BSD/GNU make) passing the language code:

    $ make -e SPHINXOPTS="-D language='de'" html
    

That’s all!

Tip

Translating locally and on Transifex

If you want to push all language’s po files, you can be done by using tx push -t command. Watch out! This operation overwrites translations in Transifex.

In other words, if you have updated each in the service and local po files, it would take much time and effort to integrate them.

Using Weblate service for team translation

Read more in Weblate’s documentation.

Contributing to Sphinx reference translation

The recommended way for new contributors to translate Sphinx reference is to join the translation team on Transifex.

There is a sphinx translation page for Sphinx (master) documentation.

  1. Login to Transifex service.

  2. Go to sphinx translation page.

  3. Click Request language and fill form.

  4. Wait acceptance by Transifex sphinx translation maintainers.

  5. (After acceptance) Translate on Transifex.

Detail is here: https://help.transifex.com/en/articles/6248698-getting-started-as-a-translator

Translation progress and statistics

Added in version 7.1.0.

During the rendering process, Sphinx marks each translatable node with a translated attribute, indicating if a translation was found for the text in that node.

The translation_progress_classes configuration value can be used to add a class to each element, depending on the value of the translated attribute.

The |translation progress| substitution can be used to display the percentage of nodes that have been translated on a per-document basis.

Footnotes