Weblate internals¶

Note

This chapter will give you basic overview of Weblate internals.

Weblate derives most of its code structure from, and is based on Django.

Directory structure¶

Quick overview of directory structure of Weblate main repository:

docs: Source code for this documentation, which can be built using Sphinx.
dev-docker: Docker code to run development server, see Running Weblate locally in Docker.
weblate: Source code of Weblate as a Django application, see Weblate internals.
weblate/static: Client files (CSS, Javascript and images), see Weblate frontend.

Modules¶

Weblate consists of several Django applications (some optional, see Optional Weblate modules):

accounts

User account, profiles and notifications.

addons

Add-ons to tweak Weblate behavior, see Add-ons.

api

API based on Django REST framework.

auth

Authentication and permissions.

billing

The optional Billing module.

checks

Translation string Quality checks module.

fonts

Font rendering checks module.

formats

File format abstraction layer based on translate-toolkit.

gitexport

The optional Git exporter module.

lang

Module defining language and plural models.

legal

The optional Legal module module.

machinery

Integration of machine translation services.

memory

Built-in translation memory, see Translation Memory.

screenshots

Screenshots management and OCR module.

trans

Main module handling translations.

utils

Various helper utilities.

vcs

Version control system abstraction.

wladmin

Django admin interface customization.

Background tasks internals¶

Hint

This section describes Celery task internals. Background tasks using Celery describes how to configure Celery to run the tasks.

Weblate uses Celery to execute tasks in the background. Some tasks are event-triggered, and some tasks are schedule-triggered.

The Celery Beat is used for scheduling tasks, and django-celery-beat is used to store the periodic task schedule in the database. The tasks schedule is configured in tasks.py in each of the Django apps.

The tasks are consumed using several queues; the routing is configured in settings.py. The queues were designed to separate different types of workload:

celery: The default queue where background tasks are processed.
notify: Delivers notification e-mails, both for events within Weblate and for authentication or registration. This is a separate queue to make e-mail delivery smooth even if there is a backlog of other tasks.
memory: Updates translation memory entries. The updating queue can be long when importing new strings, and long processing does not matter much here, so having a separate queue avoids blocking other tasks.
backup: The backup tasks cannot be executed in parallel, and a single dedicated worker makes this easier.
translate: Automatic translation tasks are known to take long because they hit external services.