mix localize.download_locales (Localize v0.39.0)

Downloads locale ETF files from the Localize CDN and stores them in the configured locale cache directory.

This task is intended to be run at build time (e.g. in a Dockerfile or CI pipeline) so that all required locales are available in the cache before the application starts. This avoids the need for runtime downloads in production.

Usage

mix localize.download_locales

Downloads the configured :supported_locales. When :supported_locales is not configured (meaning all CLDR locales are supported), prompts for confirmation before downloading.

mix localize.download_locales en fr de ja

Downloads the specified locales.

mix localize.download_locales --all

Downloads all CLDR locales without prompting.

mix localize.download_locales --force

--force does two things: (1) when :supported_locales is not configured, it downloads all locales without prompting (useful in CI/Docker where there is no interactive terminal); and (2) it re-downloads every requested locale even if a current copy already exists in the configured cache directory, bypassing the "already current" skip.

Output directory

Files are written to the directory returned by Localize.Locale.Provider.locale_cache_dir/0, which defaults to Application.app_dir(:localize, "priv/localize/locales").

Override with:

config :localize, locale_cache_dir: "/path/to/cache"

Skip behaviour

A locale is reported (current) and skipped only when a version-matching copy already exists in the configured cache directory — the same directory the task writes to. The bundled fallback directory inside the :localize dependency (Application.app_dir(:localize, …)) is deliberately not consulted for this decision, so a copy shipped with the dependency never prevents the task from populating your configured directory. Use --force to re-download regardless of the current copy.

Compile-time configuration

The task only loads compile-time configuration (config/config.exs and any imported env-specific files) and never evaluates config/runtime.exs. This makes it safe to run inside "build-only" environments (such as Docker images) where production-only environment variables are deliberately not available.

The task itself reads only :localize's own compile-time config.

Examples

Pre-populate the cache for a Docker build:

# Dockerfile
RUN mix localize.download_locales

Download specific locales for testing:

mix localize.download_locales en de ja zh

Download everything in a non-interactive environment:

mix localize.download_locales --force