Docker Debian based image does not have default locale set - Developers’ Notes

iRonin IT Team

2019-03-08•developers notes, docker

Here’s an easy fix for when Docker and the sablon gem don’t want to cooperate: just update your locale.

A problem with the sablon gem occured when our team was developing an application locally in a Docker container. The Docker image based on `Debian Jessie` didn't have `locale` set which caused an encoding issue in `sablon`.

We updated our Dockerfile with the following lines to make sure `locale` is correctly set to `utf-8`:

RUN sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen && \
    echo 'LANG="en_US.UTF-8"'>/etc/default/locale && \
    dpkg-reconfigure --frontend=noninteractive locales && \
    update-locale LANG=en_US.UTF-8
ENV LANG en_US.UTF-8
ENV LANG en_US.UTF-8
ENV LANGUAGE en_US.UTF-8
ENV LC_ALL en_US.UTF-8

In Ubuntu, there is the `update-locale` tool which lets you do it quickly: (`update-locale en_US.UTF-8`)

Today’s Developers’ Notes were delivered by Łukasz, our Web Application Development Team Leader. Watch out for more useful tips in the future!