Dockerfile

# Production mode Dockerfile
# This Dockerfile is also using the .tool-versions file and asdf
FROM ubuntu:latest

# Packages for asdf & erlang build
RUN apt-get update -q && apt install -y libssl-dev zlib1g-dev automake autoconf curl git unzip gcc libncurses5-dev libncursesw5-dev build-essential && adduser --shell /bin/bash --home /asdf --disabled-password asdf
ENV PATH="${PATH}:/asdf/.asdf/shims:/asdf/.asdf/bin"

# Creating the main directory
RUN mkdir /www
RUN chown asdf:asdf /www
WORKDIR /www

# install asdf
USER asdf
RUN git clone --depth 1 https://github.com/asdf-vm/asdf.git $HOME/.asdf && \
    echo '. $HOME/.asdf/asdf.sh' >> $HOME/.bashrc && \
    echo '. $HOME/.asdf/asdf.sh' >> $HOME/.profile

# asdf plugins 
RUN asdf plugin-add erlang https://github.com/michallepicki/asdf-erlang-prebuilt-ubuntu-20.04 && asdf plugin-add elixir && asdf plugin-add nodejs && asdf plugin-add yarn
COPY .tool-versions /www

# install only the plugins that are needed in production
RUN asdf install erlang && asdf install elixir && asdf install yarn && asdf install nodejs
ENV MIX_ENV=prod

# definition and lock files for packages
COPY --chown=asdf:asdf package.json yarn.lock mix.exs mix.lock /www/
# needed for mix
ENV LANG=C.UTF-8

# install elixir & node packages
RUN mix local.rebar --force && mix local.hex --force && mix deps.get --only prod && mix deps.compile && yarn

# copy all the project
COPY --chown=asdf:asdf . /www 
COPY --chown=asdf:asdf priv/docker-entrypoint.sh /www/docker-entrypoint.sh 
RUN chmod a+x docker-entrypoint.sh 

# Building assets
ENV NODE_ENV=production
RUN env SKIP_LOADING_PROD_SECRETS=true mix assets.deploy && rm -rf /var/www/node_modules

# we skip loading the prod secrets for the phx.digest & compile since they are not available yet
RUN env SKIP_LOADING_PROD_SECRETS=true mix phx.digest
RUN env SKIP_LOADING_PROD_SECRETS=true mix compile
CMD /www/docker-entrypoint.sh