Dockerfile

ARG ELIXIR_VERSION=1.18
ARG OTP_VERSION=28.1.1
ARG ALPINE_VERSION=3.23.2

ARG BUILDER_IMAGE="hexpm/elixir:${ELIXIR_VERSION}-erlang-${OTP_VERSION}-alpine-${ALPINE_VERSION}"
ARG RUNNER_IMAGE="alpine:${ALPINE_VERSION}"

FROM ${BUILDER_IMAGE} as builder

# install build dependencies
RUN apk update && apk add build-base git \
    && rm -rf /var/cache/apk/*

# prepare build dir
WORKDIR /app

# install hex + rebar
RUN mix local.hex --force && \
    mix local.rebar --force

# set build ENV
ENV MIX_ENV="prod"

# install mix dependencies
COPY mix.exs mix.lock ./
RUN mix deps.get --only $MIX_ENV
RUN mkdir config

# copy compile-time config files before we compile dependencies
# to ensure any relevant config change will trigger the dependencies
# to be re-compiled.
COPY config/config.exs config/${MIX_ENV}.exs config/
RUN mix deps.compile

COPY priv priv

COPY lib lib

COPY assets assets

# compile assets
RUN mix assets.deploy

# Compile the release
RUN mix compile

# Changes to config/runtime.exs don't require recompiling the code
COPY config/runtime.exs config/

RUN mix release

# start a new build stage so that the final image will only contain
# the compiled release and other runtime necessities
FROM ${RUNNER_IMAGE}

RUN apk update && \
  apk add libstdc++ openssl ncurses-libs ca-certificates \
  && rm -rf /var/cache/apk/*

WORKDIR "/app"
RUN chown nobody /app

# set runner ENV
ENV MIX_ENV="prod"

# Only copy the final release from the build stage
COPY --from=builder --chown=nobody:root /app/_build/${MIX_ENV}/rel/discovery ./

USER nobody

# If using an environment that doesn't automatically reap zombie processes, it is
# advised to add an init process such as tini via `apt-get install`
# above and adding an entrypoint. See https://github.com/krallin/tini for details
# ENTRYPOINT ["/tini", "--"]

CMD ["/app/bin/discovery", "start"]