Dockerfile

FROM elixir:1.11.3-alpine as build

# install build dependencies
RUN apk add --update git build-base nodejs npm yarn py-pip

RUN mkdir /app
WORKDIR /app

# install Hex + Rebar
RUN mix do local.hex --force, local.rebar --force

# set build ENV
ENV MIX_ENV=prod

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

# build assets
COPY assets assets
RUN cd assets && npm install && npm run deploy
RUN mix phx.digest

# build project
COPY priv priv
COPY lib lib
RUN mix compile

# build release
# at this point we should copy the rel directory but
# we are not using it so we can omit it
# COPY rel rel
RUN mix release

# prepare release image
FROM alpine:3.13 AS app

# install runtime dependencies
RUN apk add --update bash openssl postgresql-client curl

EXPOSE 4000
ENV MIX_ENV=prod
ENV ERL_INETRC=/app/erl_inetrc

# prepare app directory
RUN mkdir /app
WORKDIR /app

# copy release to app container
COPY --from=build /app/_build/prod/rel/szurupull .
COPY entrypoint.sh .
COPY erl_inetrc .
RUN chown -R nobody: /app
USER nobody

ENV HOME=/app
CMD ["bash", "/app/entrypoint.sh"]