Dockerfile

# Stage 1: Builder (base image that can be used for local deve or to run unit tests on CI)
FROM ruby:3.1.2 as builder
RUN mkdir /app
WORKDIR /app
RUN apt-get update -qq && \
    apt-get -y install build-essential
ADD Gemfile /app/Gemfile
ADD Gemfile.lock /app/Gemfile.lock
RUN bundle install

# Stage 2: develop (for local development setup)
FROM builder as develop
CMD [ "bundle", "exec", "rails", "s", "-b", "0.0.0.0" ]

# Stage 3: prod-build (intermediate stage that builds prod artifacts)
FROM builder as prod-build
COPY . /app
RUN rails assets:precompile
RUN bundle config set --local without 'development test' && \
    bundle config set --local path /rubygems
RUN bundle install

# Stage 4: prod (image that will be deployed all of the environments - qa, staging, prod etc.)
FROM ruby:3.1.2-slim as prod
RUN mkdir /app
WORKDIR /app
COPY --from=prod-build /app /app
COPY --from=prod-build /rubygems /rubygems
COPY --from=prod-build /usr/lib/aarch64-linux-gnu/libmariadb.so.3 /usr/lib/aarch64-linux-gnu/libmariadb.so.3
RUN bundle config set --local without 'development test' && \
    bundle config set --local path /rubygems
CMD [ "bundle", "exec", "rails", "s", "-b", "0.0.0.0" ]