A Dockerfile for Ruby on Rails

Dockerfile

FROM ruby:2.6.3-alpine AS builder
ARG RAILS_MASTER_KEY
ENV BUNDLE_APP_CONFIG=.bundle \
    BUNDLE_PATH=vendor/bundle \
    RAILS_ENV=production
RUN apk add -U --no-cache build-base \
                          libxml2-dev \
                          libxslt-dev \
                          postgresql-dev \
                          nodejs \
                          shared-mime-info \
                          tzdata && \
    gem install rubygems-update \
                bundler
WORKDIR /usr/src/app
RUN bundle config clean true && \
    bundle config deployment true && \
    bundle config ignore_messages true && \
    bundle config jobs 8 && \
    bundle config without development:test
COPY Gemfile Gemfile.lock ./
RUN bundle config build.sassc --disable-march-tune-native && \
    bundle install && \
    rm -rf vendor/bundle/ruby/${RUBY_MAJOR}.0/cache/*.gem && \
    find vendor/bundle/ruby/${RUBY_MAJOR}.0/gems/ -name *.c -delete && \
    find vendor/bundle/ruby/${RUBY_MAJOR}.0/gems/ -name *.o -delete
COPY . .
RUN bin/rails assets:precompile && \
    rm -rf tmp/cache \
           vendor/assets && \
    ls app/assets | grep -v fonts | xargs -I {} rm -rf app/assets/{}


FROM ruby:2.6.3-alpine
ENV BUNDLE_APP_CONFIG=.bundle \
    BUNDLE_PATH=vendor/bundle \
    RAILS_ENV=production \
    RAILS_SERVE_STATIC_FILES=true \
    RAILS_LOG_TO_STDOUT=true
RUN apk add -U --no-cache postgresql-client \
                          nodejs \
                          tzdata \
                          imagemagick && \
    gem install rubygems-update \
                bundler
WORKDIR /usr/src/app
COPY --from=builder /usr/src/app .
EXPOSE 3000
CMD ["bin/rails", "server", "-b", "0.0.0.0"]