toy/Dockerfile

FROM ruby:alpine AS base

WORKDIR /app

RUN <<EOT
  gem update --system --no-document
  gem install -N bundler
  apk update
  apk upgrade --no-cache
EOT

RUN mkdir -p /run/app


FROM base AS build

RUN <<EOT
  apk add gcc musl-dev ruby-dev make
EOT

COPY Gemfile* .

RUN <<EOT
  bundle config set --local without development
  bundle install
EOT

FROM build AS dev

WORKDIR /app

RUN <<EOT
  bundle install
EOT

CMD [ "sleep", "infinity" ]

FROM base

# RUN useradd ruby --home /app --shell /bin/sh
RUN adduser ruby -h /app -D

RUN mkdir -p /run/app

RUN chown ruby:ruby /run/app

USER ruby:ruby

COPY --from=build /usr/local/bundle /usr/local/bundle
COPY --from=build --chown=ruby:ruby /app /app

COPY --chown=ruby:ruby . .

EXPOSE 4567
CMD [ "bundle", "exec", "rackup", "--host", "0.0.0.0", "--port", "4567" ]