medium-multi-stage-dockerfile-bundler-stage

Dockerfile

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# Stage: bundler
FROM ruby as bundler
LABEL description="Install and cache gems for all environments"

WORKDIR /home/app

# Copy the Gemfile and Gemfile.lock
COPY Gemfile* /home/app/

# Install build deps as virtual dependencies.
#
# - build-base -- used to install gcc, make, etc.
# - libxml2-dev -- used to install nokogiri native extension
# - libxslt-dev -- used to install nokogiri native extension
RUN apk add --update --no-cache --virtual .build-deps \
   build-base \
   libxml2-dev \
   libxslt-dev \
 && bundle config build.nokogiri --use-system-libraries \
 && bundle install --frozen --deployment --jobs 4 --retry 3 \
 # Remove unneeded files (*/.git, *.o, *.c) but keeps cached gems for later stages
 && find vendor/bundle/ -name ".git" -exec rm -rv {} + \
 && find vendor/bundle/ -name "*.c" -delete \
 && find vendor/bundle/ -name "*.o" -delete \
 && rm -rf vendor/bundle/ruby/*/cache \
 # Remove unneeded build deps
 && apk del .build-deps