Dockerfile

# 1: Use ruby 2.3.3 as base:
FROM ruby:2.3.3-alpine

# 3: We'll add the app's binaries path to $PATH, and set the environment name to 'production':
ENV PATH=/usr/src/app/bin:$PATH

RUN adduser -u 9000 -D app

# 4: Copy just the Gemfile & Gemfile.lock, to avoid the build cache failing whenever any other
# file changed and installing dependencies all over again - a must if your'e developing this
# Dockerfile...
ADD ./belugas-ruby.gemspec* /usr/src/app/
ADD ./lib/belugas/ruby/version.rb /usr/src/app/lib/belugas/ruby/version.rb
ADD ./Gemfile* /usr/src/app/

# 5: Install build + runtime dependencies, install/build the app gems, and remove build deps:
RUN set -ex \
    && apk add --no-cache --virtual .app-rundeps icu-libs \
    && apk add --no-cache --virtual .app-builddeps build-base icu-dev cmake \
    && cd /usr/src/app \
    && bundle install --without development test \
    && apk del .app-builddeps

# 6: Copy the rest of the application code, then change the owner of the code to 'app':
ADD . /usr/src/app

VOLUME /code
WORKDIR /code

CMD ["/usr/src/app/bin/belugas-ruby", "analyze"]