Docker snippet for rubygems

README.md

Usage:

dev build

dev run --rm projectname rspec

OR

dev run --rm projectname ruby -Ilib:../lib test/test_foo.rb

docker-compose.yml

version: '2'
services:
  projectname:
    build: .
    image: projectname:dev
    stdin_open: true
    tty: true
    volumes:
      - bundler-data:/usr/local/bundle
      - .:/srv
volumes:
  bundler-data:
    driver: local

docker-entrypoint.sh

#!/bin/dumb-init /bin/bash

if [ "$(stat -c %u /usr/local/bundle)" = '0' ]; then
  chown deploy:deploy /usr/local/bundle
fi

if [ "$(which "$1")" = '' ]; then
  if [ "$(ls -A /usr/local/bundle/bin)" = '' ]; then
    echo 'command not in path and bundler not initialized'
    echo 'running bundle install'
    gosu deploy bundle install
  fi
fi

if [ "$1" = 'bundle' ]; then
  set -- gosu deploy "$@"
elif [ "$1" = 'ruby' ]; then
  set -- gosu deploy "$@"
  gosu deploy bash -c 'bundle check || bundle install'
elif ls /usr/local/bundle/bin | grep -q "\b$1\b"; then
  set -- gosu deploy bundle exec "$@"

  gosu deploy bash -c 'bundle check || bundle install'
fi

exec "$@"

Dockerfile

FROM outstand/ruby-base:2.4.2-alpine

RUN addgroup -S deploy && \
    adduser -S -G deploy deploy && \
    mv /usr/local/bin/rake /usr/local/bin/rake.back && \
    apk add --no-cache bash build-base linux-headers tzdata curl curl-dev less && \
    apk upgrade --no-cache

WORKDIR /srv
COPY . /srv/
RUN chown -R deploy:deploy /srv

COPY docker-entrypoint.sh /docker-entrypoint.sh

ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["sh"]