Ruby and Rails docker example

docker-compose.yml

version: '2'
services:
  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: password
      MYSQL_USER: mysql
      MYSQL_PASSWORD: password
    
  web:
    build: .
    links:
      - db
    volumes:
      - .:/home/ticketbuster/repo
    ports:
      - '3000:3000'
    env_file:
      - .env
    restart: always
    command: foreman start

Dockerfile

FROM ruby:2.3.1-alpine
MAINTAINER Keifer Furzland <kfrz.code@gmail.com>

# Env
ENV REFRESHED_AT 2016-09-21
ENV REPO_DIR /home/ticketbuster/repo
ENV GEM_HOME /home/ticketbuster/gems
ENV ENV_FILE /home/ticketbuster/repo/.env
ENV BUILD_PACKAGES bash libffi-dev openssl-dev linux-headers zlib-dev readline-dev yaml-dev git curl-dev ruby-dev build-base
ENV RUBY_PACKAGES ruby-io-console ruby-bundler nodejs libxml2-dev mysql-dev mariadb-dev

RUN apk update && \
    apk upgrade && \
    apk add $BUILD_PACKAGES && \
    apk add $RUBY_PACKAGES && \
    rm -rf /var/cache/apk/*

# We're adding a specific GID and UID so we can seamlessly scale to clusters
# Also we want to run the app as this user for great justice
# -D says no password -- this maybe should change, although docker is isolated as it is. 
#RUN addgroup -g 7891 ticketbuster && \
#    adduser -h /home/ticketbuster -s /bin/false -u 7892 -G ticketbuster ticketbuster -D

# Create and switch to repo dir
RUN mkdir -p $GEM_HOME $REPO_DIR
WORKDIR $REPO_DIR

# Copy the rest of the app
# RUN git clone ssh://git@gitlab.com:kfrz/ticketbuster.git
ADD . $REPO_DIR

# Symlink vendor
RUN ln -sn /home/ticketbuster/repo/vendor/bundle $GEM_HOME
#RUN chown -R ticketbuster:ticketbuster $REPO_DIR && chown -R ticketbuster:ticketbuster $GEM_HOME && chmod -R a+w $REPO_DIR && chmod -R a+w 0644 $GEM_HOME
#USER ticketbuster

# Install gems. Bundler won't allow us to install with documentation.
#### NOTE: In production, the bundle command should be appended with `--without development test`
COPY Gemfile* $REPO_DIR/
RUN gem install bundle && gem install tzinfo-data && bundle install --jobs=6 --path=$GEM_HOME

# Provide a Healthcheck for Docker risk mitigation
HEALTHCHECK --interval=3600s --timeout=20s --retries=2 CMD curl http://localhost:3000 || exit 1

# Define an entrypoint for default
ENTRYPOINT ["bundle", "exec"]

# Default command, running app as a service 
CMD ["bundle", "exec", "foreman", "start"]