FROM ruby:2.6.3
RUN apt-get update -qq && apt-get install -y nodejs postgresql-client
RUN mkdir /myapp
WORKDIR /myapp
COPY . /myapp
RUN gem update --system
RUN bundle install
RUN yarn install --check-files

# Add a script to be executed every time the container starts.
COPY entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/entrypoint.sh
ENTRYPOINT ["entrypoint.sh"]
EXPOSE 3000

# Start the main process.
CMD ["rails", "server", "-e", "production", "-b", "0.0.0.0"]
# Production
# CMD ["rails", "server", "-b", "0.0.0.0"]

#!/bin/bash
set -e

# Remove a potentially pre-existing server.pid for Rails.
rm -f /myapp/tmp/pids/server.pid

# Then exec the container's main process (what's set as CMD in the Dockerfile).
exec "$@"

version: '3'
services:
  db:
    image: postgres
    volumes:
      - ./tmp/db:/var/lib/postgresql/data
  web:
    build: .
    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/myapp
    ports:
      - "3000:3000"
    depends_on:
      - db

default: &default
  adapter: postgresql
  encoding: unicode
  host: db
  username: postgres
  password:
  pool: 5

development:
  <<: *default
  database: myapp_development


test:
  <<: *default
  database: myapp_test

docker-compose build
docker-compose up
docker-compose run web rake db:create
docker-compose run web rake db:migrate #or docker-compose run web rake db:create db:migrate

$ docker-compose up
Creating network "blog_default" with the default driver
Creating blog_db_1 ... done
Creating blog_web_1 ... done
Attaching to blog_db_1, blog_web_1
db_1   | 2019-06-28 03:09:42.063 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
db_1   | 2019-06-28 03:09:42.063 UTC [1] LOG:  listening on IPv6 address "::", port 5432
db_1   | 2019-06-28 03:09:42.113 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
db_1   | 2019-06-28 03:09:42.210 UTC [24] LOG:  database system was shut down at 2019-06-28 03:09:21 UTC
db_1   | 2019-06-28 03:09:42.242 UTC [1] LOG:  database system is ready to accept connections
web_1  | WARNING: Use strings for Figaro configuration. 305150117040730 was converted to "305150117040730".
web_1  | => Booting Puma
web_1  | => Rails 6.0.0.rc1 application starting in development 
web_1  | => Run `rails server --help` for more startup options
web_1  | Puma starting in single mode...
web_1  | * Version 3.12.1 (ruby 2.6.1-p33), codename: Llamas in Pajamas
web_1  | * Min threads: 5, max threads: 5
web_1  | * Environment: development
web_1  | * Listening on tcp://0.0.0.0:3000
web_1  | Use Ctrl-C to stop

$ docker-compose down
Stopping blog_db_1 ... done
Removing blog_web_run_1 ... done
Removing blog_db_1      ... done
Removing network blog_default

docker-compose run -e "RAILS_ENV=test" app rake test