Docker basics for Ruby on Rails

docker-compose.yml

version: '3.8'
services:
  db:
    image: postgres:latest
    restart: always
    environment: 
      - POSTGRES_PASSWORD=password
    ports:
      - "5432:5432"
    volumes: 
      - "dbdata:/var/lib/postgresql/data"

  redis:
    image: redis:latest
    ports:
      - "6379:6379"
      
  web:
    build: .
    ports: 
      - "3000:3000"
    depends_on: 
      - db
      - redis
    environment: 
      - DATABASE_URL=postgres://postgres:password@db:5432/postgres
      - REDIS_URL=redis://redis:6379
    volumes: 
      - .:/app

volumes: 
  dbdata:

Dockerfile

FROM ruby:3.0.0-alpine

RUN apk add --update --virtual \
  runtime-deps \
  postgresql-dev \
  postgresql-client \
  build-base \
  libxml2-dev \
  libxslt-dev \
  nodejs \
  yarn \
  libffi-dev \
  readline \
  libc-dev \
  linux-headers \
  readline-dev \
  file \
  imagemagick \
  git \
  tzdata && rm -rf /var/cache/apk/*

WORKDIR /app
COPY . /app/

ENV BUNDLE_PATH /gems

RUN yarn install
RUN bundle install

ENTRYPOINT [ "bin/rails" ]
EXPOSE 3000

CMD [ "s", "-b", "0.0.0.0" ]