Environment construction of Rails5 + MySQL8.0 + top-level volumes with docker-compose

Rails5 + MySQL on Docker environment construction by too polite Docker-compose (Docker for Mac) It is almost the same content as. So if you want to know more, please go there. It's a little different, such as different versions of mysql and using top-level volumes.

environment

• MacOS 10.15.7
• Docker Desktop for Mac
• Ruby 2.7.1
• Rails 5.2.4.4
• MySQL 8.0.21

$ mkdir rails_docker
$ cd rails_docker

$ vi Dockerfile

Dockerfile

FROM ruby:2.7.1

RUN apt-get update -qq && \
    apt-get install -y build-essential \
                       libpq-dev \
                       nodejs \
    && rm -rf /var/lib/apt/lists/*

RUN mkdir /recruit_web
ENV APP_ROOT /recruit_web
WORKDIR $APP_ROOT

ADD ./Gemfile $APP_ROOT/Gemfile
ADD ./Gemfile.lock $APP_ROOT/Gemfile.lock

RUN bundle install
ADD . $APP_ROOT

$ vi Gemfile

Gemfile

source 'https://rubygems.org'
gem 'rails',  '~> 5.2.4', '>= 5.2.4.4'

$ touch Gemfile.lock

$ vi docker-compose.yml

docker-compose.yml

version: '3'
services:
  db:
    image: mysql:8.0.21
    volumes:
      - db_data:/var/lib/mysql
    networks:
      - rails_docker_network
    environment:
        MYSQL_DATABASE: root
        MYSQL_ROOT_PASSWORD: password
    # mysql8.0 authentication plugin(caching_sha2_password)Mysql_native_Change to password
    command: --default-authentication-plugin=mysql_native_password
    container_name: rails_db_container
  web:
    build: .
    depends_on:
      - db
    command: rails s -p 3000 -b '0.0.0.0'
    volumes:
      - .:/recruit_web
    networks:
      - rails_docker_network
    ports:
      - "3000:3000"
    container_name: rails_web_container

volumes:
  db_data:

networks:
  rails_docker_network:
    name: rails_docker_network

$ docker-compose run web rails new . --force --database=mysql --skip-bundle

$ vi /confing/database.yml

database.yml

default: &default
  adapter: mysql2
  encoding: utf8
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  username: root #add to
  password: password #add to
  host: db #add to

$ docker-compose build
$ docker-compose up -d

If you execute the following command, a database will be created and you can access it on localhost: 3000.

$ docker-compose run web rails db:create

Where it gets stuck

docker-compose.yml

version: '3'
services:
  db:
    image: mysql:8.0.21
    volumes:
      - db_data:/var/lib/mysql
    environment:
        MYSQL_DATABASE: root
        MYSQL_ROOT_PASSWORD: password
    #I got an error if I specified the following
    ports:
      - "3306:3306 

  web:
    build: .
    command: rails s -p 3000 -b '0.0.0.0'
    volumes:
      - .:/app_sample
    ports:
      - "3000:3000"
    #I got an error if I specified the following(not recommended+I didn't need it because the name would be resolved without it)
    links:
      - db

volumes:
  db_data:

For some reason, if you specify the public ports of links and db

Mysql2::Error::ConnectionError: Access denied for user 'root'@'172.19.0.4' (using password: YES)

I was angry and stumbled considerably. .. ..

For the time being, I realized that I didn't need the port and deleted it. It seems that links can be resolved even if it is not deprecated from the document, so delete it https://docs.docker.com/compose/networking/

I would appreciate if you could improve anything.