[RAILS] Docker environment construction

Docker environment construction

I had a hard time with meta meta, so I will leave it as a memo Also, docker's Official is the strongest There are many parts that I do not fully understand, so I would appreciate it if you could tell me any descriptions that should be corrected. rails 6 MySQL

procedure

Generate a directory with any name in any directory

As it is

Generation and description of Dockerfile

Move to the directory generated above in the terminal

Terminal

% touch Dockerfile

Dockerfile

FROM ruby:2.6.5
RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - \
    && echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list \
    && apt-get update -qq \
    && apt-get install -y nodejs yarn \
    && mkdir /myapp
WORKDIR /myapp
COPY Gemfile /myapp/Gemfile
COPY Gemfile.lock /myapp/Gemfile.lock
RUN bundle install
COPY . /myapp

COPY entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/entrypoint.sh
ENTRYPOINT ["entrypoint.sh"]
EXPOSE 3000

CMD ["rails", "server", "-b", "0.0.0.0"]

Gemfile settings / description

Terminal

% touch Gemfile

Gemfile

source 'https://rubygems.org'
gem 'rails', '~>6'

Generating Gemfile.lock

Terminal

% touch Gemfile.lock

The contents can be empty

Generation / description of entrypoint.sh

Terminal

% touch entrypoint.sh

entrypoint.sh

#!/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 "$@"

Generate and describe docker-compose.yml

Terminal

% touch docker-compose.yml

docker-compose.yml

version: '3'
services:
  db:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: password
    ports:
      - '3306:3306'
    command: --default-authentication-plugin=mysql_native_password
    volumes:
      - mysql-data:/var/lib/mysql
  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
    stdin_open: true
    tty: true
volumes:
  mysql-data:
    driver: local

Rails application generation

Terminal

docker-compose run --no-deps web rails new . --force --database=mysql

Modify database.yml

config/database.yml

default: &default
  adapter: mysql2
  encoding: utf8mb4
  pool: 5
  username: root
  password: password
  host: db

development:
  <<: *default
  database: myapp_development

test:
  <<: *default
  database: myapp_test

Rebuild Docker

It is necessary to execute this command when writing in Gemfile and Dockerfile

Terminal

% docker-compose build

Creating a database

Terminal

% docker-compose run web rails db:create

Launch the app

Terminal

% docker-compose up

Complete if the welcome page is always displayed on localhost: 3000 You may be required to install webpacker etc. on the way