Building Rails 6 and PostgreSQL environment with Docker

Build environment with Rails6 + PostgreSQL with Docker

As a memorandum of my own, I will leave an article on how to build an environment with Rails 6 + PostgreSQL with Docker. This time, we will create the app name as shopping_app.

Each version of the environment to create

• Ruby 2.7.2
• Rails 6.0.3
• PostgreSQL 13.0

Directory structure

 .
 ├── Dockerfile
 ├── docker-compose.yml
 └── shopping_app
     ├── Gemfile
     └── Gemfile.lock

Creating a Dockerfile

First, create a Dockerfile.

FROM ruby:2.7.2
ENV LANG C.UTF-8


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

RUN apt-get update -qq && \
    apt-get install -y build-essential \
            libpq-dev \
            nodejs \
            postgresql-client yarn

RUN mkdir /app
RUN mkdir /app/shopping_app

ENV APP_ROOT /app/shopping_app
WORKDIR $APP_ROOT

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

RUN bundle install

ADD . $APP_ROOT

Create docker-compose.yml

Create docker-compose.yml. This time the port is set to 1501.

version: '3'
services:
  postgres:
    image: postgres
    ports:
      - "3306:3306"
    volumes:
      - ./tmp/db:/var/lib/postgresql/data #For MacOS
    environment:
      POSTGRES_USER: 'admin'
      POSTGRES_PASSWORD: 'admin-pass'
    restart: always
  app:
    build: .
    image: rails
    container_name: 'app'
    command: bundle exec rails s -p 1501 -b '0.0.0.0'
    ports:
      - "1501:1501"
    environment:
      VIRTUAL_PORT: 80
    volumes:
      - ./shopping_app:/app/shopping_app
    depends_on:
      - postgres
    restart: always

volumes:
  app_postgre:
    external: true

Creating a Gemfile

source 'https://rubygems.org'
gem 'rails', '6.0.3'

You can leave Gemfile.lock empty.

Build container to create app

$ docker-compose run app rails new . --force --database=postgresql --skip-bundle

webpacker install

docker-compose run app rails webpacker:install

Database creation and configuration

Set the database.yml of the created app.

default: &default
  adapter: postgresql
  encoding: unicode
  # For details on connection pooling, see Rails configuration guide
  # https://guides.rubyonrails.org/configuring.html#database-pooling
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  #Describe the following
  user: admin
  password: admin-pass
  host: postgres

build image

docker-compose build

Creating Database

docker-compose run app rails db:create

This completes the construction. Launch the app with the following command

docker-compose up

http://localhost:1501/ If you access, it will be displayed on the following screen.

that's all.