I tried to build a simple application using Dockder + Rails Scaffold

Introduction

How to build an application in Ruby on Rails using Docker-compose by referring to books, videos, and Qiita articles I had a hard time, so I tried various things and finally got it to work, so I will leave the final file and execution procedure.

Work procedure

File creation

Dockerfile
docker-compose.yml
Gemfile
Gemfile.lock

#Ruby in image name(Ver2.6.5)Specify the image of the execution environment of
FROM ruby:2.6.5

#Update the list of packages and install the packages required to build the rails environment
RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs

#Create a directory for your project
RUN mkdir /myapp

#Set to working directory
WORKDIR /myapp

#Copy to project directory
COPY Gemfile /myapp/Gemfile
COPY Gemfile.lock /myapp/Gemfile.lock

#Execute bundle install
RUN bundle install

#Copy all the contents of the build context to myapp
COPY . /myapp

docker-compose.yml

version: '3'
services:
  db:
    #Get image of postgres
    image: postgres
    environment:
      POSTGRES_USER: 'postgresql'
      POSTGRES_PASSWORD: 'postgresql-pass'
    restart: always
    volumes:
      - pgdatavol:/var/lib/postgresql/data
  web:
    #Build and use images from Dockerfile
    build: .
    #Executed when container starts
    command: bundle exec rails s -p 3000 -b '0.0.0.0'
    #Current directory/Bind mount to myapp
    volumes:
      - .:/myapp
    #Publish at 3000 and transfer to 3000 in container
    ports:
      - "3000:3000"
    #Start the db service before starting the web service
    depends_on:
      - db
#Create pgdatabol volume for data persistence and mount postgresql data area
volumes:
  pgdatavol:

source 'https://rubygems.org'
gem 'rails', '5.2.4.2'

Gemfile.lock

rails application creation

docker-compose run web rails new . --force --database=postgresql

Fixed database config file used for rails project

database.yml

default: &default
  adapter: postgresql
  encoding: unicode
  # --------add to--------
  host: db
  username: postgresql
  password: postgresql-pass
  # --------So far--------

Start in detach mode (background)

docker-compose up -d

What to do if bundle install is not reflected

docker-compose build --no-cache

Database creation command

docker-compose run web rails db:create

Create a simple application with Scaffold

docker-compose run web bin/rails g scaffold User name:string

docker-compose run web bin/rails db:migrate

http://localhost:3000/users

Reference URL

[I've just started Docker, so I've summarized it in an easy-to-understand manner](https://qiita.com/gold-kou/items/44860fbda1a34a001fc1#%E3%83%9B%E3%82%B9%E3%83%88% E5% 9E% 8B% E4% BB% AE% E6% 83% B3% E5% 8C% 96)

How to delete Docker image and container

[Creating a Docker container, starting and stopping](https://qiita.com/kooohei/items/0e788a2ce8c30f9dba53#5%E3%82%B3%E3%83%B3%E3%83%86%E3%83% 8A% E3% 81% AE% E5% 81% 9C% E6% AD% A2)

I should have bundle install in the image with Docker Compose + Rails, but I get an error if there is no gem.

Solution for Docker not bundle install in container