Rails environment construction with Docker (personal apocalypse)

Creating a Dockerfile

-#Build context
% mkdir product-register
% cd product-register
-#Gemfile and Gemfile.Creating a lock
% touch Gemfile Gemfile.lock
-#Editing Gemfile
% vim Gemfile

product-register/Gemfile

source 'https://rubygems.org'
gem 'rails', '~>5.2'

-#Editing the Dockerfile
% vim Dockerfile

product-register/Dockerfile

FROM ruby:2.5
RUN apt-get update && apt-get install -y && \
    buile-essential \
    libpq-dev \
    nodejs \
    postgresql-client \
    yarn
WORKDIR /product-register
COPY Gemfile Gemfile.lock /product-register/
RUN bundle install

-#Creating a container
% docker build .

Description of docker-compose.yml

-# docker-compose.edit yml
% vim docker-compose.yml

docker-compose.yml

version: '3'

services:
  web:
    build: .
    ports:
      - '3000:3000'
    volumes:
      - '.:/product-register'
    tty: true
    stdin_open: true

-#Container launch
% docker-compose up -d
-#When working inside a container
% docker-compose exec web bash

Rails setup

-#Since application creation, DB setting, and bundle are done with Dockerfile — skip
# rails new . —force —database=postgresql —skip-bundle
-#Confirm that the contents of Gemfile have changed on the host side
% cat Gemfile
-#I need to bundle install, so stop once
# exit
$ docker-compose down
-# docker-If you do compose up, the previous image will be used, so build again
$ docker-compose up —build -d
% docker-compose exec web bash
-#Start rails server
$ rails s -b 0.0.0.0

I can connect with localhost: 3000, but I get an error page because I have not set the DB.

DB setup

config/database.yml

default: &default
  adapter: postgresql
  encoding: unicode
  host: db
  user: postgres
  port: 5432
  password: <%= ENV.fetch("DATABASE_PASSWORD") %>
  # For details on connection pooling, see Rails configuration guide
  # http://guides.rubyonrails.org/configuring.html#database-pooling
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

Since it is not desirable to write Password directly for security reasons, call it with an environment variable.

Modify docker-compose.yml

docker-compose.yml

version: '3'
#docker volume Data is saved here
volumes: 
  db-data:

services:
  web:
    build: .
    ports:
      - '3000:3000'
    volumes:
      - '.:/product-register'
#Environment variable settings of the container, originally the password should not be written directly.
    environment:
      - 'DATABASE_PASSWORD=postgres'
    tty: true
    stdin_open: true
#Created once the db service is created
    depends_on:
      - db
#You can access db from the web
    links:
      - db
#postgres container
  db:
    image: postgres
#Host db-Store data in data
    volumes:
      - 'db-data:/var/lib/postgresql/data'
    environment:
      - 'POSTGRES_USER=postgres'
      - 'POSTGRES_PASSWORD=postgres'

Start with docker-compose

% docker-compose up -d
-#You can see that the two services are running
Creating product-register_db_1 ... done
Recreating product-register_web_1 ... done
% docker-compose exec web bash
-#DB creation
# rails db:create
Created database 'product-register_development'
Created database 'product-register_test'

You can see that the database has been created. From here you can create Rails apps.

Make an app and check the operation

-#Make a simple app with scaffold
# rails g scaffold product name:string price:integer vender:string
-#Define the created table
# rails db:migrate
-#Start the server
# rails s -b 0.0.0.0

You can connect with localhost: 3000 and you can see that the rails page is displayed. You can connect to apps made with localhost: 3000 / products.