[RUBY] Rails API server environment construction using docker-compose

About the author

I went through Progate's Ruby and Rails courses. After that, I made an environment with Docker and made an API server with Rails.

About this article

At Progate I learned how to write rails including views, but I wanted to use Rails only as an API server. Also, since I wanted to develop with docker, I created a Rails development environment by referring to the official Quick Start. Summarize the know-how gained in the process.

I will write about Gem used in API server development in another article.

Premise

Understand how to use Docker and docker-compose

environment

Ruby 2.7 MySQL 5.7 VSCode Mac 10.14.5 For viewing the Sequel Pro database

Until Rails new

First, create a project folder. Here, it is rails-sample. And create a Dockerfile directly under this

FROM ruby:2.7

RUN apt-get update -qq && apt-get install -y
RUN mkdir /myapp
WORKDIR /myapp
COPY Gemfile /myapp/Gemfile
COPY Gemfile.lock /myapp/Gemfile.lock
RUN bundle install

# Add a script to be executed every time the container starts.
COPY entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/entrypoint.sh
ENTRYPOINT ["entrypoint.sh"]

Next, prepare a Gemfile to install rails

source 'https://rubygems.org'
gem 'rails', '~>5'

Create an empty Gemfile.lock

touch Gemfile.lock

Create ʻentrypoint.sh` described in Dockerfile

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 "$@"

See Docker Official Quick Start for why these files are created.

Create docker-compose.yml

docker-compose.yml

version: '3'
services:
  server:
    build: .
    tty: true
    volumes:
      - .:/myapp
    working_dir: /myapp
    ports:
      - "3000:3000"
    depends_on:
      - mysql
    command: bash
    # command: > 
    #   bash -c "rm -f tmp/pids/server.pid &&
    #       bundle exec rails s -p 3000 -b '0.0.0.0'"
  mysql:
    image: mysql:5.7
    ports:
      - "3306:3306"
    environment:
      MYSQL_ROOT_PASSWORD: mysql
    volumes:
      - "./mysql/db-data/:/var/lib/mysql" #Data persistence
      - "./mysql/my.cnf:/etc/mysql/conf.d/my.cnf" #Necessary to use Japanese as data

For MySQL data persistence and Japanese support

Create rails-sample> mysql> db-data folder. Create my.cnf under mysql folder

my.cnf

[mysqld]
character-set-server=utf8

Up to this point, this is the configuration.

If you can do that, do rails new.

docker-compose run server rails new . -MC --force --api --database=mysql --skip-active-storage

Look up the options in the rails command and command help, and omit the ones you don't think you need. The important options are:

--force //Overwrite files on rails new
--api //Do not generate unnecessary views for api development
--database=myql //The default is sqlite, but specify mysql

You can make various things with this.

So, here, Gemfile and Gemfile.lock are overwritten and new. In order to reflect this in the image

docker-compose build

There is a need to.

If you know the gem you need in advance, write it in the Gemfile here.

This completes rails new

Write a configuration file to connect to mysql.

config > database.yml

database.yml

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

development:
  <<: *default
  host: mysql
  database: myapp_development

...
test:
  <<: *default
  host: mysql
  database: myapp_test

Since production is unnecessary, I commented it out completely The host name is the service name of docker-compose.yml password is also specified in docker-compose.yml

If you can, start the container with docker-compose up -d and go inside with VS Code's Attach Shell.

rails db:create

Create a DB with

root@dc075120af8a:/myapp# rails db:create
...
Created database 'myapp_development'
Created database 'myapp_test'

Now you have a database. If you connect with Sequel Pro, you can confirm that the database is created

After that, as you learned in Progate, you can create a table by creating a model and migrating.

reference

Docker Official Quick Start English Please note that the content is old in Japanese.

Rails Guide API-only application by Rails