Rails Quickstart for container hosting

Ref https://github.com/KarmaComputing/container-hosting

Create a new controller

Note, use docker-compose exec app /usr/src/app/app/bin/rails not bin/rails generate. This is because you want to run the command inside your container, not on your host. This means you don't need ruby installed on your local laptop, which means no version mismatch issues!

This is based on the [official Ruby guide](See https://guides.rubyonrails.org/getting_started.html#say-hello-rails).

docker-compose exec app /usr/src/app/app/bin/rails generate controller Articles index --skip-routes

Generate a model (database table)

Official guide

docker-compose exec app /usr/src/app/app/bin/rails generate model Article title:string body:text

Expected output:

(main)$ docker-compose exec app /usr/src/app/app/bin/rails generate model Article title:string body:text
      invoke  active_record
      create    db/migrate/20220731172200_create_articles.rb
      create    app/models/article.rb
      invoke    test_unit
      create      test/models/article_test.rb
      create      test/fixtures/articles.yml

Correct permissions:

sudo chown -R $USER:$USER app/*

Run the database migration(s)

docker-compose exec -w /usr/src/app/app app /usr/src/app/app/bin/rails db:migrate

Expected output:

== 20220731172200 CreateArticles: migrating ===================================
-- create_table(:articles)
   -> 0.0296s
== 20220731172200 CreateArticles: migrated (0.0297s) ==========================

Enter the rails console

docker-compose exec -w /usr/src/app/app app /usr/src/app/app/bin/rails console

Expected output:

Loading development environment (Rails 7.0.3.1)
irb(main):001:0>

Create/Insert an article

irb> article = Article.new(title: "Hello Rails", body: "I am on Rails!")

Expected output:

irb(main):002:0> article.save
  TRANSACTION (0.2ms)  begin transaction
  Article Create (0.9ms)  INSERT INTO "articles" ("title", "body", "created_at", "updated_at") VALUES (?, ?, ?, ?)  [["title", "Hello Rails"], ["body", "I am on Rails!"], ["created_at", "2022-07-31 19:02:48.402426"], ["updated_at", "2022-07-31 19:02:48.402426"]]                                                          
  TRANSACTION (9.8ms)  commit transaction                       
=> true                                                         
irb(main):003:0>

You can also do:

irb(main):007:0> Article.find(1)

irb(main):007:0> Article.all()

Display all articles in the template (templates)

Official docs

In your file: app/controllers/articles_controller.rb:

class ArticlesController < ApplicationController
  def index
    @articles = Article.all
  end
end

In your file: app/views/articles/index.html.erb

<h1>Articles</h1>

<ul>
  <% @articles.each do |article| %>
    <li>
      <%= article.title %>
    </li>
  <% end %>
</ul>