Rails Docker Base

This is a template for creating Docker based Rails development environments.

Get Started

docker-compose run --no-deps rails rails new . --skip-spring --skip-bootsnap --database=postgresql

Select n when asked to override the README.md and Gemfile:

	exist
	conflict  README.md
Overwrite /usr/src/app/README.md? (enter "h" for help) [Ynaqdhm] n
	skip  README.md
	create  Rakefile
	create  .ruby-version
	create  config.ru
	create  .gitignore
	conflict  Gemfile
Overwrite /usr/src/app/Gemfile? (enter "h" for help) [Ynaqdhm] n

Setup

Database

Update the config/database.yml with the correct database credientials and create the database, and create the database within the database container using the connection details provided. Please note the host field is set to db, the database container name:

adapter: mysql2
encoding: utf8mb4
pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
username: root
password: root
host: database

Gems

Add the Gems you want, ie:

gem "anycable-rails", "~> 1.0"
gem "connection_pool"
gem "hiredis"
gem 'redis', '~> 4.0', require: ["redis", "redis/connection/hiredis"]
gem "sidekiq"
gem "stimulus_reflex"

group :development, :test do
	gem 'pry-byebug'
end

Note, you will have to run docker-compose up --build after adding Gems. If the container is running you can run docker-compose exec rails bundle install

Sidekiq

Update the sidekiq.yml with any additionally required queues:

---
:concurrency: 5
staging:
	:concurrency: 10
production:
	:concurrency: 20
:queues:
	- critical
	- default
	- low

Action Cable

Add the following to your application.html.erb

<%= action_cable_meta_tag %>

By default this is set to async, however a Redis server is available, and required if you wish to send broadcasts outside the local process, from the rails console for instance.

Change ACTION_CABLE_ADAPTER to redis.

AnyCable

Setup AnyCable by running the following command:

docker-compose run --no-deps rails rails g anycable:setup

👋 Welcome to AnyCable interactive installer.
  conflict  config/cable.yml
Overwrite /usr/src/app/config/cable.yml? (enter "h" for help) [Ynaqdhm] y
	 force  config/cable.yml
	create  config/anycable.yml
	  info  ✅ 'config.action_cable.url' has been configured

You can skip the rest of the installation. Inside of anycable.yml change rpc_host: "127.0.0.1:50051" to rpc_host: "0.0.0.0:50051"

Searchkick

If you are using Searchkick, add the initialier to config/initializers/searchkick.rb and add the following:

Searchkick.client = Elasticsearch::Client.new(hosts: ["elasticsearch:9200"], retry_on_failure: true)

Vips

Vips is installed on the image, to test Vips, go into the rails container docker-compose exec rails bash, then move to the public directory cd /usr/src/app/public. If you add an image file here, for example called "1.jpg", then you can use the following to rotate it 90 degrees and save it as "2.jpg", vips rot 1.jpg 2.jpg d90.

Development Web Console

To get the web console working from within the Docker container, add the following to your application.rb

config.web_console.whitelisted_ips = ['172.16.0.0/12', '192.168.0.0/16']

Adding Yarn/NPM packages

To add new packages with Yarn, use the following on the command line:

docker-compose exec rails yarn add <package>

Finalising the container

The container was built during the run process which created the Rails app, but we need to bring them up and copy all the new Gems and Node packages over:

docker-compose up --build

Changing Rails configuration

If you wish to make changes to Rails configuration files, use:

docker-compose stop rails
docker-compose start rails

This will bring the container up in the background with the new configuration.

Executing commands

To execute a command on a running container, use the following command:

# docker-compose exec <container_name> <command>
docker-compose exec rails rails db:migrate

Debugging

Byebug/Pry wont work within a normally running container, to get around this, you can start the containers in the background with the -d flag, then manually attach to the running rails container:

docker-compose up -d; docker attach rails_docker_base_rails_1