[Override Dockerfile / Gemfile for local development] # Add the following files to your project root

0_README.md

Key points

• Run docker compose run web bundle && docker compose build to update your Gemfile.lock before building the image
• Gemfile.dev should be nearly identical to Gemfile but also contain development gems such as 'debug' and 'solargraph-rails'
• Dockerfile.dev should be nearly identical to Dockerfile, except for the FROM image version, COPY Gemfile.dev Gemfile, COPY Gemfile.lock Gemfile.lock, and possibly using the root user
• Remember to revert your Gemfile.lock before committing, e.g. git checkout develop -- Gemfile.lock

docker-compose.override.yml

# Use Dockerfile.dev to upgrade Ruby and Gemfile.dev to add local dev gems such as 'debug' and 'solargraph-rails'

services:
  web:
    build:
      context: .
      dockerfile: Dockerfile.dev
    volumes:
      - .:/app
      - ./Gemfile.dev:/app/Gemfile

Dockerfile.dev

# ! DEV ONLY - UPGRADE RUBY
ARG RUBY_VERSION=2.7.8

# Server setup
FROM ruby:${RUBY_VERSION} as base
WORKDIR /app
RUN apt-get update -qq
RUN apt-get install --no-install-recommends -y --allow-downgrades \
    build-essential \
    libpq-dev \
    netcat \
    less

RUN apt-get purge -y --auto-remove
RUN rm -rf /var/lib/apt/lists/*

# Prep for gem installation
# NOTE: The following `gem update` command is necessary to avoid a RubyGems warning.
#       Also Bundler v2.3.26 is the last version that works with Ruby 2.5.
#       When Ruby gets upgraded, the following command can change to: `RUN gem install bundler`
RUN gem update --system 3.2.3 && gem install bundler -v 2.3.26

# App build
FROM base as gemset

# ! DEV ONLY - USE Gemfile.dev TO INSTALL DEBUGGER
COPY Gemfile.dev Gemfile
COPY Gemfile.lock Gemfile.lock

RUN bundle update --bundler && bundle install

# App env setup
FROM base
ENV LANG=C.UTF-8 LC_ALL=C.UTF-8
ENV RACK_ENV=development
COPY --from=gemset /usr/local/bundle /usr/local/bundle
COPY . .

EXPOSE 3000/tcp

CMD ["bundle", "exec", "rails", "s",  "-p",  "3000",  "-b", "0.0.0.0"]

Gemfile.dev

# frozen_string_literal: true

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '3.1.2'

# Bundle edge Rails instead: gem "rails", github: "rails/rails", branch: "main"
gem 'rails', '~> 7.0.4'

# Use mysql as the database for Active Record
gem 'mysql2', '~> 0.5'

# Use the Puma web server [https://github.com/puma/puma]
gem 'puma', '~> 5.0'

# Build JSON APIs with ease [https://github.com/rails/jbuilder]
# gem "jbuilder"

# Use Redis adapter to run Action Cable in production
# gem "redis", "~> 4.0"

# Use Kredis to get higher-level data types in Redis [https://github.com/rails/kredis]
# gem "kredis"

# Use Active Model has_secure_password [https://guides.rubyonrails.org/active_model_basics.html#securepassword]
# gem "bcrypt", "~> 3.1.7"

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: %i[mingw mswin x64_mingw jruby]

# Reduces boot times through caching; required in config/boot.rb
gem 'bootsnap', require: false

# Use Active Storage variants [https://guides.rubyonrails.org/active_storage_overview.html#transforming-images]
# gem "image_processing", "~> 1.2"

# Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin AJAX possible
# gem "rack-cors"

# Enable JSON API serialization
gem 'active_model_serializers'

group :development, :test do
  gem 'byebug'

  # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem
  gem 'debug', platforms: %i[mri mingw x64_mingw] # ! DEV ONLY

  gem 'rspec-rails'
  gem 'rubocop-rails'
end

group :development do
  gem 'solargraph-rails' # ! DEV ONLY

  # Speed up commands on slow machines / big apps [https://github.com/rails/spring]
  # gem "spring"
end

group :test do
  gem 'factory_bot_rails'
  gem 'faker'
end