Ruby on Rails Code Reading Part 1 - Rails Startup

This article was originally published on bmf-tech.com.

Overview

This is a record of the code reading process for Ruby on Rails.

Preparation

1. Create a new project with rails new RailsCodeReading.
2. Add the following to the Gemfile:

gem 'pg'
gem 'pry-rails'
gem 'pry-doc'
gem 'pry-byebug'
gem 'byebug'

1. Run bundle config set path '.bundle' and then execute bundle install.

Code Reading

Read the code up to the server execution part after executing the rails server command until Rails starts.

1. rails/rails - railties/lib/rails/commands/server/server_command.rb#L132
   • The actual server command
   • rails/rails - railties/lib/rails/commands/server/server_command.rb#L32
     • Server startup process
     • super() calls Rackup::Server's start
2. rails/rails - railties/lib/rails/rackup/server.rb#L8
   • Requires rackup/server
3. rack/rackup - lib/rackup/server.rb#L300
   • rack/rackup - lib/rackup/server.rb#L341
     • server.run calls the server startup process
4. puma/puma - lib/rack/handler/puma.rb#L67
   • The server called by server.run depends on the server used by the application
   • If using Puma, this run is called

References

• railsguides.jp - Rails Initialization Process