Rails 初始化过程

#!/usr/bin/env ruby
APP_PATH = File.expand_path("../config/application", __dir__)
require_relative "../config/boot"
require "rails/commands"

ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../Gemfile", __dir__)

require "bundler/setup" # Set up gems listed in the Gemfile.
require "bootsnap/setup" # Speed up boot time by caching expensive operations.

require "rails/command"

aliases = {
  "g"  => "generate",
  "d"  => "destroy",
  "c"  => "console",
  "s"  => "server",
  "db" => "dbconsole",
  "r"  => "runner",
  "t"  => "test"
}

command = ARGV.shift
command = aliases[command] || command

Rails::Command.invoke command, ARGV

module Rails
  module Command
    class << self
      def invoke(full_namespace, args = [], **config)
        args = ["--help"] if rails_new_with_no_path?(args)

        full_namespace = full_namespace.to_s
        namespace, command_name = split_namespace(full_namespace)
        command = find_by_namespace(namespace, command_name)

        with_argv(args) do
          if command && command.all_commands[command_name]
            command.perform(command_name, args, config)
          else
            invoke_rake(full_namespace, args, config)
          end
        end
      rescue UnrecognizedCommandError => error
        if error.name == full_namespace && command && command_name == full_namespace
          command.perform("help", [], config)
        else
          puts error.detailed_message
        end
        exit(1)
      end
    end
  end
end

module Rails
  module Command
    class ServerCommand < Base # :nodoc:
      def perform
        set_application_directory!
        prepare_restart

        Rails::Server.new(server_options).tap do |server|
          # Require application after server sets environment to propagate
          # the --environment option.
          require APP_PATH
          Dir.chdir(Rails.application.root)

          if server.serveable?
            print_boot_information(server.server, server.served_url)
            after_stop_callback = -> { say "Exiting" unless options[:daemon] }
            server.start(after_stop_callback)
          else
            say rack_server_suggestion(options[:using])
          end
        end
      end
    end
  end
end

module Rails
  class Server < Rackup::Server
    def initialize(options = nil)
      @default_options = options || {}
      super(@default_options)
      set_environment
    end
  end
end

module Rackup
  class Server
    def initialize(options = nil)
      @ignore_options = []

      if options
        @use_default_options = false
        @options = options
        @app = options[:app] if options[:app]
      else
        @use_default_options = true
        @options = parse_options(ARGV)
      end
    end
  end
end

module Rails
  module Command
    class ServerCommand < Base # :nodoc:
      no_commands do
        def server_options
          {
            user_supplied_options: user_supplied_options,
            server:                options[:using],
            log_stdout:            log_to_stdout?,
            Port:                  port,
            Host:                  host,
            DoNotReverseLookup:    true,
            config:                options[:config],
            environment:           environment,
            daemonize:             options[:daemon],
            pid:                   pid,
            caching:               options[:dev_caching],
            restart_cmd:           restart_command,
            early_hints:           early_hints
          }
        end
      end
    end
  end
end

module Rails
  module Server
    def set_environment
      ENV["RAILS_ENV"] ||= options[:environment]
    end
  end
end

module Rails
  class Server < ::Rackup::Server
    def start(after_stop_callback = nil)
      trap(:INT) { exit }
      create_tmp_directories
      setup_dev_caching
      log_to_stdout if options[:log_stdout]

      super()
      # ...
    end

    private
      def setup_dev_caching
        if options[:environment] == "development"
          Rails::DevCaching.enable_by_argument(options[:caching])
        end
      end

      def create_tmp_directories
        %w(cache pids sockets).each do |dir_to_make|
          FileUtils.mkdir_p(File.join(Rails.root, "tmp", dir_to_make))
        end
      end

      def log_to_stdout
        wrapped_app # touch the app so the logger is set up

        console = ActiveSupport::Logger.new(STDOUT)
        console.formatter = Rails.logger.formatter
        console.level = Rails.logger.level

        unless ActiveSupport::Logger.logger_outputs_to?(Rails.logger, STDERR, STDOUT)
          Rails.logger.broadcast_to(console)
        end
      end
  end
end

module Rackup
  class Server
    def start(&block)
      if options[:warn]
        $-w = true
      end

      if includes = options[:include]
        $LOAD_PATH.unshift(*includes)
      end

      Array(options[:require]).each do |library|
        require library
      end

      if options[:debug]
        $DEBUG = true
        require "pp"
        p options[:server]
        pp wrapped_app
        pp app
      end

      check_pid! if options[:pid]

      # Touch the wrapped app, so that the config.ru is loaded before
      # daemonization (i.e. before chdir, etc).
      handle_profiling(options[:heapfile], options[:profile_mode], options[:profile_file]) do
        wrapped_app
      end

      daemonize_app if options[:daemonize]

      write_pid if options[:pid]

      trap(:INT) do
        if server.respond_to?(:shutdown)
          server.shutdown
        else
          exit
        end
      end

      server.run(wrapped_app, **options, &block)
    end
  end
end

module Rackup
  class Server
    def wrapped_app
      @wrapped_app ||= build_app app
    end
  end
end

module Rackup
  class Server
    def app
      @app ||= options[:builder] ? build_app_from_string : build_app_and_options_from_config
    end

    # ...

    private
      def build_app_and_options_from_config
        if !::File.exist? options[:config]
          abort "configuration #{options[:config]} not found"
        end

        Rack::Builder.parse_file(self.options[:config])
      end

      def build_app_from_string
        Rack::Builder.new_from_string(self.options[:builder])
      end
  end
end

# This file is used by Rack-based servers to start the application.

require_relative "config/environment"

run Rails.application
Rails.application.load_server

module Rack
  class Builder
    def self.load_file(path, **options)
      # ...
      new_from_string(config, path, **options)
    end

    # ...

    def self.new_from_string(builder_script, path = "(rackup)", **options)
      builder = self.new(**options)

      # We want to build a variant of TOPLEVEL_BINDING with self as a Rack::Builder instance.
      # We cannot use instance_eval(String) as that would resolve constants differently.
      binding = BUILDER_TOPLEVEL_BINDING.call(builder)
      eval(builder_script, binding, path)

      builder.to_app
    end
  end
end

require_relative "config/environment"

require_relative "application"

require_relative "boot"

require "rails/all"

require "rails"

%w(
  active_record/railtie
  active_storage/engine
  action_controller/railtie
  action_view/railtie
  action_mailer/railtie
  active_job/railtie
  action_cable/engine
  action_mailbox/engine
  action_text/engine
  rails/test_unit/railtie
).each do |railtie|
  begin
    require railtie
  rescue LoadError
  end
end

def initialize!(group = :default) # :nodoc:
  raise "Application has been already initialized." if @initialized
  run_initializers(group, self)
  @initialized = true
  self
end

def run_initializers(group = :default, *args)
  return if instance_variable_defined?(:@ran)
  initializers.tsort_each do |initializer|
    initializer.run(*args) if initializer.belongs_to?(group)
  end
  @ran = true
end

module Rackup
  class Server
    def app
      @app ||= options[:builder] ? build_app_from_string : build_app_and_options_from_config
    end

    # ...

    private
      def build_app_and_options_from_config
        if !::File.exist? options[:config]
          abort "configuration #{options[:config]} not found"
        end

        Rack::Builder.parse_file(self.options[:config])
      end

      def build_app_from_string
        Rack::Builder.new_from_string(self.options[:builder])
      end
  end
end

module Rackup
  class Server
    private
      def build_app(app)
        middleware[options[:environment]].reverse_each do |middleware|
          middleware = middleware.call(self) if middleware.respond_to?(:call)
          next unless middleware
          klass, *args = middleware
          app = klass.new(app, *args)
        end
        app
      end
  end
end

server.run(wrapped_app, **options, &block)

module Rack
  module Handler
    module Puma
      # ...
      def self.run(app, options = {})
        conf = self.config(app, options)

        log_writer = options.delete(:Silent) ? ::Puma::LogWriter.strings : ::Puma::LogWriter.stdio

        launcher = ::Puma::Launcher.new(conf, log_writer: log_writer, events: @events)

        yield launcher if block_given?
        begin
          launcher.run
        rescue Interrupt
          puts "* Gracefully stopping, waiting for requests to finish"
          launcher.stop
          puts "* Goodbye!"
        end
      end
      # ...
    end
  end
end