rails, rack, unicorn or puma, nginx の関係についてちゃんと理解したい

だいぶメモ書きです。

表題の件、まだ曖昧にしか理解できてない。

ググっても浅い情報しか出てこないし、各ライブラリのソースコードを読んでみたけどどう繋がってるか、それぞれどんな役割を担っているか把握するのムズいなぁ…。

結論

色々調べてここまで分かった。

「クライアント側 nginx <-> puma or unicorn <-> rack <-> rails DB 側」的な感じ
rails（や sinatra）はつまるところ rack の仕様に沿って env（HTTPリクエスト）をもらって [status, headers, body]（HTTP レスポンス）を返すだけのプログラムである

rack

HTTP server としてのインターフェースを提供する。 #call とか。

Rackとは何か - Qiita

rails

rack アプリケーション。 rack の仕様に沿った #call を実装する。

とりあえず actionpack の Action Dispatch でリクエストをさばき、 Action Controller でレスポンスを生成していく感じなのかな？

Response#rack_response でレスポンス生成してる？

ちなみに以下のようなコードを差し込んだ時のログはこんな感じ。

class HogeController < ApplicationController
  def index
    caller.each{ |line| p line}
    ...
  end
end

ログ

Started GET "/" for 127.0.0.1 at 2019-09-17 11:10:00 +0900
Processing by WelcomeController#index as HTML
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/abstract_controller/base.rb:194:in `process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_controller/metal/rendering.rb:30:in `process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/abstract_controller/callbacks.rb:42:in `block in process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/callbacks.rb:132:in `run_callbacks'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/abstract_controller/callbacks.rb:41:in `process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_controller/metal/rescue.rb:22:in `process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/notifications.rb:168:in `block in instrument'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/notifications/instrumenter.rb:23:in `instrument'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/notifications.rb:168:in `instrument'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_controller/metal/instrumentation.rb:32:in `process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_controller/metal/params_wrapper.rb:256:in `process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activerecord-5.2.0/lib/active_record/railties/controller_runtime.rb:24:in `process_action'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/abstract_controller/base.rb:134:in `process'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionview-5.2.0/lib/action_view/rendering.rb:32:in `process'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_controller/metal.rb:191:in `dispatch'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_controller/metal.rb:252:in `dispatch'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/routing/route_set.rb:52:in `dispatch'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/routing/route_set.rb:34:in `serve'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/journey/router.rb:52:in `block in serve'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/journey/router.rb:35:in `each'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/journey/router.rb:35:in `serve'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/routing/route_set.rb:840:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/omniauth-1.8.1/lib/omniauth/strategy.rb:190:in `call!'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/omniauth-1.8.1/lib/omniauth/strategy.rb:168:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/omniauth-1.8.1/lib/omniauth/builder.rb:63:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/tempfile_reaper.rb:15:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/etag.rb:25:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/conditional_get.rb:25:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/head.rb:12:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/http/content_security_policy.rb:18:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/session/abstract/id.rb:232:in `context'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/session/abstract/id.rb:226:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/cookies.rb:670:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activerecord-5.2.0/lib/active_record/migration.rb:559:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/callbacks.rb:98:in `run_callbacks'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/callbacks.rb:26:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/executor.rb:14:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/debug_exceptions.rb:61:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/web-console-3.6.2/lib/web_console/middleware.rb:135:in `call_app'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/web-console-3.6.2/lib/web_console/middleware.rb:30:in `block in call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/web-console-3.6.2/lib/web_console/middleware.rb:20:in `catch'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/web-console-3.6.2/lib/web_console/middleware.rb:20:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/railties-5.2.0/lib/rails/rack/logger.rb:38:in `call_app'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/railties-5.2.0/lib/rails/rack/logger.rb:26:in `block in call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/tagged_logging.rb:71:in `block in tagged'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/tagged_logging.rb:28:in `tagged'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/tagged_logging.rb:71:in `tagged'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/railties-5.2.0/lib/rails/rack/logger.rb:26:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/sprockets-rails-3.2.1/lib/sprockets/rails/quiet_assets.rb:13:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/remote_ip.rb:81:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/request_id.rb:27:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/method_override.rb:22:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/runtime.rb:22:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.0/lib/active_support/cache/strategy/local_cache_middleware.rb:29:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/executor.rb:14:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.0/lib/action_dispatch/middleware/static.rb:127:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/rack-2.0.5/lib/rack/sendfile.rb:111:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/railties-5.2.0/lib/rails/engine.rb:524:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/puma-3.11.4/lib/puma/configuration.rb:225:in `call'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/puma-3.11.4/lib/puma/server.rb:632:in `handle_request'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/puma-3.11.4/lib/puma/server.rb:446:in `process_client'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/puma-3.11.4/lib/puma/server.rb:306:in `block in run'"
"/Users/daidoshota/training/perfect_rails_awesome_events/vendor/bundle/ruby/2.5.0/gems/puma-3.11.4/lib/puma/thread_pool.rb:120:in `block in spawn_thread'"
  Rendering welcome/index.html.erb within layouts/application
  Event Load (3.2ms)  SELECT "events".* FROM "events" WHERE (start_time > '2019-09-17 02:10:00.146381') ORDER BY "events"."start_time" ASC
  ↳ app/views/welcome/index.html.erb:6
  Rendered welcome/index.html.erb within layouts/application (17.7ms)
Completed 200 OK in 96ms (Views: 70.1ms | ActiveRecord: 13.1ms)

ラストが actionpack/lib/action_controller/metal/basic_implicit_render.rb の send_action。

最後まで追えてない気がするけど。

Railsはアクセスをどう処理しているのか(1)

module function Kernel.#caller (Ruby 2.6.0)