Cloud9で「rails g devise:views」を実行するとエラーが発生

Question

railsでdeviseを使うにあたりターミナルで、以下を実行しました。

rails g devise:views

しかしこのように「requiredが定義されていない」というエラーが出てしまいます。

/home/ec2-user/environment/rails_projects/recipegram/config/environments/development.rb:55:in `<top (required)>': undefined local variable or method `config' for main:Object (NameError)
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-5.0.7.2/lib/active_support/dependencies.rb:293:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-5.0.7.2/lib/active_support/dependencies.rb:293:in `block in require'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-5.0.7.2/lib/active_support/dependencies.rb:259:in `load_dependency'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-5.0.7.2/lib/active_support/dependencies.rb:293:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/engine.rb:600:in `block (2 levels) in <class:Engine>'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/engine.rb:599:in `each'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/engine.rb:599:in `block in <class:Engine>'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/initializable.rb:30:in `instance_exec'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/initializable.rb:30:in `run'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/initializable.rb:55:in `block in run_initializers'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:228:in `block in tsort_each'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:350:in `block (2 levels) in each_strongly_connected_component'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:422:in `block (2 levels) in each_strongly_connected_component_from'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:431:in `each_strongly_connected_component_from'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:421:in `block in each_strongly_connected_component_from'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/initializable.rb:44:in `each'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/initializable.rb:44:in `tsort_each_child'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:415:in `call'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:415:in `each_strongly_connected_component_from'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:349:in `block in each_strongly_connected_component'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:347:in `each'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:347:in `call'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:347:in `each_strongly_connected_component'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:226:in `tsort_each'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/tsort.rb:205:in `tsort_each'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/initializable.rb:54:in `run_initializers'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/railties-5.0.7.2/lib/rails/application.rb:352:in `initialize!'
        from /home/ec2-user/environment/rails_projects/recipegram/config/environment.rb:5:in `<top (required)>'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-5.0.7.2/lib/active_support/dependencies.rb:293:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-5.0.7.2/lib/active_support/dependencies.rb:293:in `block in require'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-5.0.7.2/lib/active_support/dependencies.rb:259:in `load_dependency'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-5.0.7.2/lib/active_support/dependencies.rb:293:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/spring-2.1.1/lib/spring/application.rb:106:in `preload'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/spring-2.1.1/lib/spring/application.rb:157:in `serve'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/spring-2.1.1/lib/spring/application.rb:145:in `block in run'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/spring-2.1.1/lib/spring/application.rb:139:in `loop'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/spring-2.1.1/lib/spring/application.rb:139:in `run'
        from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/spring-2.1.1/lib/spring/application/boot.rb:19:in `<top (required)>'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
        from /home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
        from -e:1:in `<main>'

原因となっているであろう「development.rb」ファイルを見ても、なぜ55行目がエラーになるのかどうしても分かりません。

development.rb

Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

  # In the development environment your application's code is reloaded on
  # every request. This slows down response time but is perfect for development
  # since you don't have to restart the web server when you make code changes.
  config.cache_classes = false

  # Do not eager load code on boot.
  config.eager_load = false

  # Show full error reports.
  config.consider_all_requests_local = true

  # Enable/disable caching. By default caching is disabled.
  if Rails.root.join('tmp/caching-dev.txt').exist?
    config.action_controller.perform_caching = true

    config.cache_store = :memory_store
    config.public_file_server.headers = {
      'Cache-Control' => 'public, max-age=172800'
    }
  else
    config.action_controller.perform_caching = false

    config.cache_store = :null_store
  end

  # Don't care if the mailer can't send.
  config.action_mailer.raise_delivery_errors = false

  config.action_mailer.perform_caching = false

  # Print deprecation notices to the Rails logger.
  config.active_support.deprecation = :log

  # Raise an error on page load if there are pending migrations.
  config.active_record.migration_error = :page_load

  # Debug mode disables concatenation and preprocessing of assets.
  # This option may cause significant delays in view rendering with a large
  # number of complex assets.
  config.assets.debug = true

  # Suppress logger output for asset requests.
  config.assets.quiet = true

  # Raises error for missing translations
  # config.action_view.raise_on_missing_translations = true

  # Use an evented file watcher to asynchronously detect changes in source code,
  # routes, locales, etc. This feature depends on the listen gem.
  config.file_watcher = ActiveSupport::EventedFileUpdateChecker
end
config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }

ちなみにGemfileの編集とインストール、デフォルトURLの指定やroot_urlの指定、flashメッセージの設定はすでにしています。

routes.rb

Rails.application.routes.draw do
  root to: "home#index"
end

application.html.erb

<!DOCTYPE html>
<html>
  <head>
    <title></title>
    <%= csrf_meta_tags %>

    <%= stylesheet_link_tag    'application', media: 'all', 'data-turbolinks-track': 'reload' %>
    <%= javascript_include_tag 'application', 'data-turbolinks-track': 'reload' %>
  </head>

  <body>
    <% if flash[:notice] %>
    <div class="notification is-info">
       <p class="notice"><%= notice %></p>
    </div>
    <% end %>
    
    <% if flash[:alert] %>
    <div class="notification is-danger">
       <p class="alert"><%= alert %></p>
    </div>
    <% end %>
    <%= yield %>
  </body>
</html>

お手上げ状態なので、アドバイスいただけると幸いです。

Answer 1

.../environments/development.rb:55:in <top (required)>': undefined local variable or method config' for main:Object (NameError)

このエラーの読み方は
「トップレベル(≒グローバルスコープ)にconfigメソッドもしくはローカル変数が見つからない」
です。

development.rbの55行目を見るとendの直後に

config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }

があります

他の行と同様に
Rails.application.configure do～endの中に入れる必要があります。

Comments

[nem96]

アドバイスいただきありがとうございます。
おっしゃる通りendの中に記述したらエラー解消できました！