rails new --minimal gives you a minimal rails stack.

Your app will not include any of the following:

- action_cable
- active_storage
- action_text
- action_mailer
- action_mailbox
- bootsnap
- javascript
- jbuilder
- rack mini profiler
- spring
- system tests
- turbolinks
- webconsole
- webpack

Co-authored-by: dhh <david@loudthinking.com>

Author: hahmed

railties/CHANGELOG.md

@@ -1,3 +1,24 @@
+*   Create a new rails app using a minimal stack.
+
+      `rails new cool_app --minimal`
+
+    All the following are excluded from your minimal stack:
+
+    - action_cable
+    - action_mailbox
+    - action_mailer
+    - action_text
+    - active_job
+    - active_storage
+    - bootsnap
+    - jbuilder
+    - spring
+    - system_tests
+    - turbolinks
+    - webpack
+
+    *Haroon Ahmed*, *DHH*
+
 *   Add default ENV variable option with BACKTRACE to turn off backtrace cleaning when debugging framework code in the
     generated config/initializers/backtrace_silencers.rb.
 

railties/lib/rails/generators/app_base.rb

@@ -52,6 +52,9 @@ def self.add_shared_options_for(name)
         class_option :skip_active_record,  type: :boolean, aliases: "-O", default: false,
                                            desc: "Skip Active Record files"
 
+        class_option :skip_active_job,     type: :boolean, default: false,
+                                           desc: "Skip Active Job"
+
         class_option :skip_active_storage, type: :boolean, default: false,
                                            desc: "Skip Active Storage files"
 
@@ -76,6 +79,9 @@ def self.add_shared_options_for(name)
         class_option :skip_turbolinks,     type: :boolean, default: false,
                                            desc: "Skip turbolinks gem"
 
+        class_option :skip_jbuilder,       type: :boolean, default: false,
+                                           desc: "Skip jbuilder gem"
+
         class_option :skip_test,           type: :boolean, aliases: "-T", default: false,
                                            desc: "Skip test files"
 
@@ -204,7 +210,8 @@ def include_all_railties? # :doc:
             :skip_action_mailer,
             :skip_test,
             :skip_sprockets,
-            :skip_action_cable
+            :skip_action_cable,
+            :skip_active_job
           ),
           skip_active_storage?,
           skip_action_mailbox?,
@@ -245,6 +252,10 @@ def skip_action_text? # :doc:
         options[:skip_action_text] || skip_active_storage?
       end
 
+      def skip_dev_gems? # :doc:
+        options[:skip_dev_gems]
+      end
+
       class GemfileEntry < Struct.new(:name, :version, :comment, :options, :commented_out)
         def initialize(name, version, comment, options = {}, commented_out = false)
           super
@@ -327,6 +338,7 @@ def webpacker_gemfile_entry
       end
 
       def jbuilder_gemfile_entry
+        return [] if options[:skip_jbuilder]
         comment = "Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder"
         GemfileEntry.new "jbuilder", "~> 2.7", comment, {}, options[:api]
       end

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -272,6 +272,9 @@ class AppGenerator < AppBase
       class_option :api, type: :boolean,
                          desc: "Preconfigure smaller stack for API only apps"
 
+      class_option :minimal, type: :boolean,
+                             desc: "Preconfigure a minimal rails app"
+
       class_option :skip_bundle, type: :boolean, aliases: "-B", default: false,
                                  desc: "Don't run bundle install"
 
@@ -294,6 +297,29 @@ def initialize(*args)
           self.options = options.merge(skip_sprockets: true, skip_javascript: true).freeze
         end
 
+        if options[:minimal]
+          self.options = options.merge(
+            skip_action_cable: true,
+            skip_action_mailer: true,
+            skip_action_mailbox: true,
+            skip_action_text: true,
+            skip_active_job: true,
+            skip_active_storage: true,
+            skip_bootsnap: true,
+            skip_dev_gems: true,
+            skip_javascript: true,
+            skip_jbuilder: true,
+            skip_spring: true,
+            skip_system_test: true,
+            skip_webpack_install: true,
+            skip_turbolinks: true).tap do |option|
+              if option[:webpack]
+                option[:skip_webpack_install] = false
+                option[:skip_javascript] = false
+              end
+            end.freeze
+        end
+
         @after_bundle_callbacks = []
       end
 
@@ -446,11 +472,18 @@ def delete_public_files_if_api_option
       end
 
       def delete_js_folder_skipping_javascript
-        if options[:skip_javascript]
+        if options[:skip_javascript] && !options[:minimal]
           remove_dir "app/javascript"
         end
       end
 
+      def delete_js_packs_when_minimal_skipping_webpack
+        if options[:minimal] && options[:skip_webpack_install]
+          remove_dir "app/javascript/packs"
+          keep_file  "app/javascript"
+        end
+      end
+
       def delete_assets_initializer_skipping_sprockets
         if options[:skip_sprockets]
           remove_file "config/initializers/assets.rb"
@@ -508,6 +541,12 @@ def finish_template
         build(:leftovers)
       end
 
+      def delete_active_job_folder_if_skipping_active_job
+        if options[:skip_active_job]
+          remove_dir "app/jobs"
+        end
+      end
+
       public_task :apply_rails_template, :run_bundle
       public_task :generate_bundler_binstub, :generate_spring_binstub
       public_task :run_webpack

railties/lib/rails/generators/rails/app/templates/Gemfile.tt

@@ -44,7 +44,7 @@ end
 
 <% end -%>
 group :development do
-<%- unless options.api? -%>
+<%- unless options.api? || options.skip_dev_gems? -%>
   # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
   <%- if options.dev? || options.edge? || options.master? -%>
   gem 'web-console', github: 'rails/web-console'

railties/lib/rails/generators/rails/app/templates/config/application.rb.tt

@@ -6,7 +6,7 @@ require "rails/all"
 require "rails"
 # Pick the frameworks you want:
 require "active_model/railtie"
-require "active_job/railtie"
+<%= comment_if :skip_active_job %>require "active_job/railtie"
 <%= comment_if :skip_active_record %>require "active_record/railtie"
 <%= comment_if :skip_active_storage %>require "active_storage/engine"
 require "action_controller/railtie"

railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt

@@ -66,9 +66,11 @@ Rails.application.configure do
   # Use a different cache store in production.
   # config.cache_store = :mem_cache_store
 
+  <%- unless options[:skip_active_job] -%>
   # Use a real queuing backend for Active Job (and separate queues per environment).
   # config.active_job.queue_adapter     = :resque
   # config.active_job.queue_name_prefix = "<%= app_name %>_production"
+  <%- end -%>
 
   <%- unless options.skip_action_mailer? -%>
   config.action_mailer.perform_caching = false

railties/test/generators/app_generator_test.rb

@@ -618,6 +618,22 @@ def test_generator_if_skip_test_is_given
     assert_no_directory("test")
   end
 
+  def test_generator_if_skip_jbuilder_is_given
+    run_generator [destination_root, "--skip-jbuilder"]
+    assert_no_gem "jbuilder"
+  end
+
+  def test_generator_if_skip_active_job_is_given
+    run_generator [destination_root, "--skip-active-job"]
+    assert_no_file "app/jobs/application.rb"
+    assert_file "config/environments/production.rb" do |content|
+      assert_no_match(/config\.active_job/, content)
+    end
+    assert_file "config/application.rb" do |content|
+      assert_match(/#\s+require\s+["']active_job\/railtie["']/, content)
+    end
+  end
+
   def test_generator_if_skip_system_test_is_given
     run_generator [destination_root, "--skip-system-test"]
     assert_no_gem "capybara"
@@ -829,7 +845,6 @@ def test_edge_option
     assert_file "Gemfile", %r{^gem\s+["']rails["'],\s+github:\s+["']#{Regexp.escape("rails/rails")}["']$}
   end
 
-
   def test_master_option
     generator([destination_root], master: true, skip_webpack_install: true)
 
@@ -1110,6 +1125,46 @@ def test_master_key_is_only_readable_by_the_owner
     end
   end
 
+  def test_minimal_rails_app
+    app_root = File.join(destination_root, "myapp")
+    run_generator [app_root, "--minimal"]
+
+    assert_no_file "#{app_root}/config/storage.yml"
+    assert_no_file "#{app_root}/config/webpacker.yml"
+    assert_no_file "#{app_root}/config/cable.yml"
+    assert_no_file "#{app_root}/bin/yarn"
+    assert_no_file "#{app_root}/views/layouts/mailer.html.erb"
+    assert_no_file "#{app_root}/config/spring.rb"
+    assert_no_file "#{app_root}/app/jobs/application.rb"
+    assert_file "#{app_root}/app/views/layouts/application.html.erb" do |content|
+      assert_no_match(/data-turbolinks-track/, content)
+    end
+    assert_file "#{app_root}/config/environments/development.rb" do |content|
+      assert_no_match(/config\.active_storage/, content)
+    end
+    assert_file "#{app_root}/config/environments/production.rb" do |content|
+      assert_no_match(/config\.active_job/, content)
+    end
+    assert_file "#{app_root}/config/boot.rb" do |content|
+      assert_no_match(/require "bootsnap\/setup"/, content)
+    end
+    assert_file "#{app_root}/config/application.rb" do |content|
+      assert_match(/#\s+require\s+["']active_job\/railtie["']/, content)
+      assert_match(/#\s+require\s+["']active_storage\/engine["']/, content)
+      assert_match(/#\s+require\s+["']action_mailer\/railtie["']/, content)
+      assert_match(/#\s+require\s+["']action_mailbox\/engine["']/, content)
+      assert_match(/#\s+require\s+["']action_text\/engine["']/, content)
+      assert_match(/#\s+require\s+["']action_cable\/engine["']/, content)
+      assert_match(/\s+require\s+["']sprockets\/railtie["']/, content)
+    end
+
+    assert_no_gem "webpacker", app_root
+    assert_no_gem "jbuilder", app_root
+    assert_no_gem "rack-mini-profiler", app_root
+    assert_no_gem "spring", app_root
+    assert_no_gem "web-console", app_root
+  end
+
   private
     def stub_rails_application(root)
       Rails.application.config.root = root
@@ -1122,16 +1177,16 @@ def action(*args, &block)
       capture(:stdout) { generator.send(*args, &block) }
     end
 
-    def assert_gem(gem, constraint = nil)
+    def assert_gem(gem, constraint = nil, app_path = ".")
       if constraint
-        assert_file "Gemfile", /^\s*gem\s+["']#{gem}["'], #{constraint}$*/
+        assert_file File.join(app_path, "Gemfile"), /^\s*gem\s+["']#{gem}["'], #{constraint}$*/
       else
-        assert_file "Gemfile", /^\s*gem\s+["']#{gem}["']$*/
+        assert_file File.join(app_path, "Gemfile"), /^\s*gem\s+["']#{gem}["']$*/
       end
     end
 
-    def assert_no_gem(gem)
-      assert_file "Gemfile" do |content|
+    def assert_no_gem(gem, app_path = ".")
+      assert_file File.join(app_path, "Gemfile") do |content|
         assert_no_match(gem, content)
       end
     end