Merge pull request #7225 from rails/eager_load

Improve eager load on Rails

11 files changed, 65 insertions, 27 deletions

diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index 3531728421..ae872f2bb0 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -16,7 +16,7 @@ module Rails
   #
   # Besides providing the same configuration as Rails::Engine and Rails::Railtie,
   # the application object has several specific configurations, for example
-  # "allow_concurrency", "cache_classes", "consider_all_requests_local", "filter_parameters",
+  # "cache_classes", "consider_all_requests_local", "filter_parameters",
   # "logger" and so forth.
   #
   # Check Rails::Application::Configuration to see them all.
@@ -216,8 +216,9 @@ module Rails
       railties.each { |r| r.run_tasks_blocks(app) }
       super
       require "rails/tasks"
+      config = self.config
       task :environment do
-        $rails_rake_task = true
+        config.eager_load = false
         require_environment!
       end
     end
@@ -296,7 +297,7 @@ module Rails
           middleware.use ::ActionDispatch::Static, paths["public"].first, config.static_cache_control
         end
 
-        middleware.use ::Rack::Lock unless config.allow_concurrency
+        middleware.use ::Rack::Lock unless config.cache_classes
         middleware.use ::Rack::Runtime
         middleware.use ::Rack::MethodOverride
         middleware.use ::ActionDispatch::RequestId
diff --git a/railties/lib/rails/application/bootstrap.rb b/railties/lib/rails/application/bootstrap.rb
index e567df7162..a1bc95550b 100644
--- a/railties/lib/rails/application/bootstrap.rb
+++ b/railties/lib/rails/application/bootstrap.rb
@@ -13,11 +13,18 @@ module Rails
         require "active_support/all" unless config.active_support.bare
       end
 
-      # Preload all frameworks specified by the Configuration#frameworks.
-      # Used by Passenger to ensure everything's loaded before forking and
-      # to avoid autoload race conditions in JRuby.
-      initializer :preload_frameworks, :group => :all do
-        ActiveSupport::Autoload.eager_autoload! if config.preload_frameworks
+      initializer :set_eager_load, :group => :all do
+        if config.eager_load.nil?
+          warn <<-INFO
+config.eager_load is set to nil. Please update your config/environments/*.rb files accordingly:
+
+  * development - set it to false
+  * test - set it to false (unless you use a tool that preloads your test environment)
+  * production - set it to true
+
+INFO
+          config.eager_load = config.cache_classes
+        end
       end
 
       # Initialize the logger early in the stack in case we need to log some deprecation.
@@ -60,7 +67,6 @@ module Rails
       end
 
       # Sets the dependency loading mechanism.
-      # TODO: Remove files from the $" and always use require.
       initializer :initialize_dependency_mechanism, :group => :all do
         ActiveSupport::Dependencies.mechanism = config.cache_classes ? :require : :load
       end
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index 2b36cc9d0d..7f05b2e7e1 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -5,11 +5,11 @@ require 'rails/engine/configuration'
 module Rails
   class Application
     class Configuration < ::Rails::Engine::Configuration
-      attr_accessor :allow_concurrency, :asset_host, :asset_path, :assets, :autoflush_log,
+      attr_accessor :asset_host, :asset_path, :assets, :autoflush_log,
                     :cache_classes, :cache_store, :consider_all_requests_local, :console,
-                    :dependency_loading, :exceptions_app, :file_watcher, :filter_parameters,
+                    :eager_load, :exceptions_app, :file_watcher, :filter_parameters,
                     :force_ssl, :helpers_paths, :logger, :log_formatter, :log_tags,
-                    :preload_frameworks, :railties_order, :relative_url_root, :secret_token,
+                    :railties_order, :relative_url_root, :secret_token,
                     :serve_static_assets, :ssl_options, :static_cache_control, :session_options,
                     :time_zone, :reload_classes_only_on_change,
                     :queue, :queue_consumer
@@ -20,11 +20,9 @@ module Rails
       def initialize(*)
         super
         self.encoding = "utf-8"
-        @allow_concurrency             = false
         @consider_all_requests_local   = false
         @filter_parameters             = []
         @helpers_paths                 = []
-        @dependency_loading            = true
         @serve_static_assets           = true
         @static_cache_control          = nil
         @force_ssl                     = false
@@ -45,6 +43,7 @@ module Rails
         @log_formatter                 = ActiveSupport::Logger::SimpleFormatter.new
         @queue                         = Rails::Queueing::Queue
         @queue_consumer                = Rails::Queueing::ThreadedConsumer
+        @eager_load                    = nil
 
         @assets = ActiveSupport::OrderedOptions.new
         @assets.enabled                  = false
@@ -91,15 +90,12 @@ module Rails
         end
       end
 
-      # Enable threaded mode. Allows concurrent requests to controller actions and
-      # multiple database connections. Also disables automatic dependency loading
-      # after boot, and disables reloading code on every request, as these are
-      # fundamentally incompatible with thread safety.
       def threadsafe!
-        @preload_frameworks = true
+        ActiveSupport::Deprecation.warn "config.threadsafe! is deprecated. Rails applications " \
+          "behave by default as thread safe in production as long as config.cache_classes and " \
+          "config.eager_load are set to true"
         @cache_classes = true
-        @dependency_loading = false
-        @allow_concurrency = true
+        @eager_load = true
         self
       end
 
diff --git a/railties/lib/rails/application/finisher.rb b/railties/lib/rails/application/finisher.rb
index 60aa40b92f..1952a0fc3a 100644
--- a/railties/lib/rails/application/finisher.rb
+++ b/railties/lib/rails/application/finisher.rb
@@ -50,9 +50,9 @@ module Rails
       end
 
       initializer :eager_load! do
-        if config.cache_classes && !(defined?($rails_rake_task) && $rails_rake_task)
+        if config.eager_load
           ActiveSupport.run_load_hooks(:before_eager_load, self)
-          eager_load!
+          config.eager_load_namespaces.each(&:eager_load!)
         end
       end
 
@@ -91,7 +91,7 @@ module Rails
 
       # Disable dependency loading during request cycle
       initializer :disable_dependency_loading do
-        if config.cache_classes && !config.dependency_loading
+        if config.eager_load
           ActiveSupport::Dependencies.unhook!
         end
       end
diff --git a/railties/lib/rails/commands/server.rb b/railties/lib/rails/commands/server.rb
index 9ef64da3ef..a684129353 100644
--- a/railties/lib/rails/commands/server.rb
+++ b/railties/lib/rails/commands/server.rb
@@ -87,6 +87,15 @@ module Rails
       middlewares = []
       middlewares << [Rails::Rack::Debugger]  if options[:debugger]
       middlewares << [::Rack::ContentLength]
+
+      # FIXME: add Rack::Lock in the case people are using webrick.
+      # This is to remain backwards compatible for those who are
+      # running webrick in production. We should consider removing this
+      # in development.
+      if server.name == 'Rack::Handler::WEBrick'
+        middlewares << [::Rack::Lock]
+      end
+
       Hash.new(middlewares)
     end
 
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 40f35ae5a6..3a5caf9f62 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -339,11 +339,16 @@ module Rails
 
     class << self
       attr_accessor :called_from, :isolated
+
       alias :isolated? :isolated
       alias :engine_name :railtie_name
 
+      delegate :eager_load!, to: :instance
+
       def inherited(base)
         unless base.abstract_railtie?
+          Rails::Railtie::Configuration.eager_load_namespaces << base
+
           base.called_from = begin
             # Remove the line number from backtraces making sure we don't leave anything behind
             call_stack = caller.map { |p| p.sub(/:\d+.*/, '') }
diff --git a/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt
index 2016eb8b05..122e7e2b34 100644
--- a/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt
+++ b/railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt
@@ -6,6 +6,9 @@
   # 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 and disable caching.
   config.consider_all_requests_local       = true
   config.action_controller.perform_caching = false
diff --git a/railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt
index 80413be0d3..a627636089 100644
--- a/railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt
+++ b/railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt
@@ -4,6 +4,12 @@
   # Code is not reloaded between requests.
   config.cache_classes = true
 
+  # Eager load code on boot. This eager loads most of Rails and
+  # your application in memory, allowing both thread web servers
+  # and those relying on copy on write to perform better.
+  # Rake tasks automatically ignore this option for performance.
+  config.eager_load = true
+
   # Full error reports are disabled and caching is turned on.
   config.consider_all_requests_local       = false
   config.action_controller.perform_caching = true
diff --git a/railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt b/railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt
index 878deb49d7..8ab27eb6e1 100644
--- a/railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt
+++ b/railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt
@@ -7,6 +7,11 @@
   # and recreated between test runs. Don't rely on the data there!
   config.cache_classes = true
 
+  # Do not eager load code on boot. This avoids loading your whole application
+  # just for the purpose of running a single test. If you are using a tool that
+  # preloads Rails for running tests, you may have to set it to true.
+  config.eager_load = false
+
   # Configure static asset server for tests with Cache-Control for performance.
   config.serve_static_assets = true
   config.static_cache_control = "public, max-age=3600"
diff --git a/railties/lib/rails/railtie.rb b/railties/lib/rails/railtie.rb
index 1cb99463cc..fba685c769 100644
--- a/railties/lib/rails/railtie.rb
+++ b/railties/lib/rails/railtie.rb
@@ -178,9 +178,6 @@ module Rails
       @config ||= Railtie::Configuration.new
     end
 
-    def eager_load!
-    end
-
     def railtie_namespace
       @railtie_namespace ||= self.class.parents.detect { |n| n.respond_to?(:railtie_namespace) }
     end
diff --git a/railties/lib/rails/railtie/configuration.rb b/railties/lib/rails/railtie/configuration.rb
index 1c6b3769a5..9dc8843887 100644
--- a/railties/lib/rails/railtie/configuration.rb
+++ b/railties/lib/rails/railtie/configuration.rb
@@ -7,6 +7,16 @@ module Rails
         @@options ||= {}
       end
 
+      # Expose the eager_load_namespaces at "module" level for convenience.
+      def self.eager_load_namespaces #:nodoc:
+        @@eager_load_namespaces ||= []
+      end
+
+      # All namespaces that are eager loaded
+      def eager_load_namespaces
+        @@eager_load_namespaces ||= []
+      end
+
       # Add files that should be watched for change.
       def watchable_files
         @@watchable_files ||= []