[AutoLoad] Autoload Fixes (#1904)

* [Autoload] allows all bits of Grape to be autoloaded

* [AutoLoad] creates a compile! method to pre load an API class

* [AutoLoad] Addresses rubocop rules, and adds a readme line

* [AutoLoad] Adds changes to changelog

* Addresses issues with danger

* Makes sure the check happens inside the Mutex

* Syntax on the README

* [AutoLoad] does not take the lock to try to compile is an instance is already present

* [AutoLoad] Tests the new methods compile! and instance_for_rack

CHANGELOG.md

@@ -3,6 +3,7 @@
 #### Features
 
 * Your contribution here.
+* [#1904](https://github.com/ruby-grape/grape/pull/1904): Allows Grape to load files on startup rather than on the first call - [@myxoh](https://github.com/myxoh).
 
 #### Fixes
 

README.md

@@ -15,6 +15,7 @@
 - [Installation](#installation)
 - [Basic Usage](#basic-usage)
 - [Mounting](#mounting)
+  - [All](#all)
   - [Rack](#rack)
   - [ActiveRecord without Rails](#activerecord-without-rails)
   - [Alongside Sinatra (or other frameworks)](#alongside-sinatra-or-other-frameworks)
@@ -261,6 +262,17 @@ end
 
 ## Mounting
 
+### All
+
+
+By default Grape will compile the routes on the first route, it is possible to pre-load routes using the `compile!` method.
+
+```ruby
+Twitter::API.compile!
+```
+
+This can be added to your `config.ru` (if using rackup), `application.rb` (if using rails), or any file that loads your server.
+
 ### Rack
 
 The above sample creates a Rack application that can be run from a rackup `config.ru` file
@@ -270,6 +282,13 @@ with `rackup`:
 run Twitter::API
 ```
 
+(With pre-loading you can use)
+
+```ruby
+Twitter::API.compile!
+run Twitter::API
+```
+
 And would respond to the following routes:
 
     GET /api/statuses/public_timeline

lib/grape.rb

@@ -54,106 +54,124 @@ module Http
 
   module Exceptions
     extend ::ActiveSupport::Autoload
-    autoload :Base
-    autoload :Validation
-    autoload :ValidationArrayErrors
-    autoload :ValidationErrors
-    autoload :MissingVendorOption
-    autoload :MissingMimeType
-    autoload :MissingOption
-    autoload :InvalidFormatter
-    autoload :InvalidVersionerOption
-    autoload :UnknownValidator
-    autoload :UnknownOptions
-    autoload :UnknownParameter
-    autoload :InvalidWithOptionForRepresent
-    autoload :IncompatibleOptionValues
-    autoload :MissingGroupTypeError,          'grape/exceptions/missing_group_type'
-    autoload :UnsupportedGroupTypeError,      'grape/exceptions/unsupported_group_type'
-    autoload :InvalidMessageBody
-    autoload :InvalidAcceptHeader
-    autoload :InvalidVersionHeader
-    autoload :MethodNotAllowed
-    autoload :InvalidResponse
+    eager_autoload do
+      autoload :Base
+      autoload :Validation
+      autoload :ValidationArrayErrors
+      autoload :ValidationErrors
+      autoload :MissingVendorOption
+      autoload :MissingMimeType
+      autoload :MissingOption
+      autoload :InvalidFormatter
+      autoload :InvalidVersionerOption
+      autoload :UnknownValidator
+      autoload :UnknownOptions
+      autoload :UnknownParameter
+      autoload :InvalidWithOptionForRepresent
+      autoload :IncompatibleOptionValues
+      autoload :MissingGroupTypeError,          'grape/exceptions/missing_group_type'
+      autoload :UnsupportedGroupTypeError,      'grape/exceptions/unsupported_group_type'
+      autoload :InvalidMessageBody
+      autoload :InvalidAcceptHeader
+      autoload :InvalidVersionHeader
+      autoload :MethodNotAllowed
+      autoload :InvalidResponse
+    end
   end
 
   module Extensions
     extend ::ActiveSupport::Autoload
-
-    autoload :DeepMergeableHash
-    autoload :DeepSymbolizeHash
-    autoload :DeepHashWithIndifferentAccess
-    autoload :Hash
-
+    eager_autoload do
+      autoload :DeepMergeableHash
+      autoload :DeepSymbolizeHash
+      autoload :DeepHashWithIndifferentAccess
+      autoload :Hash
+    end
     module ActiveSupport
       extend ::ActiveSupport::Autoload
-
-      autoload :HashWithIndifferentAccess
+      eager_autoload do
+        autoload :HashWithIndifferentAccess
+      end
     end
 
     module Hashie
       extend ::ActiveSupport::Autoload
-
-      autoload :Mash
+      eager_autoload do
+        autoload :Mash
+      end
     end
   end
 
   module Middleware
     extend ::ActiveSupport::Autoload
-    autoload :Base
-    autoload :Versioner
-    autoload :Formatter
-    autoload :Error
-    autoload :Globals
-    autoload :Stack
+    eager_autoload do
+      autoload :Base
+      autoload :Versioner
+      autoload :Formatter
+      autoload :Error
+      autoload :Globals
+      autoload :Stack
+    end
 
     module Auth
       extend ::ActiveSupport::Autoload
-      autoload :Base
-      autoload :DSL
-      autoload :StrategyInfo
-      autoload :Strategies
+      eager_autoload do
+        autoload :Base
+        autoload :DSL
+        autoload :StrategyInfo
+        autoload :Strategies
+      end
     end
 
     module Versioner
       extend ::ActiveSupport::Autoload
-      autoload :Path
-      autoload :Header
-      autoload :Param
-      autoload :AcceptVersionHeader
+      eager_autoload do
+        autoload :Path
+        autoload :Header
+        autoload :Param
+        autoload :AcceptVersionHeader
+      end
     end
   end
 
   module Util
     extend ::ActiveSupport::Autoload
-    autoload :InheritableValues
-    autoload :StackableValues
-    autoload :ReverseStackableValues
-    autoload :InheritableSetting
-    autoload :StrictHashConfiguration
-    autoload :Registrable
+    eager_autoload do
+      autoload :InheritableValues
+      autoload :StackableValues
+      autoload :ReverseStackableValues
+      autoload :InheritableSetting
+      autoload :StrictHashConfiguration
+      autoload :Registrable
+    end
   end
 
   module ErrorFormatter
     extend ::ActiveSupport::Autoload
-    autoload :Base
-    autoload :Json
-    autoload :Txt
-    autoload :Xml
+    eager_autoload do
+      autoload :Base
+      autoload :Json
+      autoload :Txt
+      autoload :Xml
+    end
   end
 
   module Formatter
     extend ::ActiveSupport::Autoload
-    autoload :Json
-    autoload :SerializableHash
-    autoload :Txt
-    autoload :Xml
+    eager_autoload do
+      autoload :Json
+      autoload :SerializableHash
+      autoload :Txt
+      autoload :Xml
+    end
   end
 
   module Parser
     extend ::ActiveSupport::Autoload
-    autoload :Json
-    autoload :Xml
+    eager_autoload do
+      autoload :Json
+      autoload :Xml
+    end
   end
 
   module DSL
@@ -177,19 +195,25 @@ module DSL
 
   class API
     extend ::ActiveSupport::Autoload
-    autoload :Helpers
+    eager_autoload do
+      autoload :Helpers
+    end
   end
 
   module Presenters
     extend ::ActiveSupport::Autoload
-    autoload :Presenter
+    eager_autoload do
+      autoload :Presenter
+    end
   end
 
   module ServeFile
     extend ::ActiveSupport::Autoload
-    autoload :FileResponse
-    autoload :FileBody
-    autoload :SendfileResponse
+    eager_autoload do
+      autoload :FileResponse
+      autoload :FileBody
+      autoload :SendfileResponse
+    end
   end
 end
 

lib/grape/api.rb

@@ -6,7 +6,7 @@ module Grape
   # should subclass this class in order to build an API.
   class API
     # Class methods that we want to call on the API rather than on the API object
-    NON_OVERRIDABLE = (Class.new.methods + %i[call call! configuration]).freeze
+    NON_OVERRIDABLE = (Class.new.methods + %i[call call! configuration compile!]).freeze
 
     class << self
       attr_accessor :base_instance, :instances
@@ -48,11 +48,6 @@ def override_all_methods!
       # (http://www.rubydoc.info/github/rack/rack/master/file/SPEC) for more.
       # NOTE: This will only be called on an API directly mounted on RACK
       def call(*args, &block)
-        instance_for_rack = if never_mounted?
-                              base_instance
-                            else
-                              mounted_instances.first
-                            end
         instance_for_rack.call(*args, &block)
       end
 
@@ -111,8 +106,21 @@ def method_missing(method, *args, &block)
         end
       end
 
+      def compile!
+        require 'grape/eager_load'
+        instance_for_rack.compile! # See API::Instance.compile!
+      end
+
       private
 
+      def instance_for_rack
+        if never_mounted?
+          base_instance
+        else
+          mounted_instances.first
+        end
+      end
+
       # Adds a new stage to the set up require to get a Grape::API up and running
       def add_setup(method, *args, &block)
         setup_step = { method: method, args: args, block: block }

lib/grape/api/instance.rb

@@ -61,7 +61,7 @@ def change!
         # the headers, and the body. See [the rack specification]
         # (http://www.rubydoc.info/github/rack/rack/master/file/SPEC) for more.
         def call(env)
-          LOCK.synchronize { compile } unless instance
+          compile!
           call!(env)
         end
 
@@ -79,9 +79,14 @@ def cascade(value = nil)
           end
         end
 
+        def compile!
+          return if instance
+          LOCK.synchronize { compile unless instance }
+        end
+
         # see Grape::Router#recognize_path
         def recognize_path(path)
-          LOCK.synchronize { compile } unless instance
+          compile!
           instance.router.recognize_path(path)
         end
 

lib/grape/eager_load.rb

@@ -0,0 +1,18 @@
+Grape.eager_load!
+Grape::Http.eager_load!
+Grape::Exceptions.eager_load!
+Grape::Extensions.eager_load!
+Grape::Extensions::ActiveSupport.eager_load!
+Grape::Extensions::Hashie.eager_load!
+Grape::Middleware.eager_load!
+Grape::Middleware::Auth.eager_load!
+Grape::Middleware::Versioner.eager_load!
+Grape::Util.eager_load!
+Grape::ErrorFormatter.eager_load!
+Grape::Formatter.eager_load!
+Grape::Parser.eager_load!
+Grape::DSL.eager_load!
+Grape::API.eager_load!
+Grape::Presenters.eager_load!
+Grape::ServeFile.eager_load!
+Rack::Head # AutoLoads the Rack::Head

spec/grape/api_spec.rb

@@ -885,6 +885,40 @@ class DummyFormatClass
     end
   end
 
+  describe '.compile!' do
+    it 'requires the grape/eager_load file' do
+      expect(app).to receive(:require).with('grape/eager_load') { nil }
+      app.compile!
+    end
+
+    it 'compiles the instance for rack!' do
+      stubbed_object = double(:instance_for_rack)
+      allow(app).to receive(:instance_for_rack) { stubbed_object }
+    end
+  end
+
+  # NOTE: this method is required to preserve the ability of pre-mounting
+  # the root API into a namespace, it may be deprecated in the future.
+  describe 'instance_for_rack' do
+    context 'when the app was not mounted' do
+      it 'returns the base_instance' do
+        expect(app.send(:instance_for_rack)).to eq app.base_instance
+      end
+    end
+
+    context 'when the app was mounted' do
+      it 'returns the first mounted instance' do
+        mounted_app = app
+        Class.new(Grape::API) do
+          namespace 'new_namespace' do
+            mount mounted_app
+          end
+        end
+        expect(app.send(:instance_for_rack)).to eq app.send(:mounted_instances).first
+      end
+    end
+  end
+
   describe 'filters' do
     it 'adds a before filter' do
       subject.before { @foo = 'first'  }