MONGOID-5439 Generate config/initializers/mongoid.rb (#5529)

* add mongoid.rb rails initializer

* write all available config options to the mongoid.rb initializer

* let's try loading mongoid.yml after all other config has loaded

this is so that the YAML options can override any options set in the
the config/initializers.

* remove Mongoid options from the mongoid.yml template

Preference is now for these to be specified in the
config/initializers/mongoid.rb initializer, though if present in the
mongoid.yml file, they'll still be processed.

* update docs to reference the mongoid.rb initializers

* Revert "update docs to reference the mongoid.rb initializers"

This reverts commit 05e2be9.

* prefer the YAML file for Mongoid configuration

but let's still auto-generate the default config by parsing the Mongoid::Config file...

* fix tests

* update docs

* revert changes to mongoid.yml (in favor of #5539)

docs/reference/configuration.txt

@@ -43,7 +43,13 @@ configuration file for you by running the following command:
 
   rails g mongoid:config
 
-The configuration file will be placed in ``config/mongoid.yml``.
+The configuration file will be placed in ``config/mongoid.yml``. An
+initializer will also be created and placed in
+``config/initializers/mongoid.rb``. It is recommended that all configuration
+be specified in ``config/mongoid.yml``, but if you prefer, the ``mongoid.rb``
+initializer may also be used to set configuration options. Note, though, that
+settings in ``mongoid.yml`` always take precedence over settings in the
+initializer.
 
 If you are not using Ruby on Rails, you can copy the minimal configuration
 given above and save it as ``config/mongoid.yml``.

docs/reference/rails-integration.txt

@@ -19,9 +19,14 @@ manually enabled.
 Configuration
 =============
 
-You can set Mongoid configuration options in your ``application.rb`` along with other Rails
-environment specific options by accessing config.mongoid. Options set here will override
-those set in your ``config/mongoid.yml``.
+You can set Mongoid configuration options in your ``application.rb`` along with
+other Rails environment specific options by accessing config.mongoid. The
+``mongoid:config`` generator will create an initializer in
+``config/initializers/mongoid.rb`` which can also be used for configuring
+Mongoid. Note, though, that options set in your ``config/mongoid.yml`` will
+take precendence over options set elsewhere; it is recommended that whenever
+possible you use ``mongoid.yml`` as the default location for Mongoid
+configuration.
 
 .. code-block:: ruby
 

docs/tutorials/getting-started-rails6.txt

@@ -125,10 +125,11 @@ Add Mongoid
 
     bin/rails g mongoid:config
 
-This generator will create the ``config/mongoid.yml`` configuration file,
-which is used to configure the connection to the MongoDB deployment.
-Note that as we are not using ActiveRecord we will not have a ``database.yml``
-file.
+This generator will create the ``config/mongoid.yml`` configuration file 
+(used to configure the connection to the MongoDB deployment) and the
+``config/initializers/mongoid.rb`` initializer file (which may be used for
+other Mongoid-related configuration). Note that as we are not using
+ActiveRecord we will not have a ``database.yml`` file.
 
 
 .. _run-locally:
@@ -465,8 +466,11 @@ Generate the default Mongoid configuration:
 
     bin/rails g mongoid:config
 
-This generator will create the ``config/mongoid.yml`` configuration file,
-which is used to configure the connection to the MongoDB deployment.
+This generator will create the ``config/mongoid.yml`` configuration file 
+(used to configure the connection to the MongoDB deployment) and the
+``config/initializers/mongoid.rb`` initializer file (which may be used for
+other Mongoid-related configuration). In general, it is recommended to use
+``mongoid.yml`` for all Mongoid configuration.
 
 Review the sections :ref:`Run MongoDB Locally <run-locally>` and
 :ref:`Use MongoDB Atlas <use-atlas>` to decide how you would like to deploy

docs/tutorials/getting-started-rails7.txt

@@ -95,10 +95,11 @@ Setup Mongoid
 
     bin/rails g mongoid:config
 
-This generator will create the ``config/mongoid.yml`` configuration file,
-which is used to configure the connection to the MongoDB deployment.
-Note that as we are not using ActiveRecord we will not have a ``database.yml``
-file.
+This generator will create the ``config/mongoid.yml`` configuration file 
+(used to configure the connection to the MongoDB deployment) and the
+``config/initializers/mongoid.rb`` initializer file (which may be used for
+other Mongoid-related configuration). Note that as we are not using
+ActiveRecord we will not have a ``database.yml`` file.
 
 
 .. _configure-self-managed:
@@ -333,8 +334,11 @@ Generate the default Mongoid configuration:
 
     bin/rails g mongoid:config
 
-This generator will create the ``config/mongoid.yml`` configuration file,
-which is used to configure the connection to the MongoDB deployment.
+This generator will create the ``config/mongoid.yml`` configuration file 
+(used to configure the connection to the MongoDB deployment) and the
+``config/initializers/mongoid.rb`` initializer file (which may be used for
+other Mongoid-related configuration). In general, it is recommended to use
+``mongoid.yml`` for all Mongoid configuration.
 
 Review the sections :ref:`Configure for Self Managed MongoDB <configure-self-managed>`
 and :ref:`Configure for MongoDB Atlas <configure-atlas>` to decide how you

lib/mongoid/railtie.rb

@@ -51,7 +51,11 @@ def self.rescue_responses
 
       # Initialize Mongoid. This will look for a mongoid.yml in the config
       # directory and configure mongoid appropriately.
-      initializer "mongoid.load-config" do
+      #
+      # It runs after all config/initializers have loaded, so that the YAML
+      # options can override options specified in
+      # (e.g.) config/initializers/mongoid.rb.
+      initializer "mongoid.load-config", after: :load_config_initializers do
         config_file = Rails.root.join("config", "mongoid.yml")
         if config_file.file?
           begin

lib/rails/generators/mongoid/config/config_generator.rb

@@ -5,7 +5,7 @@
 module Mongoid
   module Generators
     class ConfigGenerator < Rails::Generators::Base
-      desc "Creates a Mongoid configuration file at config/mongoid.yml"
+      desc "Creates Mongoid configuration files"
 
       argument :database_name, type: :string, optional: true
 
@@ -25,9 +25,12 @@ def app_name
       end
 
       def create_config_file
-        template 'mongoid.yml', File.join('config', "mongoid.yml")
+        template 'mongoid.yml', File.join('config', 'mongoid.yml')
       end
 
+      def create_initializer_file
+        template 'mongoid.rb', File.join('config', 'initializers', 'mongoid.rb')
+      end
     end
   end
 end

lib/rails/generators/mongoid/config/templates/mongoid.rb

@@ -0,0 +1,24 @@
+Mongoid.configure do
+  target_version = "<%= Mongoid::VERSION[/^\d+\.\d+/] %>"
+
+  # Load Mongoid behavior defaults. This automatically sets
+  # features flags (refer to documentation)
+  config.load_defaults target_version
+
+  # It is recommended to use config/mongoid.yml for most Mongoid-related
+  # configuration, whenever possible, but if you prefer, you can set
+  # configuration values here, instead:
+  # 
+  #   config.log_level = :debug
+  #
+  # Note that the settings in config/mongoid.yml always take precedence,
+  # whatever else is set here.
+end
+
+# Enable Mongo driver query cache for Rack
+# Rails.application.config.middleware.use(Mongo::QueryCache::Middleware)
+
+# Enable Mongo driver query cache for ActiveJob
+# ActiveSupport.on_load(:active_job) do
+#   include Mongo::QueryCache::Middleware::ActiveJob
+# end

spec/integration/app_spec.rb

@@ -86,50 +86,57 @@ def start_app(cmd, port, timeout)
     rv
   end
 
-  context 'new application - rails' do
-    it 'creates' do
-      install_rails
+  def prepare_new_rails_app(name)
+    install_rails
 
-      Dir.chdir(TMP_BASE) do
-        FileUtils.rm_rf('mongoid-test')
-        check_call(%w(rails new mongoid-test --skip-spring --skip-active-record), env: clean_env)
+    Dir.chdir(TMP_BASE) do
+      FileUtils.rm_rf(name)
+      check_call(%W(rails new #{name} --skip-spring --skip-active-record), env: clean_env)
 
-        Dir.chdir('mongoid-test') do
-          adjust_app_gemfile
-          check_call(%w(bundle install), env: clean_env)
+      Dir.chdir(name) do
+        adjust_rails_defaults
+        adjust_app_gemfile
+        check_call(%w(bundle install), env: clean_env)
 
-          check_call(%w(rails g model post), env: clean_env)
-          check_call(%w(rails g model comment post:belongs_to), env: clean_env)
+        yield
+      end
+    end
+  end
 
-          # https://jira.mongodb.org/browse/MONGOID-4885
-          comment_text = File.read('app/models/comment.rb')
-          comment_text.should =~ /belongs_to :post/
-          comment_text.should_not =~ /embedded_in :post/
-        end
+  context 'new application - rails' do
+    it 'creates' do
+      prepare_new_rails_app 'mongoid-test' do
+        check_call(%w(rails g model post), env: clean_env)
+        check_call(%w(rails g model comment post:belongs_to), env: clean_env)
+
+        # https://jira.mongodb.org/browse/MONGOID-4885
+        comment_text = File.read('app/models/comment.rb')
+        comment_text.should =~ /belongs_to :post/
+        comment_text.should_not =~ /embedded_in :post/
       end
     end
 
     it 'generates Mongoid config' do
-      install_rails
+      prepare_new_rails_app 'mongoid-test-config' do
+        mongoid_config_file = File.join(TMP_BASE, 'mongoid-test-config/config/mongoid.yml')
 
-      Dir.chdir(TMP_BASE) do
-        FileUtils.rm_rf('mongoid-test-config')
-        check_call(%w(rails new mongoid-test-config --skip-spring --skip-active-record), env: clean_env)
+        File.exist?(mongoid_config_file).should be false
+        check_call(%w(rails g mongoid:config), env: clean_env)
+        File.exist?(mongoid_config_file).should be true
 
-        Dir.chdir('mongoid-test-config') do
-          adjust_app_gemfile
-          check_call(%w(bundle install), env: clean_env)
-
-          mongoid_config_file = File.join(TMP_BASE,'mongoid-test-config/config/mongoid.yml')
+        config_text = File.read(mongoid_config_file)
+        config_text.should =~ /mongoid_test_config_development/
+        config_text.should =~ /mongoid_test_config_test/
+      end
+    end
 
-          File.exist?(mongoid_config_file).should be false
-          check_call(%w(rails g mongoid:config), env: clean_env)
-          File.exist?(mongoid_config_file).should be true
+    it 'generates Mongoid initializer' do
+      prepare_new_rails_app 'mongoid-test-init' do
+        mongoid_initializer = File.join(TMP_BASE, 'mongoid-test-init/config/initializers/mongoid.rb')
 
-          config_text = File.read(mongoid_config_file)
-          config_text.should =~ /mongoid_test_config_development/
-          config_text.should =~ /mongoid_test_config_test/
-        end
+        File.exist?(mongoid_initializer).should be false
+        check_call(%w(rails g mongoid:config), env: clean_env)
+        File.exist?(mongoid_initializer).should be true
       end
     end
   end