Use separate FDW classes to wrap ActiveRecord models

app/models/geo/base_fdw.rb

+class Geo::BaseFdw < ActiveRecord::Base
+  self.abstract_class = true
+
+  if Gitlab::Geo.geo_database_configured?
+    establish_connection Rails.configuration.geo_database
+  end
+
+  def self.connection
+    raise 'Geo secondary database is not configured' unless Gitlab::Geo.geo_database_configured?
+
+    super
+  end
+end

app/models/geo/fdw/lfs_object.rb

+module Geo
+  module Fdw
+    class LfsObject < ::Geo::BaseFdw
+      self.table_name = Gitlab::Geo.fdw_table('lfs_objects')
+    end
+  end
+end
+

app/models/geo/fdw/upload.rb

+module Geo
+  module Fdw
+    class Upload < ::Geo::BaseFdw
+      self.table_name = Gitlab::Geo.fdw_table('uploads')
+    end
+  end
+end

app/models/lfs_object.rb

 class LfsObject < ActiveRecord::Base
-  # EE specific modules
-  prepend EE::LfsObject
-
   has_many :lfs_objects_projects, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
   has_many :projects, through: :lfs_objects_projects
 

app/models/upload.rb

 class Upload < ActiveRecord::Base
-  # EE specific modules
-  prepend EE::Upload
-
   # Upper limit for foreground checksum processing
   CHECKSUM_THRESHOLD = 100.megabytes
 

app/workers/geo/file_download_dispatch_worker.rb

@@ -54,10 +54,10 @@ module Geo
     end
 
     def fdw_find_lfs_object_ids
-      fdw_table = "#{Gitlab::Geo.fdw_schema}.lfs_objects"
+      fdw_table = Geo::Fdw::LfsObject.table_name
 
       # Filter out objects in object storage (this is done in GeoNode#lfs_objects)
-      LfsObject.fdw.joins("LEFT OUTER JOIN file_registry ON file_registry.file_id = #{fdw_table}.id AND file_registry.file_type = 'lfs'")
+      Geo::Fdw::LfsObject.joins("LEFT OUTER JOIN file_registry ON file_registry.file_id = #{fdw_table}.id AND file_registry.file_type = 'lfs'")
         .where("#{fdw_table}.file_store IS NULL OR #{fdw_table}.file_store = #{LfsObjectUploader::LOCAL_STORE}")
         .where('file_registry.file_id IS NULL')
         .order(created_at: :desc)
@@ -67,10 +67,10 @@ module Geo
     end
 
     def fdw_find_upload_object_ids
-      fdw_table = "#{Gitlab::Geo.fdw_schema}.uploads"
+      fdw_table = Geo::Fdw::Upload.table_name
       obj_types = Geo::FileService::DEFAULT_OBJECT_TYPES.map { |val| "'#{val}'" }.join(',')
 
-      Upload.fdw.joins("LEFT OUTER JOIN file_registry ON file_registry.file_id = #{fdw_table}.id AND file_registry.file_type IN (#{obj_types})")
+      Geo::Fdw::Upload.joins("LEFT OUTER JOIN file_registry ON file_registry.file_id = #{fdw_table}.id AND file_registry.file_type IN (#{obj_types})")
         .where('file_registry.file_id IS NULL')
         .order(created_at: :desc)
         .limit(db_retrieve_batch_size)

ee/app/models/concerns/ee/geo/foreign_data_wrapped.rb

-module EE
-  module Geo
-    module ForeignDataWrapped
-      extend ActiveSupport::Concern
-
-      class_methods do
-        def fdw
-          instance = self.clone
-          instance.table_name = "#{::Gitlab::Geo.fdw_schema}.#{self.table_name}"
-          def instance.name
-            table_name
-          end
-
-          instance.establish_connection Rails.configuration.geo_database
-
-          instance
-        end
-      end
-    end
-  end
-end

ee/app/models/ee/lfs_object.rb

-module EE
-  # LfsObject EE mixin
-  #
-  # This module is intended to encapsulate EE-specific model logic
-  # and be prepended in the `LfsObject` model
-  module LfsObject
-    extend ActiveSupport::Concern
-
-    prepended do
-      prepend ::EE::Geo::ForeignDataWrapped
-    end
-  end
-end

ee/app/models/ee/project.rb

@@ -10,7 +10,6 @@ module EE
       include Elastic::ProjectsSearch
       prepend GeoAwareAvatar
       prepend ImportStatusStateMachine
-      prepend ::EE::Geo::ForeignDataWrapped
 
       before_validation :mark_remote_mirrors_for_removal
 

ee/app/models/ee/upload.rb

-module EE
-  # Upload EE mixin
-  #
-  # This module is intended to encapsulate EE-specific model logic
-  # and be prepended in the `Upload` model
-  module Upload
-    extend ActiveSupport::Concern
-
-    prepended do
-      prepend ::EE::Geo::ForeignDataWrapped
-    end
-  end
-end

lib/gitlab/geo.rb

@@ -14,6 +14,8 @@ module Gitlab
 
     SECONDARY_JOBS = %i(repository_sync_job file_download_job).freeze
 
+    FDW_SCHEMA = 'gitlab_secondary'.freeze
+
     def self.current_node
       self.cache_value(:geo_node_current) do
         GeoNode.find_by(host: Gitlab.config.gitlab.host,
@@ -77,13 +79,13 @@ module Gitlab
     def self.fdw?
       self.cache_value(:geo_fdw?) do
         ::Geo::BaseRegistry.connection.execute(
-          "SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = '#{self.fdw_schema}' AND table_type = 'FOREIGN TABLE'"
+          "SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = '#{FDW_SCHEMA}' AND table_type = 'FOREIGN TABLE'"
         ).first.fetch('count').to_i.positive?
       end
     end
 
-    def self.fdw_schema
-      'gitlab_secondary'.freeze
+    def self.fdw_table(table_name)
+      FDW_SCHEMA + ".#{table_name}"
     end
 
     def self.repository_sync_job