Extract `BaseUploader` and use it on other classes

`BaseUploader` is now the base class for `FileUploader`,
`JobArtifactUploader` and `LfsUploader`

ee/lib/gitlab/geo/replication/base_uploader.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Geo
+    module Replication
+      class BaseUploader
+        include LogHelpers
+
+        FILE_NOT_FOUND_GEO_CODE = 'FILE_NOT_FOUND'.freeze
+
+        attr_reader :object_db_id, :message
+
+        def initialize(object_db_id, message)
+          @object_db_id = object_db_id
+          @message = message
+        end
+
+        private
+
+        def success(file)
+          { code: :ok, message: 'Success', file: file }
+        end
+
+        def error(message)
+          { code: :not_found, message: message }
+        end
+
+        # A 404 implies the client made a mistake requesting that resource.
+        # In this case, we know that the resource should exist, so it is a 500 server error.
+        # We send a special "geo_code" so the secondary can mark the file as synced.
+        def file_not_found(resource)
+          {
+            code: :not_found,
+            geo_code: FILE_NOT_FOUND_GEO_CODE,
+            message: "#{resource.class.name} ##{resource.id} file not found"
+          }
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/geo/replication/file_uploader.rb

@@ -7,23 +7,9 @@ module Gitlab
       #   * Finding an Upload record
       #   * Returning the necessary response data to send the file back
       #
-      # TODO: Rearrange things so this class not inherited by JobArtifactUploader and LfsUploader
-      # Maybe rename it so it doesn't seem generic. It only works with Upload records.
-      class FileUploader
-        include LogHelpers
-
-        FILE_NOT_FOUND_GEO_CODE = 'FILE_NOT_FOUND'.freeze
-
-        attr_reader :object_db_id, :message
-
-        def initialize(object_db_id, message)
-          @object_db_id = object_db_id
-          @message = message
-        end
-
-        # rubocop: disable CodeReuse/ActiveRecord
+      class FileUploader < BaseUploader
         def execute
-          recorded_file = Upload.find_by(id: object_db_id)
+          recorded_file = fetch_resource
 
           return error('Upload not found') unless recorded_file
           return file_not_found(recorded_file) unless recorded_file.exist?
@@ -32,10 +18,16 @@ module Gitlab
           success(CarrierWave::SanitizedFile.new(recorded_file.absolute_path))
         end
 
-        # rubocop: enable CodeReuse/ActiveRecord
-
         private
 
+        # rubocop: disable CodeReuse/ActiveRecord
+
+        def fetch_resource
+          Upload.find_by(id: object_db_id)
+        end
+
+        # rubocop: enable CodeReuse/ActiveRecord
+
         def valid?(recorded_file)
           matches_requested_model?(recorded_file) &&
             matches_checksum?(recorded_file)
@@ -49,25 +41,6 @@ module Gitlab
         def matches_checksum?(recorded_file)
           message[:checksum] == Upload.hexdigest(recorded_file.absolute_path)
         end
-
-        def success(file)
-          { code: :ok, message: 'Success', file: file }
-        end
-
-        def error(message)
-          { code: :not_found, message: message }
-        end
-
-        # A 404 implies the client made a mistake requesting that resource.
-        # In this case, we know that the resource should exist, so it is a 500 server error.
-        # We send a special "geo_code" so the secondary can mark the file as synced.
-        def file_not_found(resource)
-          {
-            code: :not_found,
-            geo_code: FILE_NOT_FOUND_GEO_CODE,
-            message: "#{resource.class.name} ##{resource.id} file not found"
-          }
-        end
       end
     end
   end

ee/lib/gitlab/geo/replication/job_artifact_uploader.rb

@@ -7,11 +7,9 @@ module Gitlab
       #   * Finding an ::Ci::JobArtifact record
       #   * Returning the necessary response data to send the file back
       #
-      # TODO: Rearrange things so this class does not inherit from FileUploader
-      class JobArtifactUploader < FileUploader
-        # rubocop: disable CodeReuse/ActiveRecord
+      class JobArtifactUploader < BaseUploader
         def execute
-          job_artifact = ::Ci::JobArtifact.find_by(id: object_db_id)
+          job_artifact = fetch_resource
 
           unless job_artifact.present?
             return error('Job artifact not found')
@@ -25,6 +23,15 @@ module Gitlab
 
           success(job_artifact.file)
         end
+
+        private
+
+        # rubocop: disable CodeReuse/ActiveRecord
+
+        def fetch_resource
+          ::Ci::JobArtifact.find_by(id: object_db_id)
+        end
+
         # rubocop: enable CodeReuse/ActiveRecord
       end
     end

ee/lib/gitlab/geo/replication/lfs_uploader.rb

@@ -7,11 +7,9 @@ module Gitlab
       #   * Finding an LfsObject record
       #   * Returning the necessary response data to send the file back
       #
-      # TODO: Rearrange things so this class does not inherit from FileUploader
-      class LfsUploader < FileUploader
-        # rubocop: disable CodeReuse/ActiveRecord
+      class LfsUploader < BaseUploader
         def execute
-          lfs_object = LfsObject.find_by(id: object_db_id)
+          lfs_object = fetch_resource
 
           return error('LFS object not found') unless lfs_object
           return error('LFS object not found') if message[:checksum] != lfs_object.oid
@@ -24,6 +22,15 @@ module Gitlab
 
           success(lfs_object.file)
         end
+
+        private
+
+        # rubocop: disable CodeReuse/ActiveRecord
+
+        def fetch_resource
+          LfsObject.find_by(id: object_db_id)
+        end
+
         # rubocop: enable CodeReuse/ActiveRecord
       end
     end