1 files changed, 140 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/legacy_upload_mover.rb b/lib/gitlab/background_migration/legacy_upload_mover.rb
new file mode 100644
index 00000000000..051c1176edb
--- /dev/null
+++ b/lib/gitlab/background_migration/legacy_upload_mover.rb
@@ -0,0 +1,140 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # This class takes a legacy upload and migrates it to the correct location
+    class LegacyUploadMover
+      include Gitlab::Utils::StrongMemoize
+
+      attr_reader :upload, :project, :note
+      attr_accessor :logger
+
+      def initialize(upload)
+        @upload = upload
+        @note = Note.find_by(id: upload.model_id)
+        @project = note&.project
+        @logger = Gitlab::BackgroundMigration::Logger.build
+      end
+
+      def execute
+        return unless upload
+
+        if !project
+          # if we don't have models associated with the upload we can not move it
+          warn('Deleting upload due to model not found.')
+
+          destroy_legacy_upload
+        elsif note.is_a?(LegacyDiffNote)
+          return unless move_legacy_diff_file
+
+          migrate_upload
+        elsif !legacy_file_exists?
+          warn('Deleting upload due to file not found.')
+          destroy_legacy_upload
+        else
+          migrate_upload
+        end
+      end
+
+      private
+
+      def migrate_upload
+        return unless copy_upload_to_project
+
+        add_upload_link_to_note_text
+        destroy_legacy_file
+        destroy_legacy_upload
+      end
+
+      # we should proceed and log whenever one upload copy fails, no matter the reasons
+      # rubocop: disable Lint/RescueException
+      def copy_upload_to_project
+        @uploader = FileUploader.copy_to(legacy_file_uploader, project)
+
+        logger.info(
+          message: 'MigrateLegacyUploads: File copied successfully',
+          old_path: legacy_file_uploader.file.path, new_path: @uploader.file.path
+        )
+        true
+      rescue Exception => e
+        warn(
+          'File could not be copied to project uploads',
+          file_path: legacy_file_uploader.file.path, error: e.message
+        )
+        false
+      end
+      # rubocop: enable Lint/RescueException
+
+      def destroy_legacy_upload
+        if note
+          note.remove_attachment = true
+          note.save
+        end
+
+        if upload.destroy
+          logger.info(message: 'MigrateLegacyUploads: Upload was destroyed.', upload: upload.inspect)
+        else
+          warn('MigrateLegacyUploads: Upload destroy failed.')
+        end
+      end
+
+      def destroy_legacy_file
+        legacy_file_uploader.file.delete
+      end
+
+      def add_upload_link_to_note_text
+        new_text = "#{note.note} \n #{@uploader.markdown_link}"
+        # Bypass validations because old data may have invalid
+        # noteable values. If we fail hard here, we may kill the
+        # entire background migration, which affects a range of notes.
+        note.update_attribute(:note, new_text)
+      end
+
+      def legacy_file_uploader
+        strong_memoize(:legacy_file_uploader) do
+          uploader = upload.build_uploader
+          uploader.retrieve_from_store!(File.basename(upload.path))
+          uploader
+        end
+      end
+
+      def legacy_file_exists?
+        legacy_file_uploader.file.exists?
+      end
+
+      # we should proceed and log whenever one upload copy fails, no matter the reasons
+      # rubocop: disable Lint/RescueException
+      def move_legacy_diff_file
+        old_path = upload.absolute_path
+        old_path_sub = '-/system/note/attachment'
+
+        if !File.exist?(old_path) || !old_path.include?(old_path_sub)
+          log_legacy_diff_note_problem(old_path)
+          return false
+        end
+
+        new_path = upload.absolute_path.sub(old_path_sub, '-/system/legacy_diff_note/attachment')
+        new_dir = File.dirname(new_path)
+        FileUtils.mkdir_p(new_dir)
+
+        FileUtils.mv(old_path, new_path)
+      rescue Exception => e
+        log_legacy_diff_note_problem(old_path, new_path, e)
+        false
+      end
+
+      def warn(message, params = {})
+        logger.warn(
+          params.merge(message: "MigrateLegacyUploads: #{message}", upload: upload.inspect)
+        )
+      end
+
+      def log_legacy_diff_note_problem(old_path, new_path = nil, error = nil)
+        warn('LegacyDiffNote upload could not be moved to a new path',
+          old_path: old_path, new_path: new_path, error: error&.message
+        )
+      end
+      # rubocop: enable Lint/RescueException
+    end
+  end
+end