Migrate legacy uploads to the project location50070-legacy-attachments

Uploads coming from AttachmentUploader
need to be moved to the currently supported location
(FileUploader)

1 files changed, 128 insertions, 0 deletions

diff --git a/lib/gitlab/background_migration/migrate_legacy_uploads.rb b/lib/gitlab/background_migration/migrate_legacy_uploads.rb
new file mode 100644
index 00000000000..af1ad930aed
--- /dev/null
+++ b/lib/gitlab/background_migration/migrate_legacy_uploads.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # This migration takes all legacy uploads (that were uploaded using AttachmentUploader)
+    # and migrate them to the new (FileUploader) location (=under projects).
+    #
+    # We have dependencies (uploaders) in this migration because extracting code would add a lot of complexity
+    # and possible errors could appear as the logic in the uploaders is not trivial.
+    #
+    # This migration will be removed in 12.4 in order to get rid of a migration that depends on
+    # the application code.
+    class MigrateLegacyUploads
+      include Database::MigrationHelpers
+      include ::Gitlab::Utils::StrongMemoize
+
+      # This class takes a legacy upload and migrates it to the correct location
+      class UploadMover
+        include Gitlab::Utils::StrongMemoize
+
+        attr_reader :upload, :project, :note
+
+        def initialize(upload)
+          @upload = upload
+          @note = Note.find_by(id: upload.model_id)
+          @project = note&.project
+        end
+
+        def execute
+          return unless upload
+
+          if !project
+            # if we don't have models associated with the upload we can not move it
+            say "MigrateLegacyUploads: Deleting upload due to model not found: #{upload.inspect}"
+            destroy_legacy_upload
+          elsif note.is_a?(LegacyDiffNote)
+            handle_legacy_note_upload
+          elsif !legacy_file_exists?
+            # if we can not find the file we just remove the upload record
+            say "MigrateLegacyUploads: Deleting upload due to file not found: #{upload.inspect}"
+            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)
+
+          say "MigrateLegacyUploads: Copied file #{legacy_file_uploader.file.path} -> #{@uploader.file.path}"
+          true
+        rescue Exception => e
+          say "MigrateLegacyUploads: File #{legacy_file_uploader.file.path} couldn't be copied to project uploads. Error: #{e.message}"
+          false
+        end
+        # rubocop: enable Lint/RescueException
+
+        def destroy_legacy_upload
+          note.remove_attachment = true
+          note.save
+
+          if upload.destroy
+            say "MigrateLegacyUploads: Upload #{upload.inspect} was destroyed."
+          else
+            say "MigrateLegacyUploads: Upload #{upload.inspect} 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}"
+          note.update!(
+            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
+
+        def handle_legacy_note_upload
+          note.note += "\n \n Attachment ##{upload.id} with URL \"#{note.attachment.url}\" failed to migrate \
+               for model class #{note.class}. See #{help_doc_link}."
+          note.save
+
+          say "MigrateLegacyUploads: LegacyDiffNote ##{note.id} found, can't move the file: #{upload.inspect} for upload ##{upload.id}. See #{help_doc_link}."
+        end
+
+        def say(message)
+          Rails.logger.info(message)
+        end
+
+        def help_doc_link
+          'https://docs.gitlab.com/ee/administration/troubleshooting/migrations.html#legacy-upload-migration'
+        end
+      end
+
+      def perform(start_id, end_id)
+        Upload.where(id: start_id..end_id, uploader: 'AttachmentUploader').find_each do |upload|
+          UploadMover.new(upload).execute
+        end
+      end
+    end
+  end
+end