1 files changed, 59 insertions, 0 deletions
diff --git a/lib/gitlab/import_export/json/ndjson_writer.rb b/lib/gitlab/import_export/json/ndjson_writer.rb
new file mode 100644
index 00000000000..e74fdd74049
--- /dev/null
+++ b/lib/gitlab/import_export/json/ndjson_writer.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module ImportExport
+    module JSON
+      class NdjsonWriter
+        include Gitlab::ImportExport::CommandLineUtil
+
+        def initialize(dir_path)
+          @dir_path = dir_path
+        end
+
+        def close
+        end
+
+        def write_attributes(exportable_path, hash)
+          # It will create:
+          # tree/project.json
+          with_file("#{exportable_path}.json") do |file|
+            file.write(hash.to_json)
+          end
+        end
+
+        def write_relation(exportable_path, relation, value)
+          # It will create:
+          # tree/project/ci_cd_setting.ndjson
+          with_file(exportable_path, "#{relation}.ndjson") do |file|
+            file.write(value.to_json)
+          end
+        end
+
+        def write_relation_array(exportable_path, relation, items)
+          # It will create:
+          # tree/project/merge_requests.ndjson
+          with_file(exportable_path, "#{relation}.ndjson") do |file|
+            items.each do |item|
+              file.write(item.to_json)
+              file.write("\n")
+            end
+          end
+        end
+
+        private
+
+        def with_file(*path)
+          file_path = File.join(@dir_path, *path)
+          raise ArgumentError, "The #{file_path} already exist" if File.exist?(file_path)
+
+          # ensure that path is created
+          mkdir_p(File.dirname(file_path))
+
+          File.open(file_path, "wb") do |file|
+            yield(file)
+          end
+        end
+      end
+    end
+  end
+end