It takes too long time to build rpm package on 5.4.1 , why?

When I build rpm package on logstash-5.4.1, it always takes too long time. just as fallows:
.........
Installation successful
** Invoke artifact:clean-bundle-config (first_time)
** Execute artifact:clean-bundle-config
** Invoke artifact:generate_build_metadata (first_time)
** Execute artifact:generate_build_metadata
** Invoke license:generate-notice-file (first_time)
** Invoke bootstrap
** Invoke plugin:install-default
** Execute license:generate-notice-file
[license:generate-notice-file] Generating notice file for default plugin dependencies
** Execute artifact:rpm
[artifact:rpm] building rpm package

It just like stopping running, and will be successful after a few hours. I had never encountered this problem when build rpm pachage on logstash-2.4.1 or logstash-4.1. I couldn't find the reason ,please help me. Thank you!