I there anywhere some list of basic types usable by grok like
I should be part of grok documentation but is not there!
With thanks and wishes of great day
The docs for grok state;
Currently the only supported conversions are int and float.
You can however use mutate + convert - https://www.elastic.co/guide/en/logstash/current/plugins-filters-mutate.html#plugins-filters-mutate-convert