Set indices based on a field value

Thanks, this works with this configuration :

indices:
  - index: "functional-%{+yyyy.MM.dd}"
    when.equals:
      logger_name: "functional"
  - index: "technical-%{+yyyy.MM.dd}"
    when.equals:
      logger_name: "technical"
  - index: "other-%{+yyyy.MM.dd}"
    when.equals:
      logger_name: "other"

I open a issue here : https://github.com/elastic/beats/issues/3227