Renaming log file in filebeat and passing index name

hi can i knowif wish to renmae the log before sending to logstash. Besides that, I also wish to set index name based on respective paths. How can this be done in filebeat. I saw we have something called fields but fields will only set index name . What would be the best approach

- type: log
  paths:
    - /home/navin/log/eai_new.log
    - /home/navin/log/access.log
- type: log
  paths:
    - /home/navin/log/apps.log
    - /home/navin/log/console.log