Logstash: find out the top users

I want to know whether I can get the top 5 active users through logstash and visualize it in Kibana. the log file looks like this:

2016-02-18 13:58:30,924 comment_created=csearch, user=user107@mail.com, text=csearch
2016-02-18 13:58:35,522 highlight_created, user=user107@mail.com, text=the
2016-02-18 13:58:36,346 highlight_created, user=user107@mail.com, text=kage

in this example the user 'user107@mail.com' has made several activities and I wanna know whether logstash can filter that. At least to show that this is one of the most active users.

Use logstash KV filter to get the user

after indexing the data , getting top 5 user is quite simple using kibana...

Thanks a lot!