Ingest Logstash logs Logstash

Trying to ingest the logstash logs that i have in logstash/logstash.log and logstash/logstash.err into elasticsearch with logstash.

This is the format, I think it is a ruby hash object --
{:timestamp=>"2015-12-03T18:08:09.382000-0800", :message=>"Failed to flush outgoing items", :level=>:warn}

which filter should I use to structure these logs? I was going to use the ruby filter plugin to handle it with raw ruby, but i was wondering if there was a cleaner way?