Aha!  [mutate#split](http://logstash.net/docs/1.2.2/filters/mutate#split) looks just the ticket.

@fandrei - you'll need open a new PR against the cityindex/logstash repo to handle the `@type:ci_latency_monitor_bot` format.

Let me know if you need any pointers on how to add a [log format](https://github.com/cityindex/logsearch/wiki/How-to-create-%26-test-a-new-log-format); I can't remember if you've done one before.