simplifed version of http://riemann.io/howto.html#alerting-when-a-certain-percentage-of-events-happe

gistfile1.clj

(streams
  (where (service "riemann streams rate")
    (fixed-time-window 10
      (smap (fn [events]
        (let [event_count (count events) now (quot (System/currentTimeMillis) 1000)]
          (prn   {:host "foo" :service "bar" :metric event_count :time now})
          (index {:host "foo" :service "bar" :metric event_count :time now})
        )
      ))
    )
  )
)