A simple and modern, type safe, idiomatic Haskell client for
Prometheus monitoring. Specifically there is
no use of unsafe IO or manual ByteString construction from lists of
bytes. Batteries-included web server. . [Usage Example]
{-# LANGUAGE OverloadedStrings #-}
module Example where
import Control.Monad.IO.Class (liftIO)
import System.Metrics.Prometheus.Concurrent.Http (serveHttpTextMetricsT)
import System.Metrics.Prometheus.Concurrent.RegistryT
import System.Metrics.Prometheus.Metric.Counter (inc)
import System.Metrics.Prometheus.MetricId
main :: IO ()
main = runRegistryT $ do
-- Labels can be defined as lists or added to an empty label set
connectSuccessGauge <- registerGauge "example_connections" (fromList [("login", "success")])
connectFailureGauge <- registerGauge "example_connections" (addLabel "login" "failure" mempty)
connectCounter <- registerCounter "example_connection_total" mempty
latencyHistogram <- registerHistogram "example_round_trip_latency_ms" mempty [10, 20..100]
liftIO $ inc connectCounter -- increment a counter
-- [...] pass metric handles to the rest of the app
serveHttpTextMetricsT 8080 ["metrics"] -- http://localhost:8080/metric server
Advanced Usage
A Registry and StateT-based RegistryT are available for unit
testing or generating lists of [IO a] actions that can be
sequenced and returned from pure code to be applied.