mirror of
https://github.com/haskell-servant/servant-ekg.git
synced 2024-11-01 08:49:42 +01:00
87 lines
3.4 KiB
Haskell
87 lines
3.4 KiB
Haskell
{-# LANGUAGE DeriveAnyClass #-}
|
|
{-# LANGUAGE DeriveGeneric #-}
|
|
{-# LANGUAGE OverloadedStrings #-}
|
|
{-# LANGUAGE RecordWildCards #-}
|
|
|
|
module Servant.Ekg.Internal where
|
|
|
|
import Control.Exception
|
|
import Control.Monad
|
|
import Data.Hashable (Hashable (..))
|
|
import qualified Data.HashMap.Strict as H
|
|
import Data.Monoid
|
|
import Data.Text (Text)
|
|
import qualified Data.Text as T
|
|
import qualified Data.Text.Encoding as T
|
|
import Data.Time.Clock
|
|
import GHC.Generics (Generic)
|
|
import Network.HTTP.Types (Method, Status (..))
|
|
import Network.Wai (Middleware, responseStatus)
|
|
import System.Metrics
|
|
import qualified System.Metrics.Counter as Counter
|
|
import qualified System.Metrics.Distribution as Distribution
|
|
import qualified System.Metrics.Gauge as Gauge
|
|
|
|
data Meters = Meters
|
|
{ metersInflight :: Gauge.Gauge
|
|
, metersC2XX :: Counter.Counter
|
|
, metersC4XX :: Counter.Counter
|
|
, metersC5XX :: Counter.Counter
|
|
, metersCXXX :: Counter.Counter
|
|
, metersTime :: Distribution.Distribution
|
|
}
|
|
|
|
data APIEndpoint = APIEndpoint {
|
|
pathSegments :: [Text],
|
|
method :: Method
|
|
} deriving (Eq, Hashable, Show, Generic)
|
|
|
|
gaugeInflight :: Gauge.Gauge -> Middleware
|
|
gaugeInflight inflight application request respond =
|
|
bracket_ (Gauge.inc inflight)
|
|
(Gauge.dec inflight)
|
|
(application request respond)
|
|
|
|
-- | Count responses with 2XX, 4XX, 5XX, and XXX response codes.
|
|
countResponseCodes
|
|
:: (Counter.Counter, Counter.Counter, Counter.Counter, Counter.Counter)
|
|
-> Middleware
|
|
countResponseCodes (c2XX, c4XX, c5XX, cXXX) application request respond =
|
|
application request respond'
|
|
where
|
|
respond' res = count (responseStatus res) >> respond res
|
|
count Status{statusCode = sc }
|
|
| 200 <= sc && sc < 300 = Counter.inc c2XX
|
|
| 400 <= sc && sc < 500 = Counter.inc c4XX
|
|
| 500 <= sc && sc < 600 = Counter.inc c5XX
|
|
| otherwise = Counter.inc cXXX
|
|
|
|
responseTimeDistribution :: Distribution.Distribution -> Middleware
|
|
responseTimeDistribution dist application request respond =
|
|
bracket getCurrentTime stop $ const $ application request respond
|
|
where
|
|
stop t1 = do
|
|
t2 <- getCurrentTime
|
|
let dt = diffUTCTime t2 t1
|
|
Distribution.add dist $ fromRational $ (*1000) $ toRational dt
|
|
|
|
initializeMeters :: Store -> APIEndpoint -> IO Meters
|
|
initializeMeters store APIEndpoint{..} = do
|
|
metersInflight <- createGauge (prefix <> "in_flight") store
|
|
metersC2XX <- createCounter (prefix <> "responses.2XX") store
|
|
metersC4XX <- createCounter (prefix <> "responses.4XX") store
|
|
metersC5XX <- createCounter (prefix <> "responses.5XX") store
|
|
metersCXXX <- createCounter (prefix <> "responses.XXX") store
|
|
metersTime <- createDistribution (prefix <> "time_ms") store
|
|
|
|
return Meters{..}
|
|
|
|
where
|
|
prefix = "servant.path." <> path <> "."
|
|
path = T.intercalate "." $ pathSegments <> [T.decodeUtf8 method]
|
|
|
|
initializeMetersTable :: Store -> [APIEndpoint] -> IO (H.HashMap APIEndpoint Meters)
|
|
initializeMetersTable store endpoints = do
|
|
meters <- mapM (initializeMeters store) endpoints
|
|
|
|
return $ H.fromList (zip endpoints meters)
|