wai-middleware-prometheus (empty) → 0.1.0.0

raw patch · 5 files changed

+364/−0 lines, 5 filesdep +basedep +bytestringdep +data-defaultsetup-changed

Dependencies added: base, bytestring, data-default, doctest, http-types, prometheus-client, text, time, wai

Files

• LICENSE +202/−0
• Setup.hs +2/−0
• src/Network/Wai/Middleware/Prometheus.hs +105/−0
• tests/doctest.hs +9/−0
• wai-middleware-prometheus.cabal +46/−0

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@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,105 @@+-- | This module provides "Network.Wai" middlware for exporting "Prometheus"+-- metrics and for instrumenting WAI applications.+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE RecordWildCards #-}+module Network.Wai.Middleware.Prometheus (+    prometheus+,   PrometheusSettings (..)+,   Default.def+,   instrumentApp+,   instrumentIO+) where++import Data.Time.Clock (diffUTCTime, getCurrentTime)+import qualified Data.ByteString.Builder as BS+import qualified Data.Default as Default+import qualified Data.Text as T+import qualified Network.HTTP.Types as HTTP+import qualified Network.Wai as Wai+import qualified Prometheus as Prom+++-- | Settings that control the behavior of the Prometheus middleware.+data PrometheusSettings = PrometheusSettings {+        prometheusEndPoint             :: [T.Text]+        -- ^ The path that will be used for exporting metrics. The default value+        -- is ["metrics"] which corresponds to the path /metrics.+    ,   prometheusInstrumentApp        :: Bool+        -- ^ Whether the default instrumentation should be applied to the+        -- application. If this is set to false the application can still be+        -- instrumented using the 'instrumentApp' function. The default value is+        -- True.+    ,   prometheusInstrumentPrometheus :: Bool+        -- ^ Whether the default instrumentation should be applied to the+        -- middleware that serves the metrics endpoint. The default value is+        -- True.+    }++instance Default.Default PrometheusSettings where+    def = PrometheusSettings {+        prometheusEndPoint             = ["metrics"]+    ,   prometheusInstrumentApp        = True+    ,   prometheusInstrumentPrometheus = True+    }++{-# NOINLINE requestLatency #-}+requestLatency :: Prom.Metric (Prom.Vector Prom.Label1 Prom.Summary)+requestLatency = Prom.unsafeRegisterIO $ Prom.vector "handler"+                                       $ Prom.summary info Prom.defaultQuantiles+    where info = Prom.Info "http_request_duration_microseconds"+                           "The HTTP request latencies in microseconds."++-- | Instrument a WAI app with the default WAI metrics.+--+-- If you use this function you will likely want to override the default value+-- of 'prometheusInstrumentApp' to be false so that your app does not get double+-- instrumented.+instrumentApp :: String           -- ^ The label used to identify this app+              -> Wai.Application  -- ^ The app to instrument+              -> Wai.Application  -- ^ The instrumented app+instrumentApp handler app req respond =+    observeMicroSeconds handler (app req respond)++-- | Instrument an IO action with timing metrics. This function can be used if+-- you would like to get more fine grained metrics, for instance this can be+-- used to instrument individual end points.+--+-- If you use this function you will likely want to override the default value+-- of 'prometheusInstrumentApp' to be false so that your app does not get double+-- instrumented.+instrumentIO :: String  -- ^ The label used to identify this IO operation+             -> IO a    -- ^ The IO action to instrument+             -> IO a    -- ^ The instrumented app+instrumentIO = observeMicroSeconds++observeMicroSeconds :: String -> IO a -> IO a+observeMicroSeconds handler io = do+    start  <- getCurrentTime+    result <- io+    end    <- getCurrentTime+    let latency = fromRational $ toRational (end `diffUTCTime` start) * 1000000+    Prom.withLabel handler (Prom.observe latency) requestLatency+    return result++-- | Expose Prometheus metrics and instrument an application with some basic+-- metrics (e.g. request latency).+prometheus :: PrometheusSettings -> Wai.Middleware+prometheus PrometheusSettings{..} app req respond =+    if     Wai.requestMethod req == HTTP.methodGet+        && Wai.pathInfo req == prometheusEndPoint+    then measure measureMetrics "prometheus" $ respondWithMetrics respond+    else measure measureApp "app" $ app req respond+    where+        measureMetrics = prometheusInstrumentPrometheus+        measureApp = prometheusInstrumentApp+        measure shouldInstrument handler io+            | shouldInstrument = observeMicroSeconds handler io+            | otherwise        = io++respondWithMetrics :: (Wai.Response -> IO Wai.ResponseReceived)+                   -> IO Wai.ResponseReceived+respondWithMetrics respond = do+    metrics <- Prom.exportMetricsAsText+    respond $ Wai.responseBuilder HTTP.status200 headers $ BS.byteString metrics+    where+        headers = [(HTTP.hContentType, "text/plain; version=0.0.4")]

@@ -0,0 +1,9 @@+module Main where++import Test.DocTest++main :: IO ()+main = doctest [+        "-isrc"+    ,   "Network.Wai.Middleware.Prometheus"+    ]

@@ -0,0 +1,46 @@+name:                wai-middleware-prometheus+version:             0.1.0.0+synopsis:+    WAI middlware for exposing http://prometheus.io metrics.+description:+    WAI middlware for exposing http://prometheus.io metrics.+homepage:            https://github.com/fimad/prometheus-haskell+license:             Apache-2.0+license-file:        LICENSE+author:              Will Coster+maintainer:          willcoster@gmail.com+copyright:           2015 Will Coster+category:            Network+build-type:          Simple+cabal-version:       >=1.10++source-repository head+  type:     git+  location: https://github.com/fimad/prometheus-haskell++library+  hs-source-dirs:      src/+  default-language:    Haskell2010+  exposed-modules:+      Network.Wai.Middleware.Prometheus+  build-depends:+      base               >=4.6 && <4.8+    , bytestring         >=0.9+    , data-default+    , http-types+    , prometheus-client+    , text               >=0.11+    , time+    , wai                >=3.0+  ghc-options: -Wall++test-suite doctest+  type:                 exitcode-stdio-1.0+  default-language:     Haskell2010+  hs-source-dirs:       tests+  ghc-options:          -Wall+  main-is:              doctest.hs+  build-depends:+      base+    , doctest+    , prometheus-client