An intentionally-leaky StatsD interface to Datadog

Usage

• Use envParseStatsSettings to configure things

  data AppSettings = AppSettings
   { -- ...
   , appStatsSettings :: StatsSettings
   }

  loadSettings :: IO AppSettings
  loadSettings = Env.parse id $ AppSettings
    $ -- ...
    * envParseStatsSettings
  

This will read,

• DOGSTATSD_ENABLED=x

• DOGSTATSD_HOST=127.0.0.1

• DOGSTATSD_PORT=8125

• DOGSTATSD_TAGS=[key:value,...]

• Optionally DD_ENV, DD_SERVICE, and DD_VERSION
• Give your App a HasStatsClient instance

  data App = App
    { -- ...
    , appStatsClient :: StatsClient
    }

  instance HasStatsClient App where
    statsClientL = lens appStatsClient $ x y -> { appStatsClient = y }
  

• Use withStatsClient to build and store a client on your App when you run it

  withStatsClient appStatsSettings $ client -> do
    app <- App
      $ ...
      * pure client

    runApp app $ ...
  

• Throughout your application code, emit metrics as desired

  import qualified Freckle.App.Stats as Stats

  myFunction :: (MonadIO m, MonadReader env m, HasStatsClient env) => m ()
  myFunction = do
    start <- liftIO getCurrentTime
    result <- myAction

    Stats.increment "action.attempt"
    Stats.histogramSinceMs "action.duration" start

    case result of
      Left err -> do
        Stats.increment "action.failure"
        -- ...
      Right x -. do
        Stats.increment "action.success"
        -- ...