Network.Wai.Logging.Buffered

Middleware for buffering log messages instead of immediately writing them to a handle.

This allows easy integration with tools providing bulk publish apis like Graphite or Elasticsearch.

   main :: IO ()
   main = do
     forkIO $ runBufferedRequestLogger def
     run 8080 $ bufferedRequestLogger def waiApplication

A note about wildcards: the * wildcard is used to collapse similar URLs for easier reporting on external platforms.

Types

data Config

Configuration arguments for draining the buffer

Constructors

Config

Fields

• maxSize :: Int

  The maximum size allowed for the buffer. After this is hit messages are pushed to stdOut. Defaults to 1000

• publishIntervalSeconds :: Int

  How frequently to publish events to the sink. Defaults to 10 (seconds)

• pubFunc :: Publish

  The sink function. Defaults to print

• useWildcards :: Bool

  Determines whether to publish the original path and a * wildcarded version. Defaults to True

Instances

Default Config

Methods

def :: Config

data Event

Tracks a single Request

Constructors

Event

Fields

• path :: !ByteString

  The request URL

• reportedTime :: !UTCTime

  The time the request occurred

• duration :: !NominalDiffTime

  The request duration

Instances

Eq Event

Methods

(==) :: Event -> Event -> Bool

(/=) :: Event -> Event -> Bool

Ord Event

Methods

compare :: Event -> Event -> Ordering

(<) :: Event -> Event -> Bool

(<=) :: Event -> Event -> Bool

(>) :: Event -> Event -> Bool

(>=) :: Event -> Event -> Bool

max :: Event -> Event -> Event

min :: Event -> Event -> Event

Show Event

Methods

showsPrec :: Int -> Event -> ShowS

show :: Event -> String

showList :: [Event] -> ShowS

type Publish = [Event] -> IO ()

$setup

>>> :set -XOverloadedStrings
>>> import qualified Data.Map as M
>>> import Data.Time.Clock
>>> now <- getCurrentTime
>>> let events = Event "dummy" now <$> [1..]

A log sink.

Functions

bufferedRequestLogger :: Config -> Middleware

Collect timing on all Requests and add them to the buffer. Configuration is controlled via the provided Config

runBufferedRequestLogger :: Config -> IO ()

Based on the provided Config publishes the logged requests & drains the buffer. The ideal configuration depends on your workload, but know that each request is stored as is. I.e. if you handle 1k req/s, then you should make sure 'maxSize'/'publishIntervalSeconds' > 1000.