wai-logger-2.3.1: A logging system for WAI

Safe HaskellNone




Apache style logger for WAI applications.

An example:

{-# LANGUAGE OverloadedStrings #-}
module Main where

import Blaze.ByteString.Builder (fromByteString)
import Control.Monad.IO.Class (liftIO)
import qualified Data.ByteString.Char8 as BS
import Network.HTTP.Types (status200)
import Network.Wai (Application, responseBuilder)
import Network.Wai.Handler.Warp (run)
import Network.Wai.Logger (withStdoutLogger, ApacheLogger)

main :: IO ()
main = withStdoutLogger $ \aplogger ->
    run 3000 $ logApp aplogger

logApp :: ApacheLogger -> Application
logApp aplogger req response = do
    liftIO $ aplogger req status (Just len)
    response $ responseBuilder status hdr msg
    status = status200
    hdr = [("Content-Type", "text/plain")]
    pong = "PONG"
    msg = fromByteString pong
    len = fromIntegral $ BS.length pong


High level functions

type ApacheLogger = Request -> Status -> Maybe Integer -> IO () Source #

Apache style logger.

withStdoutLogger :: (ApacheLogger -> IO a) -> IO a Source #

Executing a function which takes ApacheLogger. This ApacheLogger writes log message to stdout. Each buffer (4K bytes) is flushed every second.

type ServerPushLogger = Request -> ByteString -> Integer -> IO () Source #

HTTP/2 server push logger in Apache style.

Creating a logger

data ApacheLoggerActions Source #

Function set of Apache style logger.

serverpushLogger :: ApacheLoggerActions -> ServerPushLogger Source #

The HTTP/2 server push logger.

logRotator :: ApacheLoggerActions -> IO () Source #

This is obsoleted. Rotation is done on-demand. So, this is now an empty action.

logRemover :: ApacheLoggerActions -> IO () Source #

Removing resources relating to Apache logger. E.g. flushing and deallocating internal buffers.


data IPAddrSource Source #

Source from which the IP source address of the client is obtained.



From the peer address of the HTTP connection.


From X-Real-IP: or X-Forwarded-For: in the HTTP header.


From the peer address if header is not found.

data LogType :: * #

Logger Type.



No logging.

LogStdout BufSize

Logging to stdout. BufSize is a buffer size

LogStderr BufSize

Logging to stdout. BufSize is a buffer size for each capability.

LogFileNoRotate FilePath BufSize

Logging to a file. BufSize is a buffer size for each capability.

LogFile FileLogSpec BufSize

Logging to a file. BufSize is a buffer size for each capability. File rotation is done on-demand.

LogCallback (LogStr -> IO ()) (IO ())

Logging with a log and flush action. run flush after log each message.

data FileLogSpec :: * #

The spec for logging files





showSockAddr :: SockAddr -> NumericAddress Source #

Convert SockAddr to NumericAddress. If the address is IPv4-embedded IPv6 address, the IPv4 is extracted.

Backward compability

clockDateCacher :: IO (DateCacheGetter, DateCacheUpdater) Source #

Returning DateCacheGetter and DateCacheUpdater.

Note: Since version 2.1.2, this function uses the auto-update package internally, and therefore the DateCacheUpdater value returned need not be called. To wit, the return value is in fact an empty action.

type ZonedDate = FormattedTime Source #

A type for zoned date.

type DateCacheUpdater = IO () Source #

Updateing cached ZonedDate. This should be called every second. See the source code of withStdoutLogger.