Network.Wai.Logger

wai-logger-2.3.0: A logging system for WAI

Safe Haskell | None
Language | Haskell2010

Network.Wai.Logger

Contents

- High level functions
- Creating a logger
- Types
- Utilities
- Backward compability

Description

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
      where
        status = status200
        hdr = [("Content-Type", "text/plain")]
        pong = "PONG"
        msg = fromByteString pong
        len = fromIntegral $ BS.length pong

Synopsis

- type ApacheLogger = Request -> Status -> Maybe Integer -> IO ()
- withStdoutLogger :: (ApacheLogger -> IO a) -> IO a
- type ServerPushLogger = Request -> ByteString -> Integer -> IO ()
- data ApacheLoggerActions
- apacheLogger :: ApacheLoggerActions -> ApacheLogger
- serverpushLogger :: ApacheLoggerActions -> ServerPushLogger
- logRotator :: ApacheLoggerActions -> IO ()
- logRemover :: ApacheLoggerActions -> IO ()
- initLogger :: IPAddrSource -> LogType -> IO FormattedTime -> IO ApacheLoggerActions
- data IPAddrSource
  - = FromSocket
  - | FromHeader
  - | FromFallback
- data LogType :: *
  - = LogNone
  - | LogStdout BufSize
  - | LogStderr BufSize
  - | LogFileNoRotate FilePath BufSize
  - | LogFile FileLogSpec BufSize
  - | LogCallback (LogStr -> IO ()) (IO ())
- data FileLogSpec :: * = FileLogSpec {
  - log_file :: FilePath
  - log_file_size :: Integer
  - log_backup_number :: Int
  }
- showSockAddr :: SockAddr -> NumericAddress
- logCheck :: LogType -> IO ()
- clockDateCacher :: IO (DateCacheGetter, DateCacheUpdater)
- type ZonedDate = FormattedTime
- type DateCacheGetter = IO ZonedDate
- type DateCacheUpdater = IO ()

# High level functions

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

Apache style logger.

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

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 () #

HTTP/2 server push logger in Apache style.

# Creating a logger

data ApacheLoggerActions #

Function set of Apache style logger.

apacheLogger :: ApacheLoggerActions -> ApacheLogger #

The Apache logger.

serverpushLogger :: ApacheLoggerActions -> ServerPushLogger #

The HTTP/2 server push logger.

logRotator :: ApacheLoggerActions -> IO () #

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

logRemover :: ApacheLoggerActions -> IO () #

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

initLogger :: IPAddrSource -> LogType -> IO FormattedTime -> IO ApacheLoggerActions #

Creating `ApacheLogger` according to `LogType`.

# Types

data IPAddrSource #

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

Constructors

FromSocket | From the peer address of the HTTP connection.
FromHeader | From X-Real-IP: or X-Forwarded-For: in the HTTP header.
FromFallback | From the peer address if header is not found.

data LogType :: * #

Logger Type.

Constructors

LogNone | 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

Constructors

FileLogSpec |
Fields log_file :: FilePath log_file_size :: Integer Max log file size (in bytes) before requiring rotation. log_backup_number :: Int Max number of rotated log files to keep around before overwriting the oldest one.

# Utilities

showSockAddr :: SockAddr -> NumericAddress #

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

logCheck :: LogType -> IO () #

# Backward compability

clockDateCacher :: IO (DateCacheGetter, DateCacheUpdater) #

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 #

A type for zoned date.

type DateCacheGetter = IO ZonedDate #

Getting cached `ZonedDate`.

type DateCacheUpdater = IO () #

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