git-annex/Utility/LogFile.hs
Joey Hess 1865b28094 assistant: Logs are rotated to avoid them using too much disk space.
This cannot completely guard against a runaway log event, and only runs
every hour anyway, but it should avoid most problems with very
long-running, active assistants using up too much space.
2013-03-01 13:30:48 -04:00

54 lines
1.1 KiB
Haskell

{- log files
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.LogFile where
import Common
import System.Posix
openLog :: FilePath -> IO Fd
openLog logfile = do
rotateLog logfile
openFd logfile WriteOnly (Just stdFileMode)
defaultFileFlags { append = True }
rotateLog :: FilePath -> IO ()
rotateLog logfile = go 0
where
go num
| num > maxLogs = return ()
| otherwise = whenM (doesFileExist currfile) $ do
go (num + 1)
renameFile currfile nextfile
where
currfile = filename num
nextfile = filename (num + 1)
filename n
| n == 0 = logfile
| otherwise = rotatedLog logfile n
rotatedLog :: FilePath -> Int -> FilePath
rotatedLog logfile n = logfile ++ "." ++ show n
{- Lists most recent logs last. -}
listLogs :: FilePath -> IO [FilePath]
listLogs logfile = filterM doesFileExist $ reverse $
logfile : map (rotatedLog logfile) [1..maxLogs]
maxLogs :: Int
maxLogs = 9
redirLog :: Fd -> IO ()
redirLog logfd = do
mapM_ (redir logfd) [stdOutput, stdError]
closeFd logfd
redir :: Fd -> Fd -> IO ()
redir newh h = do
closeFd h
void $ dupTo newh h