git-annex/Assistant/DaemonStatus.hs
Joey Hess 33b914bcf1 pending adds now retried for kqueue
Rethought how to keep track of pending adds that need to be retried later.
The commit thread already run up every second when there are changes,
so let's keep pending adds queued as changes until they're safe to add.

Also, the committer is now smarter about avoiding empty commits when
all the adds are currently unsafe, or in the rare case that an add event
for a symlink is not received in time. It may avoid them entirely.

This seems to work as before for inotify, and is untested for kqueue.

(Actually commit batching seems to be improved for inotify, although I'm
not sure why. I'm seeing only two commits made during large batch
operations, and the first of those is the non-batch mode commit.)
2012-06-20 19:29:53 -04:00

119 lines
3.9 KiB
Haskell

{- git-annex assistant daemon status
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-}
module Assistant.DaemonStatus where
import Common.Annex
import Assistant.ThreadedMonad
import Utility.ThreadScheduler
import Utility.TempFile
import Control.Concurrent
import System.Posix.Types
import Data.Time.Clock.POSIX
import Data.Time
import System.Locale
data DaemonStatus = DaemonStatus
-- False when the daemon is performing its startup scan
{ scanComplete :: Bool
-- Time when a previous process of the daemon was running ok
, lastRunning :: Maybe POSIXTime
-- True when the sanity checker is running
, sanityCheckRunning :: Bool
-- Last time the sanity checker ran
, lastSanityCheck :: Maybe POSIXTime
}
deriving (Show)
type DaemonStatusHandle = MVar DaemonStatus
newDaemonStatus :: DaemonStatus
newDaemonStatus = DaemonStatus
{ scanComplete = False
, lastRunning = Nothing
, sanityCheckRunning = False
, lastSanityCheck = Nothing
}
getDaemonStatus :: DaemonStatusHandle -> Annex DaemonStatus
getDaemonStatus = liftIO . readMVar
modifyDaemonStatus :: DaemonStatusHandle -> (DaemonStatus -> DaemonStatus) -> Annex ()
modifyDaemonStatus handle a = liftIO $ modifyMVar_ handle (return . a)
{- Load any previous daemon status file, and store it in the MVar for this
- process to use as its DaemonStatus. -}
startDaemonStatus :: Annex DaemonStatusHandle
startDaemonStatus = do
file <- fromRepo gitAnnexDaemonStatusFile
status <- liftIO $
catchDefaultIO (readDaemonStatusFile file) newDaemonStatus
liftIO $ newMVar status
{ scanComplete = False
, sanityCheckRunning = False
}
{- This thread wakes up periodically and writes the daemon status to disk. -}
daemonStatusThread :: ThreadState -> DaemonStatusHandle -> IO ()
daemonStatusThread st handle = do
checkpoint
runEvery (Seconds tenMinutes) checkpoint
where
checkpoint = runThreadState st $ do
file <- fromRepo gitAnnexDaemonStatusFile
status <- getDaemonStatus handle
liftIO $ writeDaemonStatusFile file status
{- Don't just dump out the structure, because it will change over time,
- and parts of it are not relevant. -}
writeDaemonStatusFile :: FilePath -> DaemonStatus -> IO ()
writeDaemonStatusFile file status =
viaTmp writeFile file =<< serialized <$> getPOSIXTime
where
serialized now = unlines
[ "lastRunning:" ++ show now
, "scanComplete:" ++ show (scanComplete status)
, "sanityCheckRunning:" ++ show (sanityCheckRunning status)
, "lastSanityCheck:" ++ maybe "" show (lastSanityCheck status)
]
readDaemonStatusFile :: FilePath -> IO DaemonStatus
readDaemonStatusFile file = parse <$> readFile file
where
parse = foldr parseline newDaemonStatus . lines
parseline line status
| key == "lastRunning" = parseval readtime $ \v ->
status { lastRunning = Just v }
| key == "scanComplete" = parseval readish $ \v ->
status { scanComplete = v }
| key == "sanityCheckRunning" = parseval readish $ \v ->
status { sanityCheckRunning = v }
| key == "lastSanityCheck" = parseval readtime $ \v ->
status { lastSanityCheck = Just v }
| otherwise = status -- unparsable line
where
(key, value) = separate (== ':') line
parseval parser a = maybe status a (parser value)
readtime s = do
d <- parseTime defaultTimeLocale "%s%Qs" s
Just $ utcTimeToPOSIXSeconds d
{- Checks if a time stamp was made after the daemon was lastRunning.
-
- Some slop is built in; this really checks if the time stamp was made
- at least ten minutes after the daemon was lastRunning. This is to
- ensure the daemon shut down cleanly, and deal with minor clock skew.
-
- If the daemon has never ran before, this always returns False.
-}
afterLastDaemonRun :: EpochTime -> DaemonStatus -> Bool
afterLastDaemonRun timestamp status = maybe False (< t) (lastRunning status)
where
t = realToFrac (timestamp + slop) :: POSIXTime
slop = fromIntegral tenMinutes
tenMinutes :: Int
tenMinutes = 10 * 60