diff options
author | 2012-06-13 13:35:15 -0400 | |
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committer | 2012-06-13 13:35:15 -0400 | |
commit | ff2414427b21324722ed74b754d72307084fc6a5 (patch) | |
tree | c7674bd5dfa4bab99f1356df6d93308374428a54 /Assistant/DaemonStatus.hs | |
parent | ccc50052453ccaf2db0c371c5c36b5eea3e9191a (diff) |
implement daemon status serialization to a file
Also afterLastDaemonRun, with 10 minute slop to handle majority of clock
skew issues.
Diffstat (limited to 'Assistant/DaemonStatus.hs')
-rw-r--r-- | Assistant/DaemonStatus.hs | 51 |
1 files changed, 49 insertions, 2 deletions
diff --git a/Assistant/DaemonStatus.hs b/Assistant/DaemonStatus.hs index 43a8c7e2f..3615d0e5c 100644 --- a/Assistant/DaemonStatus.hs +++ b/Assistant/DaemonStatus.hs @@ -6,16 +6,21 @@ module Assistant.DaemonStatus where import Common.Annex +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 EpochTime + , lastRunning :: Maybe POSIXTime } + deriving (Show) type DaemonStatusHandle = MVar DaemonStatus @@ -32,4 +37,46 @@ getDaemonStatus :: DaemonStatusHandle -> Annex DaemonStatus getDaemonStatus = liftIO . readMVar modifyDaemonStatus :: DaemonStatusHandle -> (DaemonStatus -> DaemonStatus) -> Annex () -modifyDaemonStatus status a = liftIO $ modifyMVar_ status (return . a) +modifyDaemonStatus handle a = liftIO $ modifyMVar_ handle (return . a) + +{- 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 <$> getPOSIXTime + where + serialized now = unlines + [ "lastRunning:" ++ show now + , "scanComplete:" ++ show (scanComplete status) + ] + +readDaemonStatusFile :: FilePath -> IO DaemonStatus +readDaemonStatusFile file = parse <$> 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 } + | 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 True (< t) (lastRunning status) + where + t = realToFrac (timestamp + slop) :: POSIXTime + slop = 10 * 60 |