propellor/Propellor/Property/Scheduled.hs

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2014-04-09 04:54:27 +00:00
module Propellor.Property.Scheduled
( period
, Recurrance(..)
, WeekDay
, MonthDay
, YearDay
) where
import Propellor
import Utility.Scheduled
import Data.Time.Clock
import Data.Time.LocalTime
import qualified Data.Map as M
-- | Makes a Property only be checked every so often.
--
-- This uses the description of the Property to keep track of when it was
-- last run.
period :: Property -> Recurrance -> Property
period prop recurrance = Property desc $ do
lasttime <- getLastChecked (propertyDesc prop)
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print lasttime
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nexttime <- fmap startTime <$> nextTime schedule lasttime
t <- localNow
if Just t >= nexttime
then do
r <- ensureProperty prop
setLastChecked t (propertyDesc prop)
return r
else noChange
where
schedule = Schedule recurrance AnyTime
desc = propertyDesc prop ++ " (period " ++ show recurrance ++ ")"
lastCheckedFile :: FilePath
lastCheckedFile = localdir </> ".lastchecked"
getLastChecked :: Desc -> IO (Maybe LocalTime)
getLastChecked desc = M.lookup desc <$> readLastChecked
localNow :: IO LocalTime
localNow = do
now <- getCurrentTime
tz <- getTimeZone now
return $ utcToLocalTime tz now
setLastChecked :: LocalTime -> Desc -> IO ()
setLastChecked time desc = do
m <- readLastChecked
writeLastChecked (M.insert desc time m)
readLastChecked :: IO (M.Map Desc LocalTime)
readLastChecked = fromMaybe M.empty <$> catchDefaultIO Nothing go
where
go = readish <$> readFile lastCheckedFile
writeLastChecked :: M.Map Desc LocalTime -> IO ()
writeLastChecked = writeFile lastCheckedFile . show