propellor/Propellor/Property/Scheduled.hs

68 lines
1.8 KiB
Haskell

module Propellor.Property.Scheduled
( period
, periodParse
, 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 <- liftIO $ getLastChecked (propertyDesc prop)
nexttime <- liftIO $ fmap startTime <$> nextTime schedule lasttime
t <- liftIO localNow
if Just t >= nexttime
then do
r <- ensureProperty prop
liftIO $ setLastChecked t (propertyDesc prop)
return r
else noChange
where
schedule = Schedule recurrance AnyTime
desc = propertyDesc prop ++ " (period " ++ fromRecurrance recurrance ++ ")"
-- | Like period, but parse a human-friendly string.
periodParse :: Property -> String -> Property
periodParse prop s = case toRecurrance s of
Just recurrance -> period prop recurrance
Nothing -> Property "periodParse" $ do
liftIO $ warningMessage $ "failed periodParse: " ++ s
noChange
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