fradrive/src/Cron.hs

255 lines
9.9 KiB
Haskell

module Cron
( evalCronMatch
, CronNextMatch(..)
, nextCronMatch
, module Cron.Types
) where
import ClassyPrelude
import Prelude (lcm)
import Cron.Types
import Data.Time
import Data.Time.Calendar.OrdinalDate (toOrdinalDate, fromOrdinalDateValid)
import Data.Time.Calendar.WeekDate (toWeekDate, fromWeekDate, fromWeekDateValid)
import Data.Time.Zones
import Numeric.Natural
import Data.Ratio ((%))
import qualified Data.Set as Set
import Utils.Lens hiding (from, to)
data CronDate = CronDate
{ cdYear, cdWeekOfYear, cdDayOfYear
, cdMonth, cdWeekOfMonth, cdDayOfMonth
, cdDayOfWeek
, cdHour, cdMinute, cdSecond :: Natural
} deriving (Eq, Show, Read)
makeLenses_ ''CronDate
evalCronMatch :: CronMatch -> Natural -> Bool
evalCronMatch CronMatchAny _ = True
evalCronMatch CronMatchNone _ = False
evalCronMatch (CronMatchSome xs) x = Set.member x $ toNullable xs
evalCronMatch (CronMatchStep step) x = (x `mod` step) == 0
evalCronMatch (CronMatchContiguous from to) x = from <= x && x <= to
evalCronMatch (CronMatchIntersect a b) x = evalCronMatch a x && evalCronMatch b x
evalCronMatch (CronMatchUnion a b) x = evalCronMatch a x || evalCronMatch b x
toCronDate :: LocalTime -> CronDate
toCronDate LocalTime{..} = CronDate{..}
where
(fromInteger -> cdYear, fromIntegral -> cdMonth, fromIntegral -> cdDayOfMonth)
= toGregorian localDay
(_, fromIntegral -> cdDayOfYear)
= toOrdinalDate localDay
(_, fromIntegral -> cdWeekOfYear, fromIntegral -> cdDayOfWeek)
= toWeekDate localDay
cdWeekOfMonth = go 1 localDay
where
go :: Natural -> Day -> Natural
go n day
| dow /= 4 = go n $ fromWeekDate y w 4 -- According to ISO week of month is determined by Thursday
| m == m' = go (succ n) day'
| otherwise = n
where
(y, w, dow) = toWeekDate day
day'
| w /= 0 = fromWeekDate y (pred w) dow
| otherwise = fromWeekDate (pred y) 53 dow
(_, m, _) = toGregorian day
(_, m', _) = toGregorian day'
TimeOfDay
{ todHour = fromIntegral -> cdHour
, todMin = fromIntegral -> cdMinute
, todSec = round -> cdSecond
} = localTimeOfDay
consistentCronDate :: CronDate -> Bool
consistentCronDate cd@CronDate{ cdWeekOfMonth = _, ..} = fromMaybe False $ do
gDay <- fromGregorianValid (fromIntegral cdYear) (fromIntegral cdMonth) (fromIntegral cdDayOfMonth)
wDay <- fromWeekDateValid (fromIntegral cdYear) (fromIntegral cdWeekOfYear) (fromIntegral cdDayOfWeek)
guard $ gDay == wDay
oDay <- fromOrdinalDateValid (fromIntegral cdYear) (fromIntegral cdDayOfYear)
guard $ wDay == oDay
guard $ ((==) `on` cdWeekOfMonth) cd (toCronDate $ LocalTime wDay (error "TimeOfDay inspected in toCronDate"))
return True
data CronNextMatch a = MatchAsap | MatchAt a | MatchNone
deriving (Eq, Ord, Show, Read, Functor)
instance Applicative CronNextMatch where
pure = MatchAt
_ <*> MatchNone = MatchNone
MatchNone <*> _ = MatchNone
_ <*> MatchAsap = MatchAsap
MatchAsap <*> _ = MatchAsap
MatchAt f <*> MatchAt x = MatchAt $ f x
instance Alternative CronNextMatch where
empty = MatchNone
x <|> MatchNone = x
MatchNone <|> x = x
_ <|> MatchAsap = MatchAsap
MatchAsap <|> _ = MatchAsap
(MatchAt a) <|> (MatchAt _) = MatchAt a
listToMatch :: [a] -> CronNextMatch a
listToMatch [] = MatchNone
listToMatch (t:_) = MatchAt t
genMatch :: Int -- ^ Period
-> Bool -- ^ Modular
-> Natural -- ^ Start value
-> CronMatch
-> [Natural]
genMatch p m st CronMatchAny = take p $ map (bool id (succ . (`mod` fromIntegral p)) m) [st..]
genMatch _ _ _ CronMatchNone = []
genMatch p m _ (CronMatchSome xs) = take p . map (bool id (succ . (`mod` fromIntegral p)) m) . Set.toAscList $ toNullable xs
genMatch p m st (CronMatchStep step) = do
start <- [st..st + step]
guard $ (start `mod` step) == 0
take (ceiling $ fromIntegral p % step) $ map (bool id (succ . (`mod` fromIntegral p)) m) [start,start + step..]
genMatch p m st (CronMatchContiguous from to) = take p . map (bool id (succ . (`mod` fromIntegral p)) m) $ [max st from..to]
genMatch _ _ _ (CronMatchIntersect CronMatchNone _) = []
genMatch _ _ _ (CronMatchIntersect _ CronMatchNone) = []
genMatch p m st (CronMatchIntersect CronMatchAny other) = genMatch p m st other
genMatch p m st (CronMatchIntersect other CronMatchAny) = genMatch p m st other
genMatch p m st (CronMatchIntersect (CronMatchStep st1) (CronMatchStep st2))
= genMatch p m st . CronMatchStep $ lcm st1 st2
genMatch p m st (CronMatchIntersect aGen bGen)
| [] <- as' = []
| (a:as) <- as' = mergeAnd (a:as) (genMatch p m a bGen)
where
as' = genMatch p m st aGen
mergeAnd [] _ = []
mergeAnd _ [] = []
mergeAnd (a:as) (b:bs)
| a < b = mergeAnd as (b:bs)
| a == b = a : mergeAnd as bs
| otherwise = mergeAnd (a:as) bs
genMatch p m st (CronMatchUnion CronMatchNone other) = genMatch p m st other
genMatch p m st (CronMatchUnion other CronMatchNone) = genMatch p m st other
genMatch p m st (CronMatchUnion CronMatchAny _) = genMatch p m st CronMatchAny
genMatch p m st (CronMatchUnion _ CronMatchAny) = genMatch p m st CronMatchAny
genMatch p m st (CronMatchUnion aGen bGen) = merge (genMatch p m st aGen) (genMatch p m st bGen)
where
merge [] bs = bs
merge as [] = as
merge (a:as) (b:bs)
| a < b = a : merge as (b:bs)
| a == b = a : merge as bs
| otherwise = b : merge (a:as) bs
nextCronMatch :: TZ -- ^ Timezone of the `Cron`-Entry
-> Maybe UTCTime -- ^ Time of last execution of the job
-> NominalDiffTime -- ^ Scheduling precision
-> UTCTime -- ^ Current time, used only for `CronCalendar`
-> Cron
-> CronNextMatch UTCTime
nextCronMatch tz mPrev prec now c@Cron{..} = case notAfter of
MatchAsap -> MatchNone
MatchAt ts
| MatchAt ts' <- nextMatch
, ts' <= ts -> MatchAt ts'
| MatchAsap <- nextMatch
, now <= ts -> MatchAsap
| otherwise -> MatchNone
MatchNone -> nextMatch
where
notAfter
| Right c' <- cronNotAfter
, Just ref <- notAfterRef
= execRef' ref False c'
| Left diff <- cronNotAfter
, Just ref <- notAfterRef
= MatchAt $ diff `addUTCTime` ref
| otherwise = MatchNone
notAfterRef
| Just prevT <- mPrev = Just prevT
| otherwise = case execRef' now False cronInitial of
MatchAsap -> error "execRef' should not return MatchAsap"
MatchAt t -> Just t
MatchNone -> Nothing
nextMatch = case mPrev of
Nothing
-> execRef now False cronInitial
Just prevT
-> case cronRepeat of
CronRepeatOnChange
| not $ matchesCron tz Nothing prec prevT c
-> let
cutoffTime = addUTCTime cronRateLimit prevT
in case execRef now False cronInitial of
MatchAsap
| now < cutoffTime -> MatchAt cutoffTime
MatchAt ts
| ts < cutoffTime -> MatchAt cutoffTime
other -> other
CronRepeatScheduled cronNext
-> case cronNext of
CronAsap
| addUTCTime cronRateLimit prevT <= now
-> MatchAsap
| otherwise
-> MatchAt $ addUTCTime cronRateLimit prevT
_other
-> execRef (addUTCTime cronRateLimit prevT) True cronNext
_other -> MatchNone
execRef ref wasExecd cronAbsolute = case execRef' ref wasExecd cronAbsolute of
MatchAt t
| t <= ref -> MatchAsap
other -> other
execRef' ref wasExecd cronAbsolute = case cronAbsolute of
CronAsap -> MatchAt ref
CronTimestamp{ cronTimestamp = localTimeToUTCTZ tz -> ts }
| ref <= ts || not wasExecd -> MatchAt ts
| otherwise -> MatchNone
CronCalendar{..} -> listToMatch $ do
let CronDate{..} = toCronDate $ utcToLocalTimeTZ tz ref
mCronYear <- genMatch 400 False cdYear cronYear
mCronWeekOfYear <- genMatch 53 True cdWeekOfYear cronWeekOfYear
mCronDayOfYear <- genMatch 366 True cdDayOfYear cronDayOfYear
mCronMonth <- genMatch 12 True cdMonth cronMonth
mCronWeekOfMonth <- genMatch 5 True cdWeekOfMonth cronWeekOfMonth
mCronDayOfMonth <- genMatch 31 True cdDayOfMonth cronDayOfMonth
mCronDayOfWeek <- genMatch 7 True cdDayOfWeek cronDayOfWeek
mCronHour <- genMatch 24 True cdHour cronHour
mCronMinute <- genMatch 60 True cdMinute cronMinute
mCronSecond <- genMatch 60 True cdSecond cronSecond
guard $ consistentCronDate CronDate
{ cdYear = mCronYear, cdMonth = mCronMonth, cdDayOfMonth = mCronDayOfMonth
, cdHour = mCronHour, cdMinute = mCronMinute, cdSecond = mCronSecond
, cdWeekOfYear = mCronWeekOfYear, cdWeekOfMonth = mCronWeekOfMonth
, cdDayOfYear = mCronDayOfYear, cdDayOfWeek = mCronDayOfWeek
}
localDay <- maybeToList $ fromGregorianValid (fromIntegral mCronYear) (fromIntegral mCronMonth) (fromIntegral mCronDayOfMonth)
let localTimeOfDay = TimeOfDay (fromIntegral mCronHour) (fromIntegral mCronMinute) (fromIntegral mCronSecond)
return $ localTimeToUTCTZ tz LocalTime{..}
CronNotScheduled -> MatchNone
matchesCron :: TZ -- ^ Timezone of the `Cron`-Entry
-> Maybe UTCTime -- ^ Previous execution of the job
-> NominalDiffTime -- ^ Scheduling precision
-> UTCTime -- ^ "Current" time
-> Cron
-> Bool
-- ^ @matchesCron tz prev prec now c@ determines whether the given `Cron`
-- specification @c@ should match @now@, under the assumption that the next
-- check will occur no earlier than @now + prec@.
matchesCron tz mPrev prec now cron = case nextCronMatch tz mPrev prec now cron of
MatchAsap -> True
MatchNone -> False
MatchAt ts -> ts <= addUTCTime prec now