164 lines
4.9 KiB
Haskell
164 lines
4.9 KiB
Haskell
{-# LANGUAGE PackageImports #-}
|
|
|
|
module Propellor.Property where
|
|
|
|
import System.Directory
|
|
import Control.Monad
|
|
import Data.Monoid
|
|
import Data.List
|
|
import Control.Monad.IfElse
|
|
import "mtl" Control.Monad.Reader
|
|
|
|
import Propellor.Types
|
|
import Propellor.Types.Attr
|
|
import Propellor.Attr
|
|
import Propellor.Engine
|
|
import Utility.Monad
|
|
import System.FilePath
|
|
|
|
-- Constructs a Property.
|
|
property :: Desc -> Propellor Result -> Property
|
|
property d s = Property d s id
|
|
|
|
-- | Combines a list of properties, resulting in a single property
|
|
-- that when run will run each property in the list in turn,
|
|
-- and print out the description of each as it's run. Does not stop
|
|
-- on failure; does propigate overall success/failure.
|
|
propertyList :: Desc -> [Property] -> Property
|
|
propertyList desc ps = Property desc (ensureProperties ps) (combineSetAttrs ps)
|
|
|
|
-- | Combines a list of properties, resulting in one property that
|
|
-- ensures each in turn, stopping on failure.
|
|
combineProperties :: Desc -> [Property] -> Property
|
|
combineProperties desc ps = Property desc (go ps NoChange) (combineSetAttrs ps)
|
|
where
|
|
go [] rs = return rs
|
|
go (l:ls) rs = do
|
|
r <- ensureProperty l
|
|
case r of
|
|
FailedChange -> return FailedChange
|
|
_ -> go ls (r <> rs)
|
|
|
|
-- | Combines together two properties, resulting in one property
|
|
-- that ensures the first, and if the first succeeds, ensures the second.
|
|
-- The property uses the description of the first property.
|
|
before :: Property -> Property -> Property
|
|
p1 `before` p2 = p2 `requires` p1
|
|
`describe` (propertyDesc p1)
|
|
|
|
-- | Makes a perhaps non-idempotent Property be idempotent by using a flag
|
|
-- file to indicate whether it has run before.
|
|
-- Use with caution.
|
|
flagFile :: Property -> FilePath -> Property
|
|
flagFile p = flagFile' p . return
|
|
|
|
flagFile' :: Property -> IO FilePath -> Property
|
|
flagFile' p getflagfile = adjustProperty p $ \satisfy -> do
|
|
flagfile <- liftIO getflagfile
|
|
go satisfy flagfile =<< liftIO (doesFileExist flagfile)
|
|
where
|
|
go _ _ True = return NoChange
|
|
go satisfy flagfile False = do
|
|
r <- satisfy
|
|
when (r == MadeChange) $ liftIO $
|
|
unlessM (doesFileExist flagfile) $ do
|
|
createDirectoryIfMissing True (takeDirectory flagfile)
|
|
writeFile flagfile ""
|
|
return r
|
|
|
|
--- | Whenever a change has to be made for a Property, causes a hook
|
|
-- Property to also be run, but not otherwise.
|
|
onChange :: Property -> Property -> Property
|
|
p `onChange` hook = Property (propertyDesc p) satisfy (combineSetAttr p hook)
|
|
where
|
|
satisfy = do
|
|
r <- ensureProperty p
|
|
case r of
|
|
MadeChange -> do
|
|
r' <- ensureProperty hook
|
|
return $ r <> r'
|
|
_ -> return r
|
|
|
|
(==>) :: Desc -> Property -> Property
|
|
(==>) = flip describe
|
|
infixl 1 ==>
|
|
|
|
-- | Makes a Property only need to do anything when a test succeeds.
|
|
check :: IO Bool -> Property -> Property
|
|
check c p = adjustProperty p $ \satisfy -> ifM (liftIO c)
|
|
( satisfy
|
|
, return NoChange
|
|
)
|
|
|
|
-- | Marks a Property as trivial. It can only return FailedChange or
|
|
-- NoChange.
|
|
--
|
|
-- Useful when it's just as expensive to check if a change needs
|
|
-- to be made as it is to just idempotently assure the property is
|
|
-- satisfied. For example, chmodding a file.
|
|
trivial :: Property -> Property
|
|
trivial p = adjustProperty p $ \satisfy -> do
|
|
r <- satisfy
|
|
if r == MadeChange
|
|
then return NoChange
|
|
else return r
|
|
|
|
-- | Makes a property that is satisfied differently depending on the host's
|
|
-- operating system.
|
|
--
|
|
-- Note that the operating system may not be declared for some hosts.
|
|
withOS :: Desc -> (Maybe System -> Propellor Result) -> Property
|
|
withOS desc a = property desc $ a =<< getOS
|
|
|
|
boolProperty :: Desc -> IO Bool -> Property
|
|
boolProperty desc a = property desc $ ifM (liftIO a)
|
|
( return MadeChange
|
|
, return FailedChange
|
|
)
|
|
|
|
-- | Undoes the effect of a property.
|
|
revert :: RevertableProperty -> RevertableProperty
|
|
revert (RevertableProperty p1 p2) = RevertableProperty p2 p1
|
|
|
|
-- | Starts accumulating the properties of a Host.
|
|
--
|
|
-- > host "example.com"
|
|
-- > & someproperty
|
|
-- > ! oldproperty
|
|
-- > & otherproperty
|
|
host :: HostName -> Host
|
|
host hn = Host [] (\_ -> newAttr hn)
|
|
|
|
-- | Adds a property to a Host
|
|
--
|
|
-- Can add Properties and RevertableProperties
|
|
(&) :: IsProp p => Host -> p -> Host
|
|
(Host ps as) & p = Host (ps ++ [toProp p]) (setAttr p . as)
|
|
|
|
infixl 1 &
|
|
|
|
-- | Adds a property to the Host in reverted form.
|
|
(!) :: Host -> RevertableProperty -> Host
|
|
(Host ps as) ! p = Host (ps ++ [toProp q]) (setAttr q . as)
|
|
where
|
|
q = revert p
|
|
|
|
infixl 1 !
|
|
|
|
-- Changes the action that is performed to satisfy a property.
|
|
adjustProperty :: Property -> (Propellor Result -> Propellor Result) -> Property
|
|
adjustProperty p f = p { propertySatisfy = f (propertySatisfy p) }
|
|
|
|
-- Combines the Attr settings of two properties.
|
|
combineSetAttr :: (IsProp p, IsProp q) => p -> q -> SetAttr
|
|
combineSetAttr p q = setAttr p . setAttr q
|
|
|
|
combineSetAttrs :: IsProp p => [p] -> SetAttr
|
|
combineSetAttrs = foldl' (.) id . map setAttr
|
|
|
|
makeChange :: IO () -> Propellor Result
|
|
makeChange a = liftIO a >> return MadeChange
|
|
|
|
noChange :: Propellor Result
|
|
noChange = return NoChange
|