propellor/src/Propellor/Types.hs

308 lines
10 KiB
Haskell

{-# LANGUAGE PackageImports #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE EmptyDataDecls #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TypeFamilies #-}
module Propellor.Types
( Host(..)
, Desc
, Property
, HasInfo
, NoInfo
, CInfo
, infoProperty
, simpleProperty
, adjustPropertySatisfy
, propertyInfo
, propertyChildren
, RevertableProperty(..)
, (<!>)
, IsProp(..)
, Combines(..)
, CombinedType
, before
, combineWith
, Info(..)
, Propellor(..)
, EndAction(..)
, module Propellor.Types.OS
, module Propellor.Types.Dns
, module Propellor.Types.Result
, propertySatisfy
, ignoreInfo
) where
import Data.Monoid
import Control.Applicative
import "mtl" Control.Monad.RWS.Strict
import "MonadCatchIO-transformers" Control.Monad.CatchIO
import qualified Data.Set as S
import qualified Data.Map as M
import Propellor.Types.OS
import Propellor.Types.Chroot
import Propellor.Types.Dns
import Propellor.Types.Docker
import Propellor.Types.PrivData
import Propellor.Types.Empty
import Propellor.Types.Val
import Propellor.Types.Result
import qualified Propellor.Types.Dns as Dns
-- | Everything Propellor knows about a system: Its hostname,
-- properties and their collected info.
data Host = Host
{ hostName :: HostName
, hostProperties :: [Property HasInfo]
, hostInfo :: Info
}
deriving (Show)
-- | Propellor's monad provides read-only access to info about the host
-- it's running on, and a writer to accumulate EndActions.
newtype Propellor p = Propellor { runWithHost :: RWST Host [EndAction] () IO p }
deriving
( Monad
, Functor
, Applicative
, MonadReader Host
, MonadWriter [EndAction]
, MonadIO
, MonadCatchIO
)
instance Monoid (Propellor Result) where
mempty = return NoChange
-- | The second action is only run if the first action does not fail.
mappend x y = do
rx <- x
case rx of
FailedChange -> return FailedChange
_ -> do
ry <- y
return (rx <> ry)
-- | An action that Propellor runs at the end, after trying to satisfy all
-- properties. It's passed the combined Result of the entire Propellor run.
data EndAction = EndAction Desc (Result -> Propellor Result)
type Desc = String
-- | The core data type of Propellor, this represents a property
-- that the system should have, and an action to ensure it has the
-- property.
data Property i where
IProperty :: Desc -> Propellor Result -> Info -> [Property HasInfo] -> Property HasInfo
SProperty :: Desc -> Propellor Result -> [Property NoInfo] -> Property NoInfo
-- | Indicates that a Property has associated Info.
data HasInfo
-- | Indicates that a Property does not have Info.
data NoInfo
-- | Type level calculation of the combination of HasInfo and/or NoInfo
type family CInfo x y
type instance CInfo HasInfo HasInfo = HasInfo
type instance CInfo HasInfo NoInfo = HasInfo
type instance CInfo NoInfo HasInfo = HasInfo
type instance CInfo NoInfo NoInfo = NoInfo
-- | Constructs a Property with associated Info.
infoProperty
:: Desc -- ^ description of the property
-> Propellor Result -- ^ action to run to satisfy the property (must be idempotent; may run repeatedly)
-> Info -- ^ info associated with the property
-> [Property i] -- ^ child properties
-> Property HasInfo
infoProperty d a i cs = IProperty d a i (map toIProperty cs)
-- | Constructs a Property with no Info.
simpleProperty :: Desc -> Propellor Result -> [Property NoInfo] -> Property NoInfo
simpleProperty = SProperty
toIProperty :: Property i -> Property HasInfo
toIProperty p@(IProperty {}) = p
toIProperty (SProperty d s cs) = IProperty d s mempty (map toIProperty cs)
toSProperty :: Property i -> Property NoInfo
toSProperty (IProperty d s _ cs) = SProperty d s (map toSProperty cs)
toSProperty p@(SProperty {}) = p
-- | Makes a version of a Proprty without its Info.
-- Use with caution!
ignoreInfo :: Property i -> Property NoInfo
ignoreInfo = toSProperty
-- | Gets the action that can be run to satisfy a Property.
-- You should never run this action directly. Use
-- 'Propellor.Engine.ensureProperty` instead.
propertySatisfy :: Property i -> Propellor Result
propertySatisfy (IProperty _ a _ _) = a
propertySatisfy (SProperty _ a _) = a
instance Show (Property NoInfo) where
show p = "property " ++ show (propertyDesc p)
instance Show (Property HasInfo) where
show p = "property " ++ show (propertyDesc p)
-- | Changes the action that is performed to satisfy a property.
adjustPropertySatisfy :: Property i -> (Propellor Result -> Propellor Result) -> Property i
adjustPropertySatisfy (IProperty d s i cs) f = IProperty d (f s) i cs
adjustPropertySatisfy (SProperty d s cs) f = SProperty d (f s) cs
propertyInfo :: Property i -> Info
propertyInfo (IProperty _ _ i _) = i
propertyInfo (SProperty {}) = mempty
-- | A Property can include a list of child properties that it also
-- satisfies. This allows them to be introspected to collect their info, etc.
propertyChildren :: Property i -> [Property i]
propertyChildren (IProperty _ _ _ cs) = cs
propertyChildren (SProperty _ _ cs) = cs
-- | A property that can be reverted.
data RevertableProperty = RevertableProperty (Property HasInfo) (Property HasInfo)
-- | Makes a revertable property; the first Property is run
-- normally and the second is run when it's reverted.
(<!>) :: Property i1 -> Property i2 -> RevertableProperty
p1 <!> p2 = RevertableProperty (toIProperty p1) (toIProperty p2)
class IsProp p where
-- | Sets description.
describe :: p -> Desc -> p
propertyDesc :: p -> Desc
toProp :: p -> Property HasInfo
toSimpleProp :: p -> Maybe (Property NoInfo)
-- | Gets the info of the property, combined with all info
-- of all children properties.
getInfoRecursive :: p -> Info
instance IsProp (Property HasInfo) where
describe (IProperty _ a i cs) d = IProperty d a i cs
propertyDesc (IProperty d _ _ _) = d
toProp = id
toSimpleProp _ = Nothing
getInfoRecursive (IProperty _ _ i cs) =
i <> mconcat (map getInfoRecursive cs)
instance IsProp (Property NoInfo) where
describe (SProperty _ a cs) d = SProperty d a cs
propertyDesc (SProperty d _ _) = d
toProp = toIProperty
toSimpleProp = Just
getInfoRecursive _ = mempty
instance IsProp RevertableProperty where
-- | Sets the description of both sides.
describe (RevertableProperty p1 p2) d =
RevertableProperty (describe p1 d) (describe p2 ("not " ++ d))
propertyDesc (RevertableProperty p1 _) = propertyDesc p1
toProp (RevertableProperty p1 _) = p1
toSimpleProp = toSimpleProp . toProp
-- | Return the Info of the currently active side.
getInfoRecursive (RevertableProperty p1 _p2) = getInfoRecursive p1
-- | Type level calculation of the type that results from combining two types
-- with `requires`.
type family CombinedType x y
type instance CombinedType (Property x) (Property y) = Property (CInfo x y)
type instance CombinedType RevertableProperty (Property NoInfo) = RevertableProperty
type instance CombinedType RevertableProperty (Property HasInfo) = RevertableProperty
type instance CombinedType RevertableProperty RevertableProperty = RevertableProperty
class Combines x y where
-- | Indicates that the first property depends on the second,
-- so before the first is ensured, the second will be ensured.
requires :: x -> y -> CombinedType x y
-- | 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 :: (IsProp x, Combines y x, IsProp (CombinedType y x)) => x -> y -> CombinedType y x
before x y = (y `requires` x) `describe` (propertyDesc x)
-- | Combines together two properties, yielding a property that
-- has the description and info of the first, and that has the second
-- property as a child. The two actions to satisfy the properties
-- are passed to a function that can combine them in arbitrary ways.
combineWith
:: (Combines (Property x) (Property y))
=> (Propellor Result -> Propellor Result -> Propellor Result)
-> Property x
-> Property y
-> CombinedType (Property x) (Property y)
combineWith f x y = adjustPropertySatisfy (x `requires` y) $ \_ ->
f (propertySatisfy $ toSProperty x) (propertySatisfy $ toSProperty y)
instance Combines (Property HasInfo) (Property HasInfo) where
requires (IProperty d1 a1 i1 cs1) y@(IProperty _d2 a2 _i2 _cs2) =
IProperty d1 (a2 <> a1) i1 (y : cs1)
instance Combines (Property HasInfo) (Property NoInfo) where
requires (IProperty d1 a1 i1 cs1) y@(SProperty _d2 a2 _cs2) =
IProperty d1 (a2 <> a1) i1 (toIProperty y : cs1)
instance Combines (Property NoInfo) (Property HasInfo) where
requires x y = requires y x
instance Combines (Property NoInfo) (Property NoInfo) where
requires (SProperty d1 a1 cs1) y@(SProperty _d2 a2 _cs2) =
SProperty d1 (a2 <> a1) (y : cs1)
instance Combines RevertableProperty (Property HasInfo) where
requires (RevertableProperty p1 p2) y =
RevertableProperty (p1 `requires` y) p2
instance Combines RevertableProperty (Property NoInfo) where
requires (RevertableProperty p1 p2) y =
RevertableProperty (p1 `requires` toIProperty y) p2
instance Combines RevertableProperty RevertableProperty where
requires (RevertableProperty x1 x2) (RevertableProperty y1 y2) =
RevertableProperty
(x1 `requires` y1)
-- when reverting, run actions in reverse order
(y2 `requires` x2)
-- | Information about a host.
data Info = Info
{ _os :: Val System
, _privData :: S.Set (PrivDataField, Maybe PrivDataSourceDesc, HostContext)
, _sshPubKey :: M.Map SshKeyType String
, _aliases :: S.Set HostName
, _dns :: S.Set Dns.Record
, _namedconf :: Dns.NamedConfMap
, _dockerinfo :: DockerInfo Host
, _chrootinfo :: ChrootInfo Host
}
deriving (Show)
instance Monoid Info where
mempty = Info mempty mempty mempty mempty mempty mempty mempty mempty
mappend old new = Info
{ _os = _os old <> _os new
, _privData = _privData old <> _privData new
, _sshPubKey = _sshPubKey new `M.union` _sshPubKey old
, _aliases = _aliases old <> _aliases new
, _dns = _dns old <> _dns new
, _namedconf = _namedconf old <> _namedconf new
, _dockerinfo = _dockerinfo old <> _dockerinfo new
, _chrootinfo = _chrootinfo old <> _chrootinfo new
}
instance Empty Info where
isEmpty i = and
[ isEmpty (_os i)
, isEmpty (_privData i)
, isEmpty (_sshPubKey i)
, isEmpty (_aliases i)
, isEmpty (_dns i)
, isEmpty (_namedconf i)
, isEmpty (_dockerinfo i)
, isEmpty (_chrootinfo i)
]