type safe targets for properties

  * Property types have been improved to indicate what systems they target.
    This prevents using eg, Property FreeBSD on a Debian system.
    Transition guide for this sweeping API change:
    - Change "host name & foo & bar"
      to     "host name $ props & foo & bar"
    - Similarly, `propertyList` and `combineProperties` need `props`
      to be used to combine together properties; they no longer accept
      lists of properties. (If you have such a list, use `toProps`.)
    - And similarly, Chroot, Docker, and Systemd container need `props`
      to be used to combine together the properies used inside them.
    - The `os` property is removed. Instead use `osDebian`, `osBuntish`,
      or `osFreeBSD`. These tell the type checker the target OS of a host.
    - Change "Property NoInfo" to "Property UnixLike"
    - Change "Property HasInfo" to "Property (HasInfo + UnixLike)"
    - Change "RevertableProperty NoInfo" to
      "RevertableProperty UnixLike UnixLike"
    - Change "RevertableProperty HasInfo" to
      "RevertableProperty (HasInfo + UnixLike) UnixLike"
    - GHC needs {-# LANGUAGE TypeOperators #-} to use these fancy types.
      This is enabled by default for all modules in propellor.cabal. But
      if you are using propellor as a library, you may need to enable it
      manually.
    - If you know a property only works on a particular OS, like Debian
      or FreeBSD, use that instead of "UnixLike". For example:
      "Property Debian"
    - It's also possible make a property support a set of OS's, for example:
      "Property (Debian + FreeBSD)"
    - Removed `infoProperty` and `simpleProperty` constructors, instead use
      `property` to construct a Property.
    - Due to the polymorphic type returned by `property`, additional type
      signatures tend to be needed when using it. For example, this will
      fail to type check, because the type checker cannot guess what type
      you intend the intermediate property "go" to have:
        foo :: Property UnixLike
        foo = go `requires` bar
	  where
		go = property "foo" (return NoChange)
      To fix, specify the type of go:
	  	go :: Property UnixLike
    - `ensureProperty` now needs to be passed a witness to the type of the
      property it's used in.
      change this:  foo = property desc $ ... ensureProperty bar
      to this:      foo = property' desc $ \w -> ... ensureProperty w bar
    - General purpose properties like cmdProperty have type "Property UnixLike".
      When using that to run a command only available on Debian, you can
      tighten the type to only the OS that your more specific property works on.
      For example:
        upgraded :: Property Debian
        upgraded = tightenTargets (cmdProperty "apt-get" ["upgrade"])
    - Several utility functions have been renamed:
      getInfo to fromInfo
      propertyInfo to getInfo
      propertyDesc to getDesc
      propertyChildren to getChildren
  * The new `pickOS` property combinator can be used to combine different
    properties, supporting different OS's, into one Property that chooses
    which to use based on the Host's OS.
  * Re-enabled -O0 in propellor.cabal to reign in ghc's memory use handling
    these complex new types.
  * Added dependency on concurrent-output; removed embedded copy.

1 files changed, 33 insertions, 24 deletions

diff --git a/src/Propellor/Property/Conductor.hs b/src/Propellor/Property/Conductor.hs
index 0d275b91..8aa18d20 100644
--- a/src/Propellor/Property/Conductor.hs
+++ b/src/Propellor/Property/Conductor.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, DeriveDataTypeable, GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE FlexibleInstances, DeriveDataTypeable, GeneralizedNewtypeDeriving, TypeFamilies #-}
 
 -- | This module adds conductors to propellor. A conductor is a Host that
 -- is responsible for running propellor on other hosts
@@ -73,7 +73,8 @@ module Propellor.Property.Conductor (
 	Conductable(..),
 ) where
 
-import Propellor.Base hiding (os)
+import Propellor.Base
+import Propellor.Container
 import Propellor.Spin (spin')
 import Propellor.PrivData.Paths
 import Propellor.Types.Info
@@ -82,21 +83,22 @@ import qualified Propellor.Property.Ssh as Ssh
 import qualified Data.Set as S
 
 -- | Class of things that can be conducted.
+--
+-- There are instances for single hosts, and for lists of hosts.
+-- With a list, each listed host will be conducted in turn. Failure to conduct
+-- one host does not prevent conducting subsequent hosts in the list, but
+-- will be propagated as an overall failure of the property.
 class Conductable c where
-	conducts :: c -> RevertableProperty HasInfo
+	conducts :: c -> RevertableProperty (HasInfo + UnixLike) (HasInfo + UnixLike)
 
 instance Conductable Host where
-	-- | Conduct the specified host.
 	conducts h = conductorFor h <!> notConductorFor h
 
--- | Each host in the list will be conducted in turn. Failure to conduct
--- one host does not prevent conducting subsequent hosts in the list, but
--- will be propagated as an overall failure of the property.
 instance Conductable [Host] where
 	conducts hs = 
-		propertyList desc (map (toProp . conducts) hs)
+		propertyList desc (toProps $ map (setupRevertableProperty . conducts) hs)
 			<!>
-		propertyList desc (map (toProp . revert . conducts) hs)
+		propertyList desc (toProps $ map (undoRevertableProperty . conducts) hs)
 	  where
 		desc = cdesc $ unwords $ map hostName hs
 
@@ -126,7 +128,7 @@ mkOrchestra = fromJust . go S.empty
   where
 	go seen h
 		| S.member (hostName h) seen = Nothing -- break loop
-		| otherwise = Just $ case getInfo (hostInfo h) of
+		| otherwise = Just $ case fromInfo (hostInfo h) of
 			ConductorFor [] -> Conducted h
 			ConductorFor l -> 
 				let seen' = S.insert (hostName h) seen
@@ -214,14 +216,15 @@ orchestrate :: [Host] -> [Host]
 orchestrate hs = map go hs
   where
 	go h
-		| isOrchestrated (getInfo (hostInfo h)) = h
+		| isOrchestrated (fromInfo (hostInfo h)) = h
 		| otherwise = foldl orchestrate' (removeold h) (map (deloop h) os)
 	os = extractOrchestras hs
 
 	removeold h = foldl removeold' h (oldconductorsof h)
-	removeold' h oldconductor = h & revert (conductedBy oldconductor)
+	removeold' h oldconductor = setContainerProps h $ containerProps h
+		! conductedBy oldconductor
 
-	oldconductors = zip hs (map (getInfo . hostInfo) hs)
+	oldconductors = zip hs (map (fromInfo . hostInfo) hs)
 	oldconductorsof h = flip mapMaybe oldconductors $ 
 		\(oldconductor, NotConductorFor l) ->
 			if any (sameHost h) l
@@ -232,7 +235,9 @@ orchestrate' :: Host -> Orchestra -> Host
 orchestrate' h (Conducted _) = h
 orchestrate' h (Conductor c l)
 	| sameHost h c = cont $ addConductorPrivData h (concatMap allHosts l)
-	| any (sameHost h) (map topHost l) = cont $ h & conductedBy c
+	| any (sameHost h) (map topHost l) = cont $
+		setContainerProps h $ containerProps h
+			& conductedBy c
 	| otherwise = cont h
   where
 	cont h' = foldl orchestrate' h' l
@@ -240,14 +245,16 @@ orchestrate' h (Conductor c l)
 -- The host this property is added to becomes the conductor for the
 -- specified Host. Note that `orchestrate` must be used for this property
 -- to have any effect.
-conductorFor :: Host -> Property HasInfo
-conductorFor h = infoProperty desc go (addInfo mempty (ConductorFor [h])) []
-	`requires` toProp (conductorKnownHost h)
+conductorFor :: Host -> Property (HasInfo + UnixLike)
+conductorFor h = go
+	`setInfoProperty` (toInfo (ConductorFor [h]))
+	`requires` setupRevertableProperty (conductorKnownHost h)
 	`requires` Ssh.installed
   where
 	desc = cdesc (hostName h)
 
-	go = ifM (isOrchestrated <$> askInfo)
+	go :: Property UnixLike
+	go = property desc $ ifM (isOrchestrated <$> askInfo)
 		( do
 			pm <- liftIO $ filterPrivData h
 				<$> readPrivDataFile privDataLocal
@@ -262,13 +269,15 @@ conductorFor h = infoProperty desc go (addInfo mempty (ConductorFor [h])) []
 		)
 
 -- Reverts conductorFor.
-notConductorFor :: Host -> Property HasInfo
-notConductorFor h = infoProperty desc (return NoChange) (addInfo mempty (NotConductorFor [h])) []
-	`requires` toProp (revert (conductorKnownHost h))
+notConductorFor :: Host -> Property (HasInfo + UnixLike)
+notConductorFor h = (doNothing :: Property UnixLike)
+	`setInfoProperty` (toInfo (NotConductorFor [h]))
+	`describe` desc
+	`requires` undoRevertableProperty (conductorKnownHost h)
   where
 	desc = "not " ++ cdesc (hostName h)
 
-conductorKnownHost :: Host -> RevertableProperty NoInfo
+conductorKnownHost :: Host -> RevertableProperty UnixLike UnixLike
 conductorKnownHost h = 
 	mk Ssh.knownHost
 		<!>
@@ -287,10 +296,10 @@ addConductorPrivData h hs = h { hostInfo = hostInfo h <> i }
 	i = mempty 
 		`addInfo` mconcat (map privinfo hs)
 		`addInfo` Orchestrated (Any True)
-	privinfo h' = forceHostContext (hostName h') $ getInfo (hostInfo h')
+	privinfo h' = forceHostContext (hostName h') $ fromInfo (hostInfo h')
 
 -- Use this property to let the specified conductor ssh in and run propellor.
-conductedBy :: Host -> RevertableProperty NoInfo
+conductedBy :: Host -> RevertableProperty UnixLike UnixLike
 conductedBy h = (setup <!> teardown)
 	`describe` ("conducted by " ++ hostName h)
   where