starting work on a Chroot module

factored out info up-propigation code rom Docker

config-joey.hs

@@ -24,7 +24,7 @@ import qualified Propellor.Property.Postfix as Postfix
 import qualified Propellor.Property.Grub as Grub
 import qualified Propellor.Property.Obnam as Obnam
 import qualified Propellor.Property.Gpg as Gpg
-import qualified Propellor.Property.Debootstrap as Debootstrap
+import qualified Propellor.Property.Chroot as Chroot
 import qualified Propellor.Property.HostingProvider.DigitalOcean as DigitalOcean
 import qualified Propellor.Property.HostingProvider.CloudAtCost as CloudAtCost
 import qualified Propellor.Property.HostingProvider.Linode as Linode
@@ -80,8 +80,12 @@ clam = standardSystem "clam.kitenet.net" Unstable "amd64"
 	! Ssh.listenPort 80
 	! Ssh.listenPort 443
 
-	& Debootstrap.built "/tmp/chroot" (System (Debian Unstable) "amd64") []
+	& Chroot.provisioned testChroot
 	
+testChroot :: Chroot.Chroot
+testChroot = Chroot.chroot "/tmp/chroot" (System (Debian Unstable) "amd64")
+	& File.hasContent "/foo" ["hello"]
+
 orca :: Host
 orca = standardSystem "orca.kitenet.net" Unstable "amd64"
 	[ "Main git-annex build box." ]

propellor.cabal

@@ -74,6 +74,7 @@ Library
     Propellor.Property.Apt
     Propellor.Property.Cmd
     Propellor.Property.Hostname
+    Propellor.Property.Chroot
     Propellor.Property.Cron
     Propellor.Property.Debootstrap
     Propellor.Property.Dns
@@ -102,6 +103,7 @@ Library
     Propellor.Property.SiteSpecific.GitHome
     Propellor.Property.SiteSpecific.JoeySites
     Propellor.Property.SiteSpecific.GitAnnexBuilder
+    Propellor.Host
     Propellor.CmdLine
     Propellor.Info
     Propellor.Message

src/Propellor.hs

@@ -33,6 +33,7 @@ module Propellor (
 	  module Propellor.Types
 	, module Propellor.Property
 	, module Propellor.Property.Cmd
+	, module Propellor.Host
 	, module Propellor.Info
 	, module Propellor.PrivData
 	, module Propellor.Engine
@@ -51,6 +52,7 @@ import Propellor.PrivData
 import Propellor.Message
 import Propellor.Exception
 import Propellor.Info
+import Propellor.Host
 
 import Utility.PartialPrelude as X
 import Utility.Process as X

src/Propellor/Host.hs

@@ -0,0 +1,64 @@
+{-# LANGUAGE PackageImports #-}
+
+module Propellor.Host where
+
+import Data.Monoid
+import qualified Data.Set as S
+
+import Propellor.Types
+import Propellor.Info
+import Propellor.Property
+import Propellor.PrivData
+
+-- | Starts accumulating the properties of a Host.
+--
+-- > host "example.com"
+-- > 	& someproperty
+-- > 	! oldproperty
+-- > 	& otherproperty
+host :: HostName -> Host
+host hn = Host hn [] mempty
+
+-- | Something that can accumulate properties.
+class Hostlike h where
+	-- | Adds a property.
+	--
+	-- Can add Properties and RevertableProperties
+	(&) :: IsProp p => h -> p -> h
+
+	-- | Like (&), but adds the property as the
+	-- first property of the host. Normally, property
+	-- order should not matter, but this is useful
+	-- when it does.
+	(&^) :: IsProp p => h -> p -> h
+
+	getHost :: h -> Host
+
+instance Hostlike Host where
+	(Host hn ps is) &  p = Host hn (ps ++ [toProp p]) (is <> getInfo p)
+	(Host hn ps is) &^ p = Host hn ([toProp p] ++ ps) (getInfo p <> is)
+	getHost h = h
+
+-- | Adds a property in reverted form.
+(!) :: Hostlike h => h -> RevertableProperty -> h
+h ! p = h & revert p
+
+infixl 1 &^
+infixl 1 &
+infixl 1 !
+
+-- | When eg, docking a container, some of the Info about the container
+-- should propigate out to the Host it's on. This includes DNS info,
+-- so that eg, aliases of the container are reflected in the dns for the
+-- host where it runs.
+--
+-- This adjusts the Property that docks a container, to include such info
+-- from the container.
+propigateInfo :: Hostlike hl => hl -> Property -> (Info -> Info) -> Property
+propigateInfo hl p f = combineProperties (propertyDesc p) $
+	p' : dnsprops ++ privprops
+  where
+	p' = p { propertyInfo = f (propertyInfo p) }
+	i = hostInfo (getHost hl)
+	dnsprops = map addDNS (S.toList $ _dns i)
+	privprops = map addPrivDataField (S.toList $ _privDataFields i)

src/Propellor/Property.hs

@@ -3,6 +3,7 @@
 module Propellor.Property where
 
 import System.Directory
+import System.FilePath
 import Control.Monad
 import Data.Monoid
 import Control.Monad.IfElse
@@ -12,7 +13,6 @@ import Propellor.Types
 import Propellor.Info
 import Propellor.Engine
 import Utility.Monad
-import System.FilePath
 
 -- Constructs a Property.
 property :: Desc -> Propellor Result -> Property
@@ -135,38 +135,6 @@ revert (RevertableProperty p1 p2) = RevertableProperty p2 p1
 unrevertable :: RevertableProperty -> Property
 unrevertable (RevertableProperty p1 _p2) = p1
 
--- | Starts accumulating the properties of a Host.
---
--- > host "example.com"
--- > 	& someproperty
--- > 	! oldproperty
--- > 	& otherproperty
-host :: HostName -> Host
-host hn = Host hn [] mempty
-
-class Hostlike h where
-	-- | Adds a property to a Host
-	--
-	-- Can add Properties and RevertableProperties
-	(&) :: IsProp p => h -> p -> h
-	-- | Like (&), but adds the property as the
-	-- first property of the host. Normally, property
-	-- order should not matter, but this is useful
-	-- when it does.
-	(&^) :: IsProp p => h -> p -> h
-
-instance Hostlike Host where
-	(Host hn ps is) &  p = Host hn (ps ++ [toProp p]) (is <> getInfo p)
-	(Host hn ps is) &^ p = Host hn ([toProp p] ++ ps) (getInfo p <> is)
-
--- | Adds a property to the Host in reverted form.
-(!) :: Hostlike h => h -> RevertableProperty -> h
-h ! p = h & revert p
-
-infixl 1 &^
-infixl 1 &
-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) }

src/Propellor/Property/Chroot.hs

@@ -0,0 +1,57 @@
+module Propellor.Property.Chroot (
+	Chroot,
+	chroot,
+	provisioned,
+) where
+
+import Propellor
+import qualified Propellor.Property.Debootstrap as Debootstrap
+
+import qualified Data.Map as M
+
+data Chroot = Chroot FilePath System Host
+
+instance Hostlike Chroot where
+	(Chroot l s h) & p = Chroot l s (h & p)
+	(Chroot l s h) &^ p = Chroot l s (h &^ p)
+	getHost (Chroot _ _ h) = h
+
+-- | Defines a Chroot at the given location, containing the specified
+-- System. Properties can be added to configure the Chroot.
+--
+-- > chroot "/srv/chroot/ghc-dev" (System (Debian Unstable) "amd64"
+-- >    & Apt.installed ["build-essential", "ghc", "haskell-platform"]
+-- >	& ...
+chroot :: FilePath -> System -> Chroot
+chroot location system = Chroot location system (Host location [] mempty)
+
+-- | Ensures that the chroot exists and is provisioned according to its
+-- properties.
+--
+-- Reverting this property removes the chroot. Note that it does not ensure
+-- that any processes that might be running inside the chroot are stopped.
+provisioned :: Chroot -> RevertableProperty
+provisioned c@(Chroot loc system _) = RevertableProperty
+	(propigateChrootInfo c (go "exists" setup))
+	(go "removed" teardown)
+  where
+	go desc a = property ("chroot " ++ loc ++ " " ++ desc) $ do
+		ensureProperties [a]
+
+	setup = provisionChroot c `requires` built
+	
+	built = case system of
+		(System (Debian _) _) -> debootstrap
+		(System (Ubuntu _) _) -> debootstrap
+
+	debootstrap = unrevertable (Debootstrap.built loc system [])
+
+	teardown = undefined
+
+propigateChrootInfo :: Chroot -> Property -> Property
+propigateChrootInfo c@(Chroot loc _ h) p = propigateInfo c p (<> chrootinfo)
+  where
+	chrootinfo = mempty $ mempty { _chroots = M.singleton loc h }
+
+provisionChroot :: Chroot -> Property
+provisionChroot = undefined

src/Propellor/Property/Docker.hs

@@ -52,7 +52,6 @@ import System.Posix.Process
 import Prelude hiding (init)
 import Data.List hiding (init)
 import Data.List.Utils
-import qualified Data.Set as S
 import qualified Data.Map as M
 
 installed :: Property
@@ -78,8 +77,10 @@ data Container = Container Image Host
 instance Hostlike Container where
 	(Container i h) & p = Container i (h & p)
 	(Container i h) &^ p = Container i (h &^ p)
+	getHost (Container _ h) = h
 
--- | Builds a Container with a given name, image, and properties.
+-- | Defines a Container with a given name, image, and properties.
+-- Properties can be added to configure the Container.
 --
 -- > container "web-server" "debian"
 -- >    & publish "80:80"
@@ -100,11 +101,9 @@ container cn image = Container image (Host cn [] info)
 --
 -- Reverting this property ensures that the container is stopped and
 -- removed.
-docked
-	:: Container
-	-> RevertableProperty
+docked :: Container -> RevertableProperty
 docked ctr@(Container _ h) = RevertableProperty
-	(propigateInfo ctr (go "docked" setup))
+	(propigateContainerInfo ctr (go "docked" setup))
 	(go "undocked" teardown)
   where
 	cn = hostName h
@@ -131,14 +130,12 @@ docked ctr@(Container _ h) = RevertableProperty
 					]
 			]
 
-propigateInfo :: Container -> Property -> Property
-propigateInfo (Container _ h@(Host hn _ containerinfo)) p =
-	combineProperties (propertyDesc p) $ p' : dnsprops ++ privprops
+propigateContainerInfo :: Container -> Property -> Property
+propigateContainerInfo ctr@(Container _ h) p =
+	propigateInfo ctr p (<> dockerinfo)
   where
-	p' = p { propertyInfo = propertyInfo p <> dockerinfo }
-	dockerinfo = dockerInfo $ mempty { _dockerContainers = M.singleton hn h }
-	dnsprops = map addDNS (S.toList $ _dns containerinfo)
-	privprops = map addPrivDataField (S.toList $ _privDataFields containerinfo)
+	dockerinfo = dockerInfo $
+		mempty { _dockerContainers = M.singleton (hostName h) h }
 
 mkContainerInfo :: ContainerId -> Container -> ContainerInfo
 mkContainerInfo cid@(ContainerId hn _cn) (Container img h) = 

src/Propellor/Types.hs

@@ -25,6 +25,7 @@ module Propellor.Types
 	, fromVal
 	, DockerInfo(..)
 	, DockerRunParam(..)
+	, ChrootInfo(..)
 	, module Propellor.Types.OS
 	, module Propellor.Types.Dns
 	) where
@@ -166,11 +167,12 @@ data Info = Info
 	, _dns :: S.Set Dns.Record
 	, _namedconf :: Dns.NamedConfMap
 	, _dockerinfo :: DockerInfo
+	, _chrootinfo :: ChrootInfo
 	}
 	deriving (Eq, Show)
 
 instance Monoid Info where
-	mempty = Info mempty mempty mempty mempty mempty mempty mempty
+	mempty = Info mempty mempty mempty mempty mempty mempty mempty mempty
 	mappend old new = Info
 		{ _os = _os old <> _os new
 		, _privDataFields = _privDataFields old <> _privDataFields new
@@ -179,6 +181,7 @@ instance Monoid Info where
 		, _dns = _dns old <> _dns new
 		, _namedconf = _namedconf old <> _namedconf new
 		, _dockerinfo = _dockerinfo old <> _dockerinfo new
+		, _chrootinfo = _chrootinfo old <> _chrootinfo new
 		}
 
 data Val a = Val a | NoVal
@@ -217,3 +220,19 @@ newtype DockerRunParam = DockerRunParam (HostName -> String)
 
 instance Show DockerRunParam where
 	show (DockerRunParam a) = a ""
+
+data ChrootInfo = ChrootInfo
+	{ _chroots :: M.Map FilePath Host
+	}
+	deriving (Show)
+
+instance Monoid ChrootInfo where
+	mempty = ChrootInfo mempty
+	mappend old new = ChrootInfo
+		{ _chroots = M.union (_chroots old) (_chroots new)
+		}
+
+instance Eq ChrootInfo where
+	x == y = and
+		[ M.keys (_chroots x) == M.keys (_chroots y)
+		]