Added Propellor.Property.Spin, which can be used to make a host be a controller of other hosts.

The hard part of this is avoiding loops of controllers. To make that work,
a ControllerChain is passed to the host that's spun, and is added to the
Info of the host being spun, where the controller property can check it
to detect an avoid a loop.

That needed an expansion of the CmdLine data type. I made the new
ControlledRun only be used when there is a ControllerChain provided.
This avoids breaking backwards compatability with old propellor
deployments, as --spin still uses SimpleRun.

Note: Making an old propellor deployment be controlled by a controller
won't work until it's been updated to this commit, so it knows about
the ControlledRun parameter.

(Untested)

1 files changed, 7 insertions, 4 deletions

diff --git a/src/Propellor/Engine.hs b/src/Propellor/Engine.hs
index 0fdbb995..87fa4cd2 100644
--- a/src/Propellor/Engine.hs
+++ b/src/Propellor/Engine.hs
@@ -26,6 +26,8 @@ import Propellor.Types
 import Propellor.Message
 import Propellor.Exception
 import Propellor.Info
+import Propellor.Types.Info
+import Propellor.Types.CmdLine
 import Propellor.Property
 import Utility.Exception
 import Utility.PartialPrelude
@@ -33,9 +35,9 @@ import Utility.Monad
 
 -- | Gets the Properties of a Host, and ensures them all,
 -- with nice display of what's being done.
-mainProperties :: Host -> IO ()
-mainProperties host = do
-	ret <- runPropellor host $
+mainProperties :: ControllerChain -> Host -> IO ()
+mainProperties cc host = do
+	ret <- runPropellor host' $
 		ensureProperties [ignoreInfo $ infoProperty "overall" (ensureProperties ps) mempty mempty]
 	h <- mkMessageHandle
         whenConsole h $
@@ -45,7 +47,8 @@ mainProperties host = do
 		FailedChange -> exitWith (ExitFailure 1)
 		_ -> exitWith ExitSuccess
   where
-	ps = map ignoreInfo $ hostProperties host
+	ps = map ignoreInfo $ hostProperties host'
+	host' = addHostInfo host (InfoVal cc)
 
 -- | Runs a Propellor action with the specified host.
 --