add PROPELLOR_DEBUG

Propellor/CmdLine.hs

@@ -1,8 +1,12 @@
 module Propellor.CmdLine where
 
-import System.Environment
+import System.Environment (getArgs)
 import Data.List
 import System.Exit
+import System.Log.Logger
+import System.Log.Formatter
+import System.Log.Handler (setFormatter, LogHandler)
+import System.Log.Handler.Simple
 
 import Propellor
 import Propellor.SimpleSh
@@ -47,7 +51,9 @@ processCmdLine = go =<< getArgs
 		Nothing -> errorMessage "--continue serialization failure"
 	go ("--simplesh":f:[]) = return $ SimpleSh f
   	go ("--chain":h:[]) = return $ Chain h
-	go (h:[]) = return $ Run h
+	go (h:[])
+		| "--" `isPrefixOf` h = usage
+		| otherwise = return $ Run h
 	go [] = do
 		s <- takeWhile (/= '\n') <$> readProcess "hostname" ["-f"]
 		if null s
@@ -56,7 +62,11 @@ processCmdLine = go =<< getArgs
 	go _ = usage
 
 defaultMain :: [HostName -> Maybe [Property]] -> IO ()
-defaultMain getprops = go True =<< processCmdLine
+defaultMain getprops = do
+	checkDebugMode
+	cmdline <- processCmdLine
+	debug ["command line: ", show cmdline]
+	go True cmdline
   where
 	go _ (Continue cmdline) = go False cmdline
 	go _ (Set host field) = setPrivData host field
@@ -301,3 +311,15 @@ getUrl = maybe nourl return =<< getM get urls
 		return $ case v of
 			Just url | not (null url) -> Just url
 			_ -> Nothing
+
+checkDebugMode :: IO ()
+checkDebugMode = go =<< getEnv "PROPELLOR_DEBUG"
+  where
+	go (Just s)
+		| s == "1" = do
+			f <- setFormatter
+				<$> streamHandler stderr DEBUG
+				<*> pure (simpleLogFormatter "[$time] $msg")
+			updateGlobalLogger rootLoggerName $ 
+				setLevel DEBUG .  setHandlers [f]
+	go _ = noop

Propellor/Message.hs

@@ -2,6 +2,7 @@ module Propellor.Message where
 
 import System.Console.ANSI
 import System.IO
+import System.Log.Logger
 
 import Propellor.Types
 
@@ -35,3 +36,7 @@ errorMessage :: String -> IO a
 errorMessage s = do
 	warningMessage s
 	error "Propellor failed!"
+
+-- | Causes a debug message to be displayed when PROPELLOR_DEBUG=1
+debug :: [String] -> IO ()
+debug = debugM "propellor" . unwords

Propellor/Property/Docker.hs

@@ -211,8 +211,11 @@ runProp field val = Containerized [param] (Property param (return NoChange))
 	param = field++"="++val
 
 -- | Lift a Property to run inside the container.
-inside :: Property -> Containerized Property
-inside p = Containerized [] p
+inside1 :: Property -> Containerized Property
+inside1 = Containerized []
+
+inside :: [Property] -> Containerized Property
+inside = Containerized [] . combineProperties
 
 -- | Set custom dns server for container.
 dns :: String -> Containerized Property

README

@@ -87,4 +87,9 @@ To securely store private data, use: propellor --set $host $field
 The field name will be something like 'Password "root"'; see PrivData.hs
 for available fields.
 
+## debugging
+
+Set PROPELLOR_DEBUG=1 to make propellor print out all the commands it runs
+and anything other debug messages Properties choose to.
+
 [1] http://reclass.pantsfullofunix.net/

config.hs

@@ -57,8 +57,10 @@ container :: HostName -> Docker.ContainerName -> Maybe (Docker.Container)
 container _ "webserver" = Just $ Docker.containerFromImage "debian"
 	[ Docker.publish "80:80"
 	, Docker.volume "/var/www:/var/www"
-	, Docker.inside $ serviceRunning "apache2"
-		`requires` Apt.installed ["apache2"]
+	, Docker.inside
+		[ serviceRunning "apache2"
+			`requires` Apt.installed ["apache2"]
+		]
 	]
 container _ _ = Nothing