Slightly better error message

Keter/App.hs

@@ -90,7 +90,11 @@ unpackBundle tf bundle appname = do
                     let rest = do
                             unpackTar dir $ Tar.read $ decompress lbs
                             let configFP = dir F.</> "config" F.</> "keter.yaml"
-                            Just config <- decodeFile $ F.encodeString configFP
+                            mconfig <- decodeFile $ F.encodeString configFP
+                            config <-
+                                case mconfig of
+                                    Just config -> return config
+                                    Nothing -> throwIO InvalidConfigFile
                             return (dir, config
                                 { configStaticHosts = Set.fromList
                                                     $ mapMaybe (fixStaticHost dir)

Keter/Prelude.hs

@@ -288,6 +288,7 @@ instance FromText Blaze.Builder where
 data KeterException = CannotParsePostgres F.FilePath
                     | ExitCodeFailure F.FilePath ExitCode
                     | NoPortsAvailable
+                    | InvalidConfigFile
     deriving (P.Show, Typeable)
 instance E.Exception KeterException
 

Keter/Process.hs

@@ -59,7 +59,7 @@ run exec dir args env logger = do
                                 attach logger $ LogPipes pout perr
                                 log $ ProcessCreated exec
                                 return (Running pid, do
-                                    liftIO $ waitForProcess pid `onException` killProcess pid
+                                    _ <- liftIO $ waitForProcess pid `onException` killProcess pid
                                     loop (Just now))
             next
     forkKIO $ loop Nothing