diff --git a/htools/Ganeti/JSON.hs b/htools/Ganeti/JSON.hs
index 132c0b22330845c120b6bcbadf28f32aa779aae8..7c7dd3423458dce17d1d799dad4db8e55aa085be 100644
--- a/htools/Ganeti/JSON.hs
+++ b/htools/Ganeti/JSON.hs
@@ -31,6 +31,7 @@ module Ganeti.JSON
   , fromObjWithDefault
   , fromKeyValue
   , fromJVal
+  , jsonHead
   , asJSObject
   , asObjectList
   , tryFromObj
@@ -125,6 +126,11 @@ fromJVal v =
                        "', error: " ++ s)
     J.Ok x -> return x
 
+-- | Helper function that returns Null or first element of the list.
+jsonHead :: (J.JSON b) => [a] -> (a -> b) -> J.JSValue
+jsonHead [] _ = J.JSNull
+jsonHead (x:_) f = J.showJSON $ f x
+
 -- | Converts a JSON value into a JSON object.
 asJSObject :: (Monad m) => J.JSValue -> m (J.JSObject J.JSValue)
 asJSObject (J.JSObject a) = return a