htools: add parsing of input node-evac messages

This is a lot of duplication with modeMreloc, which will get sorted
out once we convert mreloc to change-group.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

htools/Ganeti/HTools/IAlloc.hs

@@ -192,6 +192,19 @@ parseData body = do
                           | otherwise -> Bad $ "Invalid relocate mode " ++ s
                      Bad x -> Bad x
                 return $ MultiReloc rl_idx rl_mode
+          | optype == C.iallocatorModeNodeEvac ->
+              do
+                rl_names <- extrReq "instances"
+                rl_insts <- mapM (Container.findByName map_i) rl_names
+                let rl_idx = map Instance.idx rl_insts
+                rl_mode <-
+                   case extrReq "evac_mode" of
+                     Ok s | s == C.iallocatorNevacAll -> return ChangeAll
+                          | s == C.iallocatorNevacPri -> return ChangePrimary
+                          | s == C.iallocatorNevacSec -> return ChangeSecondary
+                          | otherwise -> Bad $ "Invalid evacuate mode " ++ s
+                     Bad x -> Bad x
+                return $ NodeEvacuate rl_idx rl_mode
 
           | otherwise -> fail ("Invalid request type '" ++ optype ++ "'")
   return $ Request rqtype cdata