htools: abstract function for parsing job ids

Both the job id and submit job result parsing are abstracted into
separate functions, so that later changes are more localised.

Also, this makes submitManyJobs itself easier to read.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

htools/Ganeti/Luxi.hs

@@ -357,6 +357,19 @@ callMethod method s = do
   let rval = validateResult result
   return rval
 
+-- | Parses a job ID.
+parseJobId :: JSValue -> Result JobId
+parseJobId (JSString x) = Ok $ fromJSString x
+parseJobId x = Bad $ "Wrong type/value for job id: " ++ show x
+
+-- | Parse job submission result.
+parseSubmitJobResult :: JSValue -> Result JobId
+parseSubmitJobResult (JSArray [JSBool True, v]) = parseJobId v
+parseSubmitJobResult (JSArray [JSBool False, JSString x]) =
+  Bad (fromJSString x)
+parseSubmitJobResult v = Bad $ "Unknown result from the master daemon" ++
+                         show v
+
 -- | Specialized submitManyJobs call.
 submitManyJobs :: Client -> [[OpCode]] -> IO (Result [JobId])
 submitManyJobs s jobs = do
@@ -364,14 +377,7 @@ submitManyJobs s jobs = do
   -- map each result (status, payload) pair into a nice Result ADT
   return $ case rval of
              Bad x -> Bad x
-             Ok (JSArray r) ->
-                 mapM (\v -> case v of
-                               JSArray [JSBool True, JSString x] ->
-                                   Ok (fromJSString x)
-                               JSArray [JSBool False, JSString x] ->
-                                   Bad (fromJSString x)
-                               _ -> Bad "Unknown result from the master daemon"
-                      ) r
+             Ok (JSArray r) -> mapM parseSubmitJobResult r
              x -> Bad ("Cannot parse response from Ganeti: " ++ show x)
 
 -- | Custom queryJobs call.