Add one new luxi query: cluster info

This is the last query that RAPI executes via opcodes and is purely
static (config values only). As such, we can convert it safely to a
query instead of job.

Reviewed-by: imsnah

daemons/ganeti-masterd

@@ -255,6 +255,10 @@ class ClientOps:
       op = opcodes.OpQueryConfigValues(output_fields=fields)
       return self._Query(op)
 
+    elif method == luxi.REQ_QUERY_CLUSTER_INFO:
+      op = opcodes.OpQueryClusterInfo()
+      return self._Query(op)
+
     elif method == luxi.REQ_QUEUE_SET_DRAIN_FLAG:
       drain_flag = args
       return queue.SetDrainFlag(drain_flag)

lib/luxi.py

@@ -54,6 +54,7 @@ REQ_QUERY_INSTANCES = "QueryInstances"
 REQ_QUERY_NODES = "QueryNodes"
 REQ_QUERY_EXPORTS = "QueryExports"
 REQ_QUERY_CONFIG_VALUES = "QueryConfigValues"
+REQ_QUERY_CLUSTER_INFO = "QueryClusterInfo"
 REQ_QUEUE_SET_DRAIN_FLAG = "SetDrainFlag"
 
 DEF_CTMO = 10
@@ -366,6 +367,9 @@ class Client(object):
   def QueryExports(self, nodes, use_locking):
     return self.CallMethod(REQ_QUERY_EXPORTS, (nodes, use_locking))
 
+  def QueryClusterInfo(self):
+    return self.CallMethod(REQ_QUERY_CLUSTER_INFO, ())
+
   def QueryConfigValues(self, fields):
     return self.CallMethod(REQ_QUERY_CONFIG_VALUES, fields)