raise from load_netconf_data instead of returning None

inventory_provider/tasks/worker.py

@@ -249,7 +249,7 @@ def load_netconf_data(hostname):
     r = get_redis(InventoryTask.config)
     netconf = r.get('netconf:' + hostname)
     if not netconf:
-        return None
+        raise InventoryTaskError('no netconf data found for %r' % hostname)
     return etree.fromstring(netconf.decode('utf-8'))
 
 
@@ -313,20 +313,19 @@ def reload_router_config(self, hostname):
 
     # get the timestamp for the current netconf data
     current_netconf_timestamp = None
-    netconf_doc = load_netconf_data(hostname)
-    if netconf_doc:
+    try:
+        netconf_doc = load_netconf_data(hostname)
         current_netconf_timestamp \
             = juniper.netconf_changed_timestamp(netconf_doc)
         logger.debug(
             'current netconf timestamp: %r' % current_netconf_timestamp)
+    except InventoryTaskError as e:
+        pass  # ok at this point if not found
 
     # load new netconf data
     netconf_refresh_config.apply(args=[hostname])
 
     netconf_doc = load_netconf_data(hostname)
-    if netconf_doc is None:
-        raise InventoryTaskError(
-            'failure loading netconf data for %r' % hostname)
 
     # return if new timestamp is the same as the original timestamp
     new_netconf_timestamp = juniper.netconf_changed_timestamp(netconf_doc)