Handle error seen on system where vlan interface map is not present (s…

…onic-net#246)

fixes sonic-net/sonic-buildimage#9996
Handle error seen on system where vlan interface map is not present.
This change requires: sonic-net/sonic-py-swsssdk#117
On chassis platform, on supervisor there are not ports available in config_db. So, there is no vlan interface map in counters db, which causes this error in syslog:

ERROR: MIBUpdater.start() caught an unexpected exception during update_data(). RuntimeError: Key '{COUNTERS_RIF_NAME_MAP}' unavailable in database '{COUNTERS_DB}'
- How I did it
Return empty dict if vlan interface map is not present in DB.

src/sonic_ax_impl/mibs/__init__.py

@@ -332,7 +332,11 @@ def init_sync_d_vlan_tables(db_conn):
     :return: tuple(vlan_name_map, oid_sai_map, oid_name_map)
     """
 
-    vlan_name_map = port_util.get_vlan_interface_oid_map(db_conn)
+    vlan_name_map = port_util.get_vlan_interface_oid_map(db_conn, blocking=False)
+
+    if not vlan_name_map:
+        logger.debug("There is no vlan interface map in counters DB")
+        return {}, {}, {}
 
     logger.debug("Vlan oid map:\n" + pprint.pformat(vlan_name_map, indent=2))
 

tests/test_mibs.py

@@ -62,3 +62,15 @@ def test_init_sync_d_queue_tables(self):
         self.assertTrue(port_queues_map == {})
         self.assertTrue(queue_stat_map == {})
         self.assertTrue(port_queue_list_map == {})
+
+    @mock.patch('swsssdk.dbconnector.SonicV2Connector.get_all', mock.MagicMock(return_value=({})))
+    def test_init_sync_d_vlan_tables(self):
+        db_conn = Namespace.init_namespace_dbs()
+
+        vlan_name_map, \
+        vlan_oid_sai_map, \
+        vlan_oid_name_map = Namespace.get_sync_d_from_all_namespace(mibs.init_sync_d_vlan_tables, db_conn)
+
+        self.assertTrue(vlan_name_map == {})
+        self.assertTrue(vlan_oid_sai_map == {})
+        self.assertTrue(vlan_oid_name_map == {})