Reduce syslog warnings when ConfigDB has no management ports (sonic-net#115)

* Ignore LLDP peer emtpy mgmt address
* No warning if no managment ports found

Author: qiluo-msft

src/sonic_ax_impl/mibs/__init__.py

@@ -165,7 +165,7 @@ def init_mgmt_interface_tables(db_conn):
     mgmt_ports_keys = db_conn.keys(CONFIG_DB, mgmt_if_entry_table(b'*'))
 
     if not mgmt_ports_keys:
-        logger.warning('No managment ports found in {}'.format(mgmt_if_entry_table(b'')))
+        logger.debug('No managment ports found in {}'.format(mgmt_if_entry_table(b'')))
         return {}, {}
 
     mgmt_ports = [key.split(mgmt_if_entry_table(b''))[-1] for key in mgmt_ports_keys]

src/sonic_ax_impl/mibs/ieee802_1ab.py

@@ -497,6 +497,10 @@ def update_rem_if_mgmt(self, if_oid, if_name):
             return
         try:
             mgmt_ip_str = lldp_kvs[b'lldp_rem_man_addr'].decode()
+            mgmt_ip_str = mgmt_ip_str.strip()
+            if len(mgmt_ip_str) == 0:
+                # the peer advertise an emtpy mgmt address
+                return
             time_mark = int(lldp_kvs[b'lldp_rem_time_mark'])
             remote_index = int(lldp_kvs[b'lldp_rem_index'])
             subtype = self.get_subtype(mgmt_ip_str)