[BFD]Clean up state_db BFD entries on swss restart (#2434)

*[BFD]Clean up state_db BFD entries on swss restart (#2434)

orchagent/bfdorch.cpp

@@ -59,6 +59,17 @@ BfdOrch::BfdOrch(DBConnector *db, string tableName, TableConnector stateDbBfdSes
     DBConnector *notificationsDb = new DBConnector("ASIC_DB", 0);
     m_bfdStateNotificationConsumer = new swss::NotificationConsumer(notificationsDb, "NOTIFICATIONS");
     auto bfdStateNotificatier = new Notifier(m_bfdStateNotificationConsumer, this, "BFD_STATE_NOTIFICATIONS");
+
+    // Clean up state database BFD entries
+    vector<string> keys;
+
+    m_stateBfdSessionTable.getKeys(keys);
+
+    for (auto alias : keys)
+    {
+        m_stateBfdSessionTable.del(alias);
+    }
+
     Orch::addExecutor(bfdStateNotificatier);
     register_state_change_notif = false;
 }

tests/test_bfd.py

@@ -464,3 +464,23 @@ def test_multipleBfdSessions(self, dvs):
         self.adb.wait_for_deleted_entry("ASIC_STATE:SAI_OBJECT_TYPE_BFD_SESSION", session3)
         self.remove_bfd_session(key4)
         self.adb.wait_for_deleted_entry("ASIC_STATE:SAI_OBJECT_TYPE_BFD_SESSION", session4)
+
+    def test_bfd_state_db_clear(self, dvs):
+        self.setup_db(dvs)
+
+        bfdSessions = self.get_exist_bfd_session()
+
+        # Create BFD session
+        fieldValues = {"local_addr": "10.0.0.1", "type": "demand_active"}
+        self.create_bfd_session("default:default:10.0.0.2", fieldValues)
+        self.adb.wait_for_n_keys("ASIC_STATE:SAI_OBJECT_TYPE_BFD_SESSION", len(bfdSessions) + 1)
+
+        # Checked created BFD session in ASIC_DB
+        createdSessions = self.get_exist_bfd_session() - bfdSessions
+        assert len(createdSessions) == 1
+        dvs.stop_swss()
+        dvs.start_swss()
+
+        time.sleep(5)
+        keys = self.sdb.get_keys("BFD_SESSION_TABLE")
+        assert len(keys) == 0