[BUG] Connector OPC-UA ASYNCIO creates too many sessions (BadTooManySessions) and do not release them when closing or disabling connector

Describe the bug

We have a compulsory "max number of sessions" within OPC-UA in our company which is 10 and a timeout of 20 minutes by default. Give this restriction, we get "BadTooManySessions" many like this after investigating we noticed that OPC-UA ASYNCIO creates sessions but do not close them in the following reproducible scenarios:

Starting point:

2 connectors "disabled" from last session (where we couldn't work any more due to "BadTooManySessions")

Scenarios/ not expected behaviours:

1) Once gateway is started:

if TB edge PE is not available (down) ==> connections is not established which is OK.
if TB edge PE is available (up) ==> it creates a new session, the 4th, even when connector is disabled. We started UAexpert with 3. This is the output of logs. We guess its because there were some pending data to be sent but its shouldnt anyways because connector is disabled in this case

Expected: Do not connect if connector is disabled.

2024-08-11 09:03:28 - |ERROR| - [tb_logger.py] - tb_logger - exception - 133 - Cannot put converted data!
Traceback (most recent call last):
  File "/home/admin/tb-iot-gateway-latest/thingsboard-gateway/venv/lib/python3.12/site-packages/thingsboard_gateway-3.5.1-py3.12.egg/thingsboard_gateway/gateway/tb_gateway_service.py", line 992, in send_to_storage
    filtered_data = self.__duplicate_detector.filter_data(connector_name, data)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'TBGatewayService' object has no attribute '_TBGatewayService__duplicate_detector'. Did you mean: '_TBGatewayService__device_filter'?
2024-08-11 09:03:28 - |DEBUG| - [opcua_uplink_converter.py] - opcua_uplink_converter - convert - 112 - Converted data: {'deviceName': 'MB107_UDC1_A0000KAO8B', 'deviceType': 'default', 'attributes': [ <DELETED_DATA_TO SHORTEN_LOG> ], 'telemetry': [<DELETED_DATA_TO SHORTEN_LOG>]}
2024-08-11 09:03:28 - |DEBUG| - [opcua_connector.py] - opcua_connector - __send_data - 493 - Data to ThingsBoard {'deviceName': 'MB107_UDC1_A0000K9J76', 'deviceType': 'default', 'attributes': [<DELETED_DATA_TO SHORTEN_LOG>], 'telemetry': [<DELETED_DATA_TO SHORTEN_LOG>]}
2024-08-11 09:03:28 - |DEBUG| - [opcua_connector.py] - opcua_connector - __send_data - 490 - {'deviceName': 'MB107_UDC1_A0000KAO8B', 'deviceType': 'default', 'attributes': [<DELETED_DATA_TO SHORTEN_LOG>], 'telemetry': [<DELETED_DATA_TO SHORTEN_LOG>]}

Note that the duplicate_detector error we don't know why its produced and it was the first time to be seen.

2) Another 2 sessions are created once a connector is started. Maybe one per timeseries? Check the configurator Expected: 1 session per connector.

{
  "server": {
    "name": "YYYYYYYYY",
    "url": "opc.tcp://xxxxxxxxx:59300/xxxxxxx/UnifiedDataCollector",
    "timeoutInMillis": 5000,
    "scanPeriodInMillis": 10000,
    "disableSubscriptions": true,
    "subCheckPeriodInMillis": 100,
    "showMap": false,
    "security": "Basic128Rsa15",
    "identity": {
      "type": "anonymous"
    },
    "mapping": [
      {
        "deviceNodePattern": "Root\\.Objects\\.Server",
        "deviceNamePattern": "MB107_UDC1_A0000K9J76",
        "attributes": [
          {
            "key": "server_uai",
            "path": "${ns=2;b=sbnFUIh4jWVrbbrxt463og==}"
          },
          {
            "key": "device_uai",
            "path": "${ns=2;b=sbnFUIh4jWVrbbrxt463og==}"
          },
          {
            "key": "site_code",
            "path": "${ns=2;b=zCGYLEQhEXoiQHQBVhcIoA==}"
          },
          {
            "key": "line",
            "path": "${ns=2;b=WrO0W3muBdo+gdCYlWooSQ==}"
          }
        ],
        "timeseries": [
          {
            "key": "/Server/ServerStatus/BuildInfo",
            "path": "${ns=0;i=2260}"
          },
          {
            "key": "/Server/UaiInfo/UaiCode",
            "path": "${ns=2;b=sbnFUIh4jWVrbbrxt463og==}"
          }
        ]
      }
    ]
  },
  "logLevel": "DEBUG",
  "name": "YYYYYYYYY_connector",
  "enableRemoteLogging": true,
  "id": "19cdae8c-1a85-4454-8892-3b40df28e650"
}

3) Sessions are not released after disabling the connector

We also tested to disable->enable->disable and additional sessions are created without releasing the previous ones

Expected: Sessions are released after disabling the connector

4) Closing gateway do not release sessions.

Expected: Sessions are released after closing gateway

Connector name (If bug in the some connector): OPC-UA asyncio Connector

Error traceback (If available): Above

Versions (please complete the following information):

OS: Ubuntu 22
Thingsboard IoT Gateway version: master branch (2024-08-11)
Python version: 3.12

thingsboard / thingsboard-gateway

[BUG] Connector OPC-UA ASYNCIO creates too many sessions (BadTooManySessions) and do not release them when closing or disabling connector #1494