Python AsyncUA OPC UA客户端报错：BadSecureChannelIdInvalid

使用Python AsyncUA库开发OPC UA客户端时，运行示例代码出现**The specified secure channel is no longer valid.(BadSecureChannelIdInvalid)**错误，最终程序以退出码1终止。

示例代码 #

import asyncio
from asyncua import Client

async def read_opcua_node(endpoint_url, node_id):
    async with Client(url=endpoint_url) as client:
        # Connect to the server
        await client.connect()

        # Read the node value
        node = await client.get_node(node_id)
        value = await node.read_value()

        # Print the result
        print(f"Value of node {node_id}: {value}")

if __name__ == "__main__":

    endpoint_url = "opc.tcp://172.10.0.13:4840"
    node_id = "ns=2;i=0"

    # Run the script
    asyncio.run(read_opcua_node(endpoint_url, node_id))

控制台报错信息 #

Requested session timeout to be 3600000ms, got 60000ms instead
Received an error: ErrorMessage(Error=StatusCode(value=2149711872), Reason=None)
Received an error: ErrorMessage(Error=StatusCode(value=2149711872), Reason=None)
Got error status from server: The specified secure channel is no longer valid.(BadSecureChannelIdInvalid)
close_secure_channel was called but connection is closed
disconnect_socket was called but connection is closed
close_session was called but connection is closed
close_secure_channel was called but connection is closed
disconnect_socket was called but connection is closed
Traceback (most recent call last):
  File "/Users/kavimuthurajas/PycharmProjects/Amber-OPCGateway/OPCUAClient.py", line 22, in <module>
    asyncio.run(read_opcua_node(endpoint_url, node_id))
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/runners.py", line 190, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py", line 653, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/Users/kavimuthurajas/PycharmProjects/Amber-OPCGateway/OPCUAClient.py", line 7, in read_opcua_node
    await client.connect()
  File "/Users/kavimuthurajas/PycharmProjects/Amber-OPCGateway/venv/lib/python3.11/site-packages/asyncua/client/client.py", line 310, in connect
    await self.create_session()
  File "/Users/kavimuthurajas/PycharmProjects/Amber-OPCGateway/venv/lib/python3.11/site-packages/asyncua/client/client.py", line 489, in create_session
    response = await self.uaclient.create_session(params)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/kavimuthurajas/PycharmProjects/Amber-OPCGateway/venv/lib/python3.11/site-packages/asyncua/client/ua_client.py", line 335, in create_session
    data = await self.protocol.send_request(request)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/kavimuthurajas/PycharmProjects/Amber-OPCGateway/venv/lib/python3.11/site-packages/asyncua/client/ua_client.py", line 170, in send_request
    raise ConnectionError("Connection is closed") from None
ConnectionError: Connection is closed

解决思路 #

• 修复连接逻辑冲突
  async with Client上下文管理器会自动完成连接和资源释放，手动调用await client.connect()会导致重复创建安全通道，引发ID无效错误。修改后的代码：

  import asyncio
  from asyncua import Client
  
  async def read_opcua_node(endpoint_url, node_id):
      async with Client(url=endpoint_url) as client:
          # 移除手动connect调用，上下文管理器已自动处理连接
          node = await client.get_node(node_id)
          value = await node.read_value()
          print(f"Value of node {node_id}: {value}")
  
  if __name__ == "__main__":
      endpoint_url = "opc.tcp://172.10.0.13:4840"
      node_id = "ns=2;i=0"
      asyncio.run(read_opcua_node(endpoint_url, node_id))
  

• 匹配会话超时设置
  日志显示服务器将请求的3600000ms超时调整为60000ms，可手动设置客户端超时匹配服务器限制：

  async with Client(url=endpoint_url) as client:
      client.set_session_timeout(60000)
      # 后续操作...
  

• 检查服务器与网络状态

  • 确认OPC UA服务器正常运行，端点opc.tcp://172.10.0.13:4840可通过telnet/nc命令测试连通性
  • 排查防火墙、NAT规则是否拦截了4840端口的通信
  • 若服务器启用安全验证，客户端需匹配对应的安全模式（如None、Sign）和安全策略（如Basic256Sha256）

• 更新AsyncUA库
  旧版本库可能存在安全通道管理bug，执行pip install --upgrade asyncua更新到最新稳定版

内容的提问来源于stack exchange，提问作者KAVI MUTHU RAJA