Error 'AttributeError: 'NoneType' object has no attribute 'kernel_ws_protocol''

General
1

Hello, we have internal instance of Jupyterlab, running on k8s cluster. After the moment I open UI, I usually experience several consecutive errors like:

[E 2023-11-17 12:07:44.475 ServerApp] 500 GET <some_path>/jupyter/api/kernels/153ad49f-6d1f-4f68-aa44-1e848b2b2dd7/channels?session_id=c3780625-5bd9-42cd-9a02-2a6dc46e3749 (266b9f0237614ad6885dbb74d6558310@10.218.43.180) 33668.23ms referer=None
[E 2023-11-17 12:07:44.476 ServerApp] Uncaught exception GET <some_path>/jupyter/api/kernels/153ad49f-6d1f-4f68-aa44-1e848b2b2dd7/channels?session_id=c3780625-5bd9-42cd-9a02-2a6dc46e3749 (10.197.217.112)
    HTTPServerRequest(protocol='http', host='<some_host>:8080', method='GET', uri='<some_path>/jupyter/api/kernels/153ad49f-6d1f-4f68-aa44-1e848b2b2dd7/channels?session_id=c3780625-5bd9-42cd-9a02-2a6dc46e3749', version='HTTP/1.1', remote_ip='10.197.217.112')
    Traceback (most recent call last):
      File "/opt/spark/work-dir/miniconda3/lib/python3.10/site-packages/tornado/web.py", line 1786, in _execute
        result = await result
      File "/opt/spark/work-dir/.local/lib/python3.10/site-packages/jupyter_server/services/kernels/websocket.py", line 65, in get
        await super().get(kernel_id=kernel_id)
      File "/opt/spark/work-dir/miniconda3/lib/python3.10/site-packages/tornado/websocket.py", line 272, in get
        await self.ws_connection.accept_connection(self)
      File "/opt/spark/work-dir/miniconda3/lib/python3.10/site-packages/tornado/websocket.py", line 862, in accept_connection
        await self._accept_connection(handler)
      File "/opt/spark/work-dir/miniconda3/lib/python3.10/site-packages/tornado/websocket.py", line 902, in _accept_connection
        self.selected_subprotocol = handler.select_subprotocol(subprotocols)
      File "/opt/spark/work-dir/.local/lib/python3.10/site-packages/jupyter_server/services/kernels/websocket.py", line 87, in select_subprotocol
        preferred_protocol = self.connection.kernel_ws_protocol
    AttributeError: 'NoneType' object has no attribute 'kernel_ws_protocol'

After those websocket is being opened and no further errors occure, nor any issues with functionality of jupyterlab I can detect:

[E 2023-11-17 12:07:44.477 ServerApp] 500 GET <some_path>/jupyter/api/kernels/153ad49f-6d1f-4f68-aa44-1e848b2b2dd7/channels?session_id=c3780625-5bd9-42cd-9a02-2a6dc46e3749 (2367bf49cb2f4e97a05df0b79a8909ea@10.197.217.112) 28037.39ms referer=None
[D 2023-11-17 12:07:44.477 ServerApp] 101 GET <some_path>/jupyter/api/kernels/153ad49f-6d1f-4f68-aa44-1e848b2b2dd7/channels?session_id=c3780625-5bd9-42cd-9a02-2a6dc46e3749 (2367bf49cb2f4e97a05df0b79a8909ea@10.197.217.112) 2884.24ms
[D 2023-11-17 12:07:44.477 ServerApp] Opening websocket <some_path>/jupyter/api/kernels/153ad49f-6d1f-4f68-aa44-1e848b2b2dd7/channels

I failed so far to locate the root-cause of this error, if anybody has any ideas on what can cause it, the help is greatly appreciated.

2

This looks like incompatibility in some package versions. Can you run pip check (assuming you use pip not conda) and jupyter --version and report the outputs?

3

It was also reported in 'NoneType' object has no attribute 'kernel_ws_protocol' · Issue #1265 · jupyter-server/jupyter_server · GitHub.

4

Thanks for your answer, here is the output of these commands

bash-4.2$ which pip3
/opt/spark/work-dir/miniconda3/bin/pip3
bash-4.2$ pip3 check
conda 23.10.0 has requirement ruamel-yaml<0.18,>=0.11.14, but you have ruamel-yaml 0.18.5.
bash-4.2$ jupyter --version
Selected Jupyter core packages...
IPython          : 8.17.2
ipykernel        : 6.26.0
ipywidgets       : not installed
jupyter_client   : 8.6.0
jupyter_core     : 5.5.0
jupyter_server   : 2.10.1
jupyterlab       : 4.0.8
nbclient         : 0.9.0
nbconvert        : 7.11.0
nbformat         : 5.9.2
notebook         : not installed
qtconsole        : not installed
traitlets        : 5.13.0
bash-4.2$ which pip
/opt/spark/work-dir/miniconda3/bin/pip
bash-4.2$ pip check
conda 23.10.0 has requirement ruamel-yaml<0.18,>=0.11.14, but you have ruamel-yaml 0.18.5.
5

Asked here as well, no solution was found so far

6

Hello!
Recently I encountered the same error, did you found solutions?
I also have this error:tornado.websocket.WebSocketClosedError
I have the error only when I want to connect Jupyter with my conda R env. my conda python envs are perfectly fine with Jupiyter.
I am already trouble shooting for few days, no luck yet.

7

Hi, unfortunately I still have no solution for this issue

8

Hi
Thanks for the reply.
Now I change to vs-code, the jupyter works there.