Deno Jupyter Kernel fails to start

[mishushakov]

Version: Deno 2.2.5

After installing the Deno Jupyter Kernel using:

deno jupyter --install

Frequently, I am seeing this error after trying to start the kernel:

Jupyter logs:

Warning "deno jupyter" is unstable and might change in the future.
[I 2025-03-26 13:45:33.599 ServerApp] Kernel started: f57210f9-ba4a-4afa-a028-f67fdb3fd06f
[I 2025-03-26 13:45:33.810 ServerApp] Connecting to kernel f57210f9-ba4a-4afa-a028-f67fdb3fd06f.
[I 2025-03-26 13:45:36.580 ServerApp] Kernel shutdown: f57210f9-ba4a-4afa-a028-f67fdb3fd06f
Client disconnected PeerIdentity(b"\xc4\x9cD\x82|~G\x9d\x9a\x7f\t!\x8f\x86j\x1f")
[W 2025-03-26 13:45:39.177 ServerApp] 404 PATCH /api/sessions/eb92e314-6aeb-4e53-b904-1b8c82778084?1742996739175 (192.168.215.1): Session not found: "Kernel 'f57210f9-ba4a-4afa-a028-f67fdb3fd06f' appears to have been culled or died unexpectedly, invalidating session 'eb92e314-6aeb-4e53-b904-1b8c82778084'. The session has been removed."
[W 2025-03-26 13:45:39.178 ServerApp] wrote error: 'Session not found: "Kernel \'f57210f9-ba4a-4afa-a028-f67fdb3fd06f\' appears to have been culled or died unexpectedly, invalidating session \'eb92e314-6aeb-4e53-b904-1b8c82778084\'. The session has been removed."'
    Traceback (most recent call last):
      File "/opt/conda/lib/python3.12/site-packages/jupyter_server/services/sessions/sessionmanager.py", line 428, in get_session
        model = await self.row_to_model(row)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      File "/opt/conda/lib/python3.12/site-packages/jupyter_server/services/sessions/sessionmanager.py", line 494, in row_to_model
        raise KeyError(msg)
    KeyError: "Kernel 'f57210f9-ba4a-4afa-a028-f67fdb3fd06f' appears to have been culled or died unexpectedly, invalidating session 'eb92e314-6aeb-4e53-b904-1b8c82778084'. The session has been removed."
    
    The above exception was the direct cause of the following exception:
    
    Traceback (most recent call last):
      File "/opt/conda/lib/python3.12/site-packages/tornado/web.py", line 1790, in _execute
        result = await result
                 ^^^^^^^^^^^^
      File "/opt/conda/lib/python3.12/site-packages/jupyter_server/auth/decorator.py", line 73, in inner
        return await out
               ^^^^^^^^^
      File "/opt/conda/lib/python3.12/site-packages/jupyter_server/services/sessions/handlers.py", line 142, in patch
        before = await sm.get_session(session_id=session_id)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      File "/opt/conda/lib/python3.12/site-packages/jupyter_server/services/sessions/sessionmanager.py", line 430, in get_session
        raise web.HTTPError(404, "Session not found: %s" % str(e)) from e
    tornado.web.HTTPError: HTTP 404: Not Found (Session not found: "Kernel 'f57210f9-ba4a-4afa-a028-f67fdb3fd06f' appears to have been culled or died unexpectedly, invalidating session 'eb92e314-6aeb-4e53-b904-1b8c82778084'. The session has been removed.")
[W 2025-03-26 13:45:39.181 ServerApp] 404 PATCH /api/sessions/eb92e314-6aeb-4e53-b904-1b8c82778084?1742996739175 (0c4428bd892141198093520e19e48b0e@192.168.215.1) 5.90ms referer=http://localhost:8888/lab/workspaces/auto-l/tree/Untitled3.ipynb

When I start the kernel programmatically via the Jupyter API it will report the state as starting, but it will be stuck in the state forever.

POST 127.0.0.1:8888/api/kernels
Content-Type: application/json

{
  "id": "dde482a0-766b-4cef-92af-a7c2d35f9b4f",
  "name": "Deno",
  "last_activity": "2025-03-26T13:56:47.259231Z",
  "execution_state": "starting",
  "connections": 0
}

{
  "id": "56a74713-8934-4fe8-9eff-29571960e6d3",
  "name": "Deno",
  "last_activity": "2025-03-26T13:58:31.543422Z",
  "execution_state": "starting",
  "connections": 0
}

after 5 seconds

POST 127.0.0.1:8888/api/kernels/9b0a430f-c80c-4259-a37d-d4a4f4d00ff2

{
  "id": "56a74713-8934-4fe8-9eff-29571960e6d3",
  "name": "Deno",
  "last_activity": "2025-03-26T13:58:31.543422Z",
  "execution_state": "starting",
  "connections": 0
}

The execution_state never becomes "idle".
Let me know if there's any way to get logs out of Deno Jupyter Server?