[asyncio] Unclosed client session in Functions

[graelo]

Hi,

I've been trying to use the two MCTS functions: everlier/mcts and haervwe/arxiv. Just for quick context, these functions perform several iterations over the initial model answer to refine it further.

I get weird errors after the each reply from ollama (see the timing below).

Nov 13 23:35:42 hostname open-webui[3723504]: INFO  [open_webui.apps.ollama.main] url: http://ollama.internal:9031
Nov 13 23:35:56 hostname open-webui[3723504]: ERROR [asyncio] Unclosed client session
Nov 13 23:35:56 hostname open-webui[3723504]: client_session: <aiohttp.client.ClientSession object at 0x7f1a73a16ad0>
Nov 13 23:35:56 hostname open-webui[3723504]: ERROR [asyncio] Unclosed connector
Nov 13 23:35:56 hostname open-webui[3723504]: connections: ['[(<aiohttp.client_proto.ResponseHandler object at 0x7f1a6d79b000>, 470696.173)]']
Nov 13 23:35:56 hostname open-webui[3723504]: connector: <aiohttp.connector.TCPConnector object at 0x7f1a6ef58b10>
Nov 13 23:35:56 hostname open-webui[3723504]: INFO  [open_webui.apps.ollama.main] url: http://ollama.internal:9031
Nov 13 23:35:56 hostname open-webui[3723504]: INFO  [open_webui.apps.ollama.main] url: http://ollama.internal:9031
Nov 13 23:35:57 hostname open-webui[3723504]: INFO  [open_webui.apps.ollama.main] url: http://ollama.internal:9031
Nov 13 23:35:57 hostname open-webui[3723504]: INFO  [open_webui.apps.ollama.main] url: http://ollama.internal:9031
Nov 13 23:35:59 hostname open-webui[3723504]: 2024-11-13 23:35:59,537 - Research - DEBUG - Tavily API response status: 200
...

and after a few iterations, the workflow fails with "Load failed"

I asked around in the discussions here, but it seems people have no issues on 0.3.35.

I've been having this issue in all the configs I tried:

• the main container, which is currently 0.3.35.
• same but with an fresh data folder
• the dev container from a few hours ago

I activated the global debug logs, and I tried to make sense of that. I suspect the implicit client session closing mechanism for streaming=True could be involved, so I tried disabling streaming mode. In the end the issue seems related to

open-webui/backend/open_webui/apps/socket/main.py

Line 67 in 96c8654

async def periodic_usage_pool_cleanup():

This function seems to be working great, it has been under scrutiny in the past few releases, so I'm inclined to say that this function reveals the problem, but does not cause it.

I should add that

• I have no errors using other functions
• I have no errors when interacting with models in ollama or openai api during normal chats.

Does any have a clue about what's going on in these types of iterative functions? Do you get the same errors as I do? I'm open to new suggestions to debug this.

Thanks!

[feuler]

I have the same error messages with functions and Traefik proxy -> #8074 (comment)

ERROR [asyncio] Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x7f64ad1afc90>

[Classic298]

I now know where this is coming from. Pipes using generate_chat_completion() function produce these open stale aiohttp connections which alone are not an issue but if piled up - aka if many of them happen, and many of these errors happen, then you WILL eventually get into trouble and your open webui instance as a whole becomes unresponsive because so many aiohttp clients are left open

[Classic298]

openwebui  | 2026-02-04 09:58:43.648 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77869e56f190>
openwebui  | 2026-02-04 09:58:43.649 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x77869e4ede10>, 511095.76138321)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x77867493af50>
openwebui  | 2026-02-04 09:58:44.456 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x735b43899f90>
openwebui  | 2026-02-04 09:58:44.456 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x735b40218fa0>, 511096.568640496)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x735b4373c5d0>
openwebui  | 2026-02-04 09:58:56.791 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77869e1c9f90>
openwebui  | 2026-02-04 09:58:56.791 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x77869e5a30e0>, 511108.896167262)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x7786758829d0>
openwebui  | 2026-02-04 09:58:57.481 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77869e334510>
openwebui  | 2026-02-04 09:58:57.481 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x7786749e7ee0>, 511109.593106993)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x77869e3f3890>
openwebui  | 2026-02-04 09:59:06.711 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x735b4354f590>
openwebui  | 2026-02-04 09:59:06.711 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x735b401eec80>, 511118.823908797)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x735b43760a50>
openwebui  | 2026-02-04 09:59:22.817 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x7d07b4a9b7d0>
openwebui  | 2026-02-04 09:59:22.817 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x7d07b63806e0>, 511134.929535402)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x7d07b4a99810>
openwebui  | 2026-02-04 09:59:23.707 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77867497b050>
openwebui  | 2026-02-04 09:59:23.707 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x7786a1ad0ec0>, 511135.819782552)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x77867586df90>
openwebui  | 2026-02-04 09:59:39.335 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77869e5b36d0>
openwebui  | 2026-02-04 09:59:39.335 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x7786a1aa1010>, 511151.446540419)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x77869e47e410>
openwebui  | 2026-02-04 09:59:43.371 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x735b32cf3290>
openwebui  | 2026-02-04 09:59:43.371 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x735b32e9d4e0>, 511155.483342628)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x735b434cc150>
openwebui  | 2026-02-04 09:59:45.653 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x735b43896c10>
openwebui  | 2026-02-04 09:59:45.653 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x735b4378e660>, 511157.765645526)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x735b4353f890>
openwebui  | 2026-02-04 09:59:52.897 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77869e413890>
openwebui  | 2026-02-04 09:59:52.898 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x77869e4ec590>, 511165.009996949)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x77869e4e7ed0>
openwebui  | 2026-02-04 10:00:25.258 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x735b435a92d0>
openwebui  | 2026-02-04 10:00:25.258 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x735b32e9fd90>, 511197.370843102)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x735b32cbe350>
openwebui  | 2026-02-04 10:00:38.461 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x735b436bbcd0>
openwebui  | 2026-02-04 10:00:38.462 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x735b401ee970>, 511210.574341599)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x735b436bba50>
openwebui  | 2026-02-04 10:01:09.272 | WARNING  | open_webui.utils.middleware:response_handler:3661 - Task was cancelled!
openwebui  | 2026-02-04 10:01:41.175 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77869fb73050>
openwebui  | 2026-02-04 10:01:41.176 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x77869e44b380>, 511273.28835099)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x77869e1f1fd0>
openwebui  | 2026-02-04 10:01:48.849 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x7786753f58d0>
openwebui  | 2026-02-04 10:01:48.849 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x77869fc97310>, 511280.961521937)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x7786753f5a90>
openwebui  | 2026-02-04 10:02:29.748 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x7786a1abd590>
openwebui  | 2026-02-04 10:02:29.748 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x77869e5a3310>, 511321.860796842)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x778674990810>
openwebui  | 2026-02-04 10:04:02.520 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x7d07b66430d0>
openwebui  | 2026-02-04 10:04:02.520 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x7d07b4b05860>, 511414.632897675)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x7d07a47a72d0>
openwebui  | 2026-02-04 10:04:26.272 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77869e4a4890>
openwebui  | 2026-02-04 10:04:26.272 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x7786a1c926d0>, 511438.38428821)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x778675c5b750>
openwebui  | 2026-02-04 10:06:12.999 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x77869fc03a10>
openwebui  | 2026-02-04 10:06:12.999 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x7786749e7b60>, 511545.112150593)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x77869fc02750>
openwebui  | 2026-02-04 10:08:18.222 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x7786753aadd0>
openwebui  | 2026-02-04 10:08:18.222 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x77867530a660>, 511670.333955067)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x7786749ae050>
openwebui  | 2026-02-04 10:08:27.519 | ERROR    | aiohttp.client:__del__:461 - Unclosed client session
openwebui  | client_session: <aiohttp.client.ClientSession object at 0x735b43417ad0>
openwebui  | 2026-02-04 10:08:27.519 | ERROR    | aiohttp.connector:__del__:388 - Unclosed connector
openwebui  | connections: ['deque([(<aiohttp.client_proto.ResponseHandler object at 0x735b401ed9b0>, 511679.630449353)])']
openwebui  | connector: <aiohttp.connector.TCPConnector object at 0x735b436690d0>

[Classic298]

#20889

this might fix it

[graelo]

Thank you!

[Classic298]

I TESTED IT IN PRODUCTION - IT WORKS

our entire production deployment became SUPER SUPER Slow because of so many not-cleaned-up aiohttp sessions

This PR fixes it for EVERYTHING. For all pipes, filters, models, and everything else