Cloud WebSocket abruptly close while using Scope

[dmtelf]

Summary

I was using Scope remote inference with webcam + Krea & all of a sudden Scope just disconnected from the cloud + there is no information in the log about it apart from this line 2026-03-17 16:15:59,738 - scope.server.cloud_connection - WARNING - Cloud WebSocket closed (code=1006, reason=None)

Cloud WebSocket closed.txt

Platform

Windows 10, 48Gb RAM

Nvidia GPU

8Gb 3070

Scope Version

0.17 app

uv Version

uv 0.7.19 (38ee6ec80 2025-07-02)

node Version

v22.17.0

[livepeer-tessa]

Thanks for the detailed log — it makes the root cause clear.

What happened: Code 1006 means the TCP connection was dropped without a WebSocket close frame ("abnormal closure"). Looking at your log:

• Connected at 15:50:49
• ~15 min of light activity while setting up
• Krea pipeline started at 16:05:57
• Disconnected at 16:15:59

There are no errors or warnings before the drop — the connection just vanishes. That's a classic sign of a NAT gateway, proxy, or firewall silently killing an "idle" TCP connection.

Root cause: The cloud WebSocket connection has no heartbeat configured. Without periodic ping frames, middleboxes (routers, proxies, firewalls) can drop the underlying TCP connection after a timeout (commonly 10–30 min). Since there's no close frame, Scope sees code=1006 with no reason.

Fix: PR #709 adds heartbeat=30.0 to the WebSocket connection — aiohttp will now send a ping frame every 30 seconds, keeping the connection alive through any middleboxes. One-line change.