`receive_text` raises `WebSocketDisconnect` once the peer has gone and
`RuntimeError` on every call after that. The loop swallowed both — the
exception was checked only to decide whether the frame held a media
subscription — and immediately made another read, which raised again. A
closed tab therefore left a coroutine reading a dead socket at full tilt:
around 15,000 turns a second, one orphaned `Queue.get()` per turn parked on
the bus queue's waiter list. The event loop stalled behind it, `/health`
answered 503 on its loop-lag check, and Docker's probe plus Traefik took
the API out of the pool mid-request — which is what `make verify` was dying
on, with `TypeError: Failed to fetch` from the browser.
The spin ended only when an event finally reached the send path and the
socket raised there, so it lasted from milliseconds to minutes depending on
what the bus happened to be carrying. Four abandoned sockets logged 2,518
`Task was destroyed but it is pending!` lines and up to 2.6s of loop lag;
twenty now log none and cost 1.0ms.
A failed read is the disconnect, so it ends the stream. The getter created
beside it is cancelled rather than abandoned: nothing reads it after the
turn that made it, and left behind it would also take an event the live
reader wanted.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CL9zvnnvcp1mvA8o7impxk
stroblmeandClaude Opus 5
32f751e115