Private
Public Access
Messages could silently stop arriving until a room switch happened to paper over it with a REST refetch. Root cause: a connection that dies without a clean close (laptop sleep, an idle connection recycled by a proxy/NAT) looks identical to a healthy-but-quiet one -- readyState stays OPEN, onclose never fires, so the already-correct reconnect and rejoin logic never runs. The backend now pings every 30s and the frontend force-closes the socket if nothing (any frame, not just a pong) arrives within 65s, routing straight through the existing reconnect/rejoin path instead of needing separate recovery logic. Also found and fixed a more severe adjacent bug while tracing this: ConnectionManager.broadcast()/send_to_user() had no per-socket error handling, so one dead or racing socket could raise inside the app's single, never-restarted Redis pubsub listener task and silently kill live delivery for every room and every user on that process until restart. Now caught and logged per-socket instead of propagating. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
72 lines
3.3 KiB
Python
72 lines
3.3 KiB
Python
import json
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import logging
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import uuid
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from redis.asyncio import Redis
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from app.ws.connection_manager import ConnectionManager
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logger = logging.getLogger(__name__)
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ROOM_CHANNEL_PREFIX = "room:"
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USER_CHANNEL_PREFIX = "user:"
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class Broadcaster:
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"""Cross-instance message fan-out (ARCHITECTURE.md phase 5).
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Publishes to a per-room or per-user Redis channel; every app instance --
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including the one that published -- subscribes via a single pattern
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subscription and forwards to its own locally connected WebSocket clients
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via ConnectionManager. A single instance just talks to itself through
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Redis, so there's no separate code path for the 1-instance vs N-instance
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case.
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Room channels carry anything scoped to a room's joined members (new
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messages, edits, reactions). User channels carry anything scoped to one
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person regardless of which rooms they've joined -- currently just
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"you've been added to a room," which by definition arrives before the
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recipient could ever have joined that room's own channel.
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"""
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def __init__(self, redis: Redis, manager: ConnectionManager) -> None:
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self._redis = redis
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self._manager = manager
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async def publish(self, room_id: uuid.UUID, payload: dict) -> None:
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await self._redis.publish(f"{ROOM_CHANNEL_PREFIX}{room_id}", json.dumps(payload))
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async def publish_to_user(self, user_id: uuid.UUID, payload: dict) -> None:
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await self._redis.publish(f"{USER_CHANNEL_PREFIX}{user_id}", json.dumps(payload))
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async def listen(self) -> None:
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pubsub = self._redis.pubsub()
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await pubsub.psubscribe(f"{ROOM_CHANNEL_PREFIX}*", f"{USER_CHANNEL_PREFIX}*")
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try:
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async for message in pubsub.listen():
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if message["type"] != "pmessage":
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continue
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# #76: this is the one pubsub listener for the whole process
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# (see main.py's lifespan) -- ConnectionManager.broadcast/
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# send_to_user already guard against one dead socket taking
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# the rest of a single fan-out down, but this belt-and-
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# suspenders catch is for anything else unexpected (a
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# malformed payload, e.g.) doing the same. An uncaught
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# exception here previously meant *this whole async for*
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# loop died silently -- no more live delivery to any room on
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# this instance, for anyone, until the process restarted.
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try:
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channel = message["channel"]
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payload = json.loads(message["data"])
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if channel.startswith(ROOM_CHANNEL_PREFIX):
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room_id = uuid.UUID(channel.removeprefix(ROOM_CHANNEL_PREFIX))
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await self._manager.broadcast(room_id, payload)
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elif channel.startswith(USER_CHANNEL_PREFIX):
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user_id = uuid.UUID(channel.removeprefix(USER_CHANNEL_PREFIX))
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await self._manager.send_to_user(user_id, payload)
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except Exception:
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logger.error("Error handling pubsub message on channel %s", message.get("channel"), exc_info=True)
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finally:
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await pubsub.punsubscribe(f"{ROOM_CHANNEL_PREFIX}*", f"{USER_CHANNEL_PREFIX}*")
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await pubsub.aclose()
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