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Presence was a per-user refcount in Redis, decremented only when a connection's cleanup ran. Anything that ended a connection without cleanup (a crash, an unclean restart, a laptop asleep with the page frozen) leaked its count forever, so those users never showed offline. Production had 19 counts for 2 live connections. Presence is now one expiring entry per connection (90s TTL) for global, per-room and focus presence, in new presence:v2:* keys. Clients renew theirs by sending any frame, which the existing 30s ping/pong already does. The server closes a human connection that sends nothing for 90s (code 4408), which catches a frozen page whose browser still answers transport pings. Bot connections can't be expected to answer pings, so the server renews theirs itself while the handler is alive. An expiry has no disconnect event to announce it, so a sweeper on each worker (one per 15s overall, via a Redis lock) prunes expired entries and broadcasts the offline transition. The old presence:* hashes are deleted at startup. Tests cover the expiry store, the sweeper, and the websocket cases. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
42 lines
1.8 KiB
Python
42 lines
1.8 KiB
Python
import uuid
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from redis.asyncio import Redis
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from app.ws.expiring_presence import ExpiringPresenceSet
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class Presence:
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"""Cross-instance "who's connected to this room," one expiring set per
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room (see ExpiringPresenceSet).
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This is what the offline-push check reads, so a leaked entry used to mean
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a user who'd gone away was still treated as "watching the room" and never
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got a push notification (#77). Entries now expire unless the connection
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keeps renewing them, so that can't outlive a dead connection by more than
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the TTL. Keys are versioned (`v2`) so the old refcount hashes
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(`presence:{room_id}`), with whatever they leaked, are never read.
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"""
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def __init__(self, redis: Redis, store: ExpiringPresenceSet | None = None) -> None:
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self._store = store or ExpiringPresenceSet(redis)
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def _key(self, room_id: uuid.UUID) -> str:
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return f"presence:v2:room:{room_id}"
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async def join(self, room_id: uuid.UUID, user_id: uuid.UUID, conn_id: str) -> None:
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key = self._key(room_id)
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# Per-room offline transitions aren't broadcast anywhere, so unlike
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# the global key there's nothing to lose by pruning here -- it just
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# keeps a busy room's set from accumulating expired entries.
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await self._store.prune(key)
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await self._store.add(key, user_id, conn_id)
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async def refresh(self, room_id: uuid.UUID, user_id: uuid.UUID, conn_id: str) -> None:
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await self._store.add(self._key(room_id), user_id, conn_id)
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async def leave(self, room_id: uuid.UUID, user_id: uuid.UUID, conn_id: str) -> None:
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await self._store.remove(self._key(room_id), user_id, conn_id)
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async def connected_user_ids(self, room_id: uuid.UUID) -> set[uuid.UUID]:
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return await self._store.live_user_ids(self._key(room_id))
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