Bounded byte-size queue for outgoing WebSocket messages. Messages are stored as pre-serialized strings. The queue enforces a maximum byte budget so that unbounded buffering cannot occur during reconnection windows.
| 9 | |
| 10 | |
| 11 | class SendQueue: |
| 12 | """Bounded byte-size queue for outgoing WebSocket messages. |
| 13 | |
| 14 | Messages are stored as pre-serialized strings. The queue enforces a |
| 15 | maximum byte budget so that unbounded buffering cannot occur during |
| 16 | reconnection windows. |
| 17 | """ |
| 18 | |
| 19 | def __init__(self, max_bytes: int = 1_048_576) -> None: |
| 20 | self._queue: list[tuple[str, int]] = [] # (data, byte_length) |
| 21 | self._bytes: int = 0 |
| 22 | self._max_bytes = max_bytes |
| 23 | self._lock = threading.Lock() |
| 24 | |
| 25 | def enqueue(self, data: str) -> None: |
| 26 | """Append *data* to the queue. |
| 27 | |
| 28 | Raises :class:`WebSocketQueueFullError` if the message would |
| 29 | exceed the byte-size limit. |
| 30 | """ |
| 31 | byte_length = len(data.encode("utf-8")) |
| 32 | with self._lock: |
| 33 | if self._bytes + byte_length > self._max_bytes: |
| 34 | raise WebSocketQueueFullError("send queue is full, message discarded") |
| 35 | self._queue.append((data, byte_length)) |
| 36 | self._bytes += byte_length |
| 37 | |
| 38 | def flush_sync(self, send: typing.Callable[[str], object]) -> None: |
| 39 | """Send every queued message via *send*. |
| 40 | |
| 41 | If *send* raises, the failing message and all subsequent messages |
| 42 | are re-queued and the error is re-raised. |
| 43 | """ |
| 44 | with self._lock: |
| 45 | pending = list(self._queue) |
| 46 | self._queue.clear() |
| 47 | self._bytes = 0 |
| 48 | |
| 49 | for i, (data, _byte_length) in enumerate(pending): |
| 50 | try: |
| 51 | send(data) |
| 52 | except Exception: |
| 53 | with self._lock: |
| 54 | remaining = pending[i:] |
| 55 | self._queue = remaining + self._queue |
| 56 | self._bytes = sum(bl for _, bl in self._queue) |
| 57 | raise |
| 58 | |
| 59 | async def flush_async(self, send: typing.Callable[[str], typing.Awaitable[object]]) -> None: |
| 60 | """Async variant of :meth:`flush_sync`.""" |
| 61 | with self._lock: |
| 62 | pending = list(self._queue) |
| 63 | self._queue.clear() |
| 64 | self._bytes = 0 |
| 65 | |
| 66 | for i, (data, _byte_length) in enumerate(pending): |
| 67 | try: |
| 68 | await send(data) |
no outgoing calls