Add WebsocketLLMService as a base class for WebSocket-based LLM services,
parallel to WebsocketTTSService/WebsocketSTTService but codifying a
transactional request-response model rather than a continuous background
receive loop.
WebsocketLLMService provides:
- Connection lifecycle (start/stop/cancel → connect/disconnect)
- _ws_send/_ws_recv with transparent ConnectionClosed handling
(auto-reconnect via exponential backoff → WebsocketReconnectedError)
- _ensure_connected with retry via _try_reconnect
OpenAIResponsesLLMService now inherits from WebsocketLLMService, removing
duplicated connection management code (_connect, _disconnect, _reconnect,
_ensure_connected, _ws_send, start, stop, cancel) and simplifying
_process_context from a loop with attempt tracking to a flat try/except
with a single retry.
- Use finally block in _disconnect to ensure state is always cleaned
up, even if websocket.close() throws — prevents stale cancellation
state (e.g. _cancel_pending_response) from polluting a new connection
- Catch ConnectionClosed in _drain_cancelled_response alongside
TimeoutError — prevents _needs_drain from staying True and bricking
the service on every subsequent inference attempt
- Fall back to OPENAI_API_KEY env var when api_key is not passed,
since the WebSocket connection uses raw websockets (not the
AsyncOpenAI client which handles this automatically)
- Use _clear_cancellation_state() instead of piecemeal resets where
appropriate
Instead of trying to filter stale events inline (unreliable — the API
doesn't provide a way to correlate events to a specific response),
drain remaining events from a cancelled response before starting the
next one. On cancellation, send response.cancel and set a drain flag.
At the start of the next _process_context, read and discard events
until a terminal event arrives, ensuring a clean connection. Falls
back to reconnecting if draining times out.
Over HTTP, previous_response_id requires store=True (30-day OpenAI-side
conversation storage). The WebSocket variant avoids this via a
connection-local in-memory cache that works with store=False. Add
comments explaining this in both class docstrings, at the store=False
parameter, and in the adapter's previous_response_id note.
