refactor(gateway): run inbox and BYO polling from FastAPI lifespan

surfsense_backend/app/gateway/inbox_worker.py

@@ -0,0 +1,55 @@
+"""FastAPI lifespan worker for gateway inbox processing."""
+
+from __future__ import annotations
+
+import asyncio
+import logging
+from contextlib import suppress
+
+from app.gateway.inbox_processor import claim_next_inbound_event, process_inbound_event
+
+logger = logging.getLogger(__name__)
+
+_task: asyncio.Task[None] | None = None
+
+
+async def _process_inbox_forever() -> None:
+    logger.info("Gateway inbox processor started in FastAPI process")
+    while True:
+        try:
+            inbox_id = await claim_next_inbound_event()
+            if inbox_id is None:
+                await asyncio.sleep(0.5)
+                continue
+            logger.info("Gateway processing inbox_id=%s", inbox_id)
+            await process_inbound_event(inbox_id)
+            logger.info("Gateway processed inbox_id=%s", inbox_id)
+        except asyncio.CancelledError:
+            raise
+        except RuntimeError as exc:
+            if str(exc) == "gateway_thread_busy":
+                logger.info("Gateway inbox_id busy; will retry from RECEIVED state")
+            else:
+                logger.exception("Gateway inbox processor failed one iteration")
+            await asyncio.sleep(1)
+        except Exception:
+            logger.exception("Gateway inbox processor failed one iteration")
+            await asyncio.sleep(1)
+
+
+async def start_gateway_inbox_worker() -> None:
+    global _task
+    if _task is not None and not _task.done():
+        return
+    _task = asyncio.create_task(_process_inbox_forever(), name="gateway-inbox-worker")
+
+
+async def stop_gateway_inbox_worker() -> None:
+    global _task
+    if _task is None:
+        return
+    _task.cancel()
+    with suppress(TimeoutError, asyncio.CancelledError):
+        await asyncio.wait_for(_task, timeout=10)
+    _task = None
+