Tu Naichao 959bf13406
fix(memory): flush memory queue on graceful shutdown to prevent loss (#4181)
* fix(memory): bounded shutdown flush via MemoryManager.shutdown_flush

Re-applies the memory-queue shutdown drain on top of the pluggable
MemoryManager abstraction (#4122): the old top-level MemoryUpdateQueue
singleton is gone, so the drain is now a backend contract instead of
host code reaching into the queue.

- MemoryManager ABC: shutdown_flush(timeout) -> bool. Every backend
  implements a bounded graceful-shutdown drain.
- DeerMem: queue.flush_sync (daemon-thread + Event.wait hard timeout
  for the uninterruptible sync LLM call; joins an in-flight worker
  first so contexts a debounce Timer already pulled out are not lost on
  exit; skips inter-item sleep on the drain path; per-item
  succeeded/failed count), exposed via shutdown_flush.
- noop: shutdown_flush is a clean no-op success.
- Gateway lifespan: call get_memory_manager().shutdown_flush(timeout)
  after channels/scheduler stop, via asyncio.to_thread, try/except
  bounded. No host-level pending/processing guard -- the backend
  short-circuits on an idle buffer, so the host cannot "forget" the
  in-flight case (structurally eliminates the guard race flagged on the
  prior revision).
- shutdown_flush_timeout_seconds added to the shared MemoryConfig
  (host-owned lifecycle budget, default 30, 1-300) + exposed on
  MemoryConfigResponse and the embedded client; config_version 25 -> 26.

Tests: queue flush_sync (7), lifespan drain incl. False-branch caplog
assertion + disabled gate (3), ABC contract noop/deermem (3).

* fix(chart): gateway grace period so memory drain is not SIGKILLed

K8s defaults terminationGracePeriodSeconds to 30s, shorter than the
Gateway's graceful-shutdown work (channel stop ~5s + memory queue drain
default 30s). Without an explicit grace period, K8s SIGKILLs the memory
drain mid-flight and silently re-introduces the loss shutdown_flush is
fixing (flagged on the prior revision).

- gateway pod: terminationGracePeriodSeconds (default 45, configurable).
- gateway container: preStop sleep (default 5, 0 disables) so the
  Service/ingress deregisters the pod before SIGTERM begins the drain.
- values.yaml + README: both configurable; README documents that the
  grace period must track memory.shutdown_flush_timeout_seconds.

* docs(memory): document shutdown_flush_timeout_seconds + lifespan drain

Add the host-shared field to the memory config list and Config Schema
summary in backend/AGENTS.md, noting the lifespan drain and the K8s
grace-period relationship.

* fix(chart): bump embedded config_version to 26

The chart's embedded `config:` block (values.yaml + README example) still
had config_version: 25 after commit f3ca8e9f raised config.example.yaml to
26, failing the validate-chart config_version drift check. Bump both to 26.
2026-07-15 20:25:41 +08:00
..