feat: add memory sync outbox worker

app/worker/memory_sync_outbox_worker.py

@@ -0,0 +1,88 @@
+"""画像投影 Outbox 消费器。
+
+外部存储通过 handler 注入；本模块只负责领取、重试、死信和 MySQL 状态更新。
+"""
+
+from collections.abc import Awaitable, Callable
+from datetime import UTC, datetime, timedelta
+from typing import Any
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.infrastructure.db import SessionFactory
+from app.model.memory import MemorySyncOutbox
+
+ProjectionHandler = Callable[[dict[str, Any]], Awaitable[Any]]
+MAX_RETRY_COUNT = 5
+
+
+class MemorySyncOutboxWorker:
+    """按目标存储独立消费画像投影事件。"""
+
+    def __init__(
+        self,
+        handlers: dict[str, ProjectionHandler],
+        *,
+        session_factory: Callable[[], AsyncSession] = SessionFactory,
+    ) -> None:
+        self.handlers = handlers
+        self.session_factory = session_factory
+
+    async def run_once(self, *, target_store: str | None = None) -> bool:
+        """领取并处理一条到期事件；没有可处理事件时返回 False。"""
+        if not self.handlers:
+            return False
+        async with self.session_factory() as session:
+            now = datetime.now(UTC).replace(tzinfo=None)
+            conditions: list[Any] = [
+                MemorySyncOutbox.status.in_({"pending", "failed"}),
+                MemorySyncOutbox.next_retry_at.is_(None)
+                | (MemorySyncOutbox.next_retry_at <= now),
+            ]
+            if target_store is not None:
+                conditions.append(MemorySyncOutbox.target_store == target_store)
+            event = await session.scalar(
+                select(MemorySyncOutbox)
+                .where(*conditions)
+                .order_by(MemorySyncOutbox.id)
+                .limit(1)
+                .with_for_update(skip_locked=True)
+            )
+            if event is None:
+                await session.rollback()
+                return False
+            handler = self.handlers.get(event.target_store)
+            if handler is None:
+                self._fail(event, "target_handler_not_configured", now, dead=True)
+                await session.commit()
+                return True
+            try:
+                await handler(event.payload)
+            except Exception as exc:
+                self._fail(event, type(exc).__name__, now)
+            else:
+                event.status = "processed"
+                event.processed_at = datetime.now(UTC).replace(tzinfo=None)
+                event.last_error = None
+                event.next_retry_at = None
+            await session.commit()
+            return True
+
+    @staticmethod
+    def _fail(
+        event: MemorySyncOutbox,
+        reason: str,
+        now: datetime,
+        *,
+        dead: bool = False,
+    ) -> None:
+        """写入可重试失败或死信状态，不吞掉失败事实。"""
+        event.retry_count = int(event.retry_count) + 1
+        event.last_error = reason[:500]
+        event.status = "dead" if dead or event.retry_count >= MAX_RETRY_COUNT else "failed"
+        event.next_retry_at = (
+            None
+            if event.status == "dead"
+            else now + timedelta(seconds=min(300, 2 ** int(event.retry_count)))
+        )