第 2 步(Neo4j)主体,三件事:
1. 新增 app/service/graph_model.py:图模型的**单一来源**。
节点标签与主属性名会被拼进 Cypher(Neo4j 的标签不能用参数占位),因此必须来自受控常量,
绝不能是调用方传入的字符串——否则就是 Cypher 注入;同时读服务与投影侧必须就"客户节点
长什么样"达成一致。此前两边各写各的(投影写 :Entity{entity_id}、读服务查
:Customer{customer_id}),结果写进去的关系永远读不出来。
另用 RELATION_SEMANTICS 补上"谁指向谁"的方向校验:底座已有关系白名单(8 种),
但白名单只约束关系名,不约束方向,这里补上,避免把 TRADED 写成 Customer→Tag。
2. 改 app/worker/graph_projection_worker.py:按 payload 的 source_type/target_type 写具体标签,
投影前校验关系方向。标签与属性名全部取自 graph_model,调用方传不进任意字符串。
3. 新增 app/service/profile_graph_projection_service.py:把画像事实投影成节点与关系,
并补上此前缺失的**投影删除客户端**(销户或记忆失效时 DETACH DELETE,同时清悬挂边)。
只投影 user_facts(与画像同源),不直接读原始记忆——否则同一件事在画像与图里会有两种说法。
图库故障一律返回 degraded 而不抛异常:投顾推荐可以暂时没有图,但不该因为图挂了
导致画像更新失败。
背景(核查发现):MemorySyncOutbox 与 GraphProjectionWorker 此前是**孤儿代码**——表建了、
worker 也实现了(含幂等、重试、死信、MERGE),但没有任何代码往 outbox 写、也没有任何地方
实例化这个 worker,整条图投影链路从未接上过。这正是图中只有 Neo4j 自带 Person/Movie
示例数据的根因。本次把"画像 → 图"这条链路接通;领域事件驱动的投影仍待接入(worker 已修好可用)。
实测验证:
· 投影客户 9001 → relations=1,随后 neighbors(PREFERS) 直接读到
{'tag_key': 'preference:risk_level=稳健型'} —— 写后读通,标签已对齐;
· delete_customer → 关系归零(degraded=False),重新投影恢复为 1,再次投影仍为 1(幂等);
· 图中标签为 Customer/Tag、关系为 PREFERS;早先探针残留的 Entity 节点已清理;
· ruff 通过、mypy 112 文件无错。
83 lines
3.8 KiB
Python
83 lines
3.8 KiB
Python
from datetime import UTC, datetime, timedelta
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from typing import Any
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from sqlalchemy import select
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from sqlalchemy.ext.asyncio import AsyncSession
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from app.model.memory import MemorySyncOutbox
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from app.service.graph_model import merge_node_clause, node_id, node_spec, relation_allowed
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from app.service.relationship_service import RelationshipService
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class GraphProjectionWorker:
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"""Projects approved domain events to Neo4j; callers provide durable dedup storage."""
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def __init__(
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self, relationships: RelationshipService, session: AsyncSession | None = None
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) -> None:
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self.relationships = relationships
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self.session = session
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self.processed_event_ids: set[str] = set()
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async def project(self, event_id: str, payload: dict[str, Any]) -> bool:
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if event_id in self.processed_event_ids:
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return False
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if self.session is not None:
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existing = await self.session.scalar(
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select(MemorySyncOutbox).where(MemorySyncOutbox.event_uuid == event_id)
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)
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if existing is not None and existing.status == "processed":
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return False
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relation = payload.get("relationship")
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if relation not in RelationshipService.ALLOWED_RELATIONSHIPS:
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raise ValueError("relationship is not allowed")
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# 节点按**类型**写标签与主属性:原先统一写 `:Entity {entity_id}`,而读服务查的是
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# `:Customer {customer_id}`,两侧从未对齐,写进去的关系永远读不出来。
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# 标签与属性名来自 `graph_model` 的受控常量,调用方传不进任意字符串。
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source_type = str(payload.get("source_type", "")).strip().lower()
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target_type = str(payload.get("target_type", "")).strip().lower()
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source = node_spec(source_type)
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target = node_spec(target_type)
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if not relation_allowed(relation, source_type, target_type):
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raise ValueError(
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f"relationship {relation} cannot connect {source_type} -> {target_type}"
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)
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query = (
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f"{merge_node_clause('a', source, 'source_id')} "
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f"{merge_node_clause('b', target, 'target_id')} "
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f"MERGE (a)-[r:{relation}]->(b) "
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"SET r.trace_id = $trace_id, r.confidence = $confidence, r.updated_at = $updated_at"
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)
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try:
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await self.relationships.driver.execute_query(
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query,
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source_id=node_id(source, payload["source_id"]),
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target_id=node_id(target, payload["target_id"]),
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trace_id=str(payload.get("trace_id", "")),
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confidence=float(payload.get("confidence", 0.0)),
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updated_at=datetime.now(UTC).replace(tzinfo=None).isoformat(),
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)
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except Exception as exc:
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if self.session is not None:
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record = await self.session.scalar(
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select(MemorySyncOutbox).where(MemorySyncOutbox.event_uuid == event_id)
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)
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if record is not None:
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record.retry_count += 1
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record.last_error = str(exc)[:500]
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record.status = "dead" if record.retry_count >= 5 else "pending"
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record.next_retry_at = datetime.now(UTC).replace(tzinfo=None) + timedelta(
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seconds=min(300, 2 ** record.retry_count)
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)
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await self.session.commit()
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raise
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self.processed_event_ids.add(event_id)
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if self.session is not None:
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record = await self.session.scalar(
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select(MemorySyncOutbox).where(MemorySyncOutbox.event_uuid == event_id)
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)
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if record is not None:
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record.status = "processed"
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await self.session.commit()
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return True
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