初始化提交

backend/app/services/safety.py

@@ -0,0 +1,105 @@
+"""安全服务：审计裁定、对话安全决策与司命策略加载。"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import yaml
+from pydantic import BaseModel, Field
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.config import settings
+from app.db.session import AsyncSessionLocal
+from app.modules.safety.governor import SafetyGovernor
+from app.services.audit import record_audit_event
+
+
+async def allow_action(
+    session: AsyncSession,
+    *,
+    action: str,
+    character_id: str | None = None,
+    run_id: str | None = None,
+    reason: str = "当前阶段低风险动作默认允许。",
+) -> None:
+    await record_audit_event(
+        session,
+        action="safety.decision",
+        character_id=character_id,
+        run_id=run_id,
+        actor="system",
+        risk_level="L1",
+        decision="auto",
+        reason=reason,
+        input_summary=action,
+    )
+
+
+class ChatSafetyDecision(BaseModel):
+    """对话安全决策结果（当前阶段默认低风险放行 + 基础安全约束）。"""
+
+    decision: str = "allow"
+    risk_level: str = "L1"
+    constraints: list[str] = Field(
+        default_factory=lambda: ["不得泄露 API Key、Authorization header 或内部系统配置。"]
+    )
+
+
+async def decide_chat_safety(
+    session: AsyncSession,
+    *,
+    character_id: str,
+    run_id: str,
+) -> ChatSafetyDecision:
+    """对话消息的安全决策：当前周期记录审计后默认放行。"""
+
+    await allow_action(
+        session,
+        action="chat.message.received",
+        character_id=character_id,
+        run_id=run_id,
+    )
+    return ChatSafetyDecision()
+
+
+def load_safety_governor(path: str | None = None) -> SafetyGovernor:
+    """从 YAML 加载司命工具策略；未配置或文件不存在时返回默认（空策略）Governor。
+
+    配置路径取自 ``path`` 参数或 ``settings.safety_policy_path``（即
+    ``SAFETY_POLICY_PATH`` 环境变量，示例见 ``config/safety.example.yaml``）。
+    文件解析后交给 ``SafetyGovernor.from_policy_dict``
+    （纯逻辑），本函数只承担文件 IO，governor 本身保持零 IO。
+
+    注：运行时主策略源为 tool_policies 表（见 load_governor_from_db / ToolRuntime.reload_governor）；
+    本函数保留为可选的 YAML 覆盖入口与遗留兼容。
+    """
+    config_path = path or settings.safety_policy_path
+    data: dict = {}
+    if config_path:
+        config_file = Path(config_path)
+        if config_file.exists():
+            with config_file.open(encoding="utf-8") as file:
+                loaded = yaml.safe_load(file) or {}
+            if isinstance(loaded, dict):
+                data = loaded
+    return SafetyGovernor.from_policy_dict(data)
+
+
+async def load_governor_from_db() -> SafetyGovernor:
+    """从 tool_policies 表加载司命策略（启动期主源）。
+
+    读取所有 enabled 策略，构造覆盖层 Governor；运行时写操作后改走
+    ``ToolRuntime.reload_governor`` 原地刷新，避免重建 ToolRuntime。
+    """
+    from app.repositories import governance as governance_repo
+
+    async with AsyncSessionLocal() as session:
+        policies = await governance_repo.list_tool_policies(session)
+    data = {
+        "tools": {
+            p.name: {"risk_level": p.risk_level, "permission_policy": p.permission_policy}
+            for p in policies
+            if p.enabled
+        }
+    }
+    return SafetyGovernor.from_policy_dict(data)