refactor(server): steward 决策链路改用 LangGraph 编排

- 新增 StewardGraphPlannerService，用 LangGraph 状态图编排意图识别→流程判断→模型/规则分支→兜底，替代原 planner 内线性调用 - 新增 StewardGraphRuntimeService 编排运行时决策与槽位决策；StewardActionContracts/Executor 统一动作合约与执行 - steward_intent_agent/application_fact_resolver/runtime_chat 适配图执行器，config 暴露图相关开关 - pyproject/uv.lock 新增 langgraph 依赖 - 新增 graph_planner/graph_runtime/action_executor 测试，更新 intent_agent/planner/fact_resolver/runtime_chat/reimbursement 测试
2026-06-24 21:58:35 +08:00
parent 545b31d32f
commit 5311c99d69
25 changed files with 3580 additions and 104 deletions
--- a/server/tests/test_steward_graph_runtime.py
+++ b/server/tests/test_steward_graph_runtime.py
@@ -0,0 +1,268 @@
+from __future__ import annotations
+
+from typing import Any
+
+import pytest
+
+from app.api.v1.endpoints import steward as steward_endpoint
+from app.core.config import get_settings
+from app.schemas.steward import (
+    StewardRuntimeDecisionRequest,
+    StewardSlotDecisionRequest,
+)
+from app.services.runtime_chat import (
+    RuntimeChatCallTrace,
+    RuntimeChatToolCall,
+    RuntimeToolCallResult,
+)
+from app.services.steward_graph_runtime import StewardGraphRuntime
+from app.services.steward_runtime_decision_agent import STEWARD_RUNTIME_DECISION_FUNCTION_NAME
+from app.services.steward_slot_decision_agent import STEWARD_SLOT_DECISION_FUNCTION_NAME
+
+
+class _FakeRuntime:
+    def __init__(
+        self,
+        payloads: dict[str, dict[str, Any] | None] | None = None,
+        *,
+        fail_functions: set[str] | None = None,
+    ) -> None:
+        self.payloads = payloads or {}
+        self.fail_functions = fail_functions or set()
+        self.called_functions: list[str] = []
+        self.last_messages: list[dict[str, Any]] = []
+
+    def complete_with_tool_call(self, messages, tools, tool_choice, **kwargs):
+        function_name = str(tool_choice["function"]["name"])
+        self.called_functions.append(function_name)
+        self.last_messages = messages
+        if function_name in self.fail_functions:
+            raise RuntimeError(f"{function_name} failed")
+        payload = self.payloads.get(function_name)
+        if payload is None:
+            return RuntimeToolCallResult(tool_call=None, calls=[])
+        return RuntimeToolCallResult(
+            tool_call=RuntimeChatToolCall(name=function_name, arguments=payload),
+            calls=[
+                RuntimeChatCallTrace(
+                    slot=function_name,
+                    provider="fake",
+                    model="fake",
+                    attempt=1,
+                    status="succeeded",
+                )
+            ],
+        )
+
+
+class _FailingGraphRuntime:
+    def __init__(self, runtime_chat_service) -> None:
+        self.runtime_chat_service = runtime_chat_service
+
+    def decide_slot(self, request):
+        raise RuntimeError("langgraph runtime unavailable")
+
+    def decide_runtime(self, request):
+        raise RuntimeError("langgraph runtime unavailable")
+
+
+@pytest.fixture(autouse=True)
+def _clear_settings_cache():
+    get_settings.cache_clear()
+    yield
+    get_settings.cache_clear()
+
+
+def test_graph_runtime_routes_slot_decision_through_langgraph_tool_node() -> None:
+    runtime = _FakeRuntime(
+        {
+            STEWARD_SLOT_DECISION_FUNCTION_NAME: {
+                "next_action": "ask_user",
+                "required_fields": ["expense_type", "time_range", "location", "reason", "transport_mode"],
+                "missing_fields": ["transport_mode"],
+                "question": "请问您这次打算怎么出行？",
+                "options": [
+                    {"field_key": "transport_mode", "label": "火车", "value": "火车"},
+                    {"field_key": "transport_mode", "label": "飞机", "value": "飞机"},
+                ],
+                "rationale": "出行方式会影响交通费用测算。",
+            }
+        }
+    )
+
+    result = StewardGraphRuntime(runtime).decide_slot(
+        StewardSlotDecisionRequest(
+            task_type="expense_application",
+            user_message="2026-02-20 至 2026-02-23，上海出差，国网仿生产服务器部署",
+            ontology_fields={
+                "expense_type": "travel",
+                "time_range": "2026-02-20 至 2026-02-23",
+                "location": "上海",
+                "reason": "国网仿生产服务器部署",
+            },
+            missing_fields=["transport_mode"],
+        )
+    )
+
+    assert result.decision_source == "llm_function_call"
+    assert result.next_action == "ask_user"
+    assert result.missing_fields == ["transport_mode"]
+    assert runtime.called_functions == [STEWARD_SLOT_DECISION_FUNCTION_NAME]
+
+
+def test_graph_runtime_slot_graph_falls_back_when_tool_node_fails() -> None:
+    runtime = _FakeRuntime(fail_functions={STEWARD_SLOT_DECISION_FUNCTION_NAME})
+
+    result = StewardGraphRuntime(runtime).decide_slot(
+        StewardSlotDecisionRequest(
+            task_type="expense_application",
+            user_message="上海出差，辅助国网仿生产部署",
+            ontology_fields={
+                "expense_type": "travel",
+                "location": "上海",
+                "reason": "辅助国网仿生产部署",
+            },
+            missing_fields=["transport_mode"],
+        )
+    )
+
+    assert result.decision_source == "rule_fallback"
+    assert result.next_action == "ask_user"
+    assert result.missing_fields == ["transport_mode"]
+    assert any(
+        trace.get("slot") == "langgraph_slot_decision"
+        and trace.get("status") == "failed"
+        for trace in result.model_call_traces
+    )
+
+
+def test_graph_runtime_merges_memory_before_runtime_action_node() -> None:
+    runtime = _FakeRuntime({STEWARD_RUNTIME_DECISION_FUNCTION_NAME: None})
+
+    result = StewardGraphRuntime(runtime).decide_runtime(
+        StewardRuntimeDecisionRequest(
+            user_message="我坐高铁",
+            runtime_state={},
+            context_json={
+                "conversation_state": {
+                    "steward_state": {
+                        "active_flow": "travel_application",
+                        "flows": {
+                            "travel_application": {
+                                "flow_id": "travel_application",
+                                "intent": "travel_application_create",
+                                "fields": {
+                                    "expense_type": "travel",
+                                    "time_range": "2026-07-02",
+                                    "location": "北京",
+                                    "reason": "客户现场支撑",
+                                },
+                                "missing_fields": ["transport_mode"],
+                            }
+                        },
+                    }
+                }
+            },
+        )
+    )
+
+    assert result.decision_source == "rule_fallback"
+    assert result.next_action == "fill_current_slot"
+    assert result.field_key == "transport_mode"
+    assert result.field_value == "我坐高铁"
+    assert result.steward_state["flows"]["travel_application"]["fields"]["transport_mode"] == "我坐高铁"
+    assert result.steward_state["flows"]["travel_application"]["missing_fields"] == []
+    assert runtime.called_functions == [STEWARD_RUNTIME_DECISION_FUNCTION_NAME]
+    assert "steward_state" in runtime.last_messages[-1]["content"]
+
+
+def test_graph_runtime_selected_flow_action_node_skips_model_call() -> None:
+    runtime = _FakeRuntime()
+
+    result = StewardGraphRuntime(runtime).decide_runtime(
+        StewardRuntimeDecisionRequest(
+            user_message="补办出差申请",
+            runtime_state={
+                "steward_state": {
+                    "active_flow": "",
+                    "pending_flow_confirmation": {
+                        "status": "pending",
+                        "candidate_flows": [
+                            {"flow_id": "travel_application", "label": "补办出差申请"},
+                            {"flow_id": "travel_reimbursement", "label": "发起费用报销"},
+                        ],
+                    },
+                    "flows": {
+                        "travel_application": {
+                            "flow_id": "travel_application",
+                            "intent": "travel_application_create",
+                            "status": "pending_flow_confirmation",
+                            "fields": {
+                                "time_range": "2026-02-20",
+                                "location": "上海",
+                                "expense_type": "travel",
+                                "reason": "辅助国网仿生产环境部署",
+                            },
+                            "missing_fields": ["transport_mode"],
+                        }
+                    },
+                }
+            },
+        )
+    )
+
+    assert result.decision_source == "rule_fallback"
+    assert result.next_action == "continue_selected_flow"
+    assert result.target_task_id == "travel_application"
+    assert result.steward_state["active_flow"] == "travel_application"
+    assert runtime.called_functions == []
+
+
+def test_slot_endpoint_helper_falls_back_to_legacy_agent_when_langgraph_runtime_fails(monkeypatch) -> None:
+    monkeypatch.setenv("STEWARD_AGENT_RUNTIME", "langgraph")
+    get_settings.cache_clear()
+    monkeypatch.setattr(steward_endpoint, "StewardGraphRuntime", _FailingGraphRuntime)
+    runtime = _FakeRuntime({STEWARD_SLOT_DECISION_FUNCTION_NAME: None})
+
+    result = steward_endpoint._decide_steward_slot(
+        StewardSlotDecisionRequest(
+            task_type="expense_application",
+            user_message="上海出差，辅助国网仿生产部署",
+            ontology_fields={
+                "expense_type": "travel",
+                "location": "上海",
+                "reason": "辅助国网仿生产部署",
+            },
+            missing_fields=["transport_mode"],
+        ),
+        runtime,
+    )
+
+    assert result.decision_source == "rule_fallback"
+    assert result.next_action == "ask_user"
+    assert runtime.called_functions == [STEWARD_SLOT_DECISION_FUNCTION_NAME]
+
+
+def test_runtime_endpoint_helper_falls_back_to_legacy_agent_when_langgraph_runtime_fails(monkeypatch) -> None:
+    monkeypatch.setenv("STEWARD_AGENT_RUNTIME", "langgraph")
+    get_settings.cache_clear()
+    monkeypatch.setattr(steward_endpoint, "StewardGraphRuntime", _FailingGraphRuntime)
+    runtime = _FakeRuntime({STEWARD_RUNTIME_DECISION_FUNCTION_NAME: None})
+
+    result = steward_endpoint._decide_steward_runtime(
+        StewardRuntimeDecisionRequest(
+            user_message="确认",
+            runtime_state={
+                "pending_steward_action": {
+                    "message_id": "msg-next-task",
+                    "target_task_id": "task-reimbursement-meal",
+                }
+            },
+        ),
+        runtime,
+    )
+
+    assert result.decision_source == "rule_fallback"
+    assert result.next_action == "continue_next_task"
+    assert result.target_message_id == "msg-next-task"
+    assert runtime.called_functions == [STEWARD_RUNTIME_DECISION_FUNCTION_NAME]