"""ServiceNow discover / preview_tools / create_tools handler 实现。 handler 签名遵循 ``OperationHandler`` 协议： ``(source_type: str, system_config: dict[str, Any]) -> Awaitable[Any]``。 handler 内部职责： 1. 从 ``system_config`` 提取 ``base_url`` / ``api_version`` / ``_resolved_token`` 等 2. 构建 ``auth_headers``（token 由 use_cases 层注入到 ``system_config["_resolved_token"]``） 3. 构造带 429 退避的 ``request_fn``，注入到生成器 payload 4. 调用 ``ServiceNowSourceGenerator.generate(payload)`` 429 退避分层（见设计文档 §6.2 / §8.2）： - discover/preview/create 阶段：本模块 ``_request_with_retry`` 实现（解析 Retry-After） - 运行时工具执行：通过工具 ``retry_policy.retry_status_codes: [429]`` 配置 """ from __future__ import annotations import asyncio from collections.abc import Awaitable, Callable from typing import TYPE_CHECKING, Any from yuxi.external_systems.exceptions import ( AuthError, DomainValidationError, ExecutionError, RateLimitExceededError, ) from yuxi.external_systems.integrations.schemas import GeneratedToolsDraft from yuxi.external_systems.integrations.servicenow.error_extractor import ( map_servicenow_error, ) from yuxi.external_systems.integrations.servicenow.generators import ( ServiceNowSourceGenerator, ) if TYPE_CHECKING: import httpx # discover/preview/create 阶段 429 退避参数 _RETRY_MAX_ATTEMPTS = 5 _RETRY_BASE_DELAY = 1.0 # ServiceNow 通用请求头（除 Authorization 外） _SERVICENOW_HEADERS: dict[str, str] = { "Accept": "application/json", } def _build_auth_headers(system_config: dict[str, Any]) -> dict[str, str]: """从 system_config 提取 token，构建 ServiceNow 请求头。 system_config 中 token 由 use_cases 层通过 ``token_manager.get_token`` 预处理后 注入到 ``system_config["_resolved_token"]["access_token"]``。handler 不自行换取 token——token 获取是 use_cases 层的职责。 """ token_info = system_config.get("_resolved_token") if not isinstance(token_info, dict) or not token_info.get("access_token"): raise AuthError("servicenow: system_config 缺少 _resolved_token，use_cases 层未注入 token") access_token = token_info["access_token"] token_type = token_info.get("token_type", "Bearer") headers = dict(_SERVICENOW_HEADERS) headers["Authorization"] = f"{token_type} {access_token}" headers["Content-Type"] = "application/json" return headers def _resolve_base_url(system_config: dict[str, Any]) -> str: """从 system_config 提取 base_url，支持 instance 动态拼接。""" connection_config = system_config.get("connection_config") or {} base_url = connection_config.get("base_url") instance = connection_config.get("instance") if not base_url and instance: base_url = f"https://{instance}.service-now.com" if not base_url: raise DomainValidationError("servicenow: system_config.connection_config.base_url 或 instance 至少需填写一项") return str(base_url) def _resolve_api_version(system_config: dict[str, Any]) -> str | None: """从 system_config 提取 api_version。""" connection_config = system_config.get("connection_config") or {} return connection_config.get("api_version") def _resolve_tables(system_config: dict[str, Any]) -> list[str] | None: """从 system_config.discovery_options.tables 提取待生成的表名列表。""" discovery_options = system_config.get("discovery_options") or {} return discovery_options.get("tables") async def _request_with_retry( method: str, url: str, headers: dict[str, str], *, max_retries: int = _RETRY_MAX_ATTEMPTS, base_delay: float = _RETRY_BASE_DELAY, ) -> httpx.Response: """handler 内部 HTTP 调用的 429 退避（仅用于 discover/preview/create 阶段）。 优先使用响应头 ``Retry-After``，否则指数退避（``base_delay * 2 ** attempt``）。 运行时工具执行的 429 退避由框架 executor + 工具 retry_policy 处理， 不在此函数范围内。 非 2xx 响应（非 429）通过 ``map_servicenow_error`` 转换为 ExternalSystemError 子类。 网络层异常（超时 / 连接错误）转换为 ``ExecutionError``。 """ import httpx try: async with httpx.AsyncClient() as client: last_response: httpx.Response | None = None for attempt in range(max_retries + 1): response = await client.request(method, url, headers=headers) if response.status_code != 429: last_response = response break if attempt == max_retries: retry_after_header = response.headers.get("Retry-After", "60") try: retry_after = int(retry_after_header) except ValueError: retry_after = 60 raise RateLimitExceededError( f"ServiceNow 限流，已重试 {max_retries} 次仍失败: {url}", retry_after=retry_after, limit_type="qps", ) # 优先使用 Retry-After 头，否则指数退避 retry_after_header = response.headers.get("Retry-After") if retry_after_header: try: delay = float(retry_after_header) except ValueError: delay = base_delay * (2**attempt) else: delay = base_delay * (2**attempt) await asyncio.sleep(delay) except httpx.RequestError as exc: raise ExecutionError(f"ServiceNow 网络请求失败: {exc}") from exc assert last_response is not None if last_response.is_success: return last_response # 非 2xx：解析错误 body 并映射为 ExternalSystemError 子类 try: error_body = last_response.json() except Exception: error_body = {"error": {"message": last_response.text}} raise map_servicenow_error(last_response.status_code, error_body) def _make_request_fn() -> Callable[[str, str, dict[str, str]], Awaitable[httpx.Response]]: """构造带 429 退避的 request_fn，供 ServiceNowMetadataClient 使用。""" async def request_fn(method: str, url: str, headers: dict[str, str]) -> httpx.Response: return await _request_with_retry(method, url, headers) return request_fn def _build_generator_payload(system_config: dict[str, Any]) -> dict[str, Any]: """从 system_config 构造生成器 payload。 生成器 payload 是 system_config 的子集，包含： - base_url: str - auth_headers: dict[str, str] - auth_config: dict — 透传到工具的 auth_config 字段 - auth_type: str — 透传到工具的 auth_type 字段 - api_version: str | None - tables: list[str] | None - request_fn: 带 429 退避的 HTTP 请求函数 """ return { "base_url": _resolve_base_url(system_config), "auth_headers": _build_auth_headers(system_config), "auth_config": system_config.get("auth_config") or {}, "auth_type": system_config.get("auth_type", "oauth2_client_credentials"), "api_version": _resolve_api_version(system_config), "tables": _resolve_tables(system_config), "request_fn": _make_request_fn(), } async def discover_servicenow( source_type: str, system_config: dict[str, Any], ) -> list[dict[str, Any]]: """discover handler：发现 ServiceNow 实例可用表（sys_db_object）。 Returns: 表摘要列表，每项含 ``name`` / ``label``。 """ from yuxi.external_systems.integrations.servicenow.metadata_discovery import ( ServiceNowMetadataClient, ) base_url = _resolve_base_url(system_config) auth_headers = _build_auth_headers(system_config) request_fn = _make_request_fn() client = ServiceNowMetadataClient( base_url=base_url, auth_headers=auth_headers, request_fn=request_fn, ) options = system_config.get("discovery_options") or {} tables = await client.list_tables( include_patterns=options.get("include_patterns"), exclude_patterns=options.get("exclude_patterns"), ) return [{"name": t["name"], "label": t.get("label", t["name"])} for t in tables] async def preview_servicenow_tools( source_type: str, system_config: dict[str, Any], ) -> list[dict[str, Any]]: """preview_tools handler：预览将生成的工具列表（不持久化）。 Returns: 工具预览列表，每项为 ExternalToolCreateInput 兼容的 dict 摘要。 """ payload = _build_generator_payload(system_config) generator = ServiceNowSourceGenerator() tools = await generator.generate(payload) return [{"slug": t["slug"], "name": t["name"], "description": t["description"]} for t in tools] async def create_servicenow_tools( source_type: str, system_config: dict[str, Any], ) -> GeneratedToolsDraft: """create_tools handler：生成工具草稿（不直接持久化）。 Returns: GeneratedToolsDraft，由 use_cases 层统一持久化。 """ payload = _build_generator_payload(system_config) generator = ServiceNowSourceGenerator() tool_configs = await generator.generate(payload) return GeneratedToolsDraft(tool_configs=tool_configs, override_existing=False)