F1: add reusable task backend resources and migrate task tools

backend/routes/assistants.py

@@ -26,6 +26,7 @@ from services.state_expressions import StateExpressionError, validate_update_rul
 from services.system_tools import RESERVED_TOOL_NAMES
 from services.tool_policy import policy_for_tool
 from services.tool_executor import ToolExecutor
+from services.task_backend_resources import validate_backend_binding
 from services.workflow_engine import WorkflowEngine
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -242,11 +243,12 @@ async def _validate_tool_bindings(
     missing = sorted(tool_ids - set(tools))
     if missing:
         raise HTTPException(400, "工具不存在或未启用: " + ", ".join(missing))
-    task_tools = [tool for tool in tools.values() if tool.type == "task"]
-    if task_tools and (body.type != "prompt" or body.runtime_mode != "pipeline"):
-        raise HTTPException(400, "后台任务工具仅支持提示词 Pipeline")
-    if len(task_tools) > 1:
-        raise HTTPException(400, "每个助手最多绑定一个后台任务工具")
+    if any(tool.type not in {"http", "mcp", "client"} for tool in tools.values()):
+        for scope, raw in raw_bindings:
+            tool = tools.get(raw.get("tool_id") or raw.get("toolId"))
+            if scope.startswith(("Action ", "Startup ")) and tool and tool.type == "task":
+                raise HTTPException(400, "任务后端不支持启动 Action")
+        raise HTTPException(400, "普通工具仅支持 HTTP/MCP/Client；任务请配置任务后端")
     reserved = sorted(
         tool.function_name
         for tool in tools.values()
@@ -287,10 +289,6 @@ async def _validate_tool_bindings(
             type=tool.type,
             definition=tool.definition or {},
         )
-        if tool.type == "task" and binding.result_assignments:
-            raise HTTPException(400, "后台任务结果通过任务通知返回，不支持结果变量映射")
-        if tool.type == "task" and scope.startswith(("Action ", "Startup ")):
-            raise HTTPException(400, "后台任务工具不支持启动 Action")
         properties, required = ToolExecutor.input_schema(runtime_tool)
         unknown = sorted(set(binding.argument_bindings) - set(properties))
         if unknown:
@@ -506,6 +504,13 @@ async def _validate_knowledge_base(session: AsyncSession, body: AssistantUpsert)
         raise HTTPException(400, "知识库不存在")
 
 
+async def _validate_task_backend(session: AsyncSession, body: AssistantUpsert) -> None:
+    try:
+        await validate_backend_binding(session, body)
+    except ValueError as exc:
+        raise HTTPException(400, str(exc)) from exc
+
+
 async def _sync_bindings(
     session: AsyncSession, assistant_id: str, resource_ids: dict[str, str]
 ) -> None:
@@ -641,6 +646,7 @@ async def _to_out(session: AsyncSession, assistant: Assistant) -> AssistantOut:
             else []
         ),
         built_in_tools=assistant.built_in_tools or {},
+        task_backend=getattr(assistant, "task_backend", None),
         prompt=assistant.prompt,
         dynamic_variable_definitions=assistant.dynamic_variable_definitions or {},
         analysis_config=assistant.analysis_config or {},
@@ -681,6 +687,7 @@ async def create_assistant(
     await _validate_vision_model(session, body)
     await _validate_analysis_model(session, body)
     await _validate_knowledge_base(session, body)
+    await _validate_task_backend(session, body)
     data = body.model_dump()
     resource_ids = data.pop("model_resource_ids")
     tool_bindings = body.tool_bindings
@@ -721,6 +728,7 @@ async def duplicate_assistant(
         raise HTTPException(404, "助手不存在")
     if source.type not in SUPPORTED_ASSISTANT_TYPES:
         raise HTTPException(410, "该助手类型已下线")
+    await _validate_task_backend(session, source)
     assistant = Assistant(
         id=f"asst_{uuid.uuid4().hex[:12]}",
         name=f"{source.name} 副本",
@@ -739,6 +747,7 @@ async def duplicate_assistant(
         prompt=source.prompt,
         dynamic_variable_definitions=dict(source.dynamic_variable_definitions or {}),
         built_in_tools=dict(source.built_in_tools or {}),
+        task_backend=dict(source.task_backend) if source.task_backend else None,
         analysis_config=dict(source.analysis_config or {}),
         api_url=source.api_url,
         api_key=source.api_key,
@@ -780,6 +789,7 @@ async def update_assistant(
     await _validate_vision_model(session, body)
     await _validate_analysis_model(session, body)
     await _validate_knowledge_base(session, body)
+    await _validate_task_backend(session, body)
     data = body.model_dump()
     resource_ids = data.pop("model_resource_ids")
     tool_bindings = body.tool_bindings