268 lines
11 KiB
Python

"""Exact-name MCP calls used by the durable ordinary-task driver."""
from __future__ import annotations
import asyncio
import logging
from collections.abc import Mapping
from datetime import timedelta
from typing import Any
from deerflow.config.extensions_config import ExtensionsConfig
from deerflow.config.paths import get_paths
from deerflow.constants import MCP_TMP_SUBDIR
from deerflow.mcp.client import build_server_params
from deerflow.mcp.context_headers import build_context_headers_interceptor
from deerflow.mcp.headers import apply_header_overrides
from deerflow.mcp.interceptors import build_mcp_tool_interceptors
from deerflow.mcp.oauth import OAuthTokenManager, build_oauth_tool_interceptor
from deerflow.mcp.session_pool import MCPSessionPool, call_pooled_session_tool, get_session_pool
logger = logging.getLogger(__name__)
def mcp_task_session_scope_key(*, user_id: str, thread_id: str) -> str:
"""Keep background calls in the same per-user/per-thread session scope."""
return f"{user_id}:{thread_id}"
def _prepare_stdio_connection(
connection: dict[str, Any],
*,
user_id: str,
thread_id: str,
) -> dict[str, Any]:
paths = get_paths()
paths.ensure_thread_dirs(thread_id, user_id=user_id)
work_dir = paths.sandbox_work_dir(thread_id, user_id=user_id)
tmp_dir = work_dir / MCP_TMP_SUBDIR
tmp_dir.mkdir(parents=True, exist_ok=True)
tmp_dir.chmod(0o700)
prepared = dict(connection)
prepared.setdefault("cwd", str(work_dir))
env = dict(prepared.get("env") or {})
env.setdefault("TMPDIR", str(tmp_dir))
env.setdefault("TMP", str(tmp_dir))
env.setdefault("TEMP", str(tmp_dir))
prepared["env"] = env
return prepared
class McpTaskToolCaller:
"""Call configured raw MCP tools without exposing them back to the Agent."""
def __init__(
self,
extensions_config: ExtensionsConfig,
*,
oauth_token_manager: OAuthTokenManager | None = None,
) -> None:
self._extensions_config = extensions_config
self._oauth_token_manager = oauth_token_manager or OAuthTokenManager.from_extensions_config(extensions_config)
context_headers_interceptor = build_context_headers_interceptor(extensions_config)
# Built once so the two chains keep an identical interceptor order and a
# custom ``mcpInterceptors`` builder is invoked exactly once.
self._submit_interceptors = build_mcp_tool_interceptors(
extensions_config,
oauth_builder=lambda config: build_oauth_tool_interceptor(
config,
token_manager=self._oauth_token_manager,
),
context_headers_builder=lambda _config: context_headers_interceptor,
)
# Submitting a durable task is awaited inline inside the Agent's tool
# call, so ``config.context.secrets`` is still reachable through the
# ambient LangGraph runtime and the submit goes out under the caller's
# own credential. The later status/cancel polls are driven by the task
# runtime long after that run ended: there is no run context to read, so
# the fail-closed interceptor would deny every poll. Those keep using
# server-level credentials (see docs/MCP_SERVER.md), which is what
# ``build_context_headers_interceptor`` warns about at startup.
if context_headers_interceptor is None:
self._interceptors = self._submit_interceptors
else:
self._interceptors = [interceptor for interceptor in self._submit_interceptors if interceptor is not context_headers_interceptor]
async def call_tool(
self,
*,
server_name: str,
tool_name: str,
arguments: dict[str, Any],
user_id: str,
thread_id: str,
request_scoped_headers: bool = False,
) -> Any:
"""Call a raw MCP tool.
``request_scoped_headers`` opts this call into the ``headers_from_context``
interceptor. Only the durable *submit* may set it: submit is awaited
inside the Agent run that carries the secrets, while status and cancel
run after that run ended.
"""
interceptors = self._submit_interceptors if request_scoped_headers else self._interceptors
server_config = self._extensions_config.get_enabled_mcp_servers().get(server_name)
if server_config is None:
raise LookupError(f"MCP task server {server_name!r} is missing or disabled in the startup configuration")
connection = build_server_params(server_name, server_config)
transport = connection.get("transport", "stdio")
scope_key = mcp_task_session_scope_key(user_id=user_id, thread_id=thread_id)
if transport == "stdio":
connection = await asyncio.to_thread(
_prepare_stdio_connection,
connection,
user_id=user_id,
thread_id=thread_id,
)
pool = get_session_pool()
session_init_timeout = server_config.session_init_timeout
if session_init_timeout is not None:
try:
session = await asyncio.wait_for(
pool.get_session(server_name, scope_key, connection),
timeout=session_init_timeout,
)
except TimeoutError:
logger.warning(
"MCP task session initialization for server '%s' timed out after %.1fs",
server_name,
session_init_timeout,
)
raise
else:
session = await pool.get_session(server_name, scope_key, connection)
return await self._invoke(
session=session,
pool=pool,
scope_key=scope_key,
connection=connection,
server_name=server_name,
tool_name=tool_name,
arguments=arguments,
timeout_seconds=server_config.tool_call_timeout,
session_init_timeout_seconds=None,
persistent_session=True,
interceptors=interceptors,
)
authorization = await self._oauth_token_manager.get_authorization_header(server_name)
if authorization:
connection["headers"] = apply_header_overrides(
connection.get("headers") or {},
{"Authorization": authorization},
)
return await self._invoke(
session=None,
pool=None,
scope_key=scope_key,
connection=connection,
server_name=server_name,
tool_name=tool_name,
arguments=arguments,
timeout_seconds=server_config.tool_call_timeout,
session_init_timeout_seconds=server_config.session_init_timeout,
persistent_session=False,
interceptors=interceptors,
)
async def _invoke(
self,
*,
session: Any | None,
pool: MCPSessionPool | None,
scope_key: str,
connection: dict[str, Any],
server_name: str,
tool_name: str,
arguments: dict[str, Any],
timeout_seconds: float | None,
session_init_timeout_seconds: float | None,
persistent_session: bool,
interceptors: list[Any],
) -> Any:
from langchain_mcp_adapters.interceptors import MCPToolCallRequest
from langchain_mcp_adapters.sessions import create_session
async def execute(request: MCPToolCallRequest) -> Any:
call_kwargs: dict[str, Any] = {}
if timeout_seconds:
call_kwargs["read_timeout_seconds"] = timedelta(seconds=timeout_seconds)
if persistent_session:
assert session is not None and pool is not None
if request.headers:
if isinstance(request.headers, Mapping):
call_kwargs["meta"] = {"headers": dict(request.headers)}
else:
logger.warning(
"Ignoring MCP interceptor headers with unsupported type: %s",
type(request.headers).__name__,
)
return await call_pooled_session_tool(
session,
pool,
server_name=server_name,
scope_key=scope_key,
tool_name=request.name,
arguments=request.args,
call_kwargs=call_kwargs,
)
effective_connection = dict(connection)
if request.headers:
effective_connection["headers"] = apply_header_overrides(
effective_connection.get("headers") or {},
dict(request.headers),
)
captured: BaseException | None = None
call_result: Any | None = None
async with create_session(effective_connection) as remote_session:
initialize = remote_session.initialize()
if session_init_timeout_seconds is not None:
await asyncio.wait_for(
initialize,
timeout=session_init_timeout_seconds,
)
else:
await initialize
try:
call = remote_session.call_tool(
request.name,
request.args,
**call_kwargs,
)
if timeout_seconds:
call_result = await asyncio.wait_for(
call,
timeout=timeout_seconds,
)
else:
call_result = await call
except BaseException as exc: # preserve adapter disconnect semantics
captured = exc
if captured is not None:
raise captured
if call_result is None:
raise RuntimeError(f"MCP task tool {request.name!r} returned no result")
return call_result
handler = execute
for interceptor in reversed(interceptors):
inner = handler
async def wrapped(request: Any, _interceptor: Any = interceptor, _inner: Any = inner) -> Any:
return await _interceptor(request, _inner)
handler = wrapped
return await handler(
MCPToolCallRequest(
name=tool_name,
args=arguments,
server_name=server_name,
runtime=None,
)
)