79 lines
3.0 KiB
Python

import logging
from typing import NotRequired, override
from langchain.agents import AgentState
from langchain.agents.middleware import AgentMiddleware
from langgraph.runtime import Runtime
from deerflow.agents.thread_state import SandboxState, ThreadDataState
from deerflow.config.deer_flow_context import DeerFlowContext
from deerflow.sandbox import get_sandbox_provider
logger = logging.getLogger(__name__)
class SandboxMiddlewareState(AgentState):
"""Compatible with the `ThreadState` schema."""
sandbox: NotRequired[SandboxState | None]
thread_data: NotRequired[ThreadDataState | None]
class SandboxMiddleware(AgentMiddleware[SandboxMiddlewareState]):
"""Create a sandbox environment and assign it to an agent.
Lifecycle Management:
- With lazy_init=True (default): Sandbox is acquired on first tool call
- With lazy_init=False: Sandbox is acquired on first agent invocation (before_agent)
- Sandbox is reused across multiple turns within the same thread
- Sandbox is NOT released after each agent call to avoid wasteful recreation
- Cleanup happens at application shutdown via SandboxProvider.shutdown()
"""
state_schema = SandboxMiddlewareState
def __init__(self, lazy_init: bool = True):
"""Initialize sandbox middleware.
Args:
lazy_init: If True, defer sandbox acquisition until first tool call.
If False, acquire sandbox eagerly in before_agent().
Default is True for optimal performance.
"""
super().__init__()
self._lazy_init = lazy_init
def _acquire_sandbox(self, thread_id: str) -> str:
provider = get_sandbox_provider()
sandbox_id = provider.acquire(thread_id)
logger.info(f"Acquiring sandbox {sandbox_id}")
return sandbox_id
@override
def before_agent(self, state: SandboxMiddlewareState, runtime: Runtime[DeerFlowContext]) -> dict | None:
# Skip acquisition if lazy_init is enabled
if self._lazy_init:
return super().before_agent(state, runtime)
# Eager initialization (original behavior)
if "sandbox" not in state or state["sandbox"] is None:
thread_id = runtime.context.thread_id
if not thread_id:
return super().before_agent(state, runtime)
sandbox_id = self._acquire_sandbox(thread_id)
logger.info(f"Assigned sandbox {sandbox_id} to thread {thread_id}")
return {"sandbox": {"sandbox_id": sandbox_id}}
return super().before_agent(state, runtime)
@override
def after_agent(self, state: SandboxMiddlewareState, runtime: Runtime[DeerFlowContext]) -> dict | None:
sandbox = state.get("sandbox")
if sandbox is not None:
sandbox_id = sandbox["sandbox_id"]
logger.info(f"Releasing sandbox {sandbox_id}")
get_sandbox_provider().release(sandbox_id)
return None
# No sandbox to release
return super().after_agent(state, runtime)