Files
deer-flow/backend/packages/harness/deerflow/agents/middlewares/token_usage_middleware.py
greatmengqi 16ed797e0e feat: add configurable log level and token usage tracking (#1301)
* feat: add configurable log level and token usage tracking

- Add `log_level` config to control deerflow module log level, synced
  to LangGraph Server via serve.sh `--server-log-level`
- Add `token_usage.enabled` config with TokenUsageMiddleware that logs
  input/output/total tokens per LLM call from usage_metadata
- Add .omc/ to .gitignore

* fix: use info level for token usage logs since feature has its own toggle

* fix: sort imports to pass lint check

---------

Co-authored-by: greatmengqi <chenmengqi.0376@bytedance.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
2026-03-25 08:13:26 +08:00

38 lines
1.1 KiB
Python

"""Middleware for logging LLM token usage."""
import logging
from typing import override
from langchain.agents import AgentState
from langchain.agents.middleware import AgentMiddleware
from langgraph.runtime import Runtime
logger = logging.getLogger(__name__)
class TokenUsageMiddleware(AgentMiddleware):
"""Logs token usage from model response usage_metadata."""
@override
def after_model(self, state: AgentState, runtime: Runtime) -> dict | None:
return self._log_usage(state)
@override
async def aafter_model(self, state: AgentState, runtime: Runtime) -> dict | None:
return self._log_usage(state)
def _log_usage(self, state: AgentState) -> None:
messages = state.get("messages", [])
if not messages:
return None
last = messages[-1]
usage = getattr(last, "usage_metadata", None)
if usage:
logger.info(
"LLM token usage: input=%s output=%s total=%s",
usage.get("input_tokens", "?"),
usage.get("output_tokens", "?"),
usage.get("total_tokens", "?"),
)
return None