Files
2026-07-13 12:36:27 +08:00

120 lines
4.1 KiB
Python

import threading
from typing import Any, Dict, List, Optional, Tuple
from langchain_core.callbacks import BaseCallbackHandler
from langchain_core.outputs import LLMResult
from langchain_core.messages import AIMessage
def _pick_int(d: Optional[Dict[str, Any]], *keys: str) -> int:
if not d:
return 0
for k in keys:
v = d.get(k)
if v is not None:
try:
return int(v)
except (TypeError, ValueError):
continue
return 0
def _extract_tokens_from_usage_dict(u: Dict[str, Any]) -> Tuple[int, int]:
"""兼容 OpenAI / Anthropic / Gemini 等字段命名。"""
tin = _pick_int(u, "input_tokens", "prompt_tokens", "cache_read_input_tokens")
tout = _pick_int(u, "output_tokens", "completion_tokens", "candidates_token_count")
return tin, tout
class StatsCallbackHandler(BaseCallbackHandler):
"""Callback handler that tracks LLM calls, tool calls, and token usage."""
def __init__(self) -> None:
super().__init__()
self._lock = threading.Lock()
self.llm_calls = 0
self.tool_calls = 0
self.tokens_in = 0
self.tokens_out = 0
def on_llm_start(
self,
serialized: Dict[str, Any],
prompts: List[str],
**kwargs: Any,
) -> None:
"""Increment LLM call counter when an LLM starts."""
with self._lock:
self.llm_calls += 1
def on_chat_model_start(
self,
serialized: Dict[str, Any],
messages: List[List[Any]],
**kwargs: Any,
) -> None:
"""Increment LLM call counter when a chat model starts."""
with self._lock:
self.llm_calls += 1
def on_llm_end(self, response: LLMResult, **kwargs: Any) -> None:
"""Extract token usage from LLM response."""
tin, tout = 0, 0
try:
generation = response.generations[0][0]
except (IndexError, TypeError):
generation = None
if generation is not None and hasattr(generation, "message"):
message = generation.message
if isinstance(message, AIMessage):
if hasattr(message, "usage_metadata") and message.usage_metadata:
um = message.usage_metadata
if isinstance(um, dict):
tin = _pick_int(um, "input_tokens", "prompt_tokens")
tout = _pick_int(um, "output_tokens", "completion_tokens")
if tin == 0 and tout == 0 and hasattr(message, "response_metadata"):
rm = message.response_metadata or {}
u = rm.get("token_usage") or rm.get("usage_metadata") or rm.get("usage")
if isinstance(u, dict):
tin, tout = _extract_tokens_from_usage_dict(u)
if tin == 0 and tout == 0 and generation is not None:
gen_info = getattr(generation, "generation_info", None) or {}
if isinstance(gen_info, dict):
u = gen_info.get("token_usage") or gen_info.get("usage")
if isinstance(u, dict):
tin, tout = _extract_tokens_from_usage_dict(u)
if tin == 0 and tout == 0:
llm_out = getattr(response, "llm_output", None)
if isinstance(llm_out, dict):
u = llm_out.get("token_usage") or llm_out.get("usage")
if isinstance(u, dict):
tin, tout = _extract_tokens_from_usage_dict(u)
if tin or tout:
with self._lock:
self.tokens_in += tin
self.tokens_out += tout
def on_tool_start(
self,
serialized: Dict[str, Any],
input_str: str,
**kwargs: Any,
) -> None:
"""Increment tool call counter when a tool starts."""
with self._lock:
self.tool_calls += 1
def get_stats(self) -> Dict[str, Any]:
"""Return current statistics."""
with self._lock:
return {
"llm_calls": self.llm_calls,
"tool_calls": self.tool_calls,
"tokens_in": self.tokens_in,
"tokens_out": self.tokens_out,
}