codeingforcoffee 4669d3c089
feat(gateway): cache-aware cost accounting (#3920)
* feat(gateway): cache-aware cost accounting + /api/console observability endpoints

- Capture prompt-cache hits (usage_metadata.input_token_details.cache_read)
  in RunJournal and SubagentTokenCollector as a sparse cache_read_tokens key
  in token_usage_by_model (JSON field — no schema migration; legacy bucket
  shapes unchanged)
- New read-only /api/console router: GET /stats (headline counters),
  GET /runs (cross-thread paginated history joined with thread titles),
  GET /usage (zero-filled daily token series + per-model breakdown);
  user-scoped, 503 on the memory database backend
- Optional models[*].pricing (currency, input_per_million,
  output_per_million, input_cache_hit_per_million) powers real spend
  estimation; cache-hit input tokens are billed at the hit price (omitted
  hit price falls back to the miss price as a conservative upper bound);
  unpriced models yield cost: null
- create_chat_model strips the presentation-only pricing block so it never
  reaches the provider client (unknown kwargs are forwarded into the
  completion payload and break live calls)
- Tests: console router SQLite round-trips, journal/collector cache capture
  incl. a DeepSeek raw-usage pin test, factory strip regression

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* refactor: address review feedback on cost sum and sparse cache_read_tokens

- console.py: replace the walrus-in-generator total-cost sum with an
  explicit loop (review noted the multi-line form reads ambiguously)
- token_collector.py: omit cache_read_tokens from usage records when the
  provider reported no cache hits, matching the journal's sparse
  per-model bucket shape; absent is treated as 0 downstream
- add a regression test pinning the sparse record shape

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: coffeeFish <codeingforcoffee@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-07-04 23:14:46 +08:00

84 lines
3.4 KiB
Python

"""Callback handler that collects LLM token usage within a subagent.
Each subagent execution creates its own collector. After the subagent
finishes, the collected records are transferred to the parent RunJournal
via :meth:`RunJournal.record_external_llm_usage_records`.
"""
from __future__ import annotations
from collections.abc import Mapping
from typing import Any
from langchain_core.callbacks import BaseCallbackHandler
class SubagentTokenCollector(BaseCallbackHandler):
"""Lightweight callback handler that collects LLM token usage within a subagent."""
def __init__(self, caller: str):
super().__init__()
self.caller = caller
self._records: list[dict[str, int | str | None]] = []
self._counted_run_ids: set[str] = set()
def on_llm_end(
self,
response: Any,
*,
run_id: Any,
tags: list[str] | None = None,
**kwargs: Any,
) -> None:
rid = str(run_id)
if rid in self._counted_run_ids:
return
for generation in response.generations:
for gen in generation:
if not hasattr(gen, "message"):
continue
usage = getattr(gen.message, "usage_metadata", None)
usage_dict = dict(usage) if usage else {}
input_tk = usage_dict.get("input_tokens", 0) or 0
output_tk = usage_dict.get("output_tokens", 0) or 0
total_tk = usage_dict.get("total_tokens", 0) or 0
if total_tk <= 0:
total_tk = input_tk + output_tk
if total_tk <= 0:
continue
# Prompt-cache hits (needed for cache-aware cost accounting)
details = usage_dict.get("input_token_details") or {}
cache_read_tk = 0
if isinstance(details, Mapping):
try:
cache_read_tk = max(int(details.get("cache_read") or 0), 0)
except (TypeError, ValueError):
cache_read_tk = 0
# Capture the model that actually produced this response so the
# parent journal can bucket tokens by real model rather than the
# lead agent's resolved model
response_metadata = getattr(gen.message, "response_metadata", None) or {}
model_name: str | None = None
if isinstance(response_metadata, Mapping):
model_name = response_metadata.get("model_name") or response_metadata.get("model")
self._counted_run_ids.add(rid)
record: dict[str, int | str | None] = {
"source_run_id": rid,
"caller": self.caller,
"model_name": model_name,
"input_tokens": input_tk,
"output_tokens": output_tk,
"total_tokens": total_tk,
}
# Sparse, matching the journal's per-model buckets: the key is
# only present when the provider actually reported cache hits.
if cache_read_tk > 0:
record["cache_read_tokens"] = cache_read_tk
self._records.append(record)
return
def snapshot_records(self) -> list[dict[str, int | str | None]]:
"""Return a copy of the accumulated usage records."""
return list(self._records)