siftlode/backend/app/quota.py

51 lines
1.4 KiB
Python
Raw Normal View History

"""Central YouTube Data API quota guard.
The whole app shares one daily budget (the API resets at midnight US Pacific time).
Steady-state work (RSS detection is free; enrichment of new videos is cheap) should
always be allowed; expensive backfill must yield to the remaining budget.
"""
from datetime import datetime
from zoneinfo import ZoneInfo
from sqlalchemy.dialects.postgresql import insert as pg_insert
from sqlalchemy.orm import Session
from app.config import settings
from app.models import ApiQuotaUsage
_PACIFIC = ZoneInfo("America/Los_Angeles")
def pacific_today():
return datetime.now(_PACIFIC).date()
def units_used_today(db: Session) -> int:
row = db.get(ApiQuotaUsage, pacific_today())
return row.units_used if row else 0
def remaining_today(db: Session) -> int:
return max(0, settings.quota_daily_budget - units_used_today(db))
def can_spend(db: Session, units: int) -> bool:
return remaining_today(db) >= units
def record_usage(db: Session, units: int) -> None:
"""Atomically add `units` to today's counter (upsert)."""
if units <= 0:
return
day = pacific_today()
stmt = (
pg_insert(ApiQuotaUsage)
.values(day=day, units_used=units)
.on_conflict_do_update(
index_elements=[ApiQuotaUsage.day],
set_={"units_used": ApiQuotaUsage.units_used + units},
)
)
db.execute(stmt)
db.commit()