siftlode/backend/app/quota.py
npeter83 dc70a978ed refactor(quota): canonical <entity>_<action> taxonomy for quota events
The quota-attribution action keys were inconsistent (mixed verbs, ad-hoc names,
English-only labels). Introduce a QuotaAction constants holder (one source of
truth), rename every attribution call site to it, and add migration 0020 to
rename historical quota_events.action values. The display label now resolves
from i18n (quotaActions.<key>, EN/HU/DE) instead of a hard-coded English map.
Scheduler job ids and progress phase labels are a separate namespace and are
left untouched.
2026-06-19 11:48:11 +02:00

108 lines
3.6 KiB
Python

"""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.
"""
import contextlib
import contextvars
from datetime import datetime, timezone
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, QuotaEvent
_PACIFIC = ZoneInfo("America/Los_Angeles")
class QuotaAction:
"""Canonical quota-attribution action keys (one source of truth).
Naming scheme: ``<entity>_<action>``, all snake_case, explicit pull/push direction.
The stored value is this machine key; the user-facing label is resolved from i18n
(frontend ``quotaActions.<key>``). Distinct from scheduler job ids and progress phase
labels — do not conflate.
"""
SUBSCRIPTIONS_PULL = "subscriptions_pull"
SUBSCRIPTIONS_RESYNC = "subscriptions_resync"
PLAYLISTS_PULL = "playlists_pull"
PLAYLISTS_PUSH = "playlists_push"
PLAYLISTS_DELETE = "playlists_delete"
VIDEOS_BACKFILL_RECENT = "videos_backfill_recent"
VIDEOS_BACKFILL_FULL = "videos_backfill_full"
VIDEOS_ENRICH = "videos_enrich"
VIDEOS_LOOKUP = "videos_lookup"
CHANNELS_DISCOVER = "channels_discover"
CHANNELS_SUBSCRIBE = "channels_subscribe"
CHANNELS_UNSUBSCRIBE = "channels_unsubscribe"
MAINTENANCE_REVALIDATE = "maintenance_revalidate"
OTHER = "other"
# Request/job-scoped attribution for quota spend: who triggered it and what kind of work.
# Set at entry points (route handlers, scheduler jobs) via attribute(); read by
# record_usage. Default = background/system, generic action.
_actor_id: contextvars.ContextVar[int | None] = contextvars.ContextVar(
"quota_actor_id", default=None
)
_action: contextvars.ContextVar[str] = contextvars.ContextVar(
"quota_action", default=QuotaAction.OTHER
)
@contextlib.contextmanager
def attribute(actor_id: int | None, action: str):
"""Attribute any quota spent in this block to `actor_id` (None = system) under `action`."""
t1 = _actor_id.set(actor_id)
t2 = _action.set(action)
try:
yield
finally:
_actor_id.reset(t1)
_action.reset(t2)
def pacific_today():
return datetime.now(_PACIFIC).date()
def pacific_day_start_utc() -> datetime:
"""UTC instant of the current Pacific day's midnight — aligns 'today' with the budget reset."""
start = datetime.now(_PACIFIC).replace(hour=0, minute=0, second=0, microsecond=0)
return start.astimezone(timezone.utc)
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) and log an attribution event."""
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)
# Audit detail: who/what spent it (per-user attribution; NULL actor = system).
db.add(QuotaEvent(user_id=_actor_id.get(), action=_action.get(), units=units))
db.commit()