feat: cron worker for renewal notifs

alembic/versions/af1c3d7e4b20_remove_service_notification_expiry_unique.py

@@ -0,0 +1,32 @@
+"""Remove global service notification expiry uniqueness.
+
+Revision ID: af1c3d7e4b20
+Revises: ee6174eeef14
+Create Date: 2026-08-20 00:00:00.000000
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+
+
+revision: str = "af1c3d7e4b20"
+down_revision: Union[str, Sequence[str], None] = "ee6174eeef14"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.drop_constraint(
+        "service_notifications_sub_expires_at_key",
+        "service_notifications",
+        type_="unique",
+    )
+
+
+def downgrade() -> None:
+    op.create_unique_constraint(
+        "service_notifications_sub_expires_at_key",
+        "service_notifications",
+        ["sub_expires_at"],
+    )

config.py

@@ -37,6 +37,7 @@ class Settings(BaseSettings):
 
     access_token_ttl: int = Field(description="Access token TTL (minutes)")
     link_code_ttl: int = Field(8, description="Link Code TTL (minutes)")
+    notification_scan_interval: int = Field(5, ge=1)
 
     min_password_length: int = Field(8)
     link_code_length: int = Field(8)

db/models/service_notifications.py

@@ -23,9 +23,7 @@ class ServiceNotification(Base):
     notify_type: Mapped[NotificationType] = mapped_column(
         Enum(NotificationType, name="notificationtype"), nullable=False
     )
-    sub_expires_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), unique=True, nullable=False
-    )
+    sub_expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
 
     status: Mapped[NotificationStatus] = mapped_column(
         Enum(NotificationStatus, name="notificationstatus"),

main.py

@@ -1,8 +1,24 @@
+import asyncio
+from contextlib import asynccontextmanager, suppress
+
 from fastapi import FastAPI
 
 from routes import routers
+from services.notifications import run_subscription_notifications
 
-app = FastAPI(debug=True)
+
+@asynccontextmanager
+async def lifespan(_: FastAPI):
+    task = asyncio.create_task(run_subscription_notifications())
+    try:
+        yield
+    finally:
+        task.cancel()
+        with suppress(asyncio.CancelledError):
+            await task
+
+
+app = FastAPI(debug=True, lifespan=lifespan)
 
 for r in routers:
     app.include_router(r)

services/notifications.py

@@ -0,0 +1,64 @@
+import asyncio
+from datetime import UTC, datetime, timedelta
+from typing import TYPE_CHECKING
+
+from sqlalchemy import select
+from sqlalchemy.dialects.postgresql import insert
+
+from config import cfg
+from db.models import ServiceNotification, Subscription
+from db.session import async_session
+from schemas.enums import NotificationType
+
+if TYPE_CHECKING:
+    from sqlalchemy.ext.asyncio import AsyncSession
+
+
+async def collect_subscription_notifications(
+    session: "AsyncSession", now: datetime | None = None
+) -> int:
+    now = now or datetime.now(UTC)
+    periods = (
+        (NotificationType.SEVEN_DAYS, now + timedelta(days=3), now + timedelta(days=7)),
+        (NotificationType.THREE_DAYS, now + timedelta(days=1), now + timedelta(days=3)),
+        (NotificationType.ONE_DAY, now, now + timedelta(days=1)),
+        (NotificationType.EXPIRED, None, now),
+    )
+    created = 0
+
+    for notification_type, starts_at, ends_at in periods:
+        conditions = [Subscription.expires_at <= ends_at]
+        if starts_at is not None:
+            conditions.append(Subscription.expires_at > starts_at)
+
+        subscriptions = await session.scalars(select(Subscription).where(*conditions))
+        rows = [
+            {
+                "subscription_id": subscription.id,
+                "notify_type": notification_type,
+                "sub_expires_at": subscription.expires_at,
+            }
+            for subscription in subscriptions
+        ]
+        if not rows:
+            continue
+
+        stmt = insert(ServiceNotification).values(rows)
+        stmt = stmt.on_conflict_do_nothing(constraint="uq_subscription_notification")
+        result = await session.execute(stmt)
+        created += result.rowcount or 0
+
+    await session.commit()
+    return created
+
+
+async def run_subscription_notifications() -> None:
+    interval = cfg.notification_scan_interval * 60
+    while True:
+        try:
+            async with async_session() as session:
+                await collect_subscription_notifications(session)
+        except Exception:
+            # A failed iteration must not stop subsequent notification checks.
+            pass
+        await asyncio.sleep(interval)

tests/test_notifications.py

@@ -0,0 +1,46 @@
+import asyncio
+from datetime import UTC, datetime, timedelta
+from types import SimpleNamespace
+
+from schemas.enums import NotificationType
+from services.notifications import collect_subscription_notifications
+
+
+class FakeSession:
+    def __init__(self, subscriptions_by_period):
+        self.subscriptions_by_period = iter(subscriptions_by_period)
+        self.executed = []
+        self.committed = False
+
+    async def scalars(self, _statement):
+        return next(self.subscriptions_by_period)
+
+    async def execute(self, statement):
+        self.executed.append(statement)
+        return SimpleNamespace(rowcount=1)
+
+    async def commit(self):
+        self.committed = True
+
+
+def test_collects_notification_for_each_expiry_period():
+    now = datetime(2026, 8, 20, tzinfo=UTC)
+    session = FakeSession(
+        [
+            [SimpleNamespace(id=1, expires_at=now + timedelta(days=6))],
+            [SimpleNamespace(id=2, expires_at=now + timedelta(days=2))],
+            [SimpleNamespace(id=3, expires_at=now + timedelta(hours=12))],
+            [SimpleNamespace(id=4, expires_at=now - timedelta(hours=1))],
+        ]
+    )
+
+    created = asyncio.run(collect_subscription_notifications(session, now))
+
+    assert created == len(session.executed)
+    assert session.committed
+    assert [statement.compile().params["notify_type_m0"] for statement in session.executed] == [
+        NotificationType.SEVEN_DAYS,
+        NotificationType.THREE_DAYS,
+        NotificationType.ONE_DAY,
+        NotificationType.EXPIRED,
+    ]