SQLAlchemy backend implementation for VintaSend.

Provides a synchronous (SQLAlchemyNotificationBackend) and an AsyncIO (SQLAlchemyAsyncIONotificationBackend) notification backend, plus a filesystem-backed attachment manager.

• Python 3.10 - 3.14
• SQLAlchemy 2.0+
• vintasend 2.0+

This release implements the full vintasend 2.0 backend contract: one-off notifications, the composable filtering / ordering API (filter_notifications), sent_at / read_at, the tenant partition key, git_commit_sha, bulk read, and the attachment manager seam.

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from vintasend.services.notification_service import NotificationService
from vintasend_sqlalchemy.services.notification_backends.sqlalchemy_notification_backend import (
    SQLAlchemyNotificationBackend,
)

from myapp.models import Notification  # your GenericNotification subclass

engine = create_engine("postgresql://...")
Session = sessionmaker(bind=engine)

backend = SQLAlchemyNotificationBackend(Session, Notification)
service = NotificationService(notification_backend=backend, notification_adapters=[...])

The AsyncIO backend takes an async_sessionmaker instead:

from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker
from vintasend_sqlalchemy.services.notification_backends.sqlalchemy_notification_backend import (
    SQLAlchemyAsyncIONotificationBackend,
)

engine = create_async_engine("postgresql+asyncpg://...")
Session = async_sessionmaker(bind=engine)
backend = SQLAlchemyAsyncIONotificationBackend(Session, Notification)

Each backend defaults to a FilesystemAttachmentManager (async: FilesystemAsyncIOAttachmentManager) that stores uploaded files under a base directory (VINTASEND_ATTACHMENTS_PATH, default vintasend_attachments/). Configure a different manager on the service to store bytes elsewhere; the backend only persists the attachment_file_records / notification_attachments rows.

The package ships Alembic helper ops so your migrations stay in sync with the models:

• create_notification_table(user_id_type) - the base notifications table.
• upgrade_notification_table_to_2_0() - adds the 2.0 columns (one-off recipient fields, sent_at, read_at, tenant, git_commit_sha) and relaxes user_id to nullable.
• create_attachment_tables() - the attachment_file_records and notification_attachments tables backing the attachment seam.

See migrations/versions/ for the reference migrations used by the test suite.