70 lines
1.9 KiB
Python
70 lines
1.9 KiB
Python
"""Async SQLAlchemy engine, session factory, and FastAPI dependency.
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Driver-agnostic: works with both aiosqlite (dev) and asyncpg (prod).
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"""
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from __future__ import annotations
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from collections.abc import AsyncGenerator
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from typing import Any
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from sqlalchemy.ext.asyncio import (
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AsyncEngine,
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AsyncSession,
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async_sessionmaker,
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create_async_engine,
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)
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from sqlalchemy.orm import DeclarativeBase
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from app.core.config import get_settings
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class Base(DeclarativeBase):
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"""Declarative base for all ORM models.
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Re-exported here so Alembic env.py can import it from a single location.
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"""
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# === Engine & Session Factory ===
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_settings = get_settings()
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# SQLite needs check_same_thread=False even for async — handled by aiosqlite.
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# echo=False in production; controlled by env if needed later.
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_engine_kwargs: dict[str, Any] = {"echo": False, "future": True}
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# For PostgreSQL asyncpg, pool sizing matters; for SQLite it's irrelevant.
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if not _settings.DATABASE_URL.startswith("sqlite"):
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_engine_kwargs["pool_size"] = 5
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_engine_kwargs["max_overflow"] = 10
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_engine_kwargs["pool_pre_ping"] = True
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engine: AsyncEngine = create_async_engine(_settings.DATABASE_URL, **_engine_kwargs)
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AsyncSessionLocal: async_sessionmaker[AsyncSession] = async_sessionmaker(
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bind=engine,
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expire_on_commit=False,
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class_=AsyncSession,
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autoflush=False,
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)
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# === Dependency ===
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async def get_db() -> AsyncGenerator[AsyncSession, None]:
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"""FastAPI dependency that yields an AsyncSession and ensures cleanup."""
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async with AsyncSessionLocal() as session:
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try:
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yield session
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except Exception:
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await session.rollback()
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raise
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# No explicit close needed — async context manager handles it.
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async def dispose_engine() -> None:
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"""Dispose of the engine on application shutdown."""
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await engine.dispose()
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