89 lines
2.1 KiB
Python
89 lines
2.1 KiB
Python
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"""Async SQLAlchemy engine/session management.
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The API is stateless: every request gets its own AsyncSession from a shared
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connection pool, and nothing is held across requests. This module never
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creates tables — schema changes always go through Alembic (see
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`migrations/`).
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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 contextlib import asynccontextmanager
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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 app.core.config import get_settings
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settings = get_settings()
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_connect_args: dict = {}
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if settings.DATABASE_BEHIND_TRANSACTION_POOLER:
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_connect_args["statement_cache_size"] = 0
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_engine: AsyncEngine = create_async_engine(
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settings.DATABASE_URL,
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pool_size=settings.DATABASE_POOL_SIZE,
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max_overflow=settings.DATABASE_MAX_OVERFLOW,
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pool_pre_ping=True,
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pool_recycle=1800,
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connect_args=_connect_args,
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echo=False,
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)
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async_session_factory = async_sessionmaker(
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bind=_engine,
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class_=AsyncSession,
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expire_on_commit=False,
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autoflush=False,
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)
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def get_engine() -> AsyncEngine:
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return _engine
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async def get_db() -> AsyncGenerator[AsyncSession, None]:
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"""FastAPI dependency yielding a request-scoped session."""
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async with async_session_factory() as session:
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yield session
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@asynccontextmanager
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async def session_scope() -> AsyncGenerator[AsyncSession, None]:
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"""Context manager for use outside request handlers (workers, scripts).
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Commits on success, rolls back on exception.
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"""
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async with async_session_factory() as session:
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try:
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yield session
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await session.commit()
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except Exception:
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await session.rollback()
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raise
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async def database_is_ready() -> bool:
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"""Cheap connectivity check used by the /ready endpoint."""
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from sqlalchemy import text
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try:
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async with _engine.connect() as conn:
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await conn.execute(text("SELECT 1"))
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return True
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except Exception:
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return False
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async def dispose_engine() -> None:
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await _engine.dispose()
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