mitlist/be/app/database.py

61 lines
2.0 KiB
Python

# app/database.py
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
from sqlalchemy.orm import sessionmaker, declarative_base
from app.config import settings
# Ensure DATABASE_URL is set before proceeding
if not settings.DATABASE_URL:
raise ValueError("DATABASE_URL is not configured in settings.")
# Create the SQLAlchemy async engine
# pool_recycle=3600 helps prevent stale connections on some DBs
engine = create_async_engine(
settings.DATABASE_URL,
echo=True, # Log SQL queries (useful for debugging)
future=True, # Use SQLAlchemy 2.0 style features
pool_recycle=3600 # Optional: recycle connections after 1 hour
)
# Create a configured "Session" class
# expire_on_commit=False prevents attributes from expiring after commit
AsyncSessionLocal = sessionmaker(
bind=engine,
class_=AsyncSession,
expire_on_commit=False,
autoflush=False,
autocommit=False,
)
# Base class for our ORM models
Base = declarative_base()
# Dependency to get DB session in path operations
async def get_session() -> AsyncSession: # type: ignore
"""
Dependency function that yields an AsyncSession.
Ensures the session is closed after the request.
"""
async with AsyncSessionLocal() as session:
yield session
# The 'async with' block handles session.close() automatically.
# Commit/rollback should be handled by the functions using the session.
async def get_transactional_session() -> AsyncSession: # type: ignore
"""
Dependency function that yields an AsyncSession and manages a transaction.
Commits the transaction if the request handler succeeds, otherwise rollbacks.
Ensures the session is closed after the request.
"""
async with AsyncSessionLocal() as session:
try:
await session.begin()
yield session
await session.commit()
except Exception:
await session.rollback()
raise
finally:
await session.close()
# Alias for backward compatibility
get_db = get_session