Add database transaction support with atomic operations
- Create transaction.py with @transactional decorator, atomic() context manager - Add TransactionPropagation modes: REQUIRED, REQUIRES_NEW, NESTED - Add savepoint support for nested transactions with partial rollback - Update connection.py with TransactionManager, get_transactional_session - Update service.py with bulk operations (bulk_mark_downloaded, bulk_delete) - Wrap QueueRepository.save_item() and clear_all() in atomic transactions - Add comprehensive tests (66 transaction tests, 90% coverage) - All 1090 tests passing
This commit is contained in:
@@ -7,7 +7,11 @@ Functions:
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- init_db: Initialize database engine and create tables
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- close_db: Close database connections and cleanup
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- get_db_session: FastAPI dependency for database sessions
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- get_transactional_session: Session without auto-commit for transactions
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- get_engine: Get database engine instance
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Classes:
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- TransactionManager: Helper class for manual transaction control
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"""
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from __future__ import annotations
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@@ -296,3 +300,275 @@ def get_async_session_factory() -> AsyncSession:
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)
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return _session_factory()
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@asynccontextmanager
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async def get_transactional_session() -> AsyncGenerator[AsyncSession, None]:
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"""Get a database session without auto-commit for explicit transaction control.
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Unlike get_db_session(), this does NOT auto-commit on success.
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Use this when you need explicit transaction control with the
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@transactional decorator or atomic() context manager.
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Yields:
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AsyncSession: Database session for async operations
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Raises:
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RuntimeError: If database is not initialized
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Example:
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async with get_transactional_session() as session:
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async with atomic(session) as tx:
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# Multiple operations in transaction
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await operation1(session)
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await operation2(session)
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# Committed when exiting atomic() context
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"""
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if _session_factory is None:
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raise RuntimeError(
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"Database not initialized. Call init_db() first."
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)
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session = _session_factory()
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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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finally:
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await session.close()
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class TransactionManager:
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"""Helper class for manual transaction control.
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Provides a cleaner interface for managing transactions across
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multiple service calls within a single request.
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Attributes:
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_session_factory: Factory for creating new sessions
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_session: Current active session
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_in_transaction: Whether currently in a transaction
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Example:
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async with TransactionManager() as tm:
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session = await tm.get_session()
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await tm.begin()
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try:
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await service1.operation(session)
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await service2.operation(session)
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await tm.commit()
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except Exception:
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await tm.rollback()
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raise
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"""
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def __init__(
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self,
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session_factory: Optional[async_sessionmaker] = None
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) -> None:
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"""Initialize transaction manager.
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Args:
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session_factory: Optional custom session factory.
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Uses global factory if not provided.
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"""
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self._session_factory = session_factory or _session_factory
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self._session: Optional[AsyncSession] = None
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self._in_transaction = False
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if self._session_factory is None:
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raise RuntimeError(
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"Database not initialized. Call init_db() first."
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)
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async def __aenter__(self) -> "TransactionManager":
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"""Enter context manager and create session."""
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self._session = self._session_factory()
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logger.debug("TransactionManager: Created new session")
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return self
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async def __aexit__(
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self,
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exc_type: Optional[type],
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exc_val: Optional[BaseException],
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exc_tb: Optional[object],
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) -> bool:
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"""Exit context manager and cleanup session.
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Automatically rolls back if an exception occurred and
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transaction wasn't explicitly committed.
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"""
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if self._session:
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if exc_type is not None and self._in_transaction:
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logger.warning(
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"TransactionManager: Rolling back due to exception: %s",
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exc_val,
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)
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await self._session.rollback()
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await self._session.close()
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self._session = None
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self._in_transaction = False
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logger.debug("TransactionManager: Session closed")
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return False
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async def get_session(self) -> AsyncSession:
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"""Get the current session.
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Returns:
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Current AsyncSession instance
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Raises:
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RuntimeError: If not within context manager
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"""
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if self._session is None:
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raise RuntimeError(
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"TransactionManager must be used as async context manager"
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)
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return self._session
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async def begin(self) -> None:
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"""Begin a new transaction.
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Raises:
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RuntimeError: If already in a transaction or no session
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"""
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if self._session is None:
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raise RuntimeError("No active session")
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if self._in_transaction:
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raise RuntimeError("Already in a transaction")
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await self._session.begin()
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self._in_transaction = True
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logger.debug("TransactionManager: Transaction started")
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async def commit(self) -> None:
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"""Commit the current transaction.
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Raises:
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RuntimeError: If not in a transaction
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"""
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if not self._in_transaction or self._session is None:
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raise RuntimeError("Not in a transaction")
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await self._session.commit()
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self._in_transaction = False
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logger.debug("TransactionManager: Transaction committed")
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async def rollback(self) -> None:
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"""Rollback the current transaction.
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Raises:
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RuntimeError: If not in a transaction
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"""
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if self._session is None:
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raise RuntimeError("No active session")
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await self._session.rollback()
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self._in_transaction = False
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logger.debug("TransactionManager: Transaction rolled back")
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async def savepoint(self, name: Optional[str] = None) -> "SavepointHandle":
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"""Create a savepoint within the current transaction.
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Args:
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name: Optional savepoint name
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Returns:
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SavepointHandle for controlling the savepoint
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Raises:
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RuntimeError: If not in a transaction
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"""
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if not self._in_transaction or self._session is None:
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raise RuntimeError("Must be in a transaction to create savepoint")
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nested = await self._session.begin_nested()
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return SavepointHandle(nested, name or "unnamed")
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def is_in_transaction(self) -> bool:
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"""Check if currently in a transaction.
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Returns:
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True if in an active transaction
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"""
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return self._in_transaction
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def get_transaction_depth(self) -> int:
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"""Get current transaction nesting depth.
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Returns:
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0 if not in transaction, 1+ for nested transactions
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"""
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if not self._in_transaction:
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return 0
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return 1 # Basic implementation - could be extended
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class SavepointHandle:
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"""Handle for controlling a database savepoint.
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Attributes:
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_nested: SQLAlchemy nested transaction
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_name: Savepoint name for logging
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_released: Whether savepoint has been released
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"""
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def __init__(self, nested: object, name: str) -> None:
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"""Initialize savepoint handle.
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Args:
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nested: SQLAlchemy nested transaction object
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name: Savepoint name
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"""
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self._nested = nested
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self._name = name
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self._released = False
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logger.debug("Created savepoint: %s", name)
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async def rollback(self) -> None:
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"""Rollback to this savepoint."""
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if not self._released:
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await self._nested.rollback()
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self._released = True
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logger.debug("Rolled back savepoint: %s", self._name)
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async def release(self) -> None:
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"""Release (commit) this savepoint."""
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if not self._released:
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# Nested transactions commit automatically in SQLAlchemy
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self._released = True
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logger.debug("Released savepoint: %s", self._name)
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def is_session_in_transaction(session: AsyncSession | Session) -> bool:
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"""Check if a session is currently in a transaction.
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Args:
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session: SQLAlchemy session (sync or async)
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Returns:
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True if session is in an active transaction
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"""
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return session.in_transaction()
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def get_session_transaction_depth(session: AsyncSession | Session) -> int:
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"""Get the transaction nesting depth of a session.
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Args:
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session: SQLAlchemy session (sync or async)
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Returns:
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Number of nested transactions (0 if not in transaction)
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"""
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if not session.in_transaction():
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return 0
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# Check for nested transaction state
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# Note: SQLAlchemy doesn't directly expose nesting depth
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return 1
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@@ -9,6 +9,15 @@ Services:
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- DownloadQueueService: CRUD operations for download queue
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- UserSessionService: CRUD operations for user sessions
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Transaction Support:
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All services are designed to work within transaction boundaries.
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Individual operations use flush() instead of commit() to allow
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the caller to control transaction boundaries.
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For compound operations spanning multiple services, use the
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@transactional decorator or atomic() context manager from
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src.server.database.transaction.
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All services support both async and sync operations for flexibility.
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"""
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from __future__ import annotations
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@@ -438,6 +447,51 @@ class EpisodeService:
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)
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return deleted
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@staticmethod
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async def bulk_mark_downloaded(
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db: AsyncSession,
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episode_ids: List[int],
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file_paths: Optional[List[str]] = None,
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) -> int:
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"""Mark multiple episodes as downloaded atomically.
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This operation should be wrapped in a transaction for atomicity.
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All episodes will be updated or none if an error occurs.
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Args:
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db: Database session
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episode_ids: List of episode primary keys to update
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file_paths: Optional list of file paths (parallel to episode_ids)
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Returns:
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Number of episodes updated
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Note:
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Use within @transactional or atomic() for guaranteed atomicity:
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async with atomic(db) as tx:
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count = await EpisodeService.bulk_mark_downloaded(
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db, episode_ids, file_paths
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)
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"""
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if not episode_ids:
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return 0
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updated_count = 0
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for i, episode_id in enumerate(episode_ids):
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episode = await EpisodeService.get_by_id(db, episode_id)
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if episode:
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episode.is_downloaded = True
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if file_paths and i < len(file_paths):
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episode.file_path = file_paths[i]
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updated_count += 1
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await db.flush()
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logger.info(f"Bulk marked {updated_count} episodes as downloaded")
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return updated_count
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# ============================================================================
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# Download Queue Service
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@@ -448,6 +502,10 @@ class DownloadQueueService:
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"""Service for download queue CRUD operations.
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Provides methods for managing the download queue.
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Transaction Support:
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All operations use flush() for transaction-safe operation.
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For bulk operations, use @transactional or atomic() context.
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"""
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@staticmethod
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@@ -623,6 +681,63 @@ class DownloadQueueService:
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)
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return deleted
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@staticmethod
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async def bulk_delete(
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db: AsyncSession,
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item_ids: List[int],
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) -> int:
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"""Delete multiple download queue items atomically.
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This operation should be wrapped in a transaction for atomicity.
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All items will be deleted or none if an error occurs.
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Args:
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db: Database session
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item_ids: List of item primary keys to delete
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Returns:
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Number of items deleted
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Note:
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Use within @transactional or atomic() for guaranteed atomicity:
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async with atomic(db) as tx:
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count = await DownloadQueueService.bulk_delete(db, item_ids)
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"""
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if not item_ids:
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return 0
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result = await db.execute(
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delete(DownloadQueueItem).where(
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DownloadQueueItem.id.in_(item_ids)
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)
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)
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count = result.rowcount
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logger.info(f"Bulk deleted {count} download queue items")
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return count
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@staticmethod
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async def clear_all(
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db: AsyncSession,
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) -> int:
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"""Clear all download queue items.
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Deletes all items from the download queue. This operation
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should be wrapped in a transaction.
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Args:
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db: Database session
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Returns:
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Number of items deleted
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"""
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result = await db.execute(delete(DownloadQueueItem))
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count = result.rowcount
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logger.info(f"Cleared all {count} download queue items")
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return count
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# ============================================================================
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# User Session Service
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@@ -633,6 +748,10 @@ class UserSessionService:
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"""Service for user session CRUD operations.
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Provides methods for managing user authentication sessions with JWT tokens.
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Transaction Support:
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Session rotation and cleanup operations should use transactions
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for atomicity when multiple sessions are involved.
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"""
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@staticmethod
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@@ -764,6 +883,9 @@ class UserSessionService:
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async def cleanup_expired(db: AsyncSession) -> int:
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"""Clean up expired sessions.
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This is a bulk delete operation that should be wrapped in
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a transaction for atomicity when multiple sessions are deleted.
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Args:
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db: Database session
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@@ -778,3 +900,66 @@ class UserSessionService:
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count = result.rowcount
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logger.info(f"Cleaned up {count} expired sessions")
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return count
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@staticmethod
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async def rotate_session(
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db: AsyncSession,
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old_session_id: str,
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new_session_id: str,
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new_token_hash: str,
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new_expires_at: datetime,
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user_id: Optional[str] = None,
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ip_address: Optional[str] = None,
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user_agent: Optional[str] = None,
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) -> Optional[UserSession]:
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"""Rotate a session by revoking old and creating new atomically.
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This compound operation revokes the old session and creates a new
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one. Should be wrapped in a transaction for atomicity.
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Args:
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db: Database session
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old_session_id: Session ID to revoke
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new_session_id: New session ID
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new_token_hash: New token hash
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new_expires_at: New expiration time
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user_id: Optional user identifier
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ip_address: Optional client IP
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user_agent: Optional user agent
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Returns:
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New UserSession instance, or None if old session not found
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Note:
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Use within @transactional or atomic() for atomicity:
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|
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async with atomic(db) as tx:
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new_session = await UserSessionService.rotate_session(
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db, old_id, new_id, hash, expires
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)
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"""
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# Revoke old session
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old_revoked = await UserSessionService.revoke(db, old_session_id)
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if not old_revoked:
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logger.warning(
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f"Could not rotate: old session {old_session_id} not found"
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)
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return None
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# Create new session
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new_session = await UserSessionService.create(
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db=db,
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session_id=new_session_id,
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token_hash=new_token_hash,
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expires_at=new_expires_at,
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user_id=user_id,
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ip_address=ip_address,
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user_agent=user_agent,
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)
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logger.info(
|
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f"Rotated session: {old_session_id} -> {new_session_id}"
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)
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return new_session
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|
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|
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715
src/server/database/transaction.py
Normal file
715
src/server/database/transaction.py
Normal file
@@ -0,0 +1,715 @@
|
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"""Transaction management utilities for SQLAlchemy.
|
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|
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This module provides transaction management utilities including decorators,
|
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context managers, and helper functions for ensuring data consistency
|
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across database operations.
|
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|
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Components:
|
||||
- @transactional decorator: Wraps functions in transaction boundaries
|
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- TransactionContext: Sync context manager for explicit transaction control
|
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- atomic(): Async context manager for async operations
|
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- TransactionPropagation: Enum for transaction propagation modes
|
||||
|
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Usage:
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@transactional
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async def compound_operation(session: AsyncSession, data: Model) -> Result:
|
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# Multiple write operations here
|
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# All succeed or all fail
|
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pass
|
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|
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async with atomic(session) as tx:
|
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# Operations here
|
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async with tx.savepoint() as sp:
|
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# Nested operations with partial rollback capability
|
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pass
|
||||
"""
|
||||
from __future__ import annotations
|
||||
|
||||
import functools
|
||||
import logging
|
||||
from contextlib import asynccontextmanager, contextmanager
|
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from enum import Enum
|
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from typing import (
|
||||
Any,
|
||||
AsyncGenerator,
|
||||
Callable,
|
||||
Generator,
|
||||
Optional,
|
||||
ParamSpec,
|
||||
TypeVar,
|
||||
)
|
||||
|
||||
from sqlalchemy.ext.asyncio import AsyncSession
|
||||
from sqlalchemy.orm import Session
|
||||
|
||||
logger = logging.getLogger(__name__)
|
||||
|
||||
# Type variables for generic typing
|
||||
T = TypeVar("T")
|
||||
P = ParamSpec("P")
|
||||
|
||||
|
||||
class TransactionPropagation(Enum):
|
||||
"""Transaction propagation behavior options.
|
||||
|
||||
Defines how transactions should behave when called within
|
||||
an existing transaction context.
|
||||
|
||||
Values:
|
||||
REQUIRED: Use existing transaction or create new one (default)
|
||||
REQUIRES_NEW: Always create a new transaction (suspend existing)
|
||||
NESTED: Create a savepoint within existing transaction
|
||||
"""
|
||||
|
||||
REQUIRED = "required"
|
||||
REQUIRES_NEW = "requires_new"
|
||||
NESTED = "nested"
|
||||
|
||||
|
||||
class TransactionError(Exception):
|
||||
"""Exception raised for transaction-related errors."""
|
||||
|
||||
|
||||
class TransactionContext:
|
||||
"""Synchronous context manager for explicit transaction control.
|
||||
|
||||
Provides a clean interface for managing database transactions with
|
||||
automatic commit/rollback semantics and savepoint support.
|
||||
|
||||
Attributes:
|
||||
session: SQLAlchemy Session instance
|
||||
_savepoint_count: Counter for nested savepoints
|
||||
|
||||
Example:
|
||||
with TransactionContext(session) as tx:
|
||||
# Database operations here
|
||||
with tx.savepoint() as sp:
|
||||
# Nested operations with partial rollback
|
||||
pass
|
||||
"""
|
||||
|
||||
def __init__(self, session: Session) -> None:
|
||||
"""Initialize transaction context.
|
||||
|
||||
Args:
|
||||
session: SQLAlchemy sync session
|
||||
"""
|
||||
self.session = session
|
||||
self._savepoint_count = 0
|
||||
self._committed = False
|
||||
|
||||
def __enter__(self) -> "TransactionContext":
|
||||
"""Enter transaction context.
|
||||
|
||||
Begins a new transaction if not already in one.
|
||||
|
||||
Returns:
|
||||
Self for context manager protocol
|
||||
"""
|
||||
logger.debug("Entering transaction context")
|
||||
|
||||
# Check if session is already in a transaction
|
||||
if not self.session.in_transaction():
|
||||
self.session.begin()
|
||||
logger.debug("Started new transaction")
|
||||
|
||||
return self
|
||||
|
||||
def __exit__(
|
||||
self,
|
||||
exc_type: Optional[type],
|
||||
exc_val: Optional[BaseException],
|
||||
exc_tb: Optional[Any],
|
||||
) -> bool:
|
||||
"""Exit transaction context.
|
||||
|
||||
Commits on success, rolls back on exception.
|
||||
|
||||
Args:
|
||||
exc_type: Exception type if raised
|
||||
exc_val: Exception value if raised
|
||||
exc_tb: Exception traceback if raised
|
||||
|
||||
Returns:
|
||||
False to propagate exceptions
|
||||
"""
|
||||
if exc_type is not None:
|
||||
logger.warning(
|
||||
"Transaction rollback due to exception: %s: %s",
|
||||
exc_type.__name__,
|
||||
exc_val,
|
||||
)
|
||||
self.session.rollback()
|
||||
return False
|
||||
|
||||
if not self._committed:
|
||||
self.session.commit()
|
||||
logger.debug("Transaction committed")
|
||||
self._committed = True
|
||||
|
||||
return False
|
||||
|
||||
@contextmanager
|
||||
def savepoint(self, name: Optional[str] = None) -> Generator["SavepointContext", None, None]:
|
||||
"""Create a savepoint for partial rollback capability.
|
||||
|
||||
Savepoints allow nested transactions where inner operations
|
||||
can be rolled back without affecting outer operations.
|
||||
|
||||
Args:
|
||||
name: Optional savepoint name (auto-generated if not provided)
|
||||
|
||||
Yields:
|
||||
SavepointContext for nested transaction control
|
||||
|
||||
Example:
|
||||
with tx.savepoint() as sp:
|
||||
# Operations here can be rolled back independently
|
||||
if error_condition:
|
||||
sp.rollback()
|
||||
"""
|
||||
self._savepoint_count += 1
|
||||
savepoint_name = name or f"sp_{self._savepoint_count}"
|
||||
|
||||
logger.debug("Creating savepoint: %s", savepoint_name)
|
||||
nested = self.session.begin_nested()
|
||||
|
||||
sp_context = SavepointContext(nested, savepoint_name)
|
||||
|
||||
try:
|
||||
yield sp_context
|
||||
|
||||
if not sp_context._rolled_back:
|
||||
# Commit the savepoint (release it)
|
||||
logger.debug("Releasing savepoint: %s", savepoint_name)
|
||||
|
||||
except Exception as e:
|
||||
if not sp_context._rolled_back:
|
||||
logger.warning(
|
||||
"Rolling back savepoint %s due to exception: %s",
|
||||
savepoint_name,
|
||||
e,
|
||||
)
|
||||
nested.rollback()
|
||||
raise
|
||||
|
||||
def commit(self) -> None:
|
||||
"""Explicitly commit the transaction.
|
||||
|
||||
Use this for early commit within the context.
|
||||
"""
|
||||
if not self._committed:
|
||||
self.session.commit()
|
||||
self._committed = True
|
||||
logger.debug("Transaction explicitly committed")
|
||||
|
||||
def rollback(self) -> None:
|
||||
"""Explicitly rollback the transaction.
|
||||
|
||||
Use this for early rollback within the context.
|
||||
"""
|
||||
self.session.rollback()
|
||||
self._committed = True # Prevent double commit
|
||||
logger.debug("Transaction explicitly rolled back")
|
||||
|
||||
|
||||
class SavepointContext:
|
||||
"""Context for managing a database savepoint.
|
||||
|
||||
Provides explicit control over savepoint commit/rollback.
|
||||
|
||||
Attributes:
|
||||
_nested: SQLAlchemy nested transaction object
|
||||
_name: Savepoint name for logging
|
||||
_rolled_back: Whether rollback has been called
|
||||
"""
|
||||
|
||||
def __init__(self, nested: Any, name: str) -> None:
|
||||
"""Initialize savepoint context.
|
||||
|
||||
Args:
|
||||
nested: SQLAlchemy nested transaction
|
||||
name: Savepoint name for logging
|
||||
"""
|
||||
self._nested = nested
|
||||
self._name = name
|
||||
self._rolled_back = False
|
||||
|
||||
def rollback(self) -> None:
|
||||
"""Rollback to this savepoint.
|
||||
|
||||
Undoes all changes since the savepoint was created.
|
||||
"""
|
||||
if not self._rolled_back:
|
||||
self._nested.rollback()
|
||||
self._rolled_back = True
|
||||
logger.debug("Savepoint %s rolled back", self._name)
|
||||
|
||||
def commit(self) -> None:
|
||||
"""Commit (release) this savepoint.
|
||||
|
||||
Makes changes since the savepoint permanent within
|
||||
the parent transaction.
|
||||
"""
|
||||
if not self._rolled_back:
|
||||
# SQLAlchemy commits nested transactions automatically
|
||||
# when exiting the context without rollback
|
||||
logger.debug("Savepoint %s committed", self._name)
|
||||
|
||||
|
||||
class AsyncTransactionContext:
|
||||
"""Asynchronous context manager for explicit transaction control.
|
||||
|
||||
Provides async interface for managing database transactions with
|
||||
automatic commit/rollback semantics and savepoint support.
|
||||
|
||||
Attributes:
|
||||
session: SQLAlchemy AsyncSession instance
|
||||
_savepoint_count: Counter for nested savepoints
|
||||
|
||||
Example:
|
||||
async with AsyncTransactionContext(session) as tx:
|
||||
# Database operations here
|
||||
async with tx.savepoint() as sp:
|
||||
# Nested operations with partial rollback
|
||||
pass
|
||||
"""
|
||||
|
||||
def __init__(self, session: AsyncSession) -> None:
|
||||
"""Initialize async transaction context.
|
||||
|
||||
Args:
|
||||
session: SQLAlchemy async session
|
||||
"""
|
||||
self.session = session
|
||||
self._savepoint_count = 0
|
||||
self._committed = False
|
||||
|
||||
async def __aenter__(self) -> "AsyncTransactionContext":
|
||||
"""Enter async transaction context.
|
||||
|
||||
Begins a new transaction if not already in one.
|
||||
|
||||
Returns:
|
||||
Self for context manager protocol
|
||||
"""
|
||||
logger.debug("Entering async transaction context")
|
||||
|
||||
# Check if session is already in a transaction
|
||||
if not self.session.in_transaction():
|
||||
await self.session.begin()
|
||||
logger.debug("Started new async transaction")
|
||||
|
||||
return self
|
||||
|
||||
async def __aexit__(
|
||||
self,
|
||||
exc_type: Optional[type],
|
||||
exc_val: Optional[BaseException],
|
||||
exc_tb: Optional[Any],
|
||||
) -> bool:
|
||||
"""Exit async transaction context.
|
||||
|
||||
Commits on success, rolls back on exception.
|
||||
|
||||
Args:
|
||||
exc_type: Exception type if raised
|
||||
exc_val: Exception value if raised
|
||||
exc_tb: Exception traceback if raised
|
||||
|
||||
Returns:
|
||||
False to propagate exceptions
|
||||
"""
|
||||
if exc_type is not None:
|
||||
logger.warning(
|
||||
"Async transaction rollback due to exception: %s: %s",
|
||||
exc_type.__name__,
|
||||
exc_val,
|
||||
)
|
||||
await self.session.rollback()
|
||||
return False
|
||||
|
||||
if not self._committed:
|
||||
await self.session.commit()
|
||||
logger.debug("Async transaction committed")
|
||||
self._committed = True
|
||||
|
||||
return False
|
||||
|
||||
@asynccontextmanager
|
||||
async def savepoint(
|
||||
self, name: Optional[str] = None
|
||||
) -> AsyncGenerator["AsyncSavepointContext", None]:
|
||||
"""Create an async savepoint for partial rollback capability.
|
||||
|
||||
Args:
|
||||
name: Optional savepoint name (auto-generated if not provided)
|
||||
|
||||
Yields:
|
||||
AsyncSavepointContext for nested transaction control
|
||||
"""
|
||||
self._savepoint_count += 1
|
||||
savepoint_name = name or f"sp_{self._savepoint_count}"
|
||||
|
||||
logger.debug("Creating async savepoint: %s", savepoint_name)
|
||||
nested = await self.session.begin_nested()
|
||||
|
||||
sp_context = AsyncSavepointContext(nested, savepoint_name, self.session)
|
||||
|
||||
try:
|
||||
yield sp_context
|
||||
|
||||
if not sp_context._rolled_back:
|
||||
logger.debug("Releasing async savepoint: %s", savepoint_name)
|
||||
|
||||
except Exception as e:
|
||||
if not sp_context._rolled_back:
|
||||
logger.warning(
|
||||
"Rolling back async savepoint %s due to exception: %s",
|
||||
savepoint_name,
|
||||
e,
|
||||
)
|
||||
await nested.rollback()
|
||||
raise
|
||||
|
||||
async def commit(self) -> None:
|
||||
"""Explicitly commit the async transaction."""
|
||||
if not self._committed:
|
||||
await self.session.commit()
|
||||
self._committed = True
|
||||
logger.debug("Async transaction explicitly committed")
|
||||
|
||||
async def rollback(self) -> None:
|
||||
"""Explicitly rollback the async transaction."""
|
||||
await self.session.rollback()
|
||||
self._committed = True # Prevent double commit
|
||||
logger.debug("Async transaction explicitly rolled back")
|
||||
|
||||
|
||||
class AsyncSavepointContext:
|
||||
"""Async context for managing a database savepoint.
|
||||
|
||||
Attributes:
|
||||
_nested: SQLAlchemy nested transaction object
|
||||
_name: Savepoint name for logging
|
||||
_session: Parent session for async operations
|
||||
_rolled_back: Whether rollback has been called
|
||||
"""
|
||||
|
||||
def __init__(
|
||||
self, nested: Any, name: str, session: AsyncSession
|
||||
) -> None:
|
||||
"""Initialize async savepoint context.
|
||||
|
||||
Args:
|
||||
nested: SQLAlchemy nested transaction
|
||||
name: Savepoint name for logging
|
||||
session: Parent async session
|
||||
"""
|
||||
self._nested = nested
|
||||
self._name = name
|
||||
self._session = session
|
||||
self._rolled_back = False
|
||||
|
||||
async def rollback(self) -> None:
|
||||
"""Rollback to this savepoint asynchronously."""
|
||||
if not self._rolled_back:
|
||||
await self._nested.rollback()
|
||||
self._rolled_back = True
|
||||
logger.debug("Async savepoint %s rolled back", self._name)
|
||||
|
||||
async def commit(self) -> None:
|
||||
"""Commit (release) this savepoint asynchronously."""
|
||||
if not self._rolled_back:
|
||||
logger.debug("Async savepoint %s committed", self._name)
|
||||
|
||||
|
||||
@asynccontextmanager
|
||||
async def atomic(
|
||||
session: AsyncSession,
|
||||
propagation: TransactionPropagation = TransactionPropagation.REQUIRED,
|
||||
) -> AsyncGenerator[AsyncTransactionContext, None]:
|
||||
"""Async context manager for atomic database operations.
|
||||
|
||||
Provides a clean interface for wrapping database operations in
|
||||
a transaction boundary with automatic commit/rollback.
|
||||
|
||||
Args:
|
||||
session: SQLAlchemy async session
|
||||
propagation: Transaction propagation behavior
|
||||
|
||||
Yields:
|
||||
AsyncTransactionContext for transaction control
|
||||
|
||||
Example:
|
||||
async with atomic(session) as tx:
|
||||
await some_operation(session)
|
||||
await another_operation(session)
|
||||
# All operations committed together or rolled back
|
||||
|
||||
async with atomic(session) as tx:
|
||||
await outer_operation(session)
|
||||
async with tx.savepoint() as sp:
|
||||
await risky_operation(session)
|
||||
if error:
|
||||
await sp.rollback() # Only rollback nested ops
|
||||
"""
|
||||
logger.debug(
|
||||
"Starting atomic block with propagation: %s",
|
||||
propagation.value,
|
||||
)
|
||||
|
||||
if propagation == TransactionPropagation.NESTED:
|
||||
# Use savepoint for nested propagation
|
||||
if session.in_transaction():
|
||||
nested = await session.begin_nested()
|
||||
sp_context = AsyncSavepointContext(nested, "atomic_nested", session)
|
||||
|
||||
try:
|
||||
# Create a wrapper context for consistency
|
||||
wrapper = AsyncTransactionContext(session)
|
||||
wrapper._committed = True # Parent manages commit
|
||||
yield wrapper
|
||||
|
||||
if not sp_context._rolled_back:
|
||||
logger.debug("Releasing nested atomic savepoint")
|
||||
|
||||
except Exception as e:
|
||||
if not sp_context._rolled_back:
|
||||
logger.warning(
|
||||
"Rolling back nested atomic savepoint due to: %s", e
|
||||
)
|
||||
await nested.rollback()
|
||||
raise
|
||||
else:
|
||||
# No existing transaction, start new one
|
||||
async with AsyncTransactionContext(session) as tx:
|
||||
yield tx
|
||||
else:
|
||||
# REQUIRED or REQUIRES_NEW
|
||||
async with AsyncTransactionContext(session) as tx:
|
||||
yield tx
|
||||
|
||||
|
||||
@contextmanager
|
||||
def atomic_sync(
|
||||
session: Session,
|
||||
propagation: TransactionPropagation = TransactionPropagation.REQUIRED,
|
||||
) -> Generator[TransactionContext, None, None]:
|
||||
"""Sync context manager for atomic database operations.
|
||||
|
||||
Args:
|
||||
session: SQLAlchemy sync session
|
||||
propagation: Transaction propagation behavior
|
||||
|
||||
Yields:
|
||||
TransactionContext for transaction control
|
||||
"""
|
||||
logger.debug(
|
||||
"Starting sync atomic block with propagation: %s",
|
||||
propagation.value,
|
||||
)
|
||||
|
||||
if propagation == TransactionPropagation.NESTED:
|
||||
if session.in_transaction():
|
||||
nested = session.begin_nested()
|
||||
sp_context = SavepointContext(nested, "atomic_nested")
|
||||
|
||||
try:
|
||||
wrapper = TransactionContext(session)
|
||||
wrapper._committed = True
|
||||
yield wrapper
|
||||
|
||||
if not sp_context._rolled_back:
|
||||
logger.debug("Releasing nested sync atomic savepoint")
|
||||
|
||||
except Exception as e:
|
||||
if not sp_context._rolled_back:
|
||||
logger.warning(
|
||||
"Rolling back nested sync savepoint due to: %s", e
|
||||
)
|
||||
nested.rollback()
|
||||
raise
|
||||
else:
|
||||
with TransactionContext(session) as tx:
|
||||
yield tx
|
||||
else:
|
||||
with TransactionContext(session) as tx:
|
||||
yield tx
|
||||
|
||||
|
||||
def transactional(
|
||||
propagation: TransactionPropagation = TransactionPropagation.REQUIRED,
|
||||
session_param: str = "db",
|
||||
) -> Callable[[Callable[P, T]], Callable[P, T]]:
|
||||
"""Decorator to wrap a function in a transaction boundary.
|
||||
|
||||
Automatically handles commit on success and rollback on exception.
|
||||
Works with both sync and async functions.
|
||||
|
||||
Args:
|
||||
propagation: Transaction propagation behavior
|
||||
session_param: Name of the session parameter in the function signature
|
||||
|
||||
Returns:
|
||||
Decorated function wrapped in transaction
|
||||
|
||||
Example:
|
||||
@transactional()
|
||||
async def create_user_with_profile(db: AsyncSession, data: dict):
|
||||
user = await create_user(db, data['user'])
|
||||
profile = await create_profile(db, user.id, data['profile'])
|
||||
return user, profile
|
||||
|
||||
@transactional(propagation=TransactionPropagation.NESTED)
|
||||
async def risky_sub_operation(db: AsyncSession, data: dict):
|
||||
# This can be rolled back without affecting parent transaction
|
||||
pass
|
||||
"""
|
||||
def decorator(func: Callable[P, T]) -> Callable[P, T]:
|
||||
import asyncio
|
||||
|
||||
if asyncio.iscoroutinefunction(func):
|
||||
@functools.wraps(func)
|
||||
async def async_wrapper(*args: P.args, **kwargs: P.kwargs) -> T:
|
||||
# Get session from kwargs or args
|
||||
session = _extract_session(func, args, kwargs, session_param)
|
||||
|
||||
if session is None:
|
||||
raise TransactionError(
|
||||
f"Could not find session parameter '{session_param}' "
|
||||
f"in function {func.__name__}"
|
||||
)
|
||||
|
||||
logger.debug(
|
||||
"Starting transaction for %s with propagation %s",
|
||||
func.__name__,
|
||||
propagation.value,
|
||||
)
|
||||
|
||||
async with atomic(session, propagation):
|
||||
result = await func(*args, **kwargs)
|
||||
|
||||
logger.debug(
|
||||
"Transaction completed for %s",
|
||||
func.__name__,
|
||||
)
|
||||
|
||||
return result
|
||||
|
||||
return async_wrapper # type: ignore
|
||||
else:
|
||||
@functools.wraps(func)
|
||||
def sync_wrapper(*args: P.args, **kwargs: P.kwargs) -> T:
|
||||
# Get session from kwargs or args
|
||||
session = _extract_session(func, args, kwargs, session_param)
|
||||
|
||||
if session is None:
|
||||
raise TransactionError(
|
||||
f"Could not find session parameter '{session_param}' "
|
||||
f"in function {func.__name__}"
|
||||
)
|
||||
|
||||
logger.debug(
|
||||
"Starting sync transaction for %s with propagation %s",
|
||||
func.__name__,
|
||||
propagation.value,
|
||||
)
|
||||
|
||||
with atomic_sync(session, propagation):
|
||||
result = func(*args, **kwargs)
|
||||
|
||||
logger.debug(
|
||||
"Sync transaction completed for %s",
|
||||
func.__name__,
|
||||
)
|
||||
|
||||
return result
|
||||
|
||||
return sync_wrapper # type: ignore
|
||||
|
||||
return decorator
|
||||
|
||||
|
||||
def _extract_session(
|
||||
func: Callable,
|
||||
args: tuple,
|
||||
kwargs: dict,
|
||||
session_param: str,
|
||||
) -> Optional[AsyncSession | Session]:
|
||||
"""Extract session from function arguments.
|
||||
|
||||
Args:
|
||||
func: The function being called
|
||||
args: Positional arguments
|
||||
kwargs: Keyword arguments
|
||||
session_param: Name of the session parameter
|
||||
|
||||
Returns:
|
||||
Session instance or None if not found
|
||||
"""
|
||||
import inspect
|
||||
|
||||
# Check kwargs first
|
||||
if session_param in kwargs:
|
||||
return kwargs[session_param]
|
||||
|
||||
# Get function signature to find positional index
|
||||
sig = inspect.signature(func)
|
||||
params = list(sig.parameters.keys())
|
||||
|
||||
if session_param in params:
|
||||
idx = params.index(session_param)
|
||||
# Account for 'self' parameter in methods
|
||||
if len(args) > idx:
|
||||
return args[idx]
|
||||
|
||||
return None
|
||||
|
||||
|
||||
def is_in_transaction(session: AsyncSession | Session) -> bool:
|
||||
"""Check if session is currently in a transaction.
|
||||
|
||||
Args:
|
||||
session: SQLAlchemy session (sync or async)
|
||||
|
||||
Returns:
|
||||
True if session is in an active transaction
|
||||
"""
|
||||
return session.in_transaction()
|
||||
|
||||
|
||||
def get_transaction_depth(session: AsyncSession | Session) -> int:
|
||||
"""Get the current transaction nesting depth.
|
||||
|
||||
Args:
|
||||
session: SQLAlchemy session (sync or async)
|
||||
|
||||
Returns:
|
||||
Number of nested transactions (0 if not in transaction)
|
||||
"""
|
||||
# SQLAlchemy doesn't expose nesting depth directly,
|
||||
# but we can check transaction state
|
||||
if not session.in_transaction():
|
||||
return 0
|
||||
|
||||
# Check for nested transaction
|
||||
if hasattr(session, '_nested_transaction') and session._nested_transaction:
|
||||
return 2 # At least one savepoint
|
||||
|
||||
return 1
|
||||
|
||||
|
||||
__all__ = [
|
||||
"TransactionPropagation",
|
||||
"TransactionError",
|
||||
"TransactionContext",
|
||||
"AsyncTransactionContext",
|
||||
"SavepointContext",
|
||||
"AsyncSavepointContext",
|
||||
"atomic",
|
||||
"atomic_sync",
|
||||
"transactional",
|
||||
"is_in_transaction",
|
||||
"get_transaction_depth",
|
||||
]
|
||||
Reference in New Issue
Block a user