37 lines
1.0 KiB
Python
37 lines
1.0 KiB
Python
''' Exports TransactionManager. '''
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from contextlib import contextmanager
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class TransactionManager(object):
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''' Helper class for managing database transactions. '''
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def __init__(self, session_factory):
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self._session_factory = session_factory
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@contextmanager
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def transaction(self):
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'''
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Provides a transactional scope around a series of DB operations that
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might change the database.
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'''
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return self._open_transaction(lambda session: session.commit)
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@contextmanager
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def read_only_transaction(self):
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'''
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Provides a transactional scope around a series of read-only DB
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operations.
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'''
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return self._open_transaction(lambda session: session.rollback)
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def _open_transaction(self, session_finalizer):
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session = self._session_factory()
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try:
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yield session
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session_finalizer(session)
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except:
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session.rollback()
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raise
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finally:
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session.close()
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