def scoped_session(session_factory, scopefunc=None):
"""Provides thread-local management of Sessions.
This is a front-end function to the [sqlalchemy.orm.scoping#ScopedSession]
class.
Usage::
Session = scoped_session(sessionmaker(autoflush=True))
To instantiate a Session object which is part of the scoped
context, instantiate normally::
session = Session()
Most session methods are available as classmethods from
the scoped session::
Session.commit()
Session.close()
To map classes so that new instances are saved in the current
Session automatically, as well as to provide session-aware
class attributes such as "query", use the `mapper` classmethod
from the scoped session::
mapper = Session.mapper
mapper(Class, table, ...)
"""
return ScopedSession(session_factory, scopefunc=scopefunc)
def scoped_session(session_factory, scopefunc=None):
"""Provides thread-local management of Sessions.
This is a front-end function to
:class:`~sqlalchemy.orm.scoping.ScopedSession`.
:param session_factory: a callable function that produces
:class:`Session` instances, such as :func:`sessionmaker` or
:func:`create_session`.
:param scopefunc: optional, TODO
:returns: an :class:`~sqlalchemy.orm.scoping.ScopedSession` instance
Usage::
Session = scoped_session(sessionmaker(autoflush=True))
To instantiate a Session object which is part of the scoped context,
instantiate normally::
session = Session()
Most session methods are available as classmethods from the scoped
session::
Session.commit()
Session.close()
"""
return ScopedSession(session_factory, scopefunc=scopefunc)
def _insert_initial_rows(cls, session_factory: ScopedSession,
liveliness_probe_s: int,
epoch_start_date: datetime,
max_claim_retries: int,
min_ms_between_claim_retries: int,
max_ms_between_claim_retries: int,
manifest_row_class: Any,
properties_class: Any) -> None:
"""
Populates the newly created manifest and properties tables with the correct data.
"""
session = session_factory()
manifest_rows = [
manifest_row_class(generator_id=i)
for i in range(cls.MAX_GENERATOR_ID)
]
properties = [
properties_class(key="liveliness_probe_s",
value=liveliness_probe_s),
properties_class(key="epoch_start_ms",
value=epoch_start_date.timestamp()),
properties_class(key="max_claim_retries", value=max_claim_retries),
properties_class(key="min_ms_between_claim_retries",
value=min_ms_between_claim_retries),
properties_class(key="max_ms_between_claim_retries",
value=max_ms_between_claim_retries)
]
try:
logging.info("Populating manifest table")
session.bulk_save_objects(manifest_rows)
logging.info("Populating properties table")
session.bulk_save_objects(properties)
session.commit()
except InvalidRequestError:
session.rollback()
finally:
session_factory.remove()
from sqlalchemy.orm.scoping import ScopedSession
from transaction._transaction import Status as ZopeStatus
import warnings
from zope.sqlalchemy import ZopeTransactionExtension
TWOPHASE = True
class AlchemistWarning(RuntimeWarning):
"""Warnings of features that will be removed in a next version.
"""
class AlchemistTransactionExtension(ZopeTransactionExtension):
def before_commit(self, session):
# zope.sqlalchemy makes an assert here, to not allow saving the session
# directly, so that commits must go through the transaction.
# Alchemist's manager worked without this, and so we must provide a
# BBB for alchemist users. We change the assert to a mare warning.
if self.transaction_manager.get().status != ZopeStatus.COMMITTING:
warnings.warn(
"Transaction must be committed using the transaction manager",
AlchemistWarning)
Session = ScopedSession(
sessionmaker(autoflush=True,
autocommit=False,
extension=AlchemistTransactionExtension(),
twophase=TWOPHASE))
def get_session_factory_of_scoped(self) -> ScopedSession:
session_factory = sessionmaker(
bind=self.engine, class_=_SessionContext) # 改成了自定义的Session类
return ScopedSession(session_factory)
