104 lines
3.4 KiB
Python
104 lines
3.4 KiB
Python
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"""Provides a thread-local transactional wrapper around the root Engine class.
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The ``threadlocal`` module is invoked when using the ``strategy="threadlocal"`` flag
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with :func:`~sqlalchemy.engine.create_engine`. This module is semi-private and is
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invoked automatically when the threadlocal engine strategy is used.
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"""
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from sqlalchemy import util
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from sqlalchemy.engine import base
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import weakref
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class TLConnection(base.Connection):
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def __init__(self, *arg, **kw):
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super(TLConnection, self).__init__(*arg, **kw)
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self.__opencount = 0
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def _increment_connect(self):
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self.__opencount += 1
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return self
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def close(self):
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if self.__opencount == 1:
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base.Connection.close(self)
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self.__opencount -= 1
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def _force_close(self):
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self.__opencount = 0
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base.Connection.close(self)
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class TLEngine(base.Engine):
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"""An Engine that includes support for thread-local managed transactions."""
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def __init__(self, *args, **kwargs):
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super(TLEngine, self).__init__(*args, **kwargs)
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self._connections = util.threading.local()
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proxy = kwargs.get('proxy')
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if proxy:
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self.TLConnection = base._proxy_connection_cls(TLConnection, proxy)
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else:
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self.TLConnection = TLConnection
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def contextual_connect(self, **kw):
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if not hasattr(self._connections, 'conn'):
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connection = None
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else:
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connection = self._connections.conn()
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if connection is None or connection.closed:
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# guards against pool-level reapers, if desired.
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# or not connection.connection.is_valid:
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connection = self.TLConnection(self, self.pool.connect(), **kw)
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self._connections.conn = conn = weakref.ref(connection)
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return connection._increment_connect()
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def begin_twophase(self, xid=None):
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if not hasattr(self._connections, 'trans'):
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self._connections.trans = []
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self._connections.trans.append(self.contextual_connect().begin_twophase(xid=xid))
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def begin_nested(self):
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if not hasattr(self._connections, 'trans'):
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self._connections.trans = []
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self._connections.trans.append(self.contextual_connect().begin_nested())
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def begin(self):
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if not hasattr(self._connections, 'trans'):
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self._connections.trans = []
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self._connections.trans.append(self.contextual_connect().begin())
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def prepare(self):
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self._connections.trans[-1].prepare()
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def commit(self):
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trans = self._connections.trans.pop(-1)
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trans.commit()
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def rollback(self):
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trans = self._connections.trans.pop(-1)
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trans.rollback()
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def dispose(self):
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self._connections = util.threading.local()
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super(TLEngine, self).dispose()
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@property
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def closed(self):
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return not hasattr(self._connections, 'conn') or \
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self._connections.conn() is None or \
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self._connections.conn().closed
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def close(self):
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if not self.closed:
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self.contextual_connect().close()
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connection = self._connections.conn()
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connection._force_close()
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del self._connections.conn
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self._connections.trans = []
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def __repr__(self):
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return 'TLEngine(%s)' % str(self.url)
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