mirror of
https://github.com/sqlalchemy/sqlalchemy.git
synced 2026-06-05 23:37:20 -04:00
Mike Bayer
2136054ca8
- change engine.Connection to _connection_cls so sphinx doesn't get upset - globally add "." to all :class:`Foo` - start naming sections that are mostly docstrings "API Documentation - blah blah" - move some ad-hoc docstrings into "API" sections, there is some inconsistency here and it may be that we just have to leave it that way - add "internals" rsts to core, orm, I'm not super thrilled how these look but they are targeted by some of the public api docs, users typically become aware of these anyway
127 lines
4.0 KiB
Python
127 lines
4.0 KiB
Python
# engine/threadlocal.py
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# Copyright (C) 2005-2011 the SQLAlchemy authors and contributors <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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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, event
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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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_tl_connection_cls = TLConnection
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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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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._tl_connection_cls(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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return self
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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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return self
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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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return self
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def __enter__(self):
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return self
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def __exit__(self, type, value, traceback):
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if type is None:
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self.commit()
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else:
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self.rollback()
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def prepare(self):
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if not hasattr(self._connections, 'trans') or \
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not self._connections.trans:
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return
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self._connections.trans[-1].prepare()
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def commit(self):
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if not hasattr(self._connections, 'trans') or \
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not self._connections.trans:
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return
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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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if not hasattr(self._connections, 'trans') or \
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not self._connections.trans:
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return
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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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