[entity] ensure the .related(entities=False) parameter is honored all the way down (closes #2755994)
As of today, such a call will always fill the relation cache by
calling .entities() on every single related rset entry.
As a consequence, the `limit` parameter handling also had to be fixed.
It was bogus in the following ways:
* not used in the related_rql, hence potentially huge database
requests, but also actually
* foolishly used in the .entities()-calling cache routine we now
bypass (this changeset ticket's main topic)
Now:
* we set a limit on the rql expression, and
* forbid caching if given a non-None limit (as we don't want to make
the cache handling code more complicated than it is already)
With this, entity.unrelated gets a better limit implementation (so the
code in related/unrelated is nice and symmetric)
Risk:
* _cw_relation_cache disappears completely, which is good, but this is
Python, so you never know ...
# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb. If not, see <http://www.gnu.org/licenses/>.
"""Source to query another RQL repository using pyro"""
__docformat__ = "restructuredtext en"
_ = unicode
import threading
from Pyro.errors import PyroError, ConnectionClosedError
from cubicweb import ConnectionError
from cubicweb.server.sources import ConnectionWrapper
from cubicweb.server.sources.remoterql import RemoteSource
class PyroRQLSource(RemoteSource):
"""External repository source, using Pyro connection"""
def get_connection(self):
try:
return self._get_connection()
except (ConnectionError, PyroError) as ex:
self.critical("can't get connection to source %s: %s", self.uri, ex)
return ConnectionWrapper()
def check_connection(self, cnx):
"""check connection validity, return None if the connection is still valid
else a new connection
"""
# we have to transfer manually thread ownership. This can be done safely
# since the connections set holding the connection is affected to one
# session/thread and can't be called simultaneously
try:
cnx._repo._transferThread(threading.currentThread())
except AttributeError:
# inmemory connection
pass
try:
return super(PyroRQLSource, self).check_connection(cnx)
except ConnectionClosedError:
# try to reconnect
return self.get_connection()