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Commit 46b304bd authored by Jeremy Hylton's avatar Jeremy Hylton
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Change the implementation of mounted connections. 

Avoid the monkey patch by creating a subclass of Connection and
installing it as the klass attribute of ZODB's DB class.  I think this
works correctly in conjunction with Zope configuration (the tests
pass) -- but I'm not qualified to say for sure.

Rework the logic of MountConnection as part of the restructuring.  The
_root_connection attribute always points to the root, never to None;
so the root object points to itself.  This change necessitated a
chance in DBTab.ClassFactories.  Add some comments there to explain
what's going on.

XXX The close() method on MountConnection is re-implementing two
methods in modules.  If those implementations change, it would need to
change, too.  We ought to find a better way to integrate it.

XXX Perhaps the mounted connection stuff should be folded into ZODB
proper.
parent 6475510a
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Showing with 95 additions and 103 deletions
lib/python/DBTab/ClassFactories.py
View file @ 46b304bd
......@@ -13,7 +13,7 @@
##############################################################################
"""Available ZODB class factories.
$Id: ClassFactories.py,v 1.2 2004/03/04 22:43:06 jim Exp $"""
$Id: ClassFactories.py,v 1.3 2004/04/15 16:41:03 jeremy Exp $"""
import OFS.Uninstalled
......@@ -75,11 +75,15 @@ def autoClassFactory(jar, module, name):
"""
# If not the root connection, use the class factory from
# the root database, otherwise use the Zope class factory.
# The default Zope configuration installs this function as the DB
# class's classFactory() method.
root_conn = getattr(jar, '_root_connection', None)
if root_conn is not jar:
root_db = getattr(root_conn, '_db', None)
if root_db is not None:
return root_db.classFactory(root_conn, module, name)
else:
return zopeClassFactory(jar, module, name)
class_factories['auto'] = autoClassFactory
......
lib/python/OFS/Application.py
View file @ 46b304bd
......@@ -12,8 +12,8 @@
##############################################################################
__doc__='''Application support
$Id: Application.py,v 1.201 2004/01/15 22:47:23 tseaver Exp $'''
__version__='$Revision: 1.201 $'[11:-2]
$Id: Application.py,v 1.202 2004/04/15 16:41:04 jeremy Exp $'''
__version__='$Revision: 1.202 $'[11:-2]
import Globals,Folder,os,sys,App.Product, App.ProductRegistry, misc_
import time, traceback, os, Products
......@@ -324,10 +324,10 @@ class AppInitializer:
def install_tempfolder_and_sdc(self):
app = self.getApp()
from Products.ZODBMountPoint.MountedObject import manage_addMounts,\
MountedObject
from Products.ZODBMountPoint.MountedObject import getConfiguration as \
getDBTabConfiguration
from Products.ZODBMountPoint.MountedObject \
import manage_addMounts, MountedObject
from Products.ZODBMountPoint.MountedObject \
import getConfiguration as getDBTabConfiguration
dbtab_config = getDBTabConfiguration()
......
lib/python/Products/ZODBMountPoint/Mount.py
View file @ 46b304bd
......@@ -13,20 +13,29 @@
##############################################################################
"""ZODB Mounted database support, simplified for DBTab.
$Id: Mount.py,v 1.3 2004/03/02 15:36:28 jeremy Exp $"""
$Id: Mount.py,v 1.4 2004/04/15 16:41:05 jeremy Exp $"""
import time, sys
import sys
try:
from cStringIO import StringIO
except:
from StringIO import StringIO
import traceback
import Persistence, Acquisition
from Acquisition import aq_base
from ZODB.POSException import MountedStorageError
from zLOG import LOG, ERROR, INFO, WARNING
from ZODB.DB import DB
from ZODB.Connection import Connection
class MountPoint(Persistence.Persistent, Acquisition.Implicit):
'''The base class for a Zope object which, when traversed,
accesses a different database.
'''
"""An object that accesses a different database when traversed.
This class is intended to be used as a base class.
"""
# Default values for non-persistent variables.
_v_data = None # An object in an open connection
......@@ -36,23 +45,19 @@ class MountPoint(Persistence.Persistent, Acquisition.Implicit):
self.id = id
def _getDB(self):
"""Hook for getting the DB object for this mount point.
"""
"""Hook for getting the DB object for this mount point."""
raise NotImplementedError
def _getDBName(self):
"""Hook for getting the name of the database for this mount point.
"""
"""Hook for getting the name of the database for this mount point."""
raise NotImplementedError
def _getRootDBName(self):
"""Hook for getting the name of the root database.
"""
"""Hook for getting the name of the root database."""
raise NotImplementedError
def _traverseToMountedRoot(self, root, mount_parent):
"""Hook for getting the object to be mounted.
"""
"""Hook for getting the object to be mounted."""
raise NotImplementedError
def __repr__(self):
......@@ -115,20 +120,13 @@ class MountPoint(Persistence.Persistent, Acquisition.Implicit):
def _test(self, parent):
'''Tests the database connection.
'''
"""Tests the database connection."""
self._getOrOpenObject(parent)
return 1
def _logConnectException(self):
'''Records info about the exception that just occurred.
'''
try:
from cStringIO import StringIO
except:
from StringIO import StringIO
import traceback
"""Records info about the exception that just occurred."""
exc = sys.exc_info()
LOG('ZODB', ERROR, 'Failed to mount database. %s (%s)' % exc[:2],
error=exc)
......@@ -137,85 +135,73 @@ class MountPoint(Persistence.Persistent, Acquisition.Implicit):
self._v_connect_error = (exc[0], exc[1], f.getvalue())
exc = None
class MountConnection(Connection):
"""Subclass of Connection that supports mounts."""
# XXX perhaps the code in this subclass should be folded into
# ZODB proper.
class ConnectionPatches:
# Changes to Connection.py that might fold into ZODB
_root_connection = None
_mounted_connections = None
def __init__(self, **kwargs):
Connection.__init__(self, **kwargs)
# The _root_connection of the actual root points to self. All
# other connections will have _root_connection over-ridden in
# _addMountedConnection().
self._root_connection = self
self._mounted_connections = {}
def _getRootConnection(self):
root_conn = self._root_connection
if root_conn is None:
return self
else:
return root_conn
return self._root_connection
def _getMountedConnection(self, name):
conns = self._getRootConnection()._mounted_connections
if conns is None:
return None
else:
return conns.get(name)
return self._root_connection._mounted_connections.get(name)
def _addMountedConnection(self, name, conn):
if conn._root_connection is not None:
raise ValueError, 'Connection %s is already mounted' % repr(conn)
root_conn = self._getRootConnection()
conns = root_conn._mounted_connections
if conns is None:
conns = {}
root_conn._mounted_connections = conns
if conns.has_key(name):
raise KeyError, 'A connection named %s already exists' % repr(name)
conn._root_connection = root_conn
if conn._root_connection is not conn:
raise ValueError("Connection %s is already mounted" % repr(conn))
conns = self._root_connection._mounted_connections
if name in conns:
raise KeyError("A connection named %s already exists" % repr(name))
conn._root_connection = self._root_connection
conns[name] = conn
def _setDB(self, odb):
self._real_setDB(odb)
conns = self._mounted_connections
if conns:
for conn in conns.values():
conn._setDB(conn._db)
def _setDB(self, odb, **kwargs):
Connection._setDB(self, odb, **kwargs)
for conn in self._mounted_connections.values():
conn._setDB(odb, **kwargs)
def close(self):
if self._root_connection is not None:
if self._root_connection is not self:
raise RuntimeError("Should not close mounted connections directly")
conns = self._mounted_connections
if conns:
for conn in conns.values():
# Notify the activity monitor
db = conn.db()
f = getattr(db, 'getActivityMonitor', None)
if f is not None:
am = f()
if am is not None:
# The code here duplicates much of the code in
# DB._closeConnection and Connection.close. A mounted
# connection can't operate independently, so we don't call
# DB._closeConnection(), which would return it to the
# connection pool; only the root connection should be
# returned.
for conn in self._mounted_connections.values():
# DB._closeConnection calls the activity monitor
am = conn._db.getActivityMonitor()
am.closedConnection(conn)
conn.cacheGC() # This is a good time to do some GC
# XXX maybe we ought to call the close callbacks.
# Connection.close does GC
conn._cache.incrgc()
conn._storage = conn._tmp = conn.new_oid = conn._opened = None
conn._debug_info = ()
# The mounted connection keeps a reference to
# its database, but nothing else.
# Note that mounted connections can not operate
# independently, so don't use _closeConnection() to
# return them to the pool. Only the root connection
# should be returned.
# Close this connection only after the mounted connections
# have been closed. Otherwise, this connection gets returned
# to the pool too early and another thread might use this
# connection before the mounted connections have all been
# closed.
self._real_close()
if 1:
# patch Connection.py.
from ZODB.Connection import Connection
Connection._real_setDB = Connection._setDB
Connection._real_close = Connection.close
Connection.close(self)
for k, v in ConnectionPatches.__dict__.items():
if not k.startswith('__'):
setattr(Connection, k, v)
# Replace the default database Connection
def install():
DB.klass = MountConnection
# XXX This shouldn't be done as a side-effect of import, but it's not
# clear where in the Zope initialization code it should be done.
install()
lib/python/Products/ZODBMountPoint/tests/testMountPoint.py
View file @ 46b304bd
......@@ -22,7 +22,9 @@ import ZODB
from OFS.Application import Application
from OFS.Folder import Folder
import App.config
from Products.ZODBMountPoint.MountedObject import manage_addMounts, getMountPoint
from Products.ZODBMountPoint.MountedObject \
import manage_addMounts, getMountPoint
from Products.ZODBMountPoint.Mount import MountConnection
from DBTab.DBTab import DBTab
try:
......@@ -36,7 +38,7 @@ class TestDBConfig:
self.mpoints = mpoints
def getDB(self):
from ZODB.config import DemoStorage
from ZODB.config import MappingStorage
from ZODB.Connection import Connection
from Zope.Startup.datatypes import ZopeDatabase
self.name = self.fname
......@@ -50,9 +52,9 @@ class TestDBConfig:
self.version_pool_size = 3
self.version_cache_size = 100
self.mount_points = self.mpoints
self.connection_class = Connection
self.connection_class = MountConnection
self.class_factory = None
self.storage = DemoStorage(self)
self.storage = MappingStorage(self)
self.container_class = None
return ZopeDatabase(self)
......
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