freeipa/ipalib/backend.py

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# Authors:
# Jason Gerard DeRose <jderose@redhat.com>
#
# Copyright (C) 2008 Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
Base classes for all backed-end plugins.
"""
import threading
import plugable
from errors import PublicError, InternalError, CommandError
from request import context, Connection, destroy_context
class Backend(plugable.Plugin):
"""
Base class for all backend plugins.
"""
class Connectible(Backend):
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"""
Base class for backend plugins that create connections.
In addition to the nicety of providing a standard connection API, all
backend plugins that create connections should use this base class so that
`request.destroy_context()` can properly close all open connections.
"""
def __init__(self, shared_instance=True):
Backend.__init__(self)
if shared_instance:
self.id = self.name
else:
self.id = '%s_%s' % (self.name, str(id(self)))
def connect(self, *args, **kw):
"""
Create thread-local connection.
"""
if hasattr(context, self.id):
raise StandardError(
"connect: 'context.%s' already exists in thread %r" % (
self.id, threading.currentThread().getName()
)
)
conn = self.create_connection(*args, **kw)
setattr(context, self.id, Connection(conn, self.disconnect))
assert self.conn is conn
self.info('Created connection context.%s' % self.id)
def create_connection(self, *args, **kw):
raise NotImplementedError('%s.create_connection()' % self.id)
def disconnect(self):
if not hasattr(context, self.id):
raise StandardError(
"disconnect: 'context.%s' does not exist in thread %r" % (
self.id, threading.currentThread().getName()
)
)
self.destroy_connection()
delattr(context, self.id)
self.info('Destroyed connection context.%s' % self.id)
def destroy_connection(self):
raise NotImplementedError('%s.destroy_connection()' % self.id)
def isconnected(self):
"""
Return ``True`` if thread-local connection on `request.context` exists.
"""
return hasattr(context, self.id)
def __get_conn(self):
"""
Return thread-local connection.
"""
if not hasattr(context, self.id):
raise AttributeError('no context.%s in thread %r' % (
self.id, threading.currentThread().getName())
)
return getattr(context, self.id).conn
conn = property(__get_conn)
class Executioner(Backend):
def create_context(self, ccache=None, client_ip=None):
"""
client_ip: The IP address of the remote client.
"""
if self.env.in_server:
self.Backend.ldap2.connect(ccache=ccache)
else:
self.Backend.xmlclient.connect(verbose=(self.env.verbose >= 2),
fallback=self.env.fallback)
if client_ip is not None:
setattr(context, "client_ip", client_ip)
def destroy_context(self):
destroy_context()
def execute(self, _name, *args, **options):
error = None
try:
if _name not in self.Command:
raise CommandError(name=_name)
result = self.Command[_name](*args, **options)
except PublicError, e:
error = e
except StandardError, e:
self.exception(
'non-public: %s: %s', e.__class__.__name__, str(e)
)
error = InternalError()
except Exception, e:
self.exception(
'unhandled exception: %s: %s', e.__class__.__name__, str(e)
)
error = InternalError()
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destroy_context()
if error is None:
return result
assert isinstance(error, PublicError)
raise error