Merge "Implement more robust connection handling for asynchronous LDAP calls"
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commit
a98f006f85
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@ -14,7 +14,6 @@
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import abc
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import codecs
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import functools
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import os.path
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import re
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import sys
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@ -635,10 +634,36 @@ def _common_ldap_initialization(url, use_tls=False, tls_cacertfile=None,
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tls_req_cert)
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class MsgId(list):
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"""Wrapper class to hold connection and msgid."""
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class AsynchronousMessage(object):
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"""A container for handling asynchronous LDAP responses.
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pass
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Some LDAP APIs, like `search_ext`, are asynchronous and return a message ID
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when the server successfully initiates the operation. Clients can use this
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message ID and the original connection to make the request to fetch the
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results using `result3`.
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This object holds the message ID, the original connection, and a callable
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weak reference Finalizer that cleans up context managers specific to the
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connection associated to the message ID.
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:param message_id: The message identifier (str).
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:param connection: The connection associated with the message identifier
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(ldappool.StateConnector).
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The `clean` attribute is a callable that cleans up the context manager used
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to create or return the connection object (weakref.finalize).
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"""
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def __init__(self, message_id, connection, context_manager):
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self.id = message_id
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self.connection = connection
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self.clean = weakref.finalize(
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self, self._cleanup_connection_context_manager, context_manager
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)
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def _cleanup_connection_context_manager(self, context_manager):
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context_manager.__exit__(None, None, None)
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def use_conn_pool(func):
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@ -792,15 +817,17 @@ class PooledLDAPHandler(LDAPHandler):
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filterstr='(objectClass=*)', attrlist=None, attrsonly=0,
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serverctrls=None, clientctrls=None,
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timeout=-1, sizelimit=0):
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"""Return a ``MsgId`` instance, it asynchronous API.
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"""Return an AsynchronousMessage instance, it asynchronous API.
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The ``MsgId`` instance can be safely used in a call to ``result3()``.
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The AsynchronousMessage instance can be safely used in a call to
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`result3()`.
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To work with ``result3()`` API in predictable manner, the same LDAP
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connection is needed which originally provided the ``msgid``. So, this
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method wraps the existing connection and ``msgid`` in a new ``MsgId``
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instance. The connection associated with ``search_ext`` is released
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once last hard reference to the ``MsgId`` instance is freed.
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To work with `result3()` API in predictable manner, the same LDAP
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connection is needed which originally provided the `msgid`. So, this
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method wraps the existing connection and `msgid` in a new
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`AsynchronousMessage` instance. The connection associated with
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`search_ext()` is released after `result3()` fetches the data
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associated with `msgid`.
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"""
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conn_ctxt = self._get_pool_connection()
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@ -813,30 +840,33 @@ class PooledLDAPHandler(LDAPHandler):
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except Exception:
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conn_ctxt.__exit__(*sys.exc_info())
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raise
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res = MsgId((conn, msgid))
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weakref.ref(res, functools.partial(conn_ctxt.__exit__,
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None, None, None))
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return res
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return AsynchronousMessage(msgid, conn, conn_ctxt)
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def result3(self, msgid, all=1, timeout=None,
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def result3(self, message, all=1, timeout=None,
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resp_ctrl_classes=None):
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"""Wait for and return the result.
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"""Wait for and return the result to an asynchronous message.
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This method returns the result of an operation previously initiated by
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one of the LDAP asynchronous operation routines (eg search_ext()). It
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returned an invocation identifier (a message id) upon successful
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initiation of their operation.
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one of the LDAP asynchronous operation routines (e.g., `search_ext()`).
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The `search_ext()` method in python-ldap returns an invocation
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identifier, or a message ID, upon successful initiation of the
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operation by the LDAP server.
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Input msgid is expected to be instance of class MsgId which has LDAP
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session/connection used to execute search_ext and message idenfier.
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The `message` is expected to be instance of class
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`AsynchronousMessage`, which contains the message ID and the connection
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used to make the original request.
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The connection associated with search_ext is released once last hard
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reference to MsgId object is freed. This will happen when function
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which requested msgId and used it in result3 exits.
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The connection and context manager associated with `search_ext()` are
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cleaned up when message.clean() is called.
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"""
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conn, msg_id = msgid
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return conn.result3(msg_id, all, timeout)
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results = message.connection.result3(message.id, all, timeout)
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# Now that we have the results from the LDAP server for the message, we
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# don't need the the context manager used to create the connection.
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message.clean()
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return results
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@use_conn_pool
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def modify_s(self, conn, dn, modlist):
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@ -997,15 +1027,15 @@ class KeystoneLDAPHandler(LDAPHandler):
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cookie='')
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page_ctrl_oid = ldap.controls.SimplePagedResultsControl.controlType
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msgid = self.conn.search_ext(base,
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scope,
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filterstr,
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attrlist,
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serverctrls=[lc])
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message = self.conn.search_ext(base,
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scope,
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filterstr,
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attrlist,
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serverctrls=[lc])
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# Endless loop request pages on ldap server until it has no data
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while True:
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# Request to the ldap server a page with 'page_size' entries
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rtype, rdata, rmsgid, serverctrls = self.conn.result3(msgid)
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rtype, rdata, rmsgid, serverctrls = self.conn.result3(message)
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# Receive the data
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res.extend(rdata)
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pctrls = [c for c in serverctrls
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@ -1021,11 +1051,11 @@ class KeystoneLDAPHandler(LDAPHandler):
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if cookie:
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# There is more data still on the server
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# so we request another page
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msgid = self.conn.search_ext(base,
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scope,
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filterstr,
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attrlist,
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serverctrls=[lc])
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message = self.conn.search_ext(base,
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scope,
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filterstr,
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attrlist,
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serverctrls=[lc])
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else:
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# Exit condition no more data on server
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break
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@ -0,0 +1,7 @@
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---
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fixes:
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- |
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[`bug 1896125 <https://bugs.launchpad.net/keystone/+bug/1896125>`_]
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Introduced more robust connection handling for asynchronous LDAP requests
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to address memory leaks fetching data from LDAP backends with low page
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sizes.
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