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""" A plugin to fetch data from a LDAP directory """
import imp
import os
import sys
import time
import traceback
from functools import partial
import Bcfg2.Options
import Bcfg2.Server.Cache
import Bcfg2.Server.Plugin
from Bcfg2.Logger import Debuggable
from Bcfg2.Utils import ClassName, safe_module_name
try:
import ldap
HAS_LDAP = True
except ImportError:
HAS_LDAP = False
class ConfigFile(Bcfg2.Server.Plugin.FileBacked):
""" Config file for the Ldap plugin """
def __init__(self, name, core, plugin):
Bcfg2.Server.Plugin.FileBacked.__init__(self, name)
self.core = core
self.plugin = plugin
self.queries = list()
self.fam.AddMonitor(name, self)
def Index(self):
""" Get the queries from the config file """
try:
module = imp.load_source(safe_module_name('Ldap', self.name),
self.name)
except: # pylint: disable=W0702
err = sys.exc_info()[1]
self.logger.error("Ldap: Failed to import %s: %s" %
(self.name, err))
return
if not hasattr(module, "__queries__"):
self.logger.error("Ldap: %s has no __queries__ list" % self.name)
return
self.queries = list()
for query in module.__queries__:
try:
self.queries.append(getattr(module, query))
except AttributeError:
self.logger.warning(
"Ldap: %s exports %s, but has no such attribute" %
(self.name, query))
if self.core.metadata_cache_mode in ['cautious', 'aggressive']:
self.core.metadata_cache.expire()
self.plugin.expire_cache()
class Ldap(Bcfg2.Server.Plugin.Plugin,
Bcfg2.Server.Plugin.ClientRunHooks,
Bcfg2.Server.Plugin.Connector):
""" The Ldap plugin allows adding data from an LDAP server
to your metadata. """
__rmi__ = Bcfg2.Server.Plugin.Plugin.__rmi__ + ['expire_cache']
experimental = True
options = [
Bcfg2.Options.Option(
cf=('ldap', 'retries'), type=int, default=3,
dest='ldap_retries',
help='The number of times to retry reaching the '
'LDAP server if a connection is broken'),
Bcfg2.Options.Option(
cf=('ldap', 'retry_delay'), type=float, default=5.0,
dest='ldap_retry_delay',
help='The time in seconds betreen retries'),
Bcfg2.Options.BooleanOption(
cf=('ldap', 'cache'), default=None, dest='ldap_cache',
help='Cache the results of the LDAP Queries until they '
'are expired using the XML-RPC RMI')]
def __init__(self, core):
Bcfg2.Server.Plugin.Plugin.__init__(self, core)
Bcfg2.Server.Plugin.Connector.__init__(self)
if not HAS_LDAP:
msg = "Python ldap module is required for Ldap plugin"
self.logger.error(msg)
raise Bcfg2.Server.Plugin.PluginInitError(msg)
self.config = ConfigFile(os.path.join(self.data, 'config.py'),
core, self)
self._hosts = dict()
def _cache(self, query_name):
""" Return the :class:`Cache <Bcfg2.Server.Cache>` for the
given query name. """
return Bcfg2.Server.Cache.Cache('Ldap', 'results', query_name)
def _execute_query(self, query, metadata):
""" Return the cached result of the given query for this host or
execute the given query and cache the result. """
result = None
if Bcfg2.Options.setup.ldap_cache is not False:
cache = self._cache(query.name)
result = cache.get(metadata.hostname, None)
if result is None:
try:
self.debug_log("Processing query '%s'" % query.name)
result = query.get_result(metadata)
if Bcfg2.Options.setup.ldap_cache is not False:
cache[metadata.hostname] = result
except: # pylint: disable=W0702
self.logger.error(
"Exception during processing of query named '%s', query "
"results will be empty and may cause bind failures" %
query.name)
for line in traceback.format_exc().split('\n'):
self.logger.error(line)
return result
def get_additional_data(self, metadata):
data = {}
self.debug_log("Found queries %s" % self.config.queries)
for query_class in self.config.queries:
try:
query = query_class()
if query.is_applicable(metadata):
self.debug_log("Processing query '%s'" % query.name)
data[query.name] = partial(
self._execute_query, query, metadata)
else:
self.debug_log("query '%s' not applicable to host '%s'" %
(query.name, metadata.hostname))
except: # pylint: disable=W0702
self.logger.error(
"Exception during preparation of query named '%s'. "
"Query will be ignored." % query_class.__name__)
for line in traceback.format_exc().split('\n'):
self.logger.error(line)
return Bcfg2.Server.Plugin.CallableDict(**data)
def start_client_run(self, metadata):
if Bcfg2.Options.setup.ldap_cache is None:
self.expire_cache(hostname=metadata.hostname)
def expire_cache(self, query=None, hostname=None):
""" Expire the cache. You can select the items to purge
per query and/or per host, or you can purge all cached
data. This is exposed as an XML-RPC RMI. """
tags = ['Ldap', 'results']
if query:
tags.append(query)
if hostname:
tags.append(hostname)
return Bcfg2.Server.Cache.expire(*tags)
class LdapConnection(Debuggable):
""" Connection to an LDAP server. """
def __init__(self, host="localhost", port=389, uri=None, options=None,
binddn=None, bindpw=None):
Debuggable.__init__(self)
if HAS_LDAP:
msg = "Python ldap module is required for Ldap plugin"
self.logger.error(msg)
raise Bcfg2.Server.Plugin.PluginInitError(msg)
self.host = host
self.port = port
self.uri = uri
self.options = options
self.binddn = binddn
self.bindpw = bindpw
self.conn = None
self.__scopes__ = {
'base': ldap.SCOPE_BASE,
'one': ldap.SCOPE_ONELEVEL,
'sub': ldap.SCOPE_SUBTREE,
}
def __del__(self):
""" Disconnection if the instance is destroyed. """
self.disconnect()
def disconnect(self):
""" If a connection to an LDAP server is available, disconnect it. """
if self.conn:
self.conn.unbund()
self.conn = None
def connect(self):
""" Open a connection to the configured LDAP server, and do a simple
bind ff both binddn and bindpw are set. """
self.disconnect()
self.conn = ldap.initialize(self.get_uri())
if self.options is not None:
for (option, value) in self.options.items():
self.conn.set_option(option, value)
if self.binddn is not None and self.bindpw is not None:
self.conn.simple_bind_s(self.binddn, self.bindpw)
def run_query(self, query):
""" Connect to the server and execute the query. If the server is
down, wait the configured amount and try to reconnect.
:param query: The query to execute on the LDAP server.
:type query: Bcfg.Server.Plugins.Ldap.LdapQuery
"""
for attempt in range(Bcfg2.Options.setup.ldap_retries + 1):
try:
if not self.conn:
self.connect()
return self.conn.search_s(
query.base, self.__scopes__[query.scope],
query.filter.replace('\\', '\\\\'), query.attrs)
except ldap.SERVER_DOWN:
self.conn = None
self.logger.error(
"LdapConnection: Server %s down. Retry %d/%d in %.2fs." %
(self.get_uri(), attempt + 1,
Bcfg2.Options.setup.ldap_retries,
Bcfg2.Options.setup.ldap_retry_delay))
time.sleep(Bcfg2.Options.setup.ldap_retry_delay)
return None
def get_uri(self):
""" The URL of the LDAP server. """
if self.uri is None:
if self.port == 636:
return "ldaps://%s" % self.host
return "ldap://%s:%d" % (self.host, self.port)
return self.uri
class LdapQuery(object):
""" Query referencing an LdapConnection and providing several
methods for query manipulation. """
#: Name of the Query, used to register it in additional data.
name = ClassName()
base = ""
scope = "sub"
filter = "(objectClass=*)"
attrs = None
connection = None
result = None
def __unicode__(self):
return "LdapQuery: %s" % self.name
def is_applicable(self, metadata): # pylint: disable=W0613
""" Check is the query should be executed for a given metadata
object.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
"""
return True
def prepare_query(self, metadata, **kwargs): # pylint: disable=W0613
""" Prepares the query based on the client metadata. You can
for example modify the filter based on the client hostname.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
"""
pass
def process_result(self, metadata, **kwargs): # pylint: disable=W0613
""" Post-process the query result.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
"""
return self.result
def get_result(self, metadata, **kwargs):
""" Handle the perparation, execution and processing of the query.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginExecutionError`
"""
if self.connection is not None:
self.prepare_query(metadata, **kwargs)
self.result = self.connection.run_query(self)
self.result = self.process_result(metadata, **kwargs)
else:
raise Bcfg2.Server.Plugin.PluginExecutionError(
'No connection defined for %s' % self.name)
return self.result
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