/usr/lib/python2.7/dist-packages/Bcfg2/Server/Plugin/interfaces.py is in bcfg2-server 1.4.0~pre2+git141-g6d40dace6358-1.
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import os
import sys
import copy
import threading
import lxml.etree
import Bcfg2.Server
import Bcfg2.Options
from Bcfg2.Compat import Queue, Empty, Full, cPickle
from Bcfg2.Server.Plugin.base import Plugin
from Bcfg2.Server.Plugin.exceptions import PluginInitError, \
MetadataRuntimeError, MetadataConsistencyError
# Since this file basically just contains abstract interface
# descriptions, just about every function declaration has unused
# arguments. Disable this pylint warning for the whole file.
# pylint: disable=W0613
class Generator(object):
""" Generator plugins contribute to literal client configurations.
That is, they generate entry contents.
An entry is generated in one of two ways:
#. The Bcfg2 core looks in the ``Entries`` dict attribute of the
plugin object. ``Entries`` is expected to be a dict whose keys
are entry tags (e.g., ``"Path"``, ``"Service"``, etc.) and
whose values are dicts; those dicts should map the ``name``
attribute of an entry to a callable that will be called to
generate the content. The callable will receive two arguments:
the abstract entry (as an lxml.etree._Element object), and the
client metadata object the entry is being generated for.
#. If the entry is not listed in ``Entries``, the Bcfg2 core calls
:func:`HandlesEntry`; if that returns True, then it calls
:func:`HandleEntry`.
"""
def HandlesEntry(self, entry, metadata):
""" HandlesEntry is the slow path method for routing
configuration binding requests. It is called if the
``Entries`` dict does not contain a method for binding the
entry.
:param entry: The entry to bind
:type entry: lxml.etree._Element
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:return: bool - Whether or not this plugin can handle the entry
:raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginExecutionError`
"""
return False
def HandleEntry(self, entry, metadata):
""" HandleEntry is the slow path method for binding
configuration binding requests. It is called if the
``Entries`` dict does not contain a method for binding the
entry, and :func:`HandlesEntry`
returns True.
:param entry: The entry to bind
:type entry: lxml.etree._Element
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:return: lxml.etree._Element - The fully bound entry
:raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginExecutionError`
"""
return entry
class Structure(object):
""" Structure Plugins contribute to abstract client
configurations. That is, they produce lists of entries that will
be generated for a client. """
def BuildStructures(self, metadata):
""" Build a list of lxml.etree._Element objects that will be
added to the top-level ``<Configuration>`` tag of the client
configuration. Consequently, each object in the list returned
by ``BuildStructures()`` must consist of a container tag
(e.g., ``<Bundle>`` or ``<Independent>``) which contains the
entry tags. It must not return a list of entry tags.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:return: list of lxml.etree._Element objects
"""
raise NotImplementedError
class Metadata(object):
""" Metadata plugins handle initial metadata construction,
accumulating data from :class:`Connector` plugins, and producing
:class:`Bcfg2.Server.Plugins.Metadata.ClientMetadata` objects. """
def viz(self, hosts, bundles, key, only_client, colors):
""" Return a string containing a graphviz document that maps
out the Metadata for :ref:`bcfg2-admin viz <server-admin-viz>`
:param hosts: Include hosts in the graph
:type hosts: bool
:param bundles: Include bundles in the graph
:type bundles: bool
:param key: Include a key in the graph
:type key: bool
:param only_client: Only include data for the specified client
:type only_client: string
:param colors: Use the specified graphviz colors
:type colors: list of strings
:return: string
"""
raise NotImplementedError
def set_version(self, client, version):
""" Set the version for the named client to the specified
version string.
:param client: Hostname of the client
:type client: string
:param profile: Client Bcfg2 version
:type profile: string
:return: None
:raises: :class:`Bcfg2.Server.Plugin.exceptions.MetadataRuntimeError`,
:class:`Bcfg2.Server.Plugin.exceptions.MetadataConsistencyError`
"""
pass
def set_profile(self, client, profile, address):
""" Set the profile for the named client to the named profile
group.
:param client: Hostname of the client
:type client: string
:param profile: Name of the profile group
:type profile: string
:param address: Address pair of ``(<ip address>, <hostname>)``
:type address: tuple
:return: None
:raises: :class:`Bcfg2.Server.Plugin.exceptions.MetadataRuntimeError`,
:class:`Bcfg2.Server.Plugin.exceptions.MetadataConsistencyError`
"""
pass
def resolve_client(self, address, cleanup_cache=False):
""" Resolve the canonical name of this client. If this method
is not implemented, the hostname claimed by the client is
used. (This may be a security risk; it's highly recommended
that you implement ``resolve_client`` if you are writing a
Metadata plugin.)
:param address: Address pair of ``(<ip address>, <hostname>)``
:type address: tuple
:param cleanup_cache: Whether or not to remove expire the
entire client hostname resolution class
:type cleanup_cache: bool
:return: string - canonical client hostname
:raises: :class:`Bcfg2.Server.Plugin.exceptions.MetadataRuntimeError`,
:class:`Bcfg2.Server.Plugin.exceptions.MetadataConsistencyError`
"""
return address[1]
def AuthenticateConnection(self, cert, user, password, address):
""" Authenticate the given client.
:param cert: an x509 certificate
:type cert: dict
:param user: The username of the user trying to authenticate
:type user: string
:param password: The password supplied by the client
:type password: string
:param addresspair: An address pair of ``(<ip address>,
<hostname>)``
:type addresspair: tuple
:return: bool - True if the authenticate succeeds, False otherwise
"""
raise NotImplementedError
def get_initial_metadata(self, client_name):
""" Return a
:class:`Bcfg2.Server.Plugins.Metadata.ClientMetadata` object
that fully describes everything the Metadata plugin knows
about the named client.
:param client_name: The hostname of the client
:type client_name: string
:return: Bcfg2.Server.Plugins.Metadata.ClientMetadata
"""
raise NotImplementedError
def merge_additional_data(self, imd, source, data):
""" Add arbitrary data from a
:class:`Connector` plugin to the given
metadata object.
:param imd: An initial metadata object
:type imd: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param source: The name of the plugin providing this data
:type source: string
:param data: The data to add
:type data: any
:return: None
"""
raise NotImplementedError
def merge_additional_groups(self, imd, groups):
""" Add groups from a
:class:`Connector` plugin to the given
metadata object.
:param imd: An initial metadata object
:type imd: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param groups: The groups to add
:type groups: list of strings
:return: None
"""
raise NotImplementedError
def update_client_list(self):
""" Re-read the cached list of clients """
raise NotImplementedError
class Connector(object):
""" Connector plugins augment client metadata instances with
additional data, additional groups, or both. """
def get_additional_groups(self, metadata):
""" Return a list of additional groups for the given client.
Each group can be either the name of a group (a string), or a
:class:`Bcfg2.Server.Plugins.Metadata.MetadataGroup` object
that defines other data besides just the name. Note that you
cannot return a
:class:`Bcfg2.Server.Plugins.Metadata.MetadataGroup` object
that clobbers a group defined by another plugin; the original
group will be used instead. For instance, assume the
following in ``Metadata/groups.xml``:
.. code-block:: xml
<Groups>
...
<Group name="foo" public="false"/>
</Groups>
You could not subsequently return a
:class:`Bcfg2.Server.Plugins.Metadata.MetadataGroup` object
with ``public=True``; a warning would be issued, and the
original (non-public) ``foo`` group would be used.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:return: list of strings or
:class:`Bcfg2.Server.Plugins.Metadata.MetadataGroup`
objects.
"""
return list()
def get_additional_data(self, metadata):
""" Return arbitrary additional data for the given
ClientMetadata object. By convention this is usually a dict
object, but doesn't need to be.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:return: dict
"""
return dict()
class Probing(object):
""" Probing plugins can collect data from clients and process it.
"""
def GetProbes(self, metadata):
""" Return a list of probes for the given client. Each probe
should be an lxml.etree._Element object that adheres to
the following specification. Each probe must the following
attributes:
* ``name``: The unique name of the probe.
* ``source``: The origin of the probe; probably the name of
the plugin that supplies the probe.
* ``interpreter``: The command that will be run on the client
to interpret the probe script. Compiled (i.e.,
non-interpreted) probes are not supported.
The text of the XML tag should be the contents of the probe,
i.e., the code that will be run on the client.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:return: list of lxml.etree._Element objects
"""
raise NotImplementedError
def ReceiveData(self, metadata, datalist):
""" Process data returned from the probes for the given
client. ``datalist`` is a list of lxml.etree._Element
objects, each of which is a single tag; the ``name`` attribute
holds the unique name of the probe that was run, and the text
contents of the tag hold the results of the probe.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param datalist: The probe data
:type datalist: list of lxml.etree._Element objects
:return: None
"""
raise NotImplementedError
class Statistics(Plugin):
""" Statistics plugins handle statistics for clients. In general,
you should avoid using Statistics and use
:class:`ThreadedStatistics` instead."""
create = False
def process_statistics(self, client, xdata):
""" Process the given XML statistics data for the specified
client.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param data: The statistics data
:type data: lxml.etree._Element
:return: None
"""
raise NotImplementedError
class Threaded(object):
""" Threaded plugins use threads in any way. The thread must be
started after daemonization, so this class implements a single
method, :func:`start_threads`, that can be used to start threads
after daemonization of the server core. """
def start_threads(self):
""" Start this plugin's threads after daemonization.
:return: None
:raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginInitError`
"""
raise NotImplementedError
class ThreadedStatistics(Statistics, Threaded, threading.Thread):
""" ThreadedStatistics plugins process client statistics in a
separate thread. """
def __init__(self, core):
Statistics.__init__(self, core)
Threaded.__init__(self)
threading.Thread.__init__(self)
# Event from the core signaling an exit
self.terminate = core.terminate
self.work_queue = Queue(100000)
self.pending_file = os.path.join(Bcfg2.Options.setup.repository, "etc",
"%s.pending" % self.name)
self.daemon = False
def start_threads(self):
self.start()
def _save(self):
"""Save any pending data to a file."""
pending_data = []
try:
while not self.work_queue.empty():
(metadata, xdata) = self.work_queue.get_nowait()
data = \
lxml.etree.tostring(xdata,
xml_declaration=False).decode("UTF-8")
pending_data.append((metadata.hostname, data))
except Empty:
pass
try:
savefile = open(self.pending_file, 'w')
cPickle.dump(pending_data, savefile)
savefile.close()
self.logger.info("Saved pending %s data" % self.name)
except (IOError, TypeError):
err = sys.exc_info()[1]
self.logger.warning("Failed to save pending data: %s" % err)
def _load(self):
"""Load any pending data from a file."""
if not os.path.exists(self.pending_file):
return True
pending_data = []
try:
savefile = open(self.pending_file, 'r')
pending_data = cPickle.load(savefile)
savefile.close()
except (IOError, cPickle.UnpicklingError):
err = sys.exc_info()[1]
self.logger.warning("Failed to load pending data: %s" % err)
return False
for (pmetadata, pdata) in pending_data:
# check that shutdown wasnt called early
if self.terminate.isSet():
return False
try:
while True:
try:
metadata = self.core.build_metadata(pmetadata)
break
except MetadataRuntimeError:
pass
self.terminate.wait(5)
if self.terminate.isSet():
return False
self.work_queue.put_nowait(
(metadata,
lxml.etree.XML(pdata, parser=Bcfg2.Server.XMLParser)))
except Full:
self.logger.warning("Queue.Full: Failed to load queue data")
break
except lxml.etree.LxmlError:
lxml_error = sys.exc_info()[1]
self.logger.error("Unable to load saved interaction: %s" %
lxml_error)
except MetadataConsistencyError:
self.logger.error("Unable to load metadata for save "
"interaction: %s" % pmetadata)
try:
os.unlink(self.pending_file)
except OSError:
self.logger.error("Failed to unlink save file: %s" %
self.pending_file)
self.logger.info("Loaded pending %s data" % self.name)
return True
def run(self):
if not self._load():
return
while not self.terminate.isSet() and self.work_queue is not None:
try:
(client, xdata) = self.work_queue.get(block=True, timeout=2)
except Empty:
continue
except:
# we want to catch all exceptions here so that a stray
# error doesn't kill the entire statistics thread. For
# instance, if a bad value gets pushed onto the queue
# and the assignment above raises TypeError, we want
# to report the error, ignore the bad value, and
# continue processing statistics.
self.logger.error("Unknown error processing statistics: %s" %
sys.exc_info()[1])
continue
self.handle_statistic(client, xdata)
if self.work_queue is not None and not self.work_queue.empty():
self._save()
def process_statistics(self, metadata, data):
try:
self.work_queue.put_nowait((metadata, copy.copy(data)))
except Full:
self.logger.warning("%s: Queue is full. Dropping interactions." %
self.name)
def handle_statistic(self, metadata, data):
""" Process the given XML statistics data for the specified
client object. This differs from the
:func:`Statistics.process_statistics` method only in that
ThreadedStatistics first adds the data to a queue, and then
processes them in a separate thread.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param data: The statistics data
:type data: lxml.etree._Element
:return: None
"""
raise NotImplementedError
# pylint: disable=C0111
# Someone who understands these interfaces better needs to write docs
# for PullSource and PullTarget
class PullSource(object):
def GetExtra(self, client):
return []
def GetCurrentEntry(self, client, e_type, e_name):
raise NotImplementedError
class PullTarget(object):
def AcceptChoices(self, entry, metadata):
raise NotImplementedError
def AcceptPullData(self, specific, new_entry, verbose):
raise NotImplementedError
# pylint: enable=C0111
class Decision(object):
""" Decision plugins produce decision lists for affecting which
entries are actually installed on clients. """
def GetDecisions(self, metadata, mode):
""" Return a list of tuples of ``(<entry type>, <entry
name>)`` to be used as the decision list for the given
client in the specified mode.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param mode: The decision mode ("whitelist" or "blacklist")
:type mode: string
:return: list of tuples
"""
raise NotImplementedError
class StructureValidator(object):
""" StructureValidator plugins can modify the list of structures
after it has been created but before the entries have been
concretely bound. """
def validate_structures(self, metadata, structures):
""" Given a list of structures (i.e., of tags that contain
entry tags), modify that list or the structures in it
in-place.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param config: A list of lxml.etree._Element objects
describing the structures (i.e., bundles) for
this client. This can be modified in place.
:type config: list of lxml.etree._Element
:returns: None
:raises: :class:`Bcfg2.Server.Plugin.exceptions.ValidationError`
"""
raise NotImplementedError
class GoalValidator(object):
""" GoalValidator plugins can modify the concretely-bound configuration of
a client as a last stage before the configuration is sent to the
client. """
def validate_goals(self, metadata, config):
""" Given a monolithic XML document of the full configuration,
modify the document in-place.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param config: The full configuration for the client
:type config: lxml.etree._Element
:returns: None
:raises: :class:`Bcfg2.Server.Plugin.exceptions:ValidationError`
"""
raise NotImplementedError
class Version(Plugin):
""" Version plugins interact with various version control systems. """
create = False
options = Plugin.options + [
Bcfg2.Options.PathOption(cf=('server', 'vcs_root'),
default='<repository>',
help='Server VCS repository root')]
#: The path to the VCS metadata file or directory, relative to the
#: base of the Bcfg2 repository. E.g., for Subversion this would
#: be ".svn"
__vcs_metadata_path__ = None
__rmi__ = Plugin.__rmi__ + ['get_revision']
def __init__(self, core):
Plugin.__init__(self, core)
if self.__vcs_metadata_path__:
self.vcs_path = os.path.join(Bcfg2.Options.setup.vcs_root,
self.__vcs_metadata_path__)
if not os.path.exists(self.vcs_path):
raise PluginInitError("%s is not present" % self.vcs_path)
else:
self.vcs_path = None
__init__.__doc__ = Plugin.__init__.__doc__ + """
.. autoattribute:: __vcs_metadata_path__ """
def get_revision(self):
""" Return the current revision of the Bcfg2 specification.
This will be included in the ``revision`` attribute of the
top-level tag of the XML configuration sent to the client.
:returns: string - the current version
"""
raise NotImplementedError
class ClientRunHooks(object):
""" ClientRunHooks can hook into various parts of a client run to
perform actions at various times without needing to pretend to be
a different plugin type. """
def start_client_run(self, metadata):
""" Invoked at the start of a client run, after all probe data
has been received and decision lists have been queried (if
applicable), but before the configuration is generated.
:param metadata: The client metadata object
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:returns: None
"""
pass
def end_client_run(self, metadata):
""" Invoked at the end of a client run, immediately after
:class:`GoalValidator` plugins have been run and just before
the configuration is returned to the client.
:param metadata: The client metadata object
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:returns: None
"""
pass
def end_statistics(self, metadata):
""" Invoked after statistics are processed for a client.
:param metadata: The client metadata object
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:returns: None
"""
pass
class ClientACLs(object):
""" ClientACLs are used to grant or deny access to different
XML-RPC calls based on client IP or metadata. """
def check_acl_ip(self, address, rmi):
""" Check if the given IP address is authorized to make the
named XML-RPC call.
:param address: The address pair of the client to check ACLs for
:type address: tuple of (<ip address>, <port>)
:param rmi: The fully-qualified name of the RPC call
:param rmi: string
:returns: bool or None - True to allow, False to deny, None to
defer to metadata ACLs
"""
return True
def check_acl_metadata(self, metadata, rmi):
""" Check if the given client is authorized to make the named
XML-RPC call.
:param metadata: The client metadata
:type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata
:param rmi: The fully-qualified name of the RPC call
:param rmi: string
:returns: bool
"""
return True
class TemplateDataProvider(object):
""" TemplateDataProvider plugins provide variables to templates
for use in rendering. """
def get_template_data(self, entry, metadata, template):
""" Get a dict of variables that will be supplied to a Cfg
template for rendering """
return dict()
def get_xml_template_data(self, structfile, metadata):
""" Get a dict of variables that will be supplied to an XML
template (e.g., a bundle) for rendering """
return dict()
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