sampledoc

Source code for Bcfg2.Server.Plugin.interfaces

""" Interface definitions for Bcfg2 server plugins """

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


[docs]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`. """
[docs] 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
[docs] 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
[docs]class Structure(object): """ Structure Plugins contribute to abstract client configurations. That is, they produce lists of entries that will be generated for a client. """
[docs] 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
[docs]class Metadata(object): """ Metadata plugins handle initial metadata construction, accumulating data from :class:`Connector` plugins, and producing :class:`Bcfg2.Server.Plugins.Metadata.ClientMetadata` objects. """
[docs] 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
[docs] 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
[docs] 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
[docs] 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]
[docs] 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
[docs] 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
[docs] 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
[docs] 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
[docs] def update_client_list(self): """ Re-read the cached list of clients """ raise NotImplementedError
[docs]class Connector(object): """ Connector plugins augment client metadata instances with additional data, additional groups, or both. """
[docs] 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()
[docs] 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()
[docs]class Probing(object): """ Probing plugins can collect data from clients and process it. """
[docs] 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
[docs] 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
[docs]class Statistics(Plugin): """ Statistics plugins handle statistics for clients. In general, you should avoid using Statistics and use :class:`ThreadedStatistics` instead.""" create = False
[docs] 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
[docs]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. """
[docs] def start_threads(self): """ Start this plugin's threads after daemonization. :return: None :raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginInitError` """ raise NotImplementedError
[docs]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: err = sys.exc_info()[1] self.logger.error("ThreadedStatistics: %s" % err) 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)
[docs] 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
[docs]class Decision(object): """ Decision plugins produce decision lists for affecting which entries are actually installed on clients. """
[docs] 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
[docs]class StructureValidator(object): """ StructureValidator plugins can modify the list of structures after it has been created but before the entries have been concretely bound. """
[docs] 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
[docs]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. """
[docs] 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
[docs]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__ """
[docs] 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
[docs]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. """
[docs] 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
[docs] 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
[docs] 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
[docs]class ClientACLs(object): """ ClientACLs are used to grant or deny access to different XML-RPC calls based on client IP or metadata. """
[docs] 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
[docs] 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
[docs]class TemplateDataProvider(object): """ TemplateDataProvider plugins provide variables to templates for use in rendering. """
[docs] 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()
[docs] 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()