sampledoc

Source code for Bcfg2.Server.Plugin.helpers

""" Helper classes for Bcfg2 server plugins """

import os
import re
import sys
import copy
import time
import glob
import logging
import operator
import lxml.etree
import Bcfg2.Server
import Bcfg2.Options
import Bcfg2.Statistics
from Bcfg2.Compat import CmpMixin, wraps
from Bcfg2.Server.Plugin.base import Debuggable, Plugin
from Bcfg2.Server.Plugin.interfaces import Generator
from Bcfg2.Server.Plugin.exceptions import SpecificityError, \
    PluginExecutionError, PluginInitError

try:
    import django  # pylint: disable=W0611
    HAS_DJANGO = True
except ImportError:
    HAS_DJANGO = False

#: A dict containing default metadata for Path entries from bcfg2.conf
DEFAULT_FILE_METADATA = Bcfg2.Options.OptionParser(
    dict(configfile=Bcfg2.Options.CFILE,
         owner=Bcfg2.Options.MDATA_OWNER,
         group=Bcfg2.Options.MDATA_GROUP,
         mode=Bcfg2.Options.MDATA_MODE,
         secontext=Bcfg2.Options.MDATA_SECONTEXT,
         important=Bcfg2.Options.MDATA_IMPORTANT,
         paranoid=Bcfg2.Options.MDATA_PARANOID,
         sensitive=Bcfg2.Options.MDATA_SENSITIVE))
DEFAULT_FILE_METADATA.parse([Bcfg2.Options.CFILE.cmd, Bcfg2.Options.CFILE])
del DEFAULT_FILE_METADATA['args']
del DEFAULT_FILE_METADATA['configfile']

LOGGER = logging.getLogger(__name__)

#: a compiled regular expression for parsing info and :info files
INFO_REGEX = re.compile(r'owner:\s*(?P<owner>\S+)|' +
                        r'group:\s*(?P<group>\S+)|' +
                        r'mode:\s*(?P<mode>\w+)|' +
                        r'secontext:\s*(?P<secontext>\S+)|' +
                        r'paranoid:\s*(?P<paranoid>\S+)|' +
                        r'sensitive:\s*(?P<sensitive>\S+)|' +
                        r'encoding:\s*(?P<encoding>\S+)|' +
                        r'important:\s*(?P<important>\S+)|' +
                        r'mtime:\s*(?P<mtime>\w+)')


[docs]def bind_info(entry, metadata, infoxml=None, default=DEFAULT_FILE_METADATA): """ Bind the file metadata in the given :class:`Bcfg2.Server.Plugin.helpers.InfoXML` object to the given entry. :param entry: The abstract entry to bind the info to :type entry: lxml.etree._Element :param metadata: The client metadata to get info for :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :param infoxml: The info.xml file to pull file metadata from :type infoxml: Bcfg2.Server.Plugin.helpers.InfoXML :param default: Default metadata to supply when the info.xml file does not include a particular attribute :type default: dict :returns: None :raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginExecutionError` """ for attr, val in list(default.items()): entry.set(attr, val) if infoxml: mdata = dict() infoxml.pnode.Match(metadata, mdata, entry=entry) if 'Info' not in mdata: msg = "Failed to set metadata for file %s" % entry.get('name') LOGGER.error(msg) raise PluginExecutionError(msg) for attr, val in list(mdata['Info'][None].items()): entry.set(attr, val)
[docs]class track_statistics(object): # pylint: disable=C0103 """ Decorator that tracks execution time for the given :class:`Plugin` method with :mod:`Bcfg2.Statistics` for reporting via ``bcfg2-admin perf`` """ def __init__(self, name=None): """ :param name: The name under which statistics for this function will be tracked. By default, the name will be the name of the function concatenated with the name of the class the function is a member of. :type name: string """ # if this is None, it will be set later during __call_ self.name = name def __call__(self, func): if self.name is None: self.name = func.__name__ @wraps(func) def inner(obj, *args, **kwargs): """ The decorated function """ name = "%s:%s" % (obj.__class__.__name__, self.name) start = time.time() try: return func(obj, *args, **kwargs) finally: Bcfg2.Statistics.stats.add_value(name, time.time() - start) return inner
[docs]class DatabaseBacked(Plugin): """ Provides capabilities for a plugin to read and write to a database. .. private-include: _use_db .. private-include: _must_lock """ #: The option to look up in :attr:`section` to determine whether or #: not to use the database capabilities of this plugin. The option #: is retrieved with #: :py:func:`ConfigParser.SafeConfigParser.getboolean`, and so must #: conform to the possible values that function can handle. option = "use_database" def __init__(self, core, datastore): Plugin.__init__(self, core, datastore) use_db = self.core.setup.cfp.getboolean(self.section, self.option, default=False) if use_db and not HAS_DJANGO: raise PluginInitError("%s.%s is True but Django not found" % (self.section, self.option)) elif use_db and not self.core.database_available: raise PluginInitError("%s.%s is True but the database is " "unavailable due to prior errors" % (self.section, self.option)) def _section(self): """ The section to look in for :attr:`DatabaseBacked.option` """ return self.name.lower() section = property(_section) @property
[docs] def _use_db(self): """ Whether or not this plugin is configured to use the database. """ use_db = self.core.setup.cfp.getboolean(self.section, self.option, default=False) if use_db and HAS_DJANGO and self.core.database_available: return True else: return False
@property
[docs] def _must_lock(self): """ Whether or not the backend database must acquire a thread lock before writing, because it does not allow multiple threads to write.""" engine = \ self.core.setup.cfp.get(Bcfg2.Options.DB_ENGINE.cf[0], Bcfg2.Options.DB_ENGINE.cf[1], default=Bcfg2.Options.DB_ENGINE.default) return engine == 'sqlite3'
@staticmethod
[docs] def get_db_lock(func): """ Decorator to be used by a method of a :class:`DatabaseBacked` plugin that will update database data. """ @wraps(func) def _acquire_and_run(self, *args, **kwargs): """ The decorated function """ if self._must_lock: # pylint: disable=W0212 try: self.core.db_write_lock.acquire() rv = func(self, *args, **kwargs) finally: self.core.db_write_lock.release() else: rv = func(self, *args, **kwargs) return rv return _acquire_and_run
[docs]class PluginDatabaseModel(object): """ A database model mixin that all database models used by :class:`Bcfg2.Server.Plugin.helpers.DatabaseBacked` plugins must inherit from. This is just a mixin; models must also inherit from django.db.models.Model to be valid Django models."""
[docs] class Meta(object): # pylint: disable=W0232 """ Model metadata options """ app_label = "Server"
[docs]class FileBacked(Debuggable): """ This object caches file data in memory. FileBacked objects are principally meant to be used as a part of :class:`Bcfg2.Server.Plugin.helpers.DirectoryBacked`. """ def __init__(self, name, fam=None): """ :param name: The full path to the file to cache and monitor :type name: string :param fam: The FAM object used to receive notifications of changes :type fam: Bcfg2.Server.FileMonitor.FileMonitor """ Debuggable.__init__(self) #: A string containing the raw data in this file self.data = '' #: The full path to the file self.name = name #: The FAM object used to receive notifications of changes self.fam = fam
[docs] def HandleEvent(self, event=None): """ HandleEvent is called whenever the FAM registers an event. :param event: The event object :type event: Bcfg2.Server.FileMonitor.Event :returns: None """ if event and event.code2str() not in ['exists', 'changed', 'created']: return try: self.data = open(self.name).read() self.Index() except IOError: err = sys.exc_info()[1] self.logger.error("Failed to read file %s: %s" % (self.name, err)) except: err = sys.exc_info()[1] self.logger.error("Failed to parse file %s: %s" % (self.name, err))
[docs] def Index(self): """ Index() is called by :func:`HandleEvent` every time the data changes, and parses the data into usable data as required.""" pass
def __repr__(self): return "%s: %s" % (self.__class__.__name__, self.name)
[docs]class DirectoryBacked(Debuggable): """ DirectoryBacked objects represent a directory that contains files, represented by objects of the type listed in :attr:`__child__`, and other directories recursively. It monitors for new files and directories to be added, and creates new objects as required to track those.""" #: The type of child objects to create for files contained within #: the directory that is tracked. Default is #: :class:`Bcfg2.Server.Plugin.helpers.FileBacked` __child__ = FileBacked #: Only track and include files whose names (not paths) match this #: compiled regex. patterns = re.compile('.*') #: Preemptively ignore files whose names (not paths) match this #: compiled regex. ``ignore`` can be set to ``None`` to ignore no #: files. If a file is encountered that does not match #: :attr:`patterns` or ``ignore``, then a warning will be produced. ignore = None def __init__(self, data, fam): """ :param data: The path to the data directory that will be monitored :type data: string :param fam: The FAM object used to receive notifications of changes :type fam: Bcfg2.Server.FileMonitor.FileMonitor .. ----- .. autoattribute:: __child__ """ Debuggable.__init__(self) self.data = os.path.normpath(data) self.fam = fam #: self.entries contains information about the files monitored #: by this object. The keys of the dict are the relative #: paths to the files. The values are the objects (of type #: :attr:`__child__`) that handle their contents. self.entries = {} #: self.handles contains information about the directories #: monitored by this object. The keys of the dict are the #: values returned by the initial fam.AddMonitor() call (which #: appear to be integers). The values are the relative paths of #: the directories. self.handles = {} # Monitor everything in the plugin's directory if not os.path.exists(self.data): self.logger.warning("%s does not exist, creating" % self.data) os.makedirs(self.data) self.add_directory_monitor('') def set_debug(self, debug): for entry in self.entries.values(): if isinstance(entry, Debuggable): entry.set_debug(debug) return Debuggable.set_debug(self, debug) def __getitem__(self, key): return self.entries[key] def __len__(self): return len(self.entries) def __delitem__(self, key): del self.entries[key] def __setitem__(self, key, val): self.entries[key] = val def __iter__(self): return iter(list(self.entries.items()))
[docs] def add_directory_monitor(self, relative): """ Add a new directory to the FAM for monitoring. :param relative: Path name to monitor. This must be relative to the plugin's directory. An empty string value ("") will cause the plugin directory itself to be monitored. :type relative: string :returns: None """ dirpathname = os.path.join(self.data, relative) if relative not in self.handles.values(): if not os.path.isdir(dirpathname): self.logger.error("%s is not a directory" % dirpathname) return reqid = self.fam.AddMonitor(dirpathname, self) self.handles[reqid] = relative
[docs] def add_entry(self, relative, event): """ Add a new file to our tracked entries, and to our FAM for monitoring. :param relative: Path name to monitor. This must be relative to the plugin's directory. :type relative: string: :param event: FAM event that caused this entry to be added. :type event: Bcfg2.Server.FileMonitor.Event :returns: None """ self.entries[relative] = self.__child__(os.path.join(self.data, relative), self.fam) self.entries[relative].HandleEvent(event)
[docs] def HandleEvent(self, event): # pylint: disable=R0912 """ Handle FAM events. This method is invoked by the FAM when it detects a change to a filesystem object we have requsted to be monitored. This method manages the lifecycle of events related to the monitored objects, adding them to our list of entries and creating objects of type :attr:`__child__` that actually do the domain-specific processing. When appropriate, it propogates events those objects by invoking their HandleEvent method in turn. :param event: FAM event that caused this entry to be added. :type event: Bcfg2.Server.FileMonitor.Event :returns: None """ action = event.code2str() # Exclude events for actions we don't care about if action == 'endExist': return if event.requestID not in self.handles: self.logger.warn("Got %s event with unknown handle (%s) for %s" % (action, event.requestID, event.filename)) return # Clean up path names event.filename = os.path.normpath(event.filename) if event.filename.startswith(self.data): # the first event we get is on the data directory itself event.filename = event.filename[len(self.data) + 1:] if self.ignore and self.ignore.search(event.filename): self.logger.debug("Ignoring event %s" % event.filename) return # Calculate the absolute and relative paths this event refers to abspath = os.path.join(self.data, self.handles[event.requestID], event.filename) relpath = os.path.join(self.handles[event.requestID], event.filename).lstrip('/') if action == 'deleted': for key in list(self.entries.keys()): if key.startswith(relpath): del self.entries[key] # We remove values from self.entries, but not # self.handles, because the FileMonitor doesn't stop # watching a directory just because it gets deleted. If it # is recreated, we will start getting notifications for it # again without having to add a new monitor. elif os.path.isdir(abspath): # Deal with events for directories if action in ['exists', 'created']: self.add_directory_monitor(relpath) elif action == 'changed': if relpath in self.entries: # Ownerships, permissions or timestamps changed on # the directory. None of these should affect the # contents of the files, though it could change # our ability to access them. # # It seems like the right thing to do is to cancel # monitoring the directory and then begin # monitoring it again. But the current FileMonitor # class doesn't support canceling, so at least let # the user know that a restart might be a good # idea. self.logger.warn("Directory properties for %s changed, " "please consider restarting the server" % abspath) else: # Got a "changed" event for a directory that we # didn't know about. Go ahead and treat it like a # "created" event, but log a warning, because this # is unexpected. self.logger.warn("Got %s event for unexpected dir %s" % (action, abspath)) self.add_directory_monitor(relpath) else: self.logger.warn("Got unknown dir event %s %s %s" % (event.requestID, event.code2str(), abspath)) elif self.patterns.search(event.filename): if action in ['exists', 'created']: self.add_entry(relpath, event) elif action == 'changed': if relpath in self.entries: self.entries[relpath].HandleEvent(event) else: # Got a "changed" event for a file that we didn't # know about. Go ahead and treat it like a # "created" event, but log a warning, because this # is unexpected. self.logger.warn("Got %s event for unexpected file %s" % (action, abspath)) self.add_entry(relpath, event) else: self.logger.warn("Got unknown file event %s %s %s" % (event.requestID, event.code2str(), abspath)) else: self.logger.warn("Could not process filename %s; ignoring" % event.filename)
[docs]class XMLFileBacked(FileBacked): """ This object parses and caches XML file data in memory. It can be used as a standalone object or as a part of :class:`Bcfg2.Server.Plugin.helpers.XMLDirectoryBacked` """ #: If ``__identifier__`` is set, then a top-level tag with the #: specified name will be required on the file being cached. Its #: value will be available as :attr:`label`. To disable this #: behavior, set ``__identifier__`` to ``None``. __identifier__ = 'name' #: If ``create`` is set, then it overrides the ``create`` argument #: to the constructor. create = None def __init__(self, filename, fam=None, should_monitor=False, create=None): """ :param filename: The full path to the file to cache and monitor :type filename: string :param fam: The FAM object used to receive notifications of changes :type fam: Bcfg2.Server.FileMonitor.FileMonitor :param should_monitor: Whether or not to monitor this file for changes. It may be useful to disable monitoring when, for instance, the file is monitored by another object (e.g., an :class:`Bcfg2.Server.Plugin.helpers.XMLDirectoryBacked` object). :type should_monitor: bool :param create: Create the file if it doesn't exist. ``create`` can be either an :class:`lxml.etree._Element` object, which will be used as initial content, or a string, which will be used as the name of the (empty) tag that will be the initial content of the file. :type create: lxml.etree._Element or string .. ----- .. autoattribute:: __identifier__ """ FileBacked.__init__(self, filename, fam=fam) #: The raw XML data contained in the file as an #: :class:`lxml.etree.ElementTree` object, with XIncludes #: processed. self.xdata = None #: The label of this file. This is determined from the #: top-level tag in the file, which must have an attribute #: specified by :attr:`__identifier__`. self.label = "" #: All entries in this file. By default, all immediate #: children of the top-level XML tag. self.entries = [] #: "Extra" files included in this file by XInclude. self.extras = [] #: Extra FAM monitors set by this object for files included by #: XInclude. self.extra_monitors = [] if ((create is not None or self.create not in [None, False]) and not os.path.exists(self.name)): toptag = create or self.create self.logger.warning("%s does not exist, creating" % self.name) if hasattr(toptag, "getroottree"): el = toptag else: el = lxml.etree.Element(toptag) el.getroottree().write(self.name, xml_declaration=False, pretty_print=True) #: Whether or not to monitor this file for changes. self.should_monitor = should_monitor if fam and should_monitor: self.fam.AddMonitor(filename, self) def _follow_xincludes(self, fname=None, xdata=None): """ follow xincludes, adding included files to self.extras """ xinclude = '%sinclude' % Bcfg2.Server.XI_NAMESPACE if xdata is None: if fname is None: xdata = self.xdata.getroottree() else: xdata = lxml.etree.parse(fname) for el in xdata.findall('//' + xinclude): name = el.get("href") if name.startswith("/"): fpath = name else: rel = fname or self.name fpath = os.path.join(os.path.dirname(rel), name) # expand globs in xinclude, a bcfg2-specific extension extras = glob.glob(fpath) if not extras: msg = "%s: %s does not exist, skipping" % (self.name, name) if el.findall('./%sfallback' % Bcfg2.Server.XI_NAMESPACE): self.logger.debug(msg) else: self.logger.error(msg) # add a FAM monitor for this path. this isn't perfect # -- if there's an xinclude of "*.xml", we'll watch # the literal filename "*.xml". but for non-globbing # filenames, it works fine. if fpath not in self.extra_monitors: self.add_monitor(fpath) parent = el.getparent() parent.remove(el) for extra in extras: if extra != self.name: lxml.etree.SubElement(parent, xinclude, href=extra) if extra not in self.extras: self.extras.append(extra) self._follow_xincludes(fname=extra) if extra not in self.extra_monitors: self.add_monitor(extra)
[docs] def Index(self): self.xdata = lxml.etree.XML(self.data, base_url=self.name, parser=Bcfg2.Server.XMLParser) self.extras = [] self._follow_xincludes() if self.extras: try: self.xdata.getroottree().xinclude() except lxml.etree.XIncludeError: err = sys.exc_info()[1] self.logger.error("XInclude failed on %s: %s" % (self.name, err)) self.entries = self.xdata.getchildren() if self.__identifier__ is not None: self.label = self.xdata.attrib[self.__identifier__]
Index.__doc__ = FileBacked.Index.__doc__
[docs] def add_monitor(self, fpath): """ Add a FAM monitor to a file that has been XIncluded. This is only done if the constructor got a ``fam`` object, regardless of whether ``should_monitor`` is set to True (i.e., whether or not the base file is monitored). :param fpath: The full path to the file to monitor :type fpath: string :returns: None """ self.extra_monitors.append(fpath) if self.fam: self.fam.AddMonitor(fpath, self)
def __iter__(self): return iter(self.entries) def __str__(self): return "%s at %s" % (self.__class__.__name__, self.name)
[docs]class StructFile(XMLFileBacked): """ StructFiles are XML files that contain a set of structure file formatting logic for handling ``<Group>`` and ``<Client>`` tags. """ #: If ``__identifier__`` is not None, then it must be the name of #: an XML attribute that will be required on the top-level tag of #: the file being cached __identifier__ = None def _include_element(self, item, metadata): """ determine if an XML element matches the metadata """ if isinstance(item, lxml.etree._Comment): # pylint: disable=W0212 return False negate = item.get('negate', 'false').lower() == 'true' if item.tag == 'Group': return negate == (item.get('name') not in metadata.groups) elif item.tag == 'Client': return negate == (item.get('name') != metadata.hostname) else: return True def _match(self, item, metadata): """ recursive helper for Match() """ if self._include_element(item, metadata): if item.tag == 'Group' or item.tag == 'Client': rv = [] if self._include_element(item, metadata): for child in item.iterchildren(): rv.extend(self._match(child, metadata)) return rv else: rv = copy.deepcopy(item) for child in rv.iterchildren(): rv.remove(child) for child in item.iterchildren(): rv.extend(self._match(child, metadata)) return [rv] else: return []
[docs] def Match(self, metadata): """ Return matching fragments of the data in this file. A tag is considered to match if all ``<Group>`` and ``<Client>`` tags that are its ancestors match the metadata given. Since tags are included unmodified, it's possible for a tag to itself match while containing non-matching children. Consequently, only the tags contained in the list returned by Match() (and *not* their descendents) should be considered to match the metadata. :param metadata: Client metadata to match against. :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :returns: list of lxml.etree._Element objects """ rv = [] for child in self.entries: rv.extend(self._match(child, metadata)) return rv
def _xml_match(self, item, metadata): """ recursive helper for XMLMatch """ if self._include_element(item, metadata): if item.tag == 'Group' or item.tag == 'Client': for child in item.iterchildren(): item.remove(child) item.getparent().append(child) self._xml_match(child, metadata) if item.text: if item.getparent().text is None: item.getparent().text = item.text else: item.getparent().text += item.text item.getparent().remove(item) else: for child in item.iterchildren(): self._xml_match(child, metadata) else: item.getparent().remove(item)
[docs] def XMLMatch(self, metadata): """ Return a rebuilt XML document that only contains the matching portions of the original file. A tag is considered to match if all ``<Group>`` and ``<Client>`` tags that are its ancestors match the metadata given. Unlike :func:`Match`, the document returned by XMLMatch will only contain matching data. All ``<Group>`` and ``<Client>`` tags will have been stripped out. :param metadata: Client metadata to match against. :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :returns: lxml.etree._Element """ rv = copy.deepcopy(self.xdata) for child in rv.iterchildren(): self._xml_match(child, metadata) return rv
[docs]class INode(object): """ INodes provide lists of things available at a particular group intersection. INodes are deprecated; new plugins should use :class:`Bcfg2.Server.Plugin.helpers.StructFile` instead. """ raw = dict( Client="lambda m, e:'%(name)s' == m.hostname and predicate(m, e)", Group="lambda m, e:'%(name)s' in m.groups and predicate(m, e)") nraw = dict( Client="lambda m, e:'%(name)s' != m.hostname and predicate(m, e)", Group="lambda m, e:'%(name)s' not in m.groups and predicate(m, e)") containers = ['Group', 'Client'] ignore = [] def __init__(self, data, idict, parent=None): self.data = data self.contents = {} if parent is None: self.predicate = lambda m, e: True else: predicate = parent.predicate if data.get('negate', 'false').lower() == 'true': psrc = self.nraw else: psrc = self.raw if data.tag in list(psrc.keys()): self.predicate = eval(psrc[data.tag] % {'name': data.get('name')}, {'predicate': predicate}) else: raise PluginExecutionError("Unknown tag: %s" % data.tag) self.children = [] self._load_children(data, idict) def _load_children(self, data, idict): """ load children """ for item in data.getchildren(): if item.tag in self.ignore: continue elif item.tag in self.containers: self.children.append(self.__class__(item, idict, self)) else: try: self.contents[item.tag][item.get('name')] = \ dict(item.attrib) except KeyError: self.contents[item.tag] = \ {item.get('name'): dict(item.attrib)} if item.text: self.contents[item.tag][item.get('name')]['__text__'] = \ item.text if item.getchildren(): self.contents[item.tag][item.get('name')]['__children__'] \ = item.getchildren() try: idict[item.tag].append(item.get('name')) except KeyError: idict[item.tag] = [item.get('name')]
[docs] def Match(self, metadata, data, entry=lxml.etree.Element("None")): """Return a dictionary of package mappings.""" if self.predicate(metadata, entry): for key in self.contents: try: data[key].update(self.contents[key]) except: # pylint: disable=W0702 data[key] = {} data[key].update(self.contents[key]) for child in self.children: child.Match(metadata, data, entry=entry)
[docs]class InfoNode (INode): """ :class:`Bcfg2.Server.Plugin.helpers.INode` implementation that includes ``<Path>`` tags, suitable for use with :file:`info.xml` files.""" raw = dict( Client="lambda m, e: '%(name)s' == m.hostname and predicate(m, e)", Group="lambda m, e: '%(name)s' in m.groups and predicate(m, e)", Path="lambda m, e: ('%(name)s' == e.get('name') or " + "'%(name)s' == e.get('realname')) and " + "predicate(m, e)") nraw = dict( Client="lambda m, e: '%(name)s' != m.hostname and predicate(m, e)", Group="lambda m, e: '%(name)s' not in m.groups and predicate(m, e)", Path="lambda m, e: '%(name)s' != e.get('name') and " + "'%(name)s' != e.get('realname') and " + "predicate(m, e)") containers = ['Group', 'Client', 'Path']
[docs]class XMLSrc(XMLFileBacked): """ XMLSrc files contain a :class:`Bcfg2.Server.Plugin.helpers.INode` hierarchy that returns matching entries. XMLSrc objects are deprecated and :class:`Bcfg2.Server.Plugin.helpers.StructFile` should be preferred where possible.""" __node__ = INode __cacheobj__ = dict __priority_required__ = True def __init__(self, filename, fam=None, should_monitor=False, create=None): XMLFileBacked.__init__(self, filename, fam, should_monitor, create) self.items = {} self.cache = None self.pnode = None self.priority = -1
[docs] def HandleEvent(self, _=None): """Read file upon update.""" self.items = {} try: xdata = lxml.etree.parse(self.name, parser=Bcfg2.Server.XMLParser).getroot() except lxml.etree.XMLSyntaxError: msg = "Failed to parse file %s: %s" % (self.name, sys.exc_info()[1]) self.logger.error(msg) raise PluginExecutionError(msg) self.pnode = self.__node__(xdata, self.items) self.cache = None try: self.priority = int(xdata.get('priority')) except (ValueError, TypeError): if self.__priority_required__: msg = "Got bogus priority %s for file %s" % \ (xdata.get('priority'), self.name) self.logger.error(msg) raise PluginExecutionError(msg)
[docs] def Cache(self, metadata): """Build a package dict for a given host.""" if self.cache is None or self.cache[0] != metadata: cache = (metadata, self.__cacheobj__()) if self.pnode is None: self.logger.error("Cache method called early for %s; " "forcing data load" % self.name) self.HandleEvent() return self.pnode.Match(metadata, cache[1]) self.cache = cache
def __str__(self): return str(self.items)
[docs]class InfoXML(XMLSrc): """ InfoXML files contain a :class:`Bcfg2.Server.Plugin.helpers.InfoNode` hierarchy that returns matching entries, suitable for use with :file:`info.xml` files.""" __node__ = InfoNode __priority_required__ = False
[docs]class XMLDirectoryBacked(DirectoryBacked): """ :class:`Bcfg2.Server.Plugin.helpers.DirectoryBacked` for XML files. """ #: Only track and include files whose names (not paths) match this #: compiled regex. patterns = re.compile(r'^.*\.xml$') #: The type of child objects to create for files contained within #: the directory that is tracked. Default is #: :class:`Bcfg2.Server.Plugin.helpers.XMLFileBacked` __child__ = XMLFileBacked
[docs]class PrioDir(Plugin, Generator, XMLDirectoryBacked): """ PrioDir handles a directory of XML files where each file has a set priority. .. ----- .. autoattribute:: __child__ """ #: The type of child objects to create for files contained within #: the directory that is tracked. Default is #: :class:`Bcfg2.Server.Plugin.helpers.XMLSrc` __child__ = XMLSrc def __init__(self, core, datastore): Plugin.__init__(self, core, datastore) Generator.__init__(self) XMLDirectoryBacked.__init__(self, self.data, self.core.fam) __init__.__doc__ = Plugin.__init__.__doc__
[docs] def HandleEvent(self, event): XMLDirectoryBacked.HandleEvent(self, event) self.Entries = {} for src in list(self.entries.values()): for itype, children in list(src.items.items()): for child in children: try: self.Entries[itype][child] = self.BindEntry except KeyError: self.Entries[itype] = {child: self.BindEntry}
HandleEvent.__doc__ = XMLDirectoryBacked.HandleEvent.__doc__ def _matches(self, entry, metadata, rules): # pylint: disable=W0613 """ Whether or not a given entry has a matching entry in this PrioDir. By default this does strict matching (i.e., the entry name is in ``rules.keys()``), but this can be overridden to provide regex matching, etc. :param entry: The entry to find a match for :type entry: lxml.etree._Element :param metadata: The metadata to get attributes for :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :rules: A dict of rules to look in for a matching rule :type rules: dict :returns: bool """ return entry.get('name') in rules
[docs] def BindEntry(self, entry, metadata): """ Bind the attributes that apply to an entry to it. The entry is modified in-place. :param entry: The entry to add attributes to. :type entry: lxml.etree._Element :param metadata: The metadata to get attributes for :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :returns: None """ attrs = self.get_attrs(entry, metadata) for key, val in list(attrs.items()): entry.attrib[key] = val
[docs] def get_attrs(self, entry, metadata): """ Get a list of attributes to add to the entry during the bind. This is a complex method, in that it both modifies the entry, and returns attributes that need to be added to the entry. That seems sub-optimal, and should probably be changed at some point. Namely: * The return value includes all XML attributes that need to be added to the entry, but it does not add them. * If text contents or child tags need to be added to the entry, they are added to the entry in place. :param entry: The entry to add attributes to. :type entry: lxml.etree._Element :param metadata: The metadata to get attributes for :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :returns: dict of <attr name>:<attr value> :raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginExecutionError` """ for src in self.entries.values(): src.Cache(metadata) matching = [src for src in list(self.entries.values()) if (src.cache and entry.tag in src.cache[1] and self._matches(entry, metadata, src.cache[1][entry.tag]))] if len(matching) == 0: raise PluginExecutionError("No matching source for entry when " "retrieving attributes for %s(%s)" % (entry.tag, entry.attrib.get('name'))) elif len(matching) == 1: index = 0 else: prio = [int(src.priority) for src in matching] if prio.count(max(prio)) > 1: msg = "Found conflicting sources with same priority for " + \ "%s:%s for %s" % (entry.tag, entry.get("name"), metadata.hostname) self.logger.error(msg) self.logger.error([item.name for item in matching]) self.logger.error("Priority was %s" % max(prio)) raise PluginExecutionError(msg) index = prio.index(max(prio)) for rname in list(matching[index].cache[1][entry.tag].keys()): if self._matches(entry, metadata, [rname]): data = matching[index].cache[1][entry.tag][rname] break else: # Fall back on __getitem__. Required if override used data = matching[index].cache[1][entry.tag][entry.get('name')] if '__text__' in data: entry.text = data['__text__'] if '__children__' in data: for item in data['__children__']: entry.append(copy.copy(item)) return dict([(key, data[key]) for key in list(data.keys()) if not key.startswith('__')])
[docs]class Specificity(CmpMixin): """ Represent the specificity of an object; i.e., what client(s) it applies to. It can be group- or client-specific, or apply to all clients. Specificity objects are sortable; objects that are less specific are considered less than objects that are more specific. Objects that apply to all clients are the least specific; objects that apply to a single client are the most specific. Objects that apply to groups are sorted by priority. """ def __init__(self, all=False, group=False, # pylint: disable=W0622 hostname=False, prio=0, delta=False): """ :param all: The object applies to all clients. :type all: bool :param group: The object applies only to the given group. :type group: string or False :param hostname: The object applies only to the named client. :type hostname: string or False :param prio: The object has the given priority relative to other objects that also apply to the same group. ``<group>`` must be specified with ``<prio>``. :type prio: int :param delta: The object is a delta (i.e., a .cat or .diff file, not a full file). Deltas are deprecated. :type delta: bool Exactly one of {all|group|hostname} should be given. """ CmpMixin.__init__(self) self.hostname = hostname self.all = all self.group = group self.prio = prio self.delta = delta
[docs] def matches(self, metadata): """ Return True if the object described by this Specificity object applies to the given client. That is, if this Specificity applies to all clients, or to a group the client is a member of, or to the client individually. :param metadata: The client metadata :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :returns: bool """ return (self.all or self.hostname == metadata.hostname or self.group in metadata.groups)
def __cmp__(self, other): # pylint: disable=R0911 """Sort most to least specific.""" if self.all: if other.all: return 0 else: return 1 elif other.all: return -1 elif self.group: if other.hostname: return 1 if other.group and other.prio > self.prio: return 1 if other.group and other.prio == self.prio: return 0 elif other.group: return -1 elif self.hostname and other.hostname: return 0 return -1 def __str__(self): rv = [self.__class__.__name__, ': '] if self.all: rv.append("all") elif self.group: rv.append("Group %s, priority %s" % (self.group, self.prio)) elif self.hostname: rv.append("Host %s" % self.hostname) if self.delta: rv.append(", delta=%s" % self.delta) return "".join(rv)
[docs]class SpecificData(object): """ A file that is specific to certain clients, groups, or all clients. """ def __init__(self, name, specific, encoding): # pylint: disable=W0613 """ :param name: The full path to the file :type name: string :param specific: A :class:`Bcfg2.Server.Plugin.helpers.Specificity` object describing what clients this file applies to. :type specific: Bcfg2.Server.Plugin.helpers.Specificity :param encoding: The encoding to use for data in this file :type encoding: string """ self.name = name self.specific = specific self.data = None
[docs] def handle_event(self, event): """ Handle a FAM event. Note that the SpecificData object itself has no FAM, so this must be produced by a parent object (e.g., :class:`Bcfg2.Server.Plugin.helpers.EntrySet`). :param event: The event that applies to this file :type event: Bcfg2.Server.FileMonitor.Event :returns: None :raises: :exc:`Bcfg2.Server.Plugin.exceptions.PluginExecutionError` """ if event.code2str() == 'deleted': return try: self.data = open(self.name).read() except UnicodeDecodeError: self.data = open(self.name, mode='rb').read() except: # pylint: disable=W0201 LOGGER.error("Failed to read file %s: %s" % (self.name, sys.exc_info()[1]))
[docs]class EntrySet(Debuggable): """ EntrySets deal with a collection of host- and group-specific files (e.g., :class:`Bcfg2.Server.Plugin.helpers.SpecificData` objects) in a single directory. EntrySets are usually used as part of :class:`Bcfg2.Server.Plugin.helpers.GroupSpool` objects.""" #: Preemptively ignore files whose names (not paths) match this #: compiled regex. ``ignore`` cannot be set to ``None``. If a #: file is encountered that does not match the ``basename`` #: argument passed to the constructor or ``ignore``, then a #: warning will be produced. ignore = re.compile(r'^(\.#.*|.*~|\..*\.(sw[px])|.*\.genshi_include)$') # The ``basename`` argument passed to the constructor will be #: processed as a string that contains a regular expression (i.e., #: *not* a compiled regex object) if ``basename_is_regex`` is True, #: and all files that match the regex will be cincluded in the #: EntrySet. If ``basename_is_regex`` is False, then it will be #: considered a plain string and filenames must match exactly. basename_is_regex = False def __init__(self, basename, path, entry_type, encoding): """ :param basename: The filename or regular expression that files in this EntrySet must match. See :attr:`basename_is_regex` for more details. :type basename: string :param path: The full path to the directory containing files for this EntrySet :type path: string :param entry_type: A callable that returns an object that represents files in this EntrySet. This will usually be a class object, but it can be an object factory or similar callable. See below for the expected signature. :type entry_type: callable :param encoding: The encoding of all files in this entry set. :type encoding: string The ``entry_type`` callable must have the following signature:: entry_type(filepath, specificity, encoding) Where the parameters are: :param filepath: Full path to file :type filepath: string :param specific: A :class:`Bcfg2.Server.Plugin.helpers.Specificity` object describing what clients this file applies to. :type specific: Bcfg2.Server.Plugin.helpers.Specificity :param encoding: The encoding to use for data in this file :type encoding: string Additionally, the object returned by ``entry_type`` must have a ``specific`` attribute that is sortable (e.g., a :class:`Bcfg2.Server.Plugin.helpers.Specificity` object). See :class:`Bcfg2.Server.Plugin.helpers.SpecificData` for an example of a class that can be used as an ``entry_type``. """ Debuggable.__init__(self, name=basename) self.path = path self.entry_type = entry_type self.entries = {} self.metadata = DEFAULT_FILE_METADATA.copy() self.infoxml = None self.encoding = encoding if self.basename_is_regex: base_pat = basename else: base_pat = re.escape(basename) pattern = r'(.*/)?' + base_pat + \ r'(\.((H_(?P<hostname>\S+))|(G(?P<prio>\d+)_(?P<group>\S+))))?$' #: ``specific`` is a regular expression that is used to #: determine the specificity of a file in this entry set. It #: must have three named groups: ``hostname``, ``prio`` (the #: priority of a group-specific file), and ``group``. The base #: regex is constructed from the ``basename`` argument. It can #: be overridden on a per-entry basis in :func:`entry_init`. self.specific = re.compile(pattern)
[docs] def get_matching(self, metadata): """ Get a list of all entries that apply to the given client. This gets all matching entries; for example, there could be an entry that applies to all clients, multiple group-specific entries, and a client-specific entry, all of which would be returned by get_matching(). You can use :func:`best_matching` to get the single best matching entry. :param metadata: The client metadata to get matching entries for :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :returns: list -- all matching ``entry_type`` objects (see the constructor docs for more details) """ return [item for item in list(self.entries.values()) if item.specific.matches(metadata)]
[docs] def best_matching(self, metadata, matching=None): """ Return the single most specific matching entry from the set of matching entries. You can use :func:`get_matching` to get all matching entries. :param metadata: The client metadata to get matching entries for :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :param matching: The set of matching entries to pick from. If this is not provided, :func:`get_matching` will be called. :type matching: list of ``entry_type`` objects (see the constructor docs for more details) :returns: a single object from the list of matching ``entry_type`` objects :raises: :class:`Bcfg2.Server.Plugin.exceptions.PluginExecutionError` if no matching entries are found """ if matching is None: matching = self.get_matching(metadata) if matching: matching.sort(key=operator.attrgetter("specific")) return matching[0] else: raise PluginExecutionError("No matching entries available for %s " "for %s" % (self.path, metadata.hostname))
[docs] def handle_event(self, event): """ Dispatch a FAM event to the appropriate function or child ``entry_type`` object. This will probably be handled by a call to :func:`update_metadata`, :func:`reset_metadata`, :func:`entry_init`, or to the ``entry_type`` ``handle_event()`` function. :param event: An event that applies to a file handled by this EntrySet :type event: Bcfg2.Server.FileMonitor.Event :returns: None """ action = event.code2str() if event.filename in ['info', 'info.xml', ':info']: if action in ['exists', 'created', 'changed']: self.update_metadata(event) elif action == 'deleted': self.reset_metadata(event) return if action in ['exists', 'created']: self.entry_init(event) else: if event.filename not in self.entries: self.logger.warning("Got %s event for unknown file %s" % (action, event.filename)) if action == 'changed': # received a bogus changed event; warn, but treat # it like a created event self.entry_init(event) return if action == 'changed': self.entries[event.filename].handle_event(event) elif action == 'deleted': del self.entries[event.filename]
[docs] def entry_init(self, event, entry_type=None, specific=None): """ Handle the creation of a file on the filesystem and the creation of an object in this EntrySet to track it. :param event: An event that applies to a file handled by this EntrySet :type event: Bcfg2.Server.FileMonitor.Event :param entry_type: Override the default ``entry_type`` for this EntrySet object and create a different object for this entry. See the constructor docs for more information on ``entry_type``. :type entry_type: callable :param specific: Override the default :attr:`specific` regular expression used by this object with a custom regular expression that will be used to determine the specificity of this entry. :type specific: compiled regular expression object :returns: None :raises: :class:`Bcfg2.Server.Plugin.exceptions.SpecificityError` """ if entry_type is None: entry_type = self.entry_type if event.filename in self.entries: self.logger.warn("Got duplicate add for %s" % event.filename) else: fpath = os.path.join(self.path, event.filename) try: spec = self.specificity_from_filename(event.filename, specific=specific) except SpecificityError: if not self.ignore.match(event.filename): self.logger.error("Could not process filename %s; ignoring" % fpath) return self.entries[event.filename] = entry_type(fpath, spec, self.encoding) self.entries[event.filename].handle_event(event)
[docs] def specificity_from_filename(self, fname, specific=None): """ Construct a :class:`Bcfg2.Server.Plugin.helpers.Specificity` object from a filename and regex. See :attr:`specific` for details on the regex. :param fname: The filename (not full path) of a file that is in this EntrySet's directory. It is not necessary to determine first if the filename matches this EntrySet's basename; that can be done by catching :class:`Bcfg2.Server.Plugin.exceptions.SpecificityError` from this function. :type fname: string :param specific: Override the default :attr:`specific` regular expression used by this object with a custom regular expression that will be used to determine the specificity of this entry. :type specific: compiled regular expression object :returns: Object representing the specificity of the file :rtype: :class:`Bcfg2.Server.Plugin.helpers.Specificity` :raises: :class:`Bcfg2.Server.Plugin.exceptions.SpecificityError` if the regex does not match the filename """ if specific is None: specific = self.specific data = specific.match(fname) if not data: raise SpecificityError(fname) kwargs = {} if data.group('hostname'): kwargs['hostname'] = data.group('hostname') elif data.group('group'): kwargs['group'] = data.group('group') kwargs['prio'] = int(data.group('prio')) else: kwargs['all'] = True if 'delta' in data.groupdict(): kwargs['delta'] = data.group('delta') return Specificity(**kwargs)
[docs] def update_metadata(self, event): """ Process changes to or creation of info, :info, and info.xml files for the EntrySet. :param event: An event that applies to an info handled by this EntrySet :type event: Bcfg2.Server.FileMonitor.Event :returns: None """ fpath = os.path.join(self.path, event.filename) if event.filename == 'info.xml': if not self.infoxml: self.infoxml = InfoXML(fpath) self.infoxml.HandleEvent(event) elif event.filename in [':info', 'info']: for line in open(fpath).readlines(): match = INFO_REGEX.match(line) if not match: self.logger.warning("Failed to match line in %s: %s" % (fpath, line)) continue else: mgd = match.groupdict() for key, value in list(mgd.items()): if value: self.metadata[key] = value if len(self.metadata['mode']) == 3: self.metadata['mode'] = "0%s" % self.metadata['mode']
[docs] def reset_metadata(self, event): """ Reset metadata to defaults if info. :info, or info.xml are removed. :param event: An event that applies to an info handled by this EntrySet :type event: Bcfg2.Server.FileMonitor.Event :returns: None """ if event.filename == 'info.xml': self.infoxml = None elif event.filename in [':info', 'info']: self.metadata = DEFAULT_FILE_METADATA.copy()
[docs] def bind_info_to_entry(self, entry, metadata): """ Shortcut to call :func:`bind_info` with the base info/info.xml for this EntrySet. :param entry: The abstract entry to bind the info to. This will be modified in place :type entry: lxml.etree._Element :param metadata: The client metadata to get info for :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :returns: None """ bind_info(entry, metadata, infoxml=self.infoxml, default=self.metadata)
[docs] def bind_entry(self, entry, metadata): """ Return the single best fully-bound entry from the set of available entries for the specified client. :param entry: The abstract entry to bind the info to :type entry: lxml.etree._Element :param metadata: The client metadata to get info for :type metadata: Bcfg2.Server.Plugins.Metadata.ClientMetadata :returns: lxml.etree._Element - the fully-bound entry """ self.bind_info_to_entry(entry, metadata) return self.best_matching(metadata).bind_entry(entry, metadata)
[docs]class GroupSpool(Plugin, Generator): """ A GroupSpool is a collection of :class:`Bcfg2.Server.Plugin.helpers.EntrySet` objects -- i.e., a directory tree, each directory in which may contain files that are specific to groups/clients/etc. """ #: ``filename_pattern`` is used as the ``basename`` argument to the #: :attr:`es_cls` callable. It may or may not be a regex, #: depending on the :attr:`EntrySet.basename_is_regex` setting. filename_pattern = "" #: ``es_child_cls`` is a callable that will be used as the #: ``entry_type`` argument to the :attr:`es_cls` callable. It must #: return objects that will represent individual files in the #: GroupSpool. For instance, #: :class:`Bcfg2.Server.Plugin.helpers.SpecificData`. es_child_cls = object #: ``es_cls`` is a callable that must return objects that will be #: used to represent directories (i.e., sets of entries) within the #: GroupSpool. E.g., #: :class:`Bcfg2.Server.Plugin.helpers.EntrySet`. The returned #: object must implement a callable called ``bind_entry`` that has #: the same signature as :attr:`EntrySet.bind_entry`. es_cls = EntrySet #: The entry type (i.e., the XML tag) handled by this GroupSpool #: object. entry_type = 'Path' def __init__(self, core, datastore): Plugin.__init__(self, core, datastore) Generator.__init__(self) #: See :class:`Bcfg2.Server.Plugins.interfaces.Generator` for #: details on the Entries attribute. self.Entries[self.entry_type] = {} #: ``entries`` is a dict whose keys are :func:`event_id` return #: values and whose values are :attr:`es_cls` objects. It ties #: the directories handled by this GroupSpools to the #: :attr:`es_cls` objects that handle each directory. self.entries = {} self.handles = {} self.AddDirectoryMonitor('') self.encoding = core.setup['encoding'] __init__.__doc__ = Plugin.__init__.__doc__
[docs] def add_entry(self, event): """ This method handles two functions: * Adding a new entry of type :attr:`es_cls` to track a new directory. * Passing off an event on a file to the correct entry object to handle it. :param event: An event that applies to a file or directory handled by this GroupSpool :type event: Bcfg2.Server.FileMonitor.Event :returns: None """ epath = self.event_path(event) ident = self.event_id(event) if os.path.isdir(epath): self.AddDirectoryMonitor(epath[len(self.data):]) if ident not in self.entries and os.path.isfile(epath): dirpath = self.data + ident self.entries[ident] = self.es_cls(self.filename_pattern, dirpath, self.es_child_cls, self.encoding) self.Entries[self.entry_type][ident] = \ self.entries[ident].bind_entry if not os.path.isdir(epath): # do not pass through directory events self.entries[ident].handle_event(event)
[docs] def event_path(self, event): """ Return the full path to the filename affected by an event. :class:`Bcfg2.Server.FileMonitor.Event` objects just contain the filename, not the full path, so this function reconstructs the fill path based on the path to the :attr:`es_cls` object that handles the event. :param event: An event that applies to a file or directory handled by this GroupSpool :type event: Bcfg2.Server.FileMonitor.Event :returns: string """ return os.path.join(self.data, self.handles[event.requestID].lstrip("/"), event.filename)
[docs] def event_id(self, event): """ Return a string that can be used to relate the event unambiguously to a single :attr:`es_cls` object in the :attr:`entries` dict. In practice, this means: * If the event is on a directory, ``event_id`` returns the full path to the directory. * If the event is on a file, ``event_id`` returns the full path to the directory the file is in. :param event: An event that applies to a file or directory handled by this GroupSpool :type event: Bcfg2.Server.FileMonitor.Event :returns: string """ epath = self.event_path(event) if os.path.isdir(epath): return os.path.join(self.handles[event.requestID].lstrip("/"), event.filename) else: return self.handles[event.requestID].rstrip("/")
def set_debug(self, debug): for entry in self.entries.values(): if hasattr(entry, "set_debug"): entry.set_debug(debug) return Plugin.set_debug(self, debug) set_debug.__doc__ = Plugin.set_debug.__doc__
[docs] def HandleEvent(self, event): """ HandleEvent is the event dispatcher for GroupSpool objects. It receives all events and dispatches them the appropriate handling object (e.g., one of the :attr:`es_cls` objects in :attr:`entries`), function (e.g., :func:`add_entry`), or behavior (e.g., deleting an entire entry set). :param event: An event that applies to a file or directory handled by this GroupSpool :type event: Bcfg2.Server.FileMonitor.Event :returns: None """ action = event.code2str() if event.filename[0] == '/': return ident = self.event_id(event) if action in ['exists', 'created']: self.add_entry(event) elif action == 'changed': if ident in self.entries: self.entries[ident].handle_event(event) else: # got a changed event for a file we didn't know # about. go ahead and process this as a 'created', but # warn self.logger.warning("Got changed event for unknown file %s" % ident) self.add_entry(event) elif action == 'deleted': fbase = self.handles[event.requestID] + event.filename if fbase in self.entries: # a directory was deleted del self.entries[fbase] del self.Entries[self.entry_type][fbase] elif ident in self.entries: self.entries[ident].handle_event(event) elif ident not in self.entries: self.logger.warning("Got deleted event for unknown file %s" % ident)
[docs] def AddDirectoryMonitor(self, relative): """ Add a FAM monitor to a new directory and set the appropriate event handler. :param relative: The path to the directory relative to the base data directory of the GroupSpool object. :type relative: string :returns: None """ if not relative.endswith('/'): relative += '/' name = self.data + relative if relative not in list(self.handles.values()): if not os.path.isdir(name): self.logger.error("Failed to open directory %s" % name) return reqid = self.core.fam.AddMonitor(name, self) self.handles[reqid] = relative