Source code for Bcfg2.Server.Lint

""" Base classes for Lint plugins and error handling """

import os
import sys
import time
import copy
import fcntl
import struct
import termios
import logging
import textwrap
import lxml.etree
import Bcfg2.Options
import Bcfg2.Server.Core
import Bcfg2.Server.Plugins
from Bcfg2.Compat import walk_packages

def _ioctl_GWINSZ(fd):  # pylint: disable=C0103
    """ get a tuple of (height, width) giving the size of the window
    from the given file descriptor """
        return struct.unpack('hh', fcntl.ioctl(fd, termios.TIOCGWINSZ, '1234'))
    except:  # pylint: disable=W0702
        return None

[docs]def get_termsize(): """ get a tuple of (width, height) giving the size of the terminal """ if not sys.stdout.isatty(): return None dims = _ioctl_GWINSZ(0) or _ioctl_GWINSZ(1) or _ioctl_GWINSZ(2) if not dims: try: fd =, os.O_RDONLY) dims = _ioctl_GWINSZ(fd) os.close(fd) except: # pylint: disable=W0702 pass if not dims: try: dims = (os.environ['LINES'], os.environ['COLUMNS']) except KeyError: return None return int(dims[1]), int(dims[0])
[docs]class Plugin(object): """ Base class for all bcfg2-lint plugins """ options = [Bcfg2.Options.Common.repository] def __init__(self, errorhandler=None, files=None): """ :param errorhandler: A :class:`Bcfg2.Server.Lint.ErrorHandler` that will be used to handle lint errors. If one is not provided, a new one will be instantiated. :type errorhandler: Bcfg2.Server.Lint.ErrorHandler :param files: A list of files to run bcfg2-lint against. (See the bcfg2-lint ``--stdin`` option.) :type files: list of strings """ #: The list of files that bcfg2-lint should be run against self.files = files self.logger = logging.getLogger('bcfg2-lint') if errorhandler is None: #: The error handler self.errorhandler = ErrorHandler() else: self.errorhandler = errorhandler self.errorhandler.RegisterErrors(self.Errors())
[docs] def Run(self): """ Run the plugin. Must be overloaded by child classes. """ raise NotImplementedError
[docs] def Errors(cls): """ Returns a dict of errors the plugin supplies, in a format suitable for passing to :func:`Bcfg2.Server.Lint.ErrorHandler.RegisterErrors`. Must be overloaded by child classes. :returns: dict """ raise NotImplementedError
[docs] def HandlesFile(self, fname): """ Returns True if the given file should be handled by the plugin according to :attr:`Bcfg2.Server.Lint.Plugin.files`, False otherwise. """ return (self.files is None or fname in self.files or os.path.join(Bcfg2.Options.setup.repository, fname) in self.files or os.path.abspath(fname) in self.files or os.path.abspath(os.path.join(Bcfg2.Options.setup.repository, fname)) in self.files)
[docs] def LintError(self, err, msg): """ Raise an error from the lint process. :param err: The name of the error being raised. This name must be a key in the dict returned by :func:`Bcfg2.Server.Lint.Plugin.Errors`. :type err: string :param msg: The freeform message to display to the end user. :type msg: string """ self.errorhandler.dispatch(err, msg)
[docs] def RenderXML(self, element, keep_text=False): """ Render an XML element for error output. This prefixes the line number and removes children for nicer display. :param element: The element to render :type element: lxml.etree._Element :param keep_text: Do not discard text content from the element for display :type keep_text: boolean """ xml = None if len(element) or element.text: el = copy.copy(element) if el.text and not keep_text: el.text = '...' for child in el.iterchildren(): el.remove(child) xml = lxml.etree.tostring( el, xml_declaration=False).decode("UTF-8").strip() else: xml = lxml.etree.tostring( element, xml_declaration=False).decode("UTF-8").strip() return " line %s: %s" % (element.sourceline, xml)
[docs]class ErrorHandler(object): """ A class to handle errors for bcfg2-lint plugins """ def __init__(self, errors=None): """ :param errors: An initial dict of errors to register :type errors: dict """ #: The number of errors passed to this error handler self.errors = 0 #: The number of warnings passed to this error handler self.warnings = 0 self.logger = logging.getLogger('bcfg2-lint') termsize = get_termsize() if termsize is not None and termsize[0] > 0: twrap = textwrap.TextWrapper(initial_indent=" ", subsequent_indent=" ", width=termsize[0]) #: A function to wrap text to the width of the terminal self._wrapper = twrap.wrap else: self._wrapper = lambda s: [s] #: A dict of registered errors self.errortypes = dict() if errors is not None: self.RegisterErrors(dict(errors.items()))
[docs] def RegisterErrors(self, errors): """ Register a dict of errors that a plugin may raise. The keys of the dict are short strings that describe each error; the values are the default error handling for that error ("error", "warning", or "silent"). :param errors: The error dict :type errors: dict """ for err, action in errors.items(): if err not in self.errortypes: if "warn" in action: self.errortypes[err] = self.warn elif "err" in action: self.errortypes[err] = self.error else: self.errortypes[err] = self.debug
[docs] def dispatch(self, err, msg): """ Dispatch an error to the correct handler. :param err: The name of the error being raised. This name must be a key in :attr:`Bcfg2.Server.Lint.ErrorHandler.errortypes`, the dict of registered errors. :type err: string :param msg: The freeform message to display to the end user. :type msg: string """ if err in self.errortypes: self.errortypes[err](msg) self.logger.debug(" (%s)" % err) else: # assume that it's an error, but complain self.error(msg) self.logger.warning("Unknown error %s" % err)
[docs] def error(self, msg): """ Log an error condition. :param msg: The freeform message to display to the end user. :type msg: string """ self.errors += 1 self._log(msg, self.logger.error, prefix="ERROR: ")
[docs] def warn(self, msg): """ Log a warning condition. :param msg: The freeform message to display to the end user. :type msg: string """ self.warnings += 1 self._log(msg, self.logger.warning, prefix="WARNING: ")
[docs] def debug(self, msg): """ Log a silent/debug condition. :param msg: The freeform message to display to the end user. :type msg: string """ self._log(msg, self.logger.debug)
def _log(self, msg, logfunc, prefix=""): """ Generic log function that logs a message with the given function after wrapping it for the terminal width. """ # a message may itself consist of multiple lines. wrap() will # elide them all into a single paragraph, which we don't want. # so we split the message into its paragraphs and wrap each # paragraph individually. this means, unfortunately, that we # lose textwrap's built-in initial indent functionality, # because we want to only treat the very first line of the # first paragraph specially. so we do some silliness. rawlines = msg.splitlines() firstline = True for rawline in rawlines: lines = self._wrapper(rawline) for line in lines: if firstline: logfunc(prefix + line.lstrip()) firstline = False else: logfunc(line)
[docs]class ServerlessPlugin(Plugin): # pylint: disable=W0223 """ Base class for bcfg2-lint plugins that are run before the server starts up (i.e., plugins that check things that may prevent the server from starting up). """ pass
[docs]class ServerPlugin(Plugin): # pylint: disable=W0223 """ Base class for bcfg2-lint plugins that check things that require the running Bcfg2 server. """ def __init__(self, core, errorhandler=None, files=None): """ :param core: The Bcfg2 server core :type core: Bcfg2.Server.Core.BaseCore :param errorhandler: A :class:`Bcfg2.Server.Lint.ErrorHandler` that will be used to handle lint errors. If one is not provided, a new one will be instantiated. :type errorhandler: Bcfg2.Server.Lint.ErrorHandler :param files: A list of files to run bcfg2-lint against. (See the bcfg2-lint ``--stdin`` option.) :type files: list of strings """ Plugin.__init__(self, errorhandler=errorhandler, files=files) #: The server core self.core = core self.logger = self.core.logger #: The metadata plugin self.metadata = self.core.metadata
[docs]class LintPluginAction(Bcfg2.Options.ComponentAction): """ We want to load all lint plugins that pertain to server plugins. In order to do this, we hijack the __call__() method of this action and add all of the server plugins on the fly """ bases = ['Bcfg2.Server.Lint'] def __call__(self, parser, namespace, values, option_string=None): plugins = getattr(Bcfg2.Options.setup, "plugins", []) for lint_plugin in walk_packages(path=__path__): if lint_plugin[1] in plugins: values.append(lint_plugin[1]) Bcfg2.Options.ComponentAction.__call__(self, parser, namespace, values, option_string)
[docs]class CLI(object): """ The bcfg2-lint CLI """ options = Bcfg2.Server.Core.Core.options + [ Bcfg2.Options.PathOption( '--lint-config', default='/etc/bcfg2-lint.conf', action=Bcfg2.Options.ConfigFileAction, help='Specify bcfg2-lint configuration file'), Bcfg2.Options.Option( "--lint-plugins", cf=('lint', 'plugins'), default=[], type=Bcfg2.Options.Types.comma_list, action=LintPluginAction, help='bcfg2-lint plugin list'), Bcfg2.Options.BooleanOption( '--list-errors', help='Show error handling'), Bcfg2.Options.BooleanOption( '--stdin', help='Operate on a list of files supplied on stdin'), Bcfg2.Options.Option( cf=("errors", '*'), dest="lint_errors", help="How to handle bcfg2-lint errors")] def __init__(self): parser = Bcfg2.Options.get_parser( description="Manage a running Bcfg2 server", components=[self]) parser.parse() self.logger = logging.getLogger(parser.prog) # automatically add Lint plugins for loaded server plugins for plugin in Bcfg2.Options.setup.plugins: try: Bcfg2.Options.setup.lint_plugins.append( getattr( __import__("Bcfg2.Server.Lint.%s" % plugin.__name__, fromlist=[plugin.__name__]), plugin.__name__)) self.logger.debug("Automatically adding lint plugin %s" % plugin.__name__) except ImportError: # no lint plugin for this server plugin self.logger.debug("No lint plugin for %s" % plugin.__name__) except AttributeError: self.logger.error("Failed to load plugin %s: %s" % (plugin.__name__, sys.exc_info()[1])) self.logger.debug("Running lint with plugins: %s" % [p.__name__ for p in Bcfg2.Options.setup.lint_plugins]) if Bcfg2.Options.setup.stdin: self.files = [s.strip() for s in sys.stdin.readlines()] else: self.files = None self.errorhandler = self.get_errorhandler() self.serverlessplugins = [] self.serverplugins = [] for plugin in Bcfg2.Options.setup.lint_plugins: if issubclass(plugin, ServerPlugin): self.serverplugins.append(plugin) else: self.serverlessplugins.append(plugin)
[docs] def run(self): """ Run bcfg2-lint """ if Bcfg2.Options.setup.list_errors: for plugin in self.serverplugins + self.serverlessplugins: self.errorhandler.RegisterErrors(getattr(plugin, 'Errors')()) print("%-35s %-35s" % ("Error name", "Handler")) for err, handler in self.errorhandler.errortypes.items(): print("%-35s %-35s" % (err, handler.__name__)) return 0 if not self.serverplugins and not self.serverlessplugins: self.logger.error("No lint plugins loaded!") return 1 self.run_serverless_plugins() if self.serverplugins: if self.errorhandler.errors: # it would be swell if we could try to start the server # even if there were errors with the serverless plugins, # but since XML parsing errors occur in the FAM thread # (not in the core server thread), there's no way we can # start the server and try to catch exceptions -- # bcfg2-lint isn't in the same stack as the exceptions. # so we're forced to assume that a serverless plugin error # will prevent the server from starting print("Serverless plugins encountered errors, skipping server " "plugins") else: self.run_server_plugins() if (self.errorhandler.errors or self.errorhandler.warnings or Bcfg2.Options.setup.verbose): print("%d errors" % self.errorhandler.errors) print("%d warnings" % self.errorhandler.warnings) if self.errorhandler.errors: return 2 elif self.errorhandler.warnings: return 3 else: return 0
[docs] def get_errorhandler(self): """ get a Bcfg2.Server.Lint.ErrorHandler object """ return Bcfg2.Server.Lint.ErrorHandler( errors=Bcfg2.Options.setup.lint_errors)
[docs] def run_serverless_plugins(self): """ Run serverless plugins """ self.logger.debug("Running serverless plugins: %s" % [p.__name__ for p in self.serverlessplugins]) for plugin in self.serverlessplugins: self.logger.debug(" Running %s" % plugin.__name__) plugin(files=self.files, errorhandler=self.errorhandler).Run()
[docs] def run_server_plugins(self): """ run plugins that require a running server to run """ core = Bcfg2.Server.Core.Core() core.load_plugins() core.block_for_fam_events(handle_events=True) try: self.logger.debug("Running server plugins: %s" % [p.__name__ for p in self.serverplugins]) for plugin in self.serverplugins: self.logger.debug(" Running %s" % plugin.__name__) plugin(core, files=self.files, errorhandler=self.errorhandler).Run() finally: core.shutdown()
def _run_plugin(self, plugin, args=None): """ Run a single bcfg2-lint plugin """ if args is None: args = [] start = time.time() # python 2.5 doesn't support mixing *magic and keyword arguments kwargs = dict(files=self.files, errorhandler=self.errorhandler) rv = plugin(*args, **kwargs).Run() self.logger.debug(" Ran %s in %0.2f seconds" % (plugin.__name__, time.time() - start)) return rv