""" 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 """
try:
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.open(os.ctermid(), 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
@classmethod
[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
