""" Base classes for Lint plugins and error handling """
import copy
import fcntl
import fnmatch
import glob
import logging
import os
import struct
import sys
import termios
import textwrap
import time
import lxml.etree
import Bcfg2.Options
import Bcfg2.Server.Core
import Bcfg2.Server.Plugins
from Bcfg2.Compat import walk_packages
from Bcfg2.Options import _debug
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 (IOError, struct.error):
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 IOError:
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 """
#: Name of the matching server plugin or None if there is no
#: matching one. If this is None the lint plugin will only loaded
#: by default if the matching server plugin is enabled, too.
__serverplugin__ = None
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] @classmethod
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] def list_matching_files(self, path):
"""list all files matching the path in self.files or the bcfg2 repo."""
if self.files is not None:
return fnmatch.filter(self.files, os.path.join('*', path))
else:
return glob.glob(os.path.join(Bcfg2.Options.setup.repository,
path))
[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):
""" Option parser action to load lint plugins """
bases = ['Bcfg2.Server.Lint']
[docs]class LintPluginOption(Bcfg2.Options.Option):
""" Option class for the lint_plugins """
[docs] def early_parsing_hook(self, namespace):
"""
We want a usefull default for the enabled lint plugins.
Therfore we use all importable plugins, that either pertain
with enabled server plugins or that has no matching plugin.
"""
plugins = [p.__name__ for p in namespace.plugins]
for loader, name, _is_pkg in walk_packages(path=__path__):
try:
module = loader.find_module(name).load_module(name)
plugin = getattr(module, name)
if plugin.__serverplugin__ is None or \
plugin.__serverplugin__ in plugins:
_debug("Automatically adding lint plugin %s" %
plugin.__name__)
self.default.append(plugin.__name__)
except ImportError:
pass
class _EarlyOptions(object):
""" We need the server.plugins options in an early parsing hook
for determining the default value for the lint_plugins. So we
create a component that is parsed before the other options. """
parse_first = True
options = [Bcfg2.Options.Common.plugins]
[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'),
LintPluginOption(
"--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, _EarlyOptions])
parser.parse()
self.logger = logging.getLogger(parser.prog)
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()
try:
core.load_plugins()
core.block_for_fam_events(handle_events=True)
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
