"""The option parser."""
import argparse
import os
import sys
from Bcfg2.version import __version__
from Bcfg2.Compat import ConfigParser
from Bcfg2.Options import Option, PathOption, _debug
__all__ = ["setup", "OptionParserException", "Parser", "get_parser",
"new_parser"]
#: The repository option. This is specified here (and imported into
#: :module:`Bcfg2.Options.Common`) rather than vice-versa due to
#: circular imports.
repository = PathOption( # pylint: disable=C0103
'-Q', '--repository', cf=('server', 'repository'),
default='/var/lib/bcfg2', help="Server repository path")
#: A module-level :class:`argparse.Namespace` object that stores all
#: configuration for Bcfg2.
setup = argparse.Namespace(version=__version__, # pylint: disable=C0103
name="Bcfg2",
uri='http://trac.mcs.anl.gov/projects/bcfg2')
[docs]class OptionParserException(Exception):
""" Base exception raised for generic option parser errors """
[docs]class Parser(argparse.ArgumentParser):
""" The Bcfg2 option parser. Most interfaces should not need to
instantiate a parser, but should instead use
:func:`Bcfg2.Options.get_parser` to get the parser that already
exists."""
#: Option for specifying the path to the Bcfg2 config file
configfile = PathOption('-C', '--config',
env="BCFG2_CONFIG_FILE",
help="Path to configuration file",
default="/etc/bcfg2.conf")
#: Verbose version string that is printed if executed with --version
_version_string = "%s %s on Python %s" % (
os.path.basename(sys.argv[0]),
__version__,
".".join(str(v) for v in sys.version_info[0:3]))
#: Builtin options that apply to all commands
options = [configfile,
Option('--version', help="Print the version and exit",
action="version", version=_version_string),
Option('-E', '--encoding', metavar='<encoding>',
default='UTF-8', help="Encoding of config files",
cf=('components', 'encoding'))]
#: Flag used in unit tests to disable actual config file reads
unit_test = False
def __init__(self, **kwargs):
""" See :class:`argparse.ArgumentParser` for a full list of
accepted parameters.
In addition to supporting all arguments and keyword arguments
from :class:`argparse.ArgumentParser`, several additional
keyword arguments are allowed.
:param components: A list of components to add to the parser.
:type components: list
:param namespace: The namespace to store options in. Default
is :attr:`Bcfg2.Options.setup`.
:type namespace: argparse.Namespace
:param add_base_options: Whether or not to add the options in
:attr:`Bcfg2.Options.Parser.options`
to the parser. Setting this to False
is default for subparsers. Default is
True.
:type add_base_options: bool
"""
self._cfp = ConfigParser.ConfigParser()
components = kwargs.pop('components', [])
#: The namespace options will be stored in.
self.namespace = kwargs.pop('namespace', setup)
if self.namespace is None:
self.namespace = setup
add_base_options = kwargs.pop('add_base_options', True)
#: Flag to indicate that this is the pre-parsing 'early' run
#: for important options like database settings that must be
#: loaded before other components can be.
self._early = kwargs.pop('early', False)
if 'add_help' not in kwargs:
kwargs['add_help'] = add_base_options
argparse.ArgumentParser.__init__(self, **kwargs)
#: Whether or not parsing has completed on all current options.
self.parsed = False
#: The argument list that was parsed.
self.argv = None
#: Components that have been added to the parser
self.components = []
#: Options that have been added to the parser
self.option_list = []
self._defaults_set = []
self._config_files = []
if add_base_options:
self.add_component(self)
if components:
for component in components:
self.add_component(component)
def _check_duplicate_cf(self, option):
"""Check for a duplicate config file option."""
[docs] def add_options(self, options):
""" Add an explicit list of options to the parser. When
possible, prefer :func:`Bcfg2.Options.Parser.add_component` to
add a whole component instead."""
_debug("Adding options: %s" % options)
self.parsed = False
for option in options:
if option not in self.option_list:
# check for duplicates
if (hasattr(option, "env") and option.env and
option.env in [o.env for o in self.option_list]):
raise OptionParserException(
"Duplicate environment variable option: %s" %
option.env)
if (hasattr(option, "cf") and option.cf and
option.cf in [o.cf for o in self.option_list]):
raise OptionParserException(
"Duplicate config file option: %s" % (option.cf,))
self.option_list.extend(option.list_options())
option.add_to_parser(self)
for opt in option.list_options():
opt.default_from_config(self._cfp)
self._defaults_set.append(opt)
[docs] def add_component(self, component):
""" Add a component (and all of its options) to the
parser. """
if component not in self.components:
_debug("Adding component %s to %s" % (component, self))
self.components.append(component)
if hasattr(component, "options"):
self.add_options(getattr(component, "options"))
def _set_defaults_from_config(self):
""" Set defaults from the config file for all options that can
come from the config file, but haven't yet had their default
set """
_debug("Setting defaults on all options")
for opt in self.option_list:
if opt not in self._defaults_set:
opt.default_from_config(self._cfp)
self._defaults_set.append(opt)
def _parse_config_options(self):
""" populate the namespace with default values for any options
that aren't already in the namespace (i.e., options without
CLI arguments) """
_debug("Parsing config file-only options")
for opt in self.option_list[:]:
if not opt.args and opt.dest not in self.namespace:
value = opt.default
if value:
for _, action in opt.actions.items():
_debug("Setting config file-only option %s to %s" %
(opt, value))
action(self, self.namespace, value)
else:
_debug("Setting config file-only option %s to %s" %
(opt, value))
setattr(self.namespace, opt.dest, value)
def _finalize(self):
""" Finalize the value of any options that require that
additional post-processing step. (Mostly
:class:`Bcfg2.Options.Actions.ComponentAction` subclasses.)
"""
_debug("Finalizing options")
for opt in self.option_list[:]:
opt.finalize(self.namespace)
def _reset_namespace(self):
""" Delete all options from the namespace except for a few
predefined values and config file options. """
self.parsed = False
_debug("Resetting namespace")
for attr in dir(self.namespace):
if (not attr.startswith("_") and
attr not in ['uri', 'version', 'name'] and
attr not in self._config_files):
_debug("Deleting %s" % attr)
delattr(self.namespace, attr)
def _parse_early_options(self):
"""Parse early options.
Early options are options that need to be parsed before other
options for some reason. These fall into two basic cases:
1. Database options, which need to be parsed so that Django
modules can be imported, since Django configuration is all
done at import-time;
2. The repository (``-Q``) option, so that ``<repository>``
macros in other options can be resolved.
"""
_debug("Option parsing phase 2: Parse early options")
early_opts = argparse.Namespace()
early_parser = Parser(add_help=False, namespace=early_opts,
early=True)
# add the repo option so we can resolve <repository>
# macros
early_parser.add_options([repository])
early_components = []
for component in self.components:
if getattr(component, "parse_first", False):
early_components.append(component)
early_parser.add_component(component)
early_parser.parse(self.argv)
_debug("Fixing up <repository> macros in early options")
for attr_name in dir(early_opts):
if not attr_name.startswith("_"):
attr = getattr(early_opts, attr_name)
if hasattr(attr, "replace"):
setattr(early_opts, attr_name,
attr.replace("<repository>",
early_opts.repository))
_debug("Early parsing complete, calling hooks")
for component in early_components:
if hasattr(component, "component_parsed_hook"):
_debug("Calling component_parsed_hook on %s" % component)
getattr(component, "component_parsed_hook")(early_opts)
_debug("Calling early parsing hooks; early options: %s" %
early_opts)
for option in self.option_list:
option.early_parsing_hook(early_opts)
[docs] def add_config_file(self, dest, cfile, reparse=True):
""" Add a config file, which triggers a full reparse of all
options. """
if dest not in self._config_files:
_debug("Adding new config file %s for %s" % (cfile, dest))
self._reset_namespace()
self._cfp.read([cfile])
self._defaults_set = []
self._set_defaults_from_config()
if reparse:
self._parse_config_options()
self._config_files.append(dest)
[docs] def reparse(self, argv=None):
""" Reparse options after they have already been parsed.
:param argv: The argument list to parse. By default,
:attr:`Bcfg2.Options.Parser.argv` is reused.
(I.e., the argument list that was initially
parsed.)
:type argv: list
"""
_debug("Reparsing all options")
self._reset_namespace()
self.parse(argv or self.argv)
[docs] def parse(self, argv=None):
""" Parse options.
:param argv: The argument list to parse. By default,
``sys.argv[1:]`` is used. This is stored in
:attr:`Bcfg2.Options.Parser.argv` for reuse by
:func:`Bcfg2.Options.Parser.reparse`.
:type argv: list
"""
_debug("Parsing options")
if argv is None:
argv = sys.argv[1:] # pragma: nocover
if self.parsed and self.argv == argv:
_debug("Returning already parsed namespace")
return self.namespace
self.argv = argv
# phase 1: get and read config file
_debug("Option parsing phase 1: Get and read main config file")
bootstrap_parser = argparse.ArgumentParser(add_help=False)
self.configfile.add_to_parser(bootstrap_parser)
self.configfile.default_from_config(self._cfp)
bootstrap = bootstrap_parser.parse_known_args(args=self.argv)[0]
# check whether the specified bcfg2.conf exists
if not self.unit_test and not os.path.exists(bootstrap.config):
self.error("Could not read %s" % bootstrap.config)
self.add_config_file(self.configfile.dest, bootstrap.config,
reparse=False)
# phase 2: re-parse command line for early options; currently,
# that's database options
if not self._early:
self._parse_early_options()
else:
_debug("Skipping parsing phase 2 in early mode")
# phase 3: re-parse command line, loading additional
# components, until all components have been loaded. On each
# iteration, set defaults from config file/environment
# variables
_debug("Option parsing phase 3: Main parser loop")
# _set_defaults_from_config must be called before _parse_config_options
# This is due to a tricky interaction between the two methods:
#
# (1) _set_defaults_from_config does what its name implies, it updates
# the "default" property of each Option based on the value that exists
# in the config.
#
# (2) _parse_config_options will look at each option and set it to the
# default value that is _currently_ defined. If the option does not
# exist in the namespace, it will be added. The method carefully
# avoids overwriting the value of an option that is already defined in
# the namespace.
#
# Thus, if _set_defaults_from_config has not been called yet when
# _parse_config_options is called, all config file options will get set
# to their hardcoded defaults. This process defines the options in the
# namespace and _parse_config_options will never look at them again.
#
# we have to do the parsing in two loops: first, we squeeze as
# much data out of the config file as we can to ensure that
# all config file settings are read before we use any default
# values. then we can start looking at the command line.
while not self.parsed:
self.parsed = True
self._set_defaults_from_config()
self._parse_config_options()
self.parsed = False
remaining = []
while not self.parsed:
self.parsed = True
_debug("Parsing known arguments")
try:
_, remaining = self.parse_known_args(args=self.argv,
namespace=self.namespace)
except OptionParserException:
self.error(sys.exc_info()[1])
self._set_defaults_from_config()
self._parse_config_options()
self._finalize()
if len(remaining) and not self._early:
self.error("Unknown options: %s" % " ".join(remaining))
# phase 4: call post-parsing hooks
if not self._early:
_debug("Option parsing phase 4: Call hooks")
for component in self.components:
if hasattr(component, "options_parsed_hook"):
_debug("Calling post-parsing hook on %s" % component)
getattr(component, "options_parsed_hook")()
return self.namespace
#: A module-level :class:`Bcfg2.Options.Parser` object that is used
#: for all parsing
_parser = Parser() # pylint: disable=C0103
def new_parser():
"""Create a new :class:`Bcfg2.Options.Parser` object.
The new object can be retrieved with
:func:`Bcfg2.Options.get_parser`. This is useful for unit
testing.
"""
global _parser
_parser = Parser()
[docs]def get_parser(description=None, components=None, namespace=None):
"""Get an existing :class:`Bcfg2.Options.Parser` object.
A Parser is created at the module level when :mod:`Bcfg2.Options`
is imported. If any arguments are given, then the existing parser
is modified before being returned.
:param description: Set the parser description
:type description: string
:param components: Load the given components in the parser
:type components: list
:param namespace: Use the given namespace instead of
:attr:`Bcfg2.Options.setup`
:type namespace: argparse.Namespace
:returns: Bcfg2.Options.Parser object
"""
if Parser.unit_test:
return Parser(description=description, components=components,
namespace=namespace)
elif (description or components or namespace):
if description:
_parser.description = description
if components is not None:
for component in components:
_parser.add_component(component)
if namespace:
_parser.namespace = namespace
return _parser
