# vim: tabstop=4 shiftwidth=4 softtabstop=4 # Copyright 2012 Red Hat, Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. r""" Configuration options which may be set on the command line or in config files. The schema for each option is defined using the Opt sub-classes, e.g.: :: common_opts = [ cfg.StrOpt('bind_host', default='0.0.0.0', help='IP address to listen on'), cfg.IntOpt('bind_port', default=9292, help='Port number to listen on') ] Options can be strings, integers, floats, booleans, lists or 'multi strings':: enabled_apis_opt = cfg.ListOpt('enabled_apis', default=['ec2', 'osapi_compute'], help='List of APIs to enable by default') DEFAULT_EXTENSIONS = [ 'nova.api.openstack.compute.contrib.standard_extensions' ] osapi_compute_extension_opt = cfg.MultiStrOpt('osapi_compute_extension', default=DEFAULT_EXTENSIONS) Option schemas are registered with the config manager at runtime, but before the option is referenced:: class ExtensionManager(object): enabled_apis_opt = cfg.ListOpt(...) def __init__(self, conf): self.conf = conf self.conf.register_opt(enabled_apis_opt) ... def _load_extensions(self): for ext_factory in self.conf.osapi_compute_extension: .... A common usage pattern is for each option schema to be defined in the module or class which uses the option:: opts = ... def add_common_opts(conf): conf.register_opts(opts) def get_bind_host(conf): return conf.bind_host def get_bind_port(conf): return conf.bind_port An option may optionally be made available via the command line. Such options must registered with the config manager before the command line is parsed (for the purposes of --help and CLI arg validation):: cli_opts = [ cfg.BoolOpt('verbose', short='v', default=False, help='Print more verbose output'), cfg.BoolOpt('debug', short='d', default=False, help='Print debugging output'), ] def add_common_opts(conf): conf.register_cli_opts(cli_opts) The config manager has two CLI options defined by default, --config-file and --config-dir:: class ConfigOpts(object): def __call__(self, ...): opts = [ MultiStrOpt('config-file', ...), StrOpt('config-dir', ...), ] self.register_cli_opts(opts) Option values are parsed from any supplied config files using openstack.common.iniparser. If none are specified, a default set is used e.g. glance-api.conf and glance-common.conf:: glance-api.conf: [DEFAULT] bind_port = 9292 glance-common.conf: [DEFAULT] bind_host = 0.0.0.0 Option values in config files override those on the command line. Config files are parsed in order, with values in later files overriding those in earlier files. The parsing of CLI args and config files is initiated by invoking the config manager e.g.:: conf = ConfigOpts() conf.register_opt(BoolOpt('verbose', ...)) conf(sys.argv[1:]) if conf.verbose: ... Options can be registered as belonging to a group:: rabbit_group = cfg.OptGroup(name='rabbit', title='RabbitMQ options') rabbit_host_opt = cfg.StrOpt('host', default='localhost', help='IP/hostname to listen on'), rabbit_port_opt = cfg.IntOpt('port', default=5672, help='Port number to listen on') def register_rabbit_opts(conf): conf.register_group(rabbit_group) # options can be registered under a group in either of these ways: conf.register_opt(rabbit_host_opt, group=rabbit_group) conf.register_opt(rabbit_port_opt, group='rabbit') If it no group attributes are required other than the group name, the group need not be explicitly registered e.g. def register_rabbit_opts(conf): # The group will automatically be created, equivalent calling:: # conf.register_group(OptGroup(name='rabbit')) conf.register_opt(rabbit_port_opt, group='rabbit') If no group is specified, options belong to the 'DEFAULT' section of config files:: glance-api.conf: [DEFAULT] bind_port = 9292 ... [rabbit] host = localhost port = 5672 use_ssl = False userid = guest password = guest virtual_host = / Command-line options in a group are automatically prefixed with the group name:: --rabbit-host localhost --rabbit-port 9999 Option values in the default group are referenced as attributes/properties on the config manager; groups are also attributes on the config manager, with attributes for each of the options associated with the group:: server.start(app, conf.bind_port, conf.bind_host, conf) self.connection = kombu.connection.BrokerConnection( hostname=conf.rabbit.host, port=conf.rabbit.port, ...) Option values may reference other values using PEP 292 string substitution:: opts = [ cfg.StrOpt('state_path', default=os.path.join(os.path.dirname(__file__), '../'), help='Top-level directory for maintaining nova state'), cfg.StrOpt('sqlite_db', default='nova.sqlite', help='file name for sqlite'), cfg.StrOpt('sql_connection', default='sqlite:///$state_path/$sqlite_db', help='connection string for sql database'), ] Note that interpolation can be avoided by using '$$'. Options may be declared as required so that an error is raised if the user does not supply a value for the option. Options may be declared as secret so that their values are not leaked into log files:: opts = [ cfg.StrOpt('s3_store_access_key', secret=True), cfg.StrOpt('s3_store_secret_key', secret=True), ... ] This module also contains a global instance of the ConfigOpts class in order to support a common usage pattern in OpenStack:: from quantum.openstack.common import cfg opts = [ cfg.StrOpt('bind_host', default='0.0.0.0'), cfg.IntOpt('bind_port', default=9292), ] CONF = cfg.CONF CONF.register_opts(opts) def start(server, app): server.start(app, CONF.bind_port, CONF.bind_host) Positional command line arguments are supported via a 'positional' Opt constructor argument:: >>> conf = ConfigOpts() >>> conf.register_cli_opt(MultiStrOpt('bar', positional=True)) True >>> conf(['a', 'b']) >>> conf.bar ['a', 'b'] It is also possible to use argparse "sub-parsers" to parse additional command line arguments using the SubCommandOpt class: >>> def add_parsers(subparsers): ... list_action = subparsers.add_parser('list') ... list_action.add_argument('id') ... >>> conf = ConfigOpts() >>> conf.register_cli_opt(SubCommandOpt('action', handler=add_parsers)) True >>> conf(args=['list', '10']) >>> conf.action.name, conf.action.id ('list', '10') """ import argparse import collections import copy import functools import glob import os import string import sys from quantum.openstack.common import iniparser class Error(Exception): """Base class for cfg exceptions.""" def __init__(self, msg=None): self.msg = msg def __str__(self): return self.msg class ArgsAlreadyParsedError(Error): """Raised if a CLI opt is registered after parsing.""" def __str__(self): ret = "arguments already parsed" if self.msg: ret += ": " + self.msg return ret class NoSuchOptError(Error, AttributeError): """Raised if an opt which doesn't exist is referenced.""" def __init__(self, opt_name, group=None): self.opt_name = opt_name self.group = group def __str__(self): if self.group is None: return "no such option: %s" % self.opt_name else: return "no such option in group %s: %s" % (self.group.name, self.opt_name) class NoSuchGroupError(Error): """Raised if a group which doesn't exist is referenced.""" def __init__(self, group_name): self.group_name = group_name def __str__(self): return "no such group: %s" % self.group_name class DuplicateOptError(Error): """Raised if multiple opts with the same name are registered.""" def __init__(self, opt_name): self.opt_name = opt_name def __str__(self): return "duplicate option: %s" % self.opt_name class RequiredOptError(Error): """Raised if an option is required but no value is supplied by the user.""" def __init__(self, opt_name, group=None): self.opt_name = opt_name self.group = group def __str__(self): if self.group is None: return "value required for option: %s" % self.opt_name else: return "value required for option: %s.%s" % (self.group.name, self.opt_name) class TemplateSubstitutionError(Error): """Raised if an error occurs substituting a variable in an opt value.""" def __str__(self): return "template substitution error: %s" % self.msg class ConfigFilesNotFoundError(Error): """Raised if one or more config files are not found.""" def __init__(self, config_files): self.config_files = config_files def __str__(self): return ('Failed to read some config files: %s' % string.join(self.config_files, ',')) class ConfigFileParseError(Error): """Raised if there is an error parsing a config file.""" def __init__(self, config_file, msg): self.config_file = config_file self.msg = msg def __str__(self): return 'Failed to parse %s: %s' % (self.config_file, self.msg) class ConfigFileValueError(Error): """Raised if a config file value does not match its opt type.""" pass def _fixpath(p): """Apply tilde expansion and absolutization to a path.""" return os.path.abspath(os.path.expanduser(p)) def _get_config_dirs(project=None): """Return a list of directors where config files may be located. :param project: an optional project name If a project is specified, following directories are returned:: ~/.${project}/ ~/ /etc/${project}/ /etc/ Otherwise, these directories:: ~/ /etc/ """ cfg_dirs = [ _fixpath(os.path.join('~', '.' + project)) if project else None, _fixpath('~'), os.path.join('/etc', project) if project else None, '/etc' ] return filter(bool, cfg_dirs) def _search_dirs(dirs, basename, extension=""): """Search a list of directories for a given filename. Iterator over the supplied directories, returning the first file found with the supplied name and extension. :param dirs: a list of directories :param basename: the filename, e.g. 'glance-api' :param extension: the file extension, e.g. '.conf' :returns: the path to a matching file, or None """ for d in dirs: path = os.path.join(d, '%s%s' % (basename, extension)) if os.path.exists(path): return path def find_config_files(project=None, prog=None, extension='.conf'): """Return a list of default configuration files. :param project: an optional project name :param prog: the program name, defaulting to the basename of sys.argv[0] :param extension: the type of the config file We default to two config files: [${project}.conf, ${prog}.conf] And we look for those config files in the following directories:: ~/.${project}/ ~/ /etc/${project}/ /etc/ We return an absolute path for (at most) one of each the default config files, for the topmost directory it exists in. For example, if project=foo, prog=bar and /etc/foo/foo.conf, /etc/bar.conf and ~/.foo/bar.conf all exist, then we return ['/etc/foo/foo.conf', '~/.foo/bar.conf'] If no project name is supplied, we only look for ${prog.conf}. """ if prog is None: prog = os.path.basename(sys.argv[0]) cfg_dirs = _get_config_dirs(project) config_files = [] if project: config_files.append(_search_dirs(cfg_dirs, project, extension)) config_files.append(_search_dirs(cfg_dirs, prog, extension)) return filter(bool, config_files) def _is_opt_registered(opts, opt): """Check whether an opt with the same name is already registered. The same opt may be registered multiple times, with only the first registration having any effect. However, it is an error to attempt to register a different opt with the same name. :param opts: the set of opts already registered :param opt: the opt to be registered :returns: True if the opt was previously registered, False otherwise :raises: DuplicateOptError if a naming conflict is detected """ if opt.dest in opts: if opts[opt.dest]['opt'] != opt: raise DuplicateOptError(opt.name) return True else: return False def set_defaults(opts, **kwargs): for opt in opts: if opt.dest in kwargs: opt.default = kwargs[opt.dest] break class Opt(object): """Base class for all configuration options. An Opt object has no public methods, but has a number of public string properties: name: the name of the option, which may include hyphens dest: the (hyphen-less) ConfigOpts property which contains the option value short: a single character CLI option name default: the default value of the option positional: True if the option is a positional CLI argument metavar: the name shown as the argument to a CLI option in --help output help: an string explaining how the options value is used """ multi = False def __init__(self, name, dest=None, short=None, default=None, positional=False, metavar=None, help=None, secret=False, required=False, deprecated_name=None): """Construct an Opt object. The only required parameter is the option's name. However, it is common to also supply a default and help string for all options. :param name: the option's name :param dest: the name of the corresponding ConfigOpts property :param short: a single character CLI option name :param default: the default value of the option :param positional: True if the option is a positional CLI argument :param metavar: the option argument to show in --help :param help: an explanation of how the option is used :param secret: true iff the value should be obfuscated in log output :param required: true iff a value must be supplied for this option :param deprecated_name: deprecated name option. Acts like an alias """ self.name = name if dest is None: self.dest = self.name.replace('-', '_') else: self.dest = dest self.short = short self.default = default self.positional = positional self.metavar = metavar self.help = help self.secret = secret self.required = required if deprecated_name is not None: self.deprecated_name = deprecated_name.replace('-', '_') else: self.deprecated_name = None def __ne__(self, another): return vars(self) != vars(another) def _get_from_config_parser(self, cparser, section): """Retrieves the option value from a MultiConfigParser object. This is the method ConfigOpts uses to look up the option value from config files. Most opt types override this method in order to perform type appropriate conversion of the returned value. :param cparser: a ConfigParser object :param section: a section name """ return self._cparser_get_with_deprecated(cparser, section) def _cparser_get_with_deprecated(self, cparser, section): """If cannot find option as dest try deprecated_name alias.""" if self.deprecated_name is not None: return cparser.get(section, [self.dest, self.deprecated_name]) return cparser.get(section, [self.dest]) def _add_to_cli(self, parser, group=None): """Makes the option available in the command line interface. This is the method ConfigOpts uses to add the opt to the CLI interface as appropriate for the opt type. Some opt types may extend this method, others may just extend the helper methods it uses. :param parser: the CLI option parser :param group: an optional OptGroup object """ container = self._get_argparse_container(parser, group) kwargs = self._get_argparse_kwargs(group) prefix = self._get_argparse_prefix('', group) self._add_to_argparse(container, self.name, self.short, kwargs, prefix, self.positional, self.deprecated_name) def _add_to_argparse(self, container, name, short, kwargs, prefix='', positional=False, deprecated_name=None): """Add an option to an argparse parser or group. :param container: an argparse._ArgumentGroup object :param name: the opt name :param short: the short opt name :param kwargs: the keyword arguments for add_argument() :param prefix: an optional prefix to prepend to the opt name :param position: whether the optional is a positional CLI argument :raises: DuplicateOptError if a naming confict is detected """ def hyphen(arg): return arg if not positional else '' args = [hyphen('--') + prefix + name] if short: args.append(hyphen('-') + short) if deprecated_name: args.append(hyphen('--') + prefix + deprecated_name) try: container.add_argument(*args, **kwargs) except argparse.ArgumentError as e: raise DuplicateOptError(e) def _get_argparse_container(self, parser, group): """Returns an argparse._ArgumentGroup. :param parser: an argparse.ArgumentParser :param group: an (optional) OptGroup object :returns: an argparse._ArgumentGroup if group is given, else parser """ if group is not None: return group._get_argparse_group(parser) else: return parser def _get_argparse_kwargs(self, group, **kwargs): """Build a dict of keyword arguments for argparse's add_argument(). Most opt types extend this method to customize the behaviour of the options added to argparse. :param group: an optional group :param kwargs: optional keyword arguments to add to :returns: a dict of keyword arguments """ if not self.positional: dest = self.dest if group is not None: dest = group.name + '_' + dest kwargs['dest'] = dest else: kwargs['nargs'] = '?' kwargs.update({'default': None, 'metavar': self.metavar, 'help': self.help, }) return kwargs def _get_argparse_prefix(self, prefix, group): """Build a prefix for the CLI option name, if required. CLI options in a group are prefixed with the group's name in order to avoid conflicts between similarly named options in different groups. :param prefix: an existing prefix to append to (e.g. 'no' or '') :param group: an optional OptGroup object :returns: a CLI option prefix including the group name, if appropriate """ if group is not None: return group.name + '-' + prefix else: return prefix class StrOpt(Opt): """ String opts do not have their values transformed and are returned as str objects. """ pass class BoolOpt(Opt): """ Bool opts are set to True or False on the command line using --optname or --noopttname respectively. In config files, boolean values are case insensitive and can be set using 1/0, yes/no, true/false or on/off. """ _boolean_states = {'1': True, 'yes': True, 'true': True, 'on': True, '0': False, 'no': False, 'false': False, 'off': False} def __init__(self, *args, **kwargs): if 'positional' in kwargs: raise ValueError('positional boolean args not supported') super(BoolOpt, self).__init__(*args, **kwargs) def _get_from_config_parser(self, cparser, section): """Retrieve the opt value as a boolean from ConfigParser.""" def convert_bool(v): value = self._boolean_states.get(v.lower()) if value is None: raise ValueError('Unexpected boolean value %r' % v) return value return [convert_bool(v) for v in self._cparser_get_with_deprecated(cparser, section)] def _add_to_cli(self, parser, group=None): """Extends the base class method to add the --nooptname option.""" super(BoolOpt, self)._add_to_cli(parser, group) self._add_inverse_to_argparse(parser, group) def _add_inverse_to_argparse(self, parser, group): """Add the --nooptname option to the option parser.""" container = self._get_argparse_container(parser, group) kwargs = self._get_argparse_kwargs(group, action='store_false') prefix = self._get_argparse_prefix('no', group) kwargs["help"] = "The inverse of --" + self.name self._add_to_argparse(container, self.name, None, kwargs, prefix, self.positional, self.deprecated_name) def _get_argparse_kwargs(self, group, action='store_true', **kwargs): """Extends the base argparse keyword dict for boolean options.""" kwargs = super(BoolOpt, self)._get_argparse_kwargs(group, **kwargs) # metavar has no effect for BoolOpt if 'metavar' in kwargs: del kwargs['metavar'] if action != 'store_true': action = 'store_false' kwargs['action'] = action return kwargs class IntOpt(Opt): """Int opt values are converted to integers using the int() builtin.""" def _get_from_config_parser(self, cparser, section): """Retrieve the opt value as a integer from ConfigParser.""" return [int(v) for v in self._cparser_get_with_deprecated(cparser, section)] def _get_argparse_kwargs(self, group, **kwargs): """Extends the base argparse keyword dict for integer options.""" return super(IntOpt, self)._get_argparse_kwargs(group, type=int, **kwargs) class FloatOpt(Opt): """Float opt values are converted to floats using the float() builtin.""" def _get_from_config_parser(self, cparser, section): """Retrieve the opt value as a float from ConfigParser.""" return [float(v) for v in self._cparser_get_with_deprecated(cparser, section)] def _get_argparse_kwargs(self, group, **kwargs): """Extends the base argparse keyword dict for float options.""" return super(FloatOpt, self)._get_argparse_kwargs(group, type=float, **kwargs) class ListOpt(Opt): """ List opt values are simple string values separated by commas. The opt value is a list containing these strings. """ class _StoreListAction(argparse.Action): """ An argparse action for parsing an option value into a list. """ def __call__(self, parser, namespace, values, option_string=None): if values is not None: values = [a.strip() for a in values.split(',')] setattr(namespace, self.dest, values) def _get_from_config_parser(self, cparser, section): """Retrieve the opt value as a list from ConfigParser.""" return [[a.strip() for a in v.split(',')] for v in self._cparser_get_with_deprecated(cparser, section)] def _get_argparse_kwargs(self, group, **kwargs): """Extends the base argparse keyword dict for list options.""" return Opt._get_argparse_kwargs(self, group, action=ListOpt._StoreListAction, **kwargs) class MultiStrOpt(Opt): """ Multistr opt values are string opts which may be specified multiple times. The opt value is a list containing all the string values specified. """ multi = True def _get_argparse_kwargs(self, group, **kwargs): """Extends the base argparse keyword dict for multi str options.""" kwargs = super(MultiStrOpt, self)._get_argparse_kwargs(group) if not self.positional: kwargs['action'] = 'append' else: kwargs['nargs'] = '*' return kwargs def _cparser_get_with_deprecated(self, cparser, section): """If cannot find option as dest try deprecated_name alias.""" if self.deprecated_name is not None: return cparser.get(section, [self.dest, self.deprecated_name], multi=True) return cparser.get(section, [self.dest], multi=True) class SubCommandOpt(Opt): """ Sub-command options allow argparse sub-parsers to be used to parse additional command line arguments. The handler argument to the SubCommandOpt contructor is a callable which is supplied an argparse subparsers object. Use this handler callable to add sub-parsers. The opt value is SubCommandAttr object with the name of the chosen sub-parser stored in the 'name' attribute and the values of other sub-parser arguments available as additional attributes. """ def __init__(self, name, dest=None, handler=None, title=None, description=None, help=None): """Construct an sub-command parsing option. This behaves similarly to other Opt sub-classes but adds a 'handler' argument. The handler is a callable which is supplied an subparsers object when invoked. The add_parser() method on this subparsers object can be used to register parsers for sub-commands. :param name: the option's name :param dest: the name of the corresponding ConfigOpts property :param title: title of the sub-commands group in help output :param description: description of the group in help output :param help: a help string giving an overview of available sub-commands """ super(SubCommandOpt, self).__init__(name, dest=dest, help=help) self.handler = handler self.title = title self.description = description def _add_to_cli(self, parser, group=None): """Add argparse sub-parsers and invoke the handler method.""" dest = self.dest if group is not None: dest = group.name + '_' + dest subparsers = parser.add_subparsers(dest=dest, title=self.title, description=self.description, help=self.help) if self.handler is not None: self.handler(subparsers) class OptGroup(object): """ Represents a group of opts. CLI opts in the group are automatically prefixed with the group name. Each group corresponds to a section in config files. An OptGroup object has no public methods, but has a number of public string properties: name: the name of the group title: the group title as displayed in --help help: the group description as displayed in --help """ def __init__(self, name, title=None, help=None): """Constructs an OptGroup object. :param name: the group name :param title: the group title for --help :param help: the group description for --help """ self.name = name if title is None: self.title = "%s options" % title else: self.title = title self.help = help self._opts = {} # dict of dicts of (opt:, override:, default:) self._argparse_group = None def _register_opt(self, opt, cli=False): """Add an opt to this group. :param opt: an Opt object :param cli: whether this is a CLI option :returns: False if previously registered, True otherwise :raises: DuplicateOptError if a naming conflict is detected """ if _is_opt_registered(self._opts, opt): return False self._opts[opt.dest] = {'opt': opt, 'cli': cli} return True def _unregister_opt(self, opt): """Remove an opt from this group. :param opt: an Opt object """ if opt.dest in self._opts: del self._opts[opt.dest] def _get_argparse_group(self, parser): if self._argparse_group is None: """Build an argparse._ArgumentGroup for this group.""" self._argparse_group = parser.add_argument_group(self.title, self.help) return self._argparse_group def _clear(self): """Clear this group's option parsing state.""" self._argparse_group = None class ParseError(iniparser.ParseError): def __init__(self, msg, lineno, line, filename): super(ParseError, self).__init__(msg, lineno, line) self.filename = filename def __str__(self): return 'at %s:%d, %s: %r' % (self.filename, self.lineno, self.msg, self.line) class ConfigParser(iniparser.BaseParser): def __init__(self, filename, sections): super(ConfigParser, self).__init__() self.filename = filename self.sections = sections self.section = None def parse(self): with open(self.filename) as f: return super(ConfigParser, self).parse(f) def new_section(self, section): self.section = section self.sections.setdefault(self.section, {}) def assignment(self, key, value): if not self.section: raise self.error_no_section() self.sections[self.section].setdefault(key, []) self.sections[self.section][key].append('\n'.join(value)) def parse_exc(self, msg, lineno, line=None): return ParseError(msg, lineno, line, self.filename) def error_no_section(self): return self.parse_exc('Section must be started before assignment', self.lineno) class MultiConfigParser(object): def __init__(self): self.parsed = [] def read(self, config_files): read_ok = [] for filename in config_files: sections = {} parser = ConfigParser(filename, sections) try: parser.parse() except IOError: continue self.parsed.insert(0, sections) read_ok.append(filename) return read_ok def get(self, section, names, multi=False): rvalue = [] for sections in self.parsed: if section not in sections: continue for name in names: if name in sections[section]: if multi: rvalue = sections[section][name] + rvalue else: return sections[section][name] if multi and rvalue != []: return rvalue raise KeyError class ConfigOpts(collections.Mapping): """ Config options which may be set on the command line or in config files. ConfigOpts is a configuration option manager with APIs for registering option schemas, grouping options, parsing option values and retrieving the values of options. """ def __init__(self): """Construct a ConfigOpts object.""" self._opts = {} # dict of dicts of (opt:, override:, default:) self._groups = {} self._args = None self._oparser = None self._cparser = None self._cli_values = {} self.__cache = {} self._config_opts = [] def _pre_setup(self, project, prog, version, usage, default_config_files): """Initialize a ConfigCliParser object for option parsing.""" if prog is None: prog = os.path.basename(sys.argv[0]) if default_config_files is None: default_config_files = find_config_files(project, prog) self._oparser = argparse.ArgumentParser(prog=prog, usage=usage) self._oparser.add_argument('--version', action='version', version=version) return prog, default_config_files def _setup(self, project, prog, version, usage, default_config_files): """Initialize a ConfigOpts object for option parsing.""" self._config_opts = [ MultiStrOpt('config-file', default=default_config_files, metavar='PATH', help='Path to a config file to use. Multiple config ' 'files can be specified, with values in later ' 'files taking precedence. The default files ' ' used are: %s' % (default_config_files, )), StrOpt('config-dir', metavar='DIR', help='Path to a config directory to pull *.conf ' 'files from. This file set is sorted, so as to ' 'provide a predictable parse order if individual ' 'options are over-ridden. The set is parsed after ' 'the file(s), if any, specified via --config-file, ' 'hence over-ridden options in the directory take ' 'precedence.'), ] self.register_cli_opts(self._config_opts) self.project = project self.prog = prog self.version = version self.usage = usage self.default_config_files = default_config_files def __clear_cache(f): @functools.wraps(f) def __inner(self, *args, **kwargs): if kwargs.pop('clear_cache', True): self.__cache.clear() return f(self, *args, **kwargs) return __inner def __call__(self, args=None, project=None, prog=None, version=None, usage=None, default_config_files=None): """Parse command line arguments and config files. Calling a ConfigOpts object causes the supplied command line arguments and config files to be parsed, causing opt values to be made available as attributes of the object. The object may be called multiple times, each time causing the previous set of values to be overwritten. Automatically registers the --config-file option with either a supplied list of default config files, or a list from find_config_files(). If the --config-dir option is set, any *.conf files from this directory are pulled in, after all the file(s) specified by the --config-file option. :param args: command line arguments (defaults to sys.argv[1:]) :param project: the toplevel project name, used to locate config files :param prog: the name of the program (defaults to sys.argv[0] basename) :param version: the program version (for --version) :param usage: a usage string (%prog will be expanded) :param default_config_files: config files to use by default :returns: the list of arguments left over after parsing options :raises: SystemExit, ConfigFilesNotFoundError, ConfigFileParseError, RequiredOptError, DuplicateOptError """ self.clear() prog, default_config_files = self._pre_setup(project, prog, version, usage, default_config_files) self._setup(project, prog, version, usage, default_config_files) self._cli_values = self._parse_cli_opts(args) self._parse_config_files() self._check_required_opts() def __getattr__(self, name): """Look up an option value and perform string substitution. :param name: the opt name (or 'dest', more precisely) :returns: the option value (after string subsititution) or a GroupAttr :raises: NoSuchOptError,ConfigFileValueError,TemplateSubstitutionError """ return self._get(name) def __getitem__(self, key): """Look up an option value and perform string substitution.""" return self.__getattr__(key) def __contains__(self, key): """Return True if key is the name of a registered opt or group.""" return key in self._opts or key in self._groups def __iter__(self): """Iterate over all registered opt and group names.""" for key in self._opts.keys() + self._groups.keys(): yield key def __len__(self): """Return the number of options and option groups.""" return len(self._opts) + len(self._groups) def reset(self): """Clear the object state and unset overrides and defaults.""" self._unset_defaults_and_overrides() self.clear() @__clear_cache def clear(self): """Clear the state of the object to before it was called. Any subparsers added using the add_cli_subparsers() will also be removed as a side-effect of this method. """ self._args = None self._cli_values.clear() self._oparser = argparse.ArgumentParser() self._cparser = None self.unregister_opts(self._config_opts) for group in self._groups.values(): group._clear() @__clear_cache def register_opt(self, opt, group=None, cli=False): """Register an option schema. Registering an option schema makes any option value which is previously or subsequently parsed from the command line or config files available as an attribute of this object. :param opt: an instance of an Opt sub-class :param cli: whether this is a CLI option :param group: an optional OptGroup object or group name :return: False if the opt was already register, True otherwise :raises: DuplicateOptError """ if group is not None: group = self._get_group(group, autocreate=True) return group._register_opt(opt, cli) if _is_opt_registered(self._opts, opt): return False self._opts[opt.dest] = {'opt': opt, 'cli': cli} return True @__clear_cache def register_opts(self, opts, group=None): """Register multiple option schemas at once.""" for opt in opts: self.register_opt(opt, group, clear_cache=False) @__clear_cache def register_cli_opt(self, opt, group=None): """Register a CLI option schema. CLI option schemas must be registered before the command line and config files are parsed. This is to ensure that all CLI options are show in --help and option validation works as expected. :param opt: an instance of an Opt sub-class :param group: an optional OptGroup object or group name :return: False if the opt was already register, True otherwise :raises: DuplicateOptError, ArgsAlreadyParsedError """ if self._args is not None: raise ArgsAlreadyParsedError("cannot register CLI option") return self.register_opt(opt, group, cli=True, clear_cache=False) @__clear_cache def register_cli_opts(self, opts, group=None): """Register multiple CLI option schemas at once.""" for opt in opts: self.register_cli_opt(opt, group, clear_cache=False) def register_group(self, group): """Register an option group. An option group must be registered before options can be registered with the group. :param group: an OptGroup object """ if group.name in self._groups: return self._groups[group.name] = copy.copy(group) @__clear_cache def unregister_opt(self, opt, group=None): """Unregister an option. :param opt: an Opt object :param group: an optional OptGroup object or group name :raises: ArgsAlreadyParsedError, NoSuchGroupError """ if self._args is not None: raise ArgsAlreadyParsedError("reset before unregistering options") if group is not None: self._get_group(group)._unregister_opt(opt) elif opt.dest in self._opts: del self._opts[opt.dest] @__clear_cache def unregister_opts(self, opts, group=None): """Unregister multiple CLI option schemas at once.""" for opt in opts: self.unregister_opt(opt, group, clear_cache=False) def import_opt(self, name, module_str, group=None): """Import an option definition from a module. Import a module and check that a given option is registered. This is intended for use with global configuration objects like cfg.CONF where modules commonly register options with CONF at module load time. If one module requires an option defined by another module it can use this method to explicitly declare the dependency. :param name: the name/dest of the opt :param module_str: the name of a module to import :param group: an option OptGroup object or group name :raises: NoSuchOptError, NoSuchGroupError """ __import__(module_str) self._get_opt_info(name, group) def import_group(self, group, module_str): """Import an option group from a module. Import a module and check that a given option group is registered. This is intended for use with global configuration objects like cfg.CONF where modules commonly register options with CONF at module load time. If one module requires an option group defined by another module it can use this method to explicitly declare the dependency. :param group: an option OptGroup object or group name :param module_str: the name of a module to import :raises: ImportError, NoSuchGroupError """ __import__(module_str) self._get_group(group) @__clear_cache def set_override(self, name, override, group=None): """Override an opt value. Override the command line, config file and default values of a given option. :param name: the name/dest of the opt :param override: the override value :param group: an option OptGroup object or group name :raises: NoSuchOptError, NoSuchGroupError """ opt_info = self._get_opt_info(name, group) opt_info['override'] = override @__clear_cache def set_default(self, name, default, group=None): """Override an opt's default value. Override the default value of given option. A command line or config file value will still take precedence over this default. :param name: the name/dest of the opt :param default: the default value :param group: an option OptGroup object or group name :raises: NoSuchOptError, NoSuchGroupError """ opt_info = self._get_opt_info(name, group) opt_info['default'] = default @__clear_cache def clear_override(self, name, group=None): """Clear an override an opt value. Clear a previously set override of the command line, config file and default values of a given option. :param name: the name/dest of the opt :param group: an option OptGroup object or group name :raises: NoSuchOptError, NoSuchGroupError """ opt_info = self._get_opt_info(name, group) opt_info.pop('override', None) @__clear_cache def clear_default(self, name, group=None): """Clear an override an opt's default value. Clear a previously set override of the default value of given option. :param name: the name/dest of the opt :param group: an option OptGroup object or group name :raises: NoSuchOptError, NoSuchGroupError """ opt_info = self._get_opt_info(name, group) opt_info.pop('default', None) def _all_opt_infos(self): """A generator function for iteration opt infos.""" for info in self._opts.values(): yield info, None for group in self._groups.values(): for info in group._opts.values(): yield info, group def _all_cli_opts(self): """A generator function for iterating CLI opts.""" for info, group in self._all_opt_infos(): if info['cli']: yield info['opt'], group def _unset_defaults_and_overrides(self): """Unset any default or override on all options.""" for info, group in self._all_opt_infos(): info.pop('default', None) info.pop('override', None) def find_file(self, name): """Locate a file located alongside the config files. Search for a file with the supplied basename in the directories which we have already loaded config files from and other known configuration directories. The directory, if any, supplied by the config_dir option is searched first. Then the config_file option is iterated over and each of the base directories of the config_files values are searched. Failing both of these, the standard directories searched by the module level find_config_files() function is used. The first matching file is returned. :param basename: the filename, e.g. 'policy.json' :returns: the path to a matching file, or None """ dirs = [] if self.config_dir: dirs.append(_fixpath(self.config_dir)) for cf in reversed(self.config_file): dirs.append(os.path.dirname(_fixpath(cf))) dirs.extend(_get_config_dirs(self.project)) return _search_dirs(dirs, name) def log_opt_values(self, logger, lvl): """Log the value of all registered opts. It's often useful for an app to log its configuration to a log file at startup for debugging. This method dumps to the entire config state to the supplied logger at a given log level. :param logger: a logging.Logger object :param lvl: the log level (e.g. logging.DEBUG) arg to logger.log() """ logger.log(lvl, "*" * 80) logger.log(lvl, "Configuration options gathered from:") logger.log(lvl, "command line args: %s", self._args) logger.log(lvl, "config files: %s", self.config_file) logger.log(lvl, "=" * 80) def _sanitize(opt, value): """Obfuscate values of options declared secret""" return value if not opt.secret else '*' * len(str(value)) for opt_name in sorted(self._opts): opt = self._get_opt_info(opt_name)['opt'] logger.log(lvl, "%-30s = %s", opt_name, _sanitize(opt, getattr(self, opt_name))) for group_name in self._groups: group_attr = self.GroupAttr(self, self._get_group(group_name)) for opt_name in sorted(self._groups[group_name]._opts): opt = self._get_opt_info(opt_name, group_name)['opt'] logger.log(lvl, "%-30s = %s", "%s.%s" % (group_name, opt_name), _sanitize(opt, getattr(group_attr, opt_name))) logger.log(lvl, "*" * 80) def print_usage(self, file=None): """Print the usage message for the current program.""" self._oparser.print_usage(file) def print_help(self, file=None): """Print the help message for the current program.""" self._oparser.print_help(file) def _get(self, name, group=None): if isinstance(group, OptGroup): key = (group.name, name) else: key = (group, name) try: return self.__cache[key] except KeyError: value = self._substitute(self._do_get(name, group)) self.__cache[key] = value return value def _do_get(self, name, group=None): """Look up an option value. :param name: the opt name (or 'dest', more precisely) :param group: an OptGroup :returns: the option value, or a GroupAttr object :raises: NoSuchOptError, NoSuchGroupError, ConfigFileValueError, TemplateSubstitutionError """ if group is None and name in self._groups: return self.GroupAttr(self, self._get_group(name)) info = self._get_opt_info(name, group) opt = info['opt'] if isinstance(opt, SubCommandOpt): return self.SubCommandAttr(self, group, opt.dest) if 'override' in info: return info['override'] values = [] if self._cparser is not None: section = group.name if group is not None else 'DEFAULT' try: value = opt._get_from_config_parser(self._cparser, section) except KeyError: pass except ValueError as ve: raise ConfigFileValueError(str(ve)) else: if not opt.multi: # No need to continue since the last value wins return value[-1] values.extend(value) name = name if group is None else group.name + '_' + name value = self._cli_values.get(name) if value is not None: if not opt.multi: return value # argparse ignores default=None for nargs='*' if opt.positional and not value: value = opt.default return value + values if values: return values if 'default' in info: return info['default'] return opt.default def _substitute(self, value): """Perform string template substitution. Substitute any template variables (e.g. $foo, ${bar}) in the supplied string value(s) with opt values. :param value: the string value, or list of string values :returns: the substituted string(s) """ if isinstance(value, list): return [self._substitute(i) for i in value] elif isinstance(value, str): tmpl = string.Template(value) return tmpl.safe_substitute(self.StrSubWrapper(self)) else: return value def _get_group(self, group_or_name, autocreate=False): """Looks up a OptGroup object. Helper function to return an OptGroup given a parameter which can either be the group's name or an OptGroup object. The OptGroup object returned is from the internal dict of OptGroup objects, which will be a copy of any OptGroup object that users of the API have access to. :param group_or_name: the group's name or the OptGroup object itself :param autocreate: whether to auto-create the group if it's not found :raises: NoSuchGroupError """ group = group_or_name if isinstance(group_or_name, OptGroup) else None group_name = group.name if group else group_or_name if group_name not in self._groups: if group is not None or not autocreate: raise NoSuchGroupError(group_name) self.register_group(OptGroup(name=group_name)) return self._groups[group_name] def _get_opt_info(self, opt_name, group=None): """Return the (opt, override, default) dict for an opt. :param opt_name: an opt name/dest :param group: an optional group name or OptGroup object :raises: NoSuchOptError, NoSuchGroupError """ if group is None: opts = self._opts else: group = self._get_group(group) opts = group._opts if opt_name not in opts: raise NoSuchOptError(opt_name, group) return opts[opt_name] def _parse_config_files(self): """Parse the config files from --config-file and --config-dir. :raises: ConfigFilesNotFoundError, ConfigFileParseError """ config_files = list(self.config_file) if self.config_dir: config_dir_glob = os.path.join(self.config_dir, '*.conf') config_files += sorted(glob.glob(config_dir_glob)) config_files = [_fixpath(p) for p in config_files] self._cparser = MultiConfigParser() try: read_ok = self._cparser.read(config_files) except iniparser.ParseError as pe: raise ConfigFileParseError(pe.filename, str(pe)) if read_ok != config_files: not_read_ok = filter(lambda f: f not in read_ok, config_files) raise ConfigFilesNotFoundError(not_read_ok) def _check_required_opts(self): """Check that all opts marked as required have values specified. :raises: RequiredOptError """ for info, group in self._all_opt_infos(): opt = info['opt'] if opt.required: if 'default' in info or 'override' in info: continue if self._get(opt.dest, group) is None: raise RequiredOptError(opt.name, group) def _parse_cli_opts(self, args): """Parse command line options. Initializes the command line option parser and parses the supplied command line arguments. :param args: the command line arguments :returns: a dict of parsed option values :raises: SystemExit, DuplicateOptError """ self._args = args for opt, group in self._all_cli_opts(): opt._add_to_cli(self._oparser, group) return vars(self._oparser.parse_args(args)) class GroupAttr(collections.Mapping): """ A helper class representing the option values of a group as a mapping and attributes. """ def __init__(self, conf, group): """Construct a GroupAttr object. :param conf: a ConfigOpts object :param group: an OptGroup object """ self._conf = conf self._group = group def __getattr__(self, name): """Look up an option value and perform template substitution.""" return self._conf._get(name, self._group) def __getitem__(self, key): """Look up an option value and perform string substitution.""" return self.__getattr__(key) def __contains__(self, key): """Return True if key is the name of a registered opt or group.""" return key in self._group._opts def __iter__(self): """Iterate over all registered opt and group names.""" for key in self._group._opts.keys(): yield key def __len__(self): """Return the number of options and option groups.""" return len(self._group._opts) class SubCommandAttr(object): """ A helper class representing the name and arguments of an argparse sub-parser. """ def __init__(self, conf, group, dest): """Construct a SubCommandAttr object. :param conf: a ConfigOpts object :param group: an OptGroup object :param dest: the name of the sub-parser """ self._conf = conf self._group = group self._dest = dest def __getattr__(self, name): """Look up a sub-parser name or argument value.""" if name == 'name': name = self._dest if self._group is not None: name = self._group.name + '_' + name return self._conf._cli_values[name] if name in self._conf: raise DuplicateOptError(name) try: return self._conf._cli_values[name] except KeyError: raise NoSuchOptError(name) class StrSubWrapper(object): """ A helper class exposing opt values as a dict for string substitution. """ def __init__(self, conf): """Construct a StrSubWrapper object. :param conf: a ConfigOpts object """ self.conf = conf def __getitem__(self, key): """Look up an opt value from the ConfigOpts object. :param key: an opt name :returns: an opt value :raises: TemplateSubstitutionError if attribute is a group """ value = getattr(self.conf, key) if isinstance(value, self.conf.GroupAttr): raise TemplateSubstitutionError( 'substituting group %s not supported' % key) return value CONF = ConfigOpts()