# 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 class or its sub-classes, for example: :: from oslo.config import cfg from oslo.config import types PortType = types.Integer(1, 65535) common_opts = [ cfg.StrOpt('bind_host', default='0.0.0.0', help='IP address to listen on.'), cfg.Opt('bind_port', type=PortType(), default=9292, help='Port number to listen on.') ] Option Types ------------ Options can have arbitrary types, you just need to pass type constructor to Opt. Type constructor is a callable object that takes a string and returns value of particular type or raises ValueError if given string can't be converted to that type. There are predefined types: strings, integers, floats, booleans, lists, 'multi strings' and 'key/value pairs' (dictionary) :: 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) Registering Options ------------------- 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 be 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) Loading Config Files -------------------- 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 oslo.config.iniparser. If none are specified, a default set is used for example 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 and those on the command line are parsed in order. The same option can appear many times, in config files or on the command line. Later values always override earlier ones. The parsing of CLI args and config files is initiated by invoking the config manager for example:: conf = ConfigOpts() conf.register_opt(BoolOpt('verbose', ...)) conf(sys.argv[1:]) if conf.verbose: ... Option Groups ------------- 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 no group attributes are required other than the group name, the group need not be explicitly registered for example:: 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 Accessing Option Values In Your Code ------------------------------------ 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 Value Interpolation -------------------------- 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:: Interpolation can be avoided by using `$$`. .. warning:: Interpolation using the values of options in groups is not yet supported. The interpolated option must be in the DEFAULT group (i.e., ``"$state_path"`` works but ``"$database.state_path"`` does not). Special Handling Instructions ----------------------------- Options may be declared as required so that an error is raised if the user does not supply a value for the option:: opts = [ cfg.StrOpt('service_name', required=True), cfg.StrOpt('image_id', required=True), ... ] 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), ... ] Global ConfigOpts ----------------- This module also contains a global instance of the ConfigOpts class in order to support a common usage pattern in OpenStack:: from oslo.config 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 --------------------------------- 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'] Sub-Parsers ----------- 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 errno import functools import glob import itertools import logging import os import string import sys import six from six import moves from oslo.config import iniparser from oslo.config import types LOG = logging.getLogger(__name__) class Error(Exception): """Base class for cfg exceptions.""" def __init__(self, msg=None): self.msg = msg def __str__(self): return self.msg class NotInitializedError(Error): """Raised if parser is not initialized yet.""" def __str__(self): return "call expression on parser has not been invoked" 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' % ",".join(self.config_files)) class ConfigDirNotFoundError(Error): """Raised if the requested config-dir is not found.""" def __init__(self, config_dir): self.config_dir = config_dir def __str__(self): return ('Failed to read config file directory: %s' % self.config_dir) 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 list(moves.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, for example 'glance-api' :param extension: the file extension, for example '.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 list(moves.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] def _normalize_group_name(group_name): if group_name == 'DEFAULT': return group_name return group_name.lower() 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 type: a callable object that takes string and returns converted and validated value 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 sample_default: a sample default value string to include in sample config files 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, type=None, dest=None, short=None, default=None, positional=False, metavar=None, help=None, secret=False, required=False, deprecated_name=None, deprecated_group=None, deprecated_opts=None, sample_default=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 type: the option's type. Must be a callable object that takes string and returns converted and validated value :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 :param deprecated_group: the group containing a deprecated alias :param deprecated_opts: array of DeprecatedOpt(s) :param sample_default: a default string for sample config files """ if name.startswith('_'): raise ValueError('illegal name %s with prefix _' % (name,)) self.name = name if type is None: type = types.String() if not callable(type): raise TypeError('type must be callable') self.type = type if dest is None: self.dest = self.name.replace('-', '_') else: self.dest = dest self.short = short self.default = default self.sample_default = sample_default self.positional = positional self.metavar = metavar self.help = help self.secret = secret self.required = required if deprecated_name is not None: deprecated_name = deprecated_name.replace('-', '_') self.deprecated_opts = copy.deepcopy(deprecated_opts) or [] if deprecated_name is not None or deprecated_group is not None: self.deprecated_opts.append(DeprecatedOpt(deprecated_name, group=deprecated_group)) def __ne__(self, another): return vars(self) != vars(another) def __eq__(self, another): return vars(self) == vars(another) __hash__ = object.__hash__ def _get_from_namespace(self, namespace, group_name): """Retrieves the option value from a _Namespace object. :param namespace: a _Namespace object :param group_name: a group name """ names = [(group_name, self.dest)] for opt in self.deprecated_opts: dname, dgroup = opt.name, opt.group if dname or dgroup: names.append((dgroup if dgroup else group_name, dname if dname else self.dest)) return namespace._get_value(names, self.multi, self.positional) 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.name if group else None) deprecated_names = [] for opt in self.deprecated_opts: deprecated_name = self._get_deprecated_cli_name(opt.name, opt.group) if deprecated_name is not None: deprecated_names.append(deprecated_name) self._add_to_argparse(parser, container, self.name, self.short, kwargs, prefix, self.positional, deprecated_names) def _add_to_argparse(self, parser, container, name, short, kwargs, prefix='', positional=False, deprecated_names=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 positional: whether the option is a positional CLI argument """ def hyphen(arg): return arg if not positional else '' args = [hyphen('--') + prefix + name] if short: args.append(hyphen('-') + short) for deprecated_name in deprecated_names: args.append(hyphen('--') + deprecated_name) parser.add_parser_argument(container, *args, **kwargs) 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_name): """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 (for example 'no' or '') :param group_name: an optional group name :returns: a CLI option prefix including the group name, if appropriate """ if group_name is not None: return group_name + '-' + prefix else: return prefix def _get_deprecated_cli_name(self, dname, dgroup, prefix=''): """Build a CLi arg name for deprecated options. Either a deprecated name or a deprecated group or both or neither can be supplied: dname, dgroup -> dgroup + '-' + dname dname -> dname dgroup -> dgroup + '-' + self.name neither -> None :param dname: a deprecated name, which can be None :param dgroup: a deprecated group, which can be None :param prefix: an prefix to append to (for example 'no' or '') :returns: a CLI argument name """ if dgroup == 'DEFAULT': dgroup = None if dname is None and dgroup is None: return None if dname is None: dname = self.name return self._get_argparse_prefix(prefix, dgroup) + dname def __lt__(self, another): return hash(self) < hash(another) # NOTE(jd) Not available for py2.6 if six.PY3: Opt = functools.total_ordering(Opt) class DeprecatedOpt(object): """Represents a Deprecated option. Here's how you can use it:: oldopts = [cfg.DeprecatedOpt('oldfoo', group='oldgroup'), cfg.DeprecatedOpt('oldfoo2', group='oldgroup2')] cfg.CONF.register_group(cfg.OptGroup('blaa')) cfg.CONF.register_opt(cfg.StrOpt('foo', deprecated_opts=oldopts), group='blaa') Multi-value options will return all new and deprecated options. For single options, if the new option is present ("[blaa]/foo" above) it will override any deprecated options present. If the new option is not present and multiple deprecated options are present, the option corresponding to the first element of deprecated_opts will be chosen. If group is None, the DeprecatedOpt lookup will happen within the same group the new option is in. For example:: oldopts = [cfg.DeprecatedOpt('oldfoo'), cfg.DeprecatedOpt('oldfoo2', group='DEFAULT')] cfg.CONF.register_group(cfg.OptGroup('blaa')) cfg.CONF.register_opt(cfg.StrOpt('foo', deprecated_opts=oldopts), group='blaa') In the example above, `oldfoo` will be looked up in the `blaa` group and `oldfoo2` in the `DEFAULT` group. """ def __init__(self, name, group=None): """Constructs an DeprecatedOpt object. :param name: the name of the option :param group: the group of the option """ self.name = name self.group = group def __key(self): return (self.name, self.group) def __eq__(self, other): return self.__key() == other.__key() def __hash__(self): return hash(self.__key()) class StrOpt(Opt): """Option with String type (for backward compatibility). :param choices: Optional sequence of valid values. """ def __init__(self, name, choices=None, **kwargs): super(StrOpt, self).__init__(name, type=types.String(choices=choices), **kwargs) class BoolOpt(Opt): """Boolean options. Bool opts are set to True or False on the command line using --optname or --noopttname respectively. In config files, boolean values are cast with Boolean type. """ def __init__(self, name, **kwargs): if 'positional' in kwargs: raise ValueError('positional boolean args not supported') super(BoolOpt, self).__init__(name, type=types.Boolean(), **kwargs) 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.name if group else None) deprecated_names = [] for opt in self.deprecated_opts: deprecated_name = self._get_deprecated_cli_name(opt.name, opt.group, prefix='no') if deprecated_name is not None: deprecated_names.append(deprecated_name) kwargs["help"] = "The inverse of --" + self.name self._add_to_argparse(parser, container, self.name, None, kwargs, prefix, self.positional, deprecated_names) 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) # type has no effect for BoolOpt, it only matters for # values that came from config files if 'type' in kwargs: del kwargs['type'] # metavar has no effect for BoolOpt if 'metavar' in kwargs: del kwargs['metavar'] kwargs['action'] = action return kwargs class IntOpt(Opt): """Opt with Integer type (for backward compatibility).""" def __init__(self, name, **kwargs): super(IntOpt, self).__init__(name, type=types.Integer(), **kwargs) class FloatOpt(Opt): """Opt with Float type (for backward compatibility).""" def __init__(self, name, **kwargs): super(FloatOpt, self).__init__(name, type=types.Float(), **kwargs) class ListOpt(Opt): """Opt with List(String) type (for backward compatibility).""" def __init__(self, name, **kwargs): super(ListOpt, self).__init__(name, type=types.List(), **kwargs) class DictOpt(Opt): """Opt with Dict(String) type (for backward compatibility).""" def __init__(self, name, **kwargs): super(DictOpt, self).__init__(name, type=types.Dict(), **kwargs) class IPOpt(Opt): """Opt with IPAddress type (either IPv4, IPv6 or both).""" def __init__(self, name, version=None, **kwargs): super(IPOpt, self).__init__(name, type=types.IPAddress(version), **kwargs) class MultiOpt(Opt): """Multi-value option. Multi opt values are typed opts which may be specified multiple times. The opt value is a list containing all the values specified. """ multi = True def __init__(self, name, item_type, **kwargs): super(MultiOpt, self).__init__(name, item_type, **kwargs) def _get_argparse_kwargs(self, group, **kwargs): """Extends the base argparse keyword dict for multi value options.""" kwargs = super(MultiOpt, self)._get_argparse_kwargs(group) if not self.positional: kwargs['action'] = 'append' else: kwargs['nargs'] = '*' return kwargs class MultiStrOpt(MultiOpt): """Multi opt with String item type (for backward compatibility).""" def __init__(self, name, **kwargs): super(MultiStrOpt, self).__init__(name, item_type=types.String(), **kwargs) class SubCommandOpt(Opt): """Sub-command options. Sub-command options allow argparse sub-parsers to be used to parse additional command line arguments. The handler argument to the SubCommandOpt constructor 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, type=types.String(), 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) # NOTE(jd) Set explicitly to True for Python 3 # See http://bugs.python.org/issue9253 for context subparsers.required = True if self.handler is not None: self.handler(subparsers) class _ConfigFileOpt(Opt): """The --config-file option. This is an private option type which handles the special processing required for --config-file options. As each --config-file option is encountered on the command line, we parse the file and store the parsed values in the _Namespace object. This allows us to properly handle the precedence of --config-file options over previous command line arguments, but not over subsequent arguments. """ class ConfigFileAction(argparse.Action): """An argparse action for --config-file. As each --config-file option is encountered, this action adds the value to the config_file attribute on the _Namespace object but also parses the configuration file and stores the values found also in the _Namespace object. """ def __call__(self, parser, namespace, values, option_string=None): """Handle a --config-file command line argument. :raises: ConfigFileParseError, ConfigFileValueError """ if getattr(namespace, self.dest, None) is None: setattr(namespace, self.dest, []) items = getattr(namespace, self.dest) items.append(values) ConfigParser._parse_file(values, namespace) def __init__(self, name, **kwargs): super(_ConfigFileOpt, self).__init__(name, lambda x: x, **kwargs) def _get_argparse_kwargs(self, group, **kwargs): """Extends the base argparse keyword dict for the config file opt.""" kwargs = super(_ConfigFileOpt, self)._get_argparse_kwargs(group) kwargs['action'] = self.ConfigFileAction return kwargs class _ConfigDirOpt(Opt): """The --config-dir option. This is an private option type which handles the special processing required for --config-dir options. As each --config-dir option is encountered on the command line, we parse the files in that directory and store the parsed values in the _Namespace object. This allows us to properly handle the precedence of --config-dir options over previous command line arguments, but not over subsequent arguments. """ class ConfigDirAction(argparse.Action): """An argparse action for --config-dir. As each --config-dir option is encountered, this action sets the config_dir attribute on the _Namespace object but also parses the configuration files and stores the values found also in the _Namespace object. """ def __call__(self, parser, namespace, values, option_string=None): """Handle a --config-dir command line argument. :raises: ConfigFileParseError, ConfigFileValueError, ConfigDirNotFoundError """ setattr(namespace, self.dest, values) values = os.path.expanduser(values) if not os.path.exists(values): raise ConfigDirNotFoundError(values) config_dir_glob = os.path.join(values, '*.conf') for config_file in sorted(glob.glob(config_dir_glob)): ConfigParser._parse_file(config_file, namespace) def __init__(self, name, **kwargs): super(_ConfigDirOpt, self).__init__(name, type=types.String(), **kwargs) def _get_argparse_kwargs(self, group, **kwargs): """Extends the base argparse keyword dict for the config dir option.""" kwargs = super(_ConfigDirOpt, self)._get_argparse_kwargs(group) kwargs['action'] = self.ConfigDirAction return kwargs 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 self.title = "%s options" % name if title is None else 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._normalized = None self.section = None def _add_normalized(self, normalized): self._normalized = normalized 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, {}) if self._normalized is not None: self._normalized.setdefault(_normalize_group_name(self.section), {}) def assignment(self, key, value): if not self.section: raise self.error_no_section() value = '\n'.join(value) def append(sections, section): sections[section].setdefault(key, []) sections[section][key].append(value) append(self.sections, self.section) if self._normalized is not None: append(self._normalized, _normalize_group_name(self.section)) 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) @classmethod def _parse_file(cls, config_file, namespace): """Parse a config file and store any values in the namespace. :raises: ConfigFileParseError, ConfigFileValueError """ config_file = _fixpath(config_file) sections = {} normalized = {} parser = cls(config_file, sections) parser._add_normalized(normalized) try: parser.parse() except iniparser.ParseError as pe: raise ConfigFileParseError(pe.filename, str(pe)) except IOError as err: if err.errno in (errno.ENOENT, errno.EACCES): namespace._file_not_found(config_file) return raise namespace._add_parsed_config_file(sections, normalized) class MultiConfigParser(object): def __init__(self): self.parsed = [] self._normalized = [] def read(self, config_files): read_ok = [] for filename in config_files: sections = {} normalized = {} parser = ConfigParser(filename, sections) parser._add_normalized(normalized) try: parser.parse() except IOError: continue self._add_parsed_config_file(sections, normalized) read_ok.append(filename) return read_ok def _add_parsed_config_file(self, sections, normalized): """Add a parsed config file to the list of parsed files. :param sections: a mapping of section name to dicts of config values :param normalized: sections mapping with section names normalized :raises: ConfigFileValueError """ self.parsed.insert(0, sections) self._normalized.insert(0, normalized) def get(self, names, multi=False): return self._get(names, multi=multi) def _get(self, names, multi=False, normalized=False): """Fetch a config file value from the parsed files. :param names: a list of (section, name) tuples :param multi: a boolean indicating whether to return multiple values :param normalized: whether to normalize group names to lowercase """ rvalue = [] def normalize(name): return _normalize_group_name(name) if normalized else name names = [(normalize(section), name) for section, name in names] for sections in (self._normalized if normalized else self.parsed): for section, name in names: if section not in sections: continue if name in sections[section]: val = sections[section][name] if multi: rvalue = val + rvalue else: return val if multi and rvalue != []: return rvalue raise KeyError class _Namespace(argparse.Namespace): """An argparse namespace which also stores config file values. As we parse command line arguments, the values get set as attributes on a namespace object. However, we also want to parse config files as they are specified on the command line and collect the values alongside the option values parsed from the command line. Note, we don't actually assign values from config files as attributes on the namespace because config file options be registered after the command line has been parsed, so we may not know how to properly parse or convert a config file value at this point. """ def __init__(self, conf): self._conf = conf self._parser = MultiConfigParser() self._files_not_found = [] def _parse_cli_opts_from_config_file(self, sections, normalized): """Parse CLI options from a config file. CLI options are special - we require they be registered before the command line is parsed. This means that as we parse config files, we can go ahead and apply the appropriate option-type specific conversion to the values in config files for CLI options. We can't do this for non-CLI options, because the schema describing those options may not be registered until after the config files are parsed. This method relies on that invariant in order to enforce proper priority of option values - i.e. that the order in which an option value is parsed, whether the value comes from the CLI or a config file, determines which value specified for a given option wins. The way we implement this ordering is that as we parse each config file, we look for values in that config file for CLI options only. Any values for CLI options found in the config file are treated like they had appeared on the command line and set as attributes on the namespace objects. Values in later config files or on the command line will override values found in this file. """ namespace = _Namespace(self._conf) namespace._parser._add_parsed_config_file(sections, normalized) for opt, group in sorted(self._conf._all_cli_opts()): group_name = group.name if group is not None else None try: value = opt._get_from_namespace(namespace, group_name) except KeyError: continue except ValueError as ve: raise ConfigFileValueError(str(ve)) if group_name is None: dest = opt.dest else: dest = group_name + '_' + opt.dest if opt.multi: if getattr(self, dest, None) is None: setattr(self, dest, []) values = getattr(self, dest) values.extend(value) else: setattr(self, dest, value) def _add_parsed_config_file(self, sections, normalized): """Add a parsed config file to the list of parsed files. :param sections: a mapping of section name to dicts of config values :param normalized: sections mapping with section names normalized :raises: ConfigFileValueError """ self._parse_cli_opts_from_config_file(sections, normalized) self._parser._add_parsed_config_file(sections, normalized) def _file_not_found(self, config_file): """Record that we were unable to open a config file. :param config_file: the path to the failed file """ self._files_not_found.append(config_file) def _get_cli_value(self, names, positional): """Fetch a CLI option value. Look up the value of a CLI option. The value itself may have come from parsing the command line or parsing config files specified on the command line. Type conversion have already been performed for CLI options at this point. :param names: a list of (section, name) tuples :param positional: whether this is a positional option """ for group_name, name in names: name = name if group_name is None else group_name + '_' + name value = getattr(self, name, None) if value is not None: # argparse ignores default=None for nargs='*' and returns [] if positional and not value: continue return value raise KeyError def _get_value(self, names, multi, positional): """Fetch a value from config files. Multiple names for a given configuration option may be supplied so that we can transparently handle files containing deprecated option names or groups. :param names: a list of (section, name) tuples :param multi: a boolean indicating whether to return multiple values :param positional: whether this is a positional option """ try: return self._get_cli_value(names, positional) except KeyError: pass names = [(g if g is not None else 'DEFAULT', n) for g, n in names] values = self._parser._get(names, multi=multi, normalized=True) return values if multi else values[-1] class _CachedArgumentParser(argparse.ArgumentParser): """class for caching/collecting command line arguments. It also sorts the arguments before initializing the ArgumentParser. We need to do this since ArgumentParser by default does not sort the argument options and the only way to influence the order of arguments in '--help' is to ensure they are added in the sorted order. """ def __init__(self, prog=None, usage=None, **kwargs): super(_CachedArgumentParser, self).__init__(prog, usage, **kwargs) self._args_cache = {} def add_parser_argument(self, container, *args, **kwargs): values = [] if container in self._args_cache: values = self._args_cache[container] values.append({'args': args, 'kwargs': kwargs}) self._args_cache[container] = values def initialize_parser_arguments(self): for container, values in six.iteritems(self._args_cache): values.sort(key=lambda x: x['args']) for argument in values: try: container.add_argument(*argument['args'], **argument['kwargs']) except argparse.ArgumentError as e: raise DuplicateOptError(e) self._args_cache = {} def parse_args(self, args=None, namespace=None): self.initialize_parser_arguments() return super(_CachedArgumentParser, self).parse_args(args, namespace) def print_help(self, file=None): self.initialize_parser_arguments() super(_CachedArgumentParser, self).print_help(file) def print_usage(self, file=None): self.initialize_parser_arguments() super(_CachedArgumentParser, self).print_usage(file) 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._namespace = None self.__cache = {} self._config_opts = [] self._validate_default_values = False 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 = _CachedArgumentParser(prog=prog, usage=usage) self._oparser.add_parser_argument(self._oparser, '--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 = [ _ConfigFileOpt('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: %(default)s.')), _ConfigDirOpt('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) specified via ' 'previous --config-file, arguments 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): result = f(self, *args, **kwargs) self.__cache.clear() return result else: return f(self, *args, **kwargs) return __inner def __call__(self, args=None, project=None, prog=None, version=None, usage=None, default_config_files=None, validate_default_values=False): """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 :param validate_default_values: whether to validate the default values :returns: the list of arguments left over after parsing options :raises: SystemExit, ConfigFilesNotFoundError, ConfigFileParseError, RequiredOptError, DuplicateOptError """ self.clear() self._validate_default_values = validate_default_values prog, default_config_files = self._pre_setup(project, prog, version, usage, default_config_files) self._setup(project, prog, version, usage, default_config_files) self._namespace = self._parse_cli_opts(args if args is not None else sys.argv[1:]) if self._namespace._files_not_found: raise ConfigFilesNotFoundError(self._namespace._files_not_found) 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 substitution) or a GroupAttr :raises: NoSuchOptError """ try: return self._get(name) except Exception: raise NoSuchOptError(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 itertools.chain(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._oparser = None self._namespace = None self._validate_default_values = False 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 registered, 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 shown 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 registered, 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 name: the filename, for example '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 (for example 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 '*' * 4 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. This method is for use after all CLI options are known registered using __call__() method. If this method is called before the __call__() is invoked, it throws NotInitializedError :param file: the File object (if None, output is on sys.stdout) :raises: NotInitializedError """ if not self._oparser: raise NotInitializedError() self._oparser.print_usage(file) def print_help(self, file=None): """Print the help message for the current program. This method is for use after all CLI options are known registered using __call__() method. If this method is called before the __call__() is invoked, it throws NotInitializedError :param file: the File object (if None, output is on sys.stdout) :raises: NotInitializedError """ if not self._oparser: raise NotInitializedError() self._oparser.print_help(file) def _get(self, name, group=None, namespace=None): if isinstance(group, OptGroup): key = (group.name, name) else: key = (group, name) try: if namespace is not None: raise KeyError return self.__cache[key] except KeyError: value = self._do_get(name, group, namespace) self.__cache[key] = value return value def _do_get(self, name, group=None, namespace=None): """Look up an option value. :param name: the opt name (or 'dest', more precisely) :param group: an OptGroup :param namespace: the namespace object that retrieves the option value from :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 self._substitute(info['override']) if namespace is None: namespace = self._namespace def convert(value): return self._convert_value(self._substitute(value, namespace), opt) if namespace is not None: group_name = group.name if group else None try: return convert(opt._get_from_namespace(namespace, group_name)) except KeyError: pass except ValueError as ve: raise ConfigFileValueError(str(ve)) if 'default' in info: return self._substitute(info['default']) if self._validate_default_values: if opt.default is not None: try: convert(opt.default) except ValueError as e: raise ConfigFileValueError( "Default value for option %s is not valid: %s" % (opt.name, str(e))) if opt.default is not None: return convert(opt.default) return None def _substitute(self, value, namespace=None): """Perform string template substitution. Substitute any template variables (for example $foo, ${bar}) in the supplied string value(s) with opt values. :param value: the string value, or list of string values :param namespace: the namespace object that retrieves the option value from :returns: the substituted string(s) """ if isinstance(value, list): return [self._substitute(i, namespace=namespace) for i in value] elif isinstance(value, str): # Treat a backslash followed by the dollar sign "\$" # the same as the string template escape "$$" as it is # a bit more natural for users if '\$' in value: value = value.replace('\$', '$$') tmpl = string.Template(value) return tmpl.safe_substitute( self.StrSubWrapper(self, namespace=namespace)) else: return value def _convert_value(self, value, opt): """Perform value type conversion. Converts values using option's type. Handles cases when value is actually a list of values (for example for multi opts). :param value: the string value, or list of string values :param opt: option definition (instance of Opt class or its subclasses) :returns: converted value """ if opt.multi: return [opt.type(v) for v in value] else: return opt.type(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. If autocreate is True, the group will be created if it's not found. If group is an instance of OptGroup, that same instance will be registered, otherwise a new instance of OptGroup will be created. :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 not autocreate: raise NoSuchGroupError(group_name) self.register_group(group or 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 _check_required_opts(self, namespace=None): """Check that all opts marked as required have values specified. :param namespace: the namespace object be checked the required options :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, namespace) 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 _Namespace object containing the parsed option values :raises: SystemExit, DuplicateOptError ConfigFileParseError, ConfigFileValueError """ self._args = args for opt, group in sorted(self._all_cli_opts(), key=lambda x: x[0].name): opt._add_to_cli(self._oparser, group) return self._parse_config_files() def _parse_config_files(self): """Parse configure files options. :raises: SystemExit, ConfigFilesNotFoundError, ConfigFileParseError, RequiredOptError, DuplicateOptError """ namespace = _Namespace(self) for arg in self._args: if arg == '--config-file' or arg.startswith('--config-file='): break else: for config_file in self.default_config_files: ConfigParser._parse_file(config_file, namespace) self._oparser.parse_args(self._args, namespace) self._validate_cli_options(namespace) return namespace def _validate_cli_options(self, namespace): for opt, group in sorted(self._all_cli_opts(), key=lambda x: x[0].name): group_name = group.name if group else None try: value = opt._get_from_namespace(namespace, group_name) except KeyError: continue value = self._substitute(value, namespace=namespace) try: self._convert_value(value, opt) except ValueError: sys.stderr.write('argument --%s: Invalid %s value: %s' % ( opt.dest, repr(opt.type), value)) raise SystemExit @__clear_cache def reload_config_files(self): """Reload configure files and parse all options :return False if reload configure files failed or else return True """ try: namespace = self._parse_config_files() if namespace._files_not_found: raise ConfigFilesNotFoundError(namespace._files_not_found) self._check_required_opts(namespace) except SystemExit as exc: LOG.warn("Caught SystemExit while reloading configure files " "with exit code: %d", exc.code) return False except Error as err: LOG.warn("Caught Error while reloading configure files: %s", err) return False else: self._namespace = namespace return True class GroupAttr(collections.Mapping): """Helper class. Represents 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): """Helper class. Represents 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 getattr(self._conf._namespace, name) if name in self._conf: raise DuplicateOptError(name) try: return getattr(self._conf._namespace, name) except AttributeError: raise NoSuchOptError(name) class StrSubWrapper(object): """Helper class. Exposes opt values as a dict for string substitution. """ def __init__(self, conf, namespace=None): """Construct a StrSubWrapper object. :param conf: a ConfigOpts object """ self.conf = conf self.namespace = namespace 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 = self.conf._get(key, namespace=self.namespace) if isinstance(value, self.conf.GroupAttr): raise TemplateSubstitutionError( 'substituting group %s not supported' % key) return value CONF = ConfigOpts()