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loader.py
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# encoding: utf-8
"""A simple configuration system."""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import argparse
import copy
import logging
import os
import re
import sys
import json
from IPython.utils.path import filefind, get_ipython_dir
from IPython.utils import py3compat
from IPython.utils.encoding import DEFAULT_ENCODING
from IPython.utils.py3compat import unicode_type, iteritems
from IPython.utils.traitlets import HasTraits, List, Any
#-----------------------------------------------------------------------------
# Exceptions
#-----------------------------------------------------------------------------
class ConfigError(Exception):
pass
class ConfigLoaderError(ConfigError):
pass
class ConfigFileNotFound(ConfigError):
pass
class ArgumentError(ConfigLoaderError):
pass
#-----------------------------------------------------------------------------
# Argparse fix
#-----------------------------------------------------------------------------
# Unfortunately argparse by default prints help messages to stderr instead of
# stdout. This makes it annoying to capture long help screens at the command
# line, since one must know how to pipe stderr, which many users don't know how
# to do. So we override the print_help method with one that defaults to
# stdout and use our class instead.
class ArgumentParser(argparse.ArgumentParser):
"""Simple argparse subclass that prints help to stdout by default."""
def print_help(self, file=None):
if file is None:
file = sys.stdout
return super(ArgumentParser, self).print_help(file)
print_help.__doc__ = argparse.ArgumentParser.print_help.__doc__
#-----------------------------------------------------------------------------
# Config class for holding config information
#-----------------------------------------------------------------------------
class LazyConfigValue(HasTraits):
"""Proxy object for exposing methods on configurable containers
Exposes:
- append, extend, insert on lists
- update on dicts
- update, add on sets
"""
_value = None
# list methods
_extend = List()
_prepend = List()
def append(self, obj):
self._extend.append(obj)
def extend(self, other):
self._extend.extend(other)
def prepend(self, other):
"""like list.extend, but for the front"""
self._prepend[:0] = other
_inserts = List()
def insert(self, index, other):
if not isinstance(index, int):
raise TypeError("An integer is required")
self._inserts.append((index, other))
# dict methods
# update is used for both dict and set
_update = Any()
def update(self, other):
if self._update is None:
if isinstance(other, dict):
self._update = {}
else:
self._update = set()
self._update.update(other)
# set methods
def add(self, obj):
self.update({obj})
def get_value(self, initial):
"""construct the value from the initial one
after applying any insert / extend / update changes
"""
if self._value is not None:
return self._value
value = copy.deepcopy(initial)
if isinstance(value, list):
for idx, obj in self._inserts:
value.insert(idx, obj)
value[:0] = self._prepend
value.extend(self._extend)
elif isinstance(value, dict):
if self._update:
value.update(self._update)
elif isinstance(value, set):
if self._update:
value.update(self._update)
self._value = value
return value
def to_dict(self):
"""return JSONable dict form of my data
Currently update as dict or set, extend, prepend as lists, and inserts as list of tuples.
"""
d = {}
if self._update:
d['update'] = self._update
if self._extend:
d['extend'] = self._extend
if self._prepend:
d['prepend'] = self._prepend
elif self._inserts:
d['inserts'] = self._inserts
return d
def _is_section_key(key):
"""Is a Config key a section name (does it start with a capital)?"""
if key and key[0].upper()==key[0] and not key.startswith('_'):
return True
else:
return False
class Config(dict):
"""An attribute based dict that can do smart merges."""
def __init__(self, *args, **kwds):
dict.__init__(self, *args, **kwds)
self._ensure_subconfig()
def _ensure_subconfig(self):
"""ensure that sub-dicts that should be Config objects are
casts dicts that are under section keys to Config objects,
which is necessary for constructing Config objects from dict literals.
"""
for key in self:
obj = self[key]
if _is_section_key(key) \
and isinstance(obj, dict) \
and not isinstance(obj, Config):
setattr(self, key, Config(obj))
def _merge(self, other):
"""deprecated alias, use Config.merge()"""
self.merge(other)
def merge(self, other):
"""merge another config object into this one"""
to_update = {}
for k, v in iteritems(other):
if k not in self:
to_update[k] = copy.deepcopy(v)
else: # I have this key
if isinstance(v, Config) and isinstance(self[k], Config):
# Recursively merge common sub Configs
self[k].merge(v)
else:
# Plain updates for non-Configs
to_update[k] = copy.deepcopy(v)
self.update(to_update)
def __contains__(self, key):
# allow nested contains of the form `"Section.key" in config`
if '.' in key:
first, remainder = key.split('.', 1)
if first not in self:
return False
return remainder in self[first]
return super(Config, self).__contains__(key)
# .has_key is deprecated for dictionaries.
has_key = __contains__
def _has_section(self, key):
return _is_section_key(key) and key in self
def copy(self):
return type(self)(dict.copy(self))
def __copy__(self):
return self.copy()
def __deepcopy__(self, memo):
import copy
return type(self)(copy.deepcopy(list(self.items())))
def __getitem__(self, key):
try:
return dict.__getitem__(self, key)
except KeyError:
if _is_section_key(key):
c = Config()
dict.__setitem__(self, key, c)
return c
elif not key.startswith('_'):
# undefined, create lazy value, used for container methods
v = LazyConfigValue()
dict.__setitem__(self, key, v)
return v
else:
raise KeyError
def __setitem__(self, key, value):
if _is_section_key(key):
if not isinstance(value, Config):
raise ValueError('values whose keys begin with an uppercase '
'char must be Config instances: %r, %r' % (key, value))
dict.__setitem__(self, key, value)
def __getattr__(self, key):
if key.startswith('__'):
return dict.__getattr__(self, key)
try:
return self.__getitem__(key)
except KeyError as e:
raise AttributeError(e)
def __setattr__(self, key, value):
if key.startswith('__'):
return dict.__setattr__(self, key, value)
try:
self.__setitem__(key, value)
except KeyError as e:
raise AttributeError(e)
def __delattr__(self, key):
if key.startswith('__'):
return dict.__delattr__(self, key)
try:
dict.__delitem__(self, key)
except KeyError as e:
raise AttributeError(e)
#-----------------------------------------------------------------------------
# Config loading classes
#-----------------------------------------------------------------------------
class ConfigLoader(object):
"""A object for loading configurations from just about anywhere.
The resulting configuration is packaged as a :class:`Config`.
Notes
-----
A :class:`ConfigLoader` does one thing: load a config from a source
(file, command line arguments) and returns the data as a :class:`Config` object.
There are lots of things that :class:`ConfigLoader` does not do. It does
not implement complex logic for finding config files. It does not handle
default values or merge multiple configs. These things need to be
handled elsewhere.
"""
def _log_default(self):
from IPython.utils.log import get_logger
return get_logger()
def __init__(self, log=None):
"""A base class for config loaders.
log : instance of :class:`logging.Logger` to use.
By default loger of :meth:`IPython.config.application.Application.instance()`
will be used
Examples
--------
>>> cl = ConfigLoader()
>>> config = cl.load_config()
>>> config
{}
"""
self.clear()
if log is None:
self.log = self._log_default()
self.log.debug('Using default logger')
else:
self.log = log
def clear(self):
self.config = Config()
def load_config(self):
"""Load a config from somewhere, return a :class:`Config` instance.
Usually, this will cause self.config to be set and then returned.
However, in most cases, :meth:`ConfigLoader.clear` should be called
to erase any previous state.
"""
self.clear()
return self.config
class FileConfigLoader(ConfigLoader):
"""A base class for file based configurations.
As we add more file based config loaders, the common logic should go
here.
"""
def __init__(self, filename, path=None, **kw):
"""Build a config loader for a filename and path.
Parameters
----------
filename : str
The file name of the config file.
path : str, list, tuple
The path to search for the config file on, or a sequence of
paths to try in order.
"""
super(FileConfigLoader, self).__init__(**kw)
self.filename = filename
self.path = path
self.full_filename = ''
def _find_file(self):
"""Try to find the file by searching the paths."""
self.full_filename = filefind(self.filename, self.path)
class JSONFileConfigLoader(FileConfigLoader):
"""A Json file loader for config"""
def load_config(self):
"""Load the config from a file and return it as a Config object."""
self.clear()
try:
self._find_file()
except IOError as e:
raise ConfigFileNotFound(str(e))
dct = self._read_file_as_dict()
self.config = self._convert_to_config(dct)
return self.config
def _read_file_as_dict(self):
with open(self.full_filename) as f:
return json.load(f)
def _convert_to_config(self, dictionary):
if 'version' in dictionary:
version = dictionary.pop('version')
else:
version = 1
self.log.warn("Unrecognized JSON config file version, assuming version {}".format(version))
if version == 1:
return Config(dictionary)
else:
raise ValueError('Unknown version of JSON config file: {version}'.format(version=version))
class PyFileConfigLoader(FileConfigLoader):
"""A config loader for pure python files.
This is responsible for locating a Python config file by filename and
path, then executing it to construct a Config object.
"""
def load_config(self):
"""Load the config from a file and return it as a Config object."""
self.clear()
try:
self._find_file()
except IOError as e:
raise ConfigFileNotFound(str(e))
self._read_file_as_dict()
return self.config
def _read_file_as_dict(self):
"""Load the config file into self.config, with recursive loading."""
# This closure is made available in the namespace that is used
# to exec the config file. It allows users to call
# load_subconfig('myconfig.py') to load config files recursively.
# It needs to be a closure because it has references to self.path
# and self.config. The sub-config is loaded with the same path
# as the parent, but it uses an empty config which is then merged
# with the parents.
# If a profile is specified, the config file will be loaded
# from that profile
def load_subconfig(fname, profile=None):
# import here to prevent circular imports
from IPython.core.profiledir import ProfileDir, ProfileDirError
if profile is not None:
try:
profile_dir = ProfileDir.find_profile_dir_by_name(
get_ipython_dir(),
profile,
)
except ProfileDirError:
return
path = profile_dir.location
else:
path = self.path
loader = PyFileConfigLoader(fname, path)
try:
sub_config = loader.load_config()
except ConfigFileNotFound:
# Pass silently if the sub config is not there. This happens
# when a user s using a profile, but not the default config.
pass
else:
self.config.merge(sub_config)
# Again, this needs to be a closure and should be used in config
# files to get the config being loaded.
def get_config():
return self.config
namespace = dict(
load_subconfig=load_subconfig,
get_config=get_config,
__file__=self.full_filename,
)
fs_encoding = sys.getfilesystemencoding() or 'ascii'
conf_filename = self.full_filename.encode(fs_encoding)
py3compat.execfile(conf_filename, namespace)
class CommandLineConfigLoader(ConfigLoader):
"""A config loader for command line arguments.
As we add more command line based loaders, the common logic should go
here.
"""
def _exec_config_str(self, lhs, rhs):
"""execute self.config.<lhs> = <rhs>
* expands ~ with expanduser
* tries to assign with raw eval, otherwise assigns with just the string,
allowing `--C.a=foobar` and `--C.a="foobar"` to be equivalent. *Not*
equivalent are `--C.a=4` and `--C.a='4'`.
"""
rhs = os.path.expanduser(rhs)
try:
# Try to see if regular Python syntax will work. This
# won't handle strings as the quote marks are removed
# by the system shell.
value = eval(rhs)
except (NameError, SyntaxError):
# This case happens if the rhs is a string.
value = rhs
exec(u'self.config.%s = value' % lhs)
def _load_flag(self, cfg):
"""update self.config from a flag, which can be a dict or Config"""
if isinstance(cfg, (dict, Config)):
# don't clobber whole config sections, update
# each section from config:
for sec,c in iteritems(cfg):
self.config[sec].update(c)
else:
raise TypeError("Invalid flag: %r" % cfg)
# raw --identifier=value pattern
# but *also* accept '-' as wordsep, for aliases
# accepts: --foo=a
# --Class.trait=value
# --alias-name=value
# rejects: -foo=value
# --foo
# --Class.trait
kv_pattern = re.compile(r'\-\-[A-Za-z][\w\-]*(\.[\w\-]+)*\=.*')
# just flags, no assignments, with two *or one* leading '-'
# accepts: --foo
# -foo-bar-again
# rejects: --anything=anything
# --two.word
flag_pattern = re.compile(r'\-\-?\w+[\-\w]*$')
class KeyValueConfigLoader(CommandLineConfigLoader):
"""A config loader that loads key value pairs from the command line.
This allows command line options to be gives in the following form::
ipython --profile="foo" --InteractiveShell.autocall=False
"""
def __init__(self, argv=None, aliases=None, flags=None, **kw):
"""Create a key value pair config loader.
Parameters
----------
argv : list
A list that has the form of sys.argv[1:] which has unicode
elements of the form u"key=value". If this is None (default),
then sys.argv[1:] will be used.
aliases : dict
A dict of aliases for configurable traits.
Keys are the short aliases, Values are the resolved trait.
Of the form: `{'alias' : 'Configurable.trait'}`
flags : dict
A dict of flags, keyed by str name. Vaues can be Config objects,
dicts, or "key=value" strings. If Config or dict, when the flag
is triggered, The flag is loaded as `self.config.update(m)`.
Returns
-------
config : Config
The resulting Config object.
Examples
--------
>>> from IPython.config.loader import KeyValueConfigLoader
>>> cl = KeyValueConfigLoader()
>>> d = cl.load_config(["--A.name='brian'","--B.number=0"])
>>> sorted(d.items())
[('A', {'name': 'brian'}), ('B', {'number': 0})]
"""
super(KeyValueConfigLoader, self).__init__(**kw)
if argv is None:
argv = sys.argv[1:]
self.argv = argv
self.aliases = aliases or {}
self.flags = flags or {}
def clear(self):
super(KeyValueConfigLoader, self).clear()
self.extra_args = []
def _decode_argv(self, argv, enc=None):
"""decode argv if bytes, using stin.encoding, falling back on default enc"""
uargv = []
if enc is None:
enc = DEFAULT_ENCODING
for arg in argv:
if not isinstance(arg, unicode_type):
# only decode if not already decoded
arg = arg.decode(enc)
uargv.append(arg)
return uargv
def load_config(self, argv=None, aliases=None, flags=None):
"""Parse the configuration and generate the Config object.
After loading, any arguments that are not key-value or
flags will be stored in self.extra_args - a list of
unparsed command-line arguments. This is used for
arguments such as input files or subcommands.
Parameters
----------
argv : list, optional
A list that has the form of sys.argv[1:] which has unicode
elements of the form u"key=value". If this is None (default),
then self.argv will be used.
aliases : dict
A dict of aliases for configurable traits.
Keys are the short aliases, Values are the resolved trait.
Of the form: `{'alias' : 'Configurable.trait'}`
flags : dict
A dict of flags, keyed by str name. Values can be Config objects
or dicts. When the flag is triggered, The config is loaded as
`self.config.update(cfg)`.
"""
self.clear()
if argv is None:
argv = self.argv
if aliases is None:
aliases = self.aliases
if flags is None:
flags = self.flags
# ensure argv is a list of unicode strings:
uargv = self._decode_argv(argv)
for idx,raw in enumerate(uargv):
# strip leading '-'
item = raw.lstrip('-')
if raw == '--':
# don't parse arguments after '--'
# this is useful for relaying arguments to scripts, e.g.
# ipython -i foo.py --matplotlib=qt -- args after '--' go-to-foo.py
self.extra_args.extend(uargv[idx+1:])
break
if kv_pattern.match(raw):
lhs,rhs = item.split('=',1)
# Substitute longnames for aliases.
if lhs in aliases:
lhs = aliases[lhs]
if '.' not in lhs:
# probably a mistyped alias, but not technically illegal
self.log.warn("Unrecognized alias: '%s', it will probably have no effect.", raw)
try:
self._exec_config_str(lhs, rhs)
except Exception:
raise ArgumentError("Invalid argument: '%s'" % raw)
elif flag_pattern.match(raw):
if item in flags:
cfg,help = flags[item]
self._load_flag(cfg)
else:
raise ArgumentError("Unrecognized flag: '%s'"%raw)
elif raw.startswith('-'):
kv = '--'+item
if kv_pattern.match(kv):
raise ArgumentError("Invalid argument: '%s', did you mean '%s'?"%(raw, kv))
else:
raise ArgumentError("Invalid argument: '%s'"%raw)
else:
# keep all args that aren't valid in a list,
# in case our parent knows what to do with them.
self.extra_args.append(item)
return self.config
class ArgParseConfigLoader(CommandLineConfigLoader):
"""A loader that uses the argparse module to load from the command line."""
def __init__(self, argv=None, aliases=None, flags=None, log=None, *parser_args, **parser_kw):
"""Create a config loader for use with argparse.
Parameters
----------
argv : optional, list
If given, used to read command-line arguments from, otherwise
sys.argv[1:] is used.
parser_args : tuple
A tuple of positional arguments that will be passed to the
constructor of :class:`argparse.ArgumentParser`.
parser_kw : dict
A tuple of keyword arguments that will be passed to the
constructor of :class:`argparse.ArgumentParser`.
Returns
-------
config : Config
The resulting Config object.
"""
super(CommandLineConfigLoader, self).__init__(log=log)
self.clear()
if argv is None:
argv = sys.argv[1:]
self.argv = argv
self.aliases = aliases or {}
self.flags = flags or {}
self.parser_args = parser_args
self.version = parser_kw.pop("version", None)
kwargs = dict(argument_default=argparse.SUPPRESS)
kwargs.update(parser_kw)
self.parser_kw = kwargs
def load_config(self, argv=None, aliases=None, flags=None):
"""Parse command line arguments and return as a Config object.
Parameters
----------
args : optional, list
If given, a list with the structure of sys.argv[1:] to parse
arguments from. If not given, the instance's self.argv attribute
(given at construction time) is used."""
self.clear()
if argv is None:
argv = self.argv
if aliases is None:
aliases = self.aliases
if flags is None:
flags = self.flags
self._create_parser(aliases, flags)
self._parse_args(argv)
self._convert_to_config()
return self.config
def get_extra_args(self):
if hasattr(self, 'extra_args'):
return self.extra_args
else:
return []
def _create_parser(self, aliases=None, flags=None):
self.parser = ArgumentParser(*self.parser_args, **self.parser_kw)
self._add_arguments(aliases, flags)
def _add_arguments(self, aliases=None, flags=None):
raise NotImplementedError("subclasses must implement _add_arguments")
def _parse_args(self, args):
"""self.parser->self.parsed_data"""
# decode sys.argv to support unicode command-line options
enc = DEFAULT_ENCODING
uargs = [py3compat.cast_unicode(a, enc) for a in args]
self.parsed_data, self.extra_args = self.parser.parse_known_args(uargs)
def _convert_to_config(self):
"""self.parsed_data->self.config"""
for k, v in iteritems(vars(self.parsed_data)):
exec("self.config.%s = v"%k, locals(), globals())
class KVArgParseConfigLoader(ArgParseConfigLoader):
"""A config loader that loads aliases and flags with argparse,
but will use KVLoader for the rest. This allows better parsing
of common args, such as `ipython -c 'print 5'`, but still gets
arbitrary config with `ipython --InteractiveShell.use_readline=False`"""
def _add_arguments(self, aliases=None, flags=None):
self.alias_flags = {}
# print aliases, flags
if aliases is None:
aliases = self.aliases
if flags is None:
flags = self.flags
paa = self.parser.add_argument
for key,value in iteritems(aliases):
if key in flags:
# flags
nargs = '?'
else:
nargs = None
if len(key) is 1:
paa('-'+key, '--'+key, type=unicode_type, dest=value, nargs=nargs)
else:
paa('--'+key, type=unicode_type, dest=value, nargs=nargs)
for key, (value, help) in iteritems(flags):
if key in self.aliases:
#
self.alias_flags[self.aliases[key]] = value
continue
if len(key) is 1:
paa('-'+key, '--'+key, action='append_const', dest='_flags', const=value)
else:
paa('--'+key, action='append_const', dest='_flags', const=value)
def _convert_to_config(self):
"""self.parsed_data->self.config, parse unrecognized extra args via KVLoader."""
# remove subconfigs list from namespace before transforming the Namespace
if '_flags' in self.parsed_data:
subcs = self.parsed_data._flags
del self.parsed_data._flags
else:
subcs = []
for k, v in iteritems(vars(self.parsed_data)):
if v is None:
# it was a flag that shares the name of an alias
subcs.append(self.alias_flags[k])
else:
# eval the KV assignment
self._exec_config_str(k, v)
for subc in subcs:
self._load_flag(subc)
if self.extra_args:
sub_parser = KeyValueConfigLoader(log=self.log)
sub_parser.load_config(self.extra_args)
self.config.merge(sub_parser.config)
self.extra_args = sub_parser.extra_args
def load_pyconfig_files(config_files, path):
"""Load multiple Python config files, merging each of them in turn.
Parameters
==========
config_files : list of str
List of config files names to load and merge into the config.
path : unicode
The full path to the location of the config files.
"""
config = Config()
for cf in config_files:
loader = PyFileConfigLoader(cf, path=path)
try:
next_config = loader.load_config()
except ConfigFileNotFound:
pass
except:
raise
else:
config.merge(next_config)
return config