|
|
# encoding: utf-8
|
|
|
"""A base class for objects that are configurable."""
|
|
|
|
|
|
# Copyright (c) IPython Development Team.
|
|
|
# Distributed under the terms of the Modified BSD License.
|
|
|
|
|
|
from __future__ import print_function
|
|
|
|
|
|
import logging
|
|
|
from copy import deepcopy
|
|
|
|
|
|
from .loader import Config, LazyConfigValue
|
|
|
from IPython.utils.traitlets import HasTraits, Instance
|
|
|
from IPython.utils.text import indent, wrap_paragraphs
|
|
|
from IPython.utils.py3compat import iteritems
|
|
|
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Helper classes for Configurables
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
class ConfigurableError(Exception):
|
|
|
pass
|
|
|
|
|
|
|
|
|
class MultipleInstanceError(ConfigurableError):
|
|
|
pass
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Configurable implementation
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
class Configurable(HasTraits):
|
|
|
|
|
|
config = Instance(Config, (), {})
|
|
|
parent = Instance('IPython.config.configurable.Configurable', allow_none=True)
|
|
|
|
|
|
def __init__(self, **kwargs):
|
|
|
"""Create a configurable given a config config.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
config : Config
|
|
|
If this is empty, default values are used. If config is a
|
|
|
:class:`Config` instance, it will be used to configure the
|
|
|
instance.
|
|
|
parent : Configurable instance, optional
|
|
|
The parent Configurable instance of this object.
|
|
|
|
|
|
Notes
|
|
|
-----
|
|
|
Subclasses of Configurable must call the :meth:`__init__` method of
|
|
|
:class:`Configurable` *before* doing anything else and using
|
|
|
:func:`super`::
|
|
|
|
|
|
class MyConfigurable(Configurable):
|
|
|
def __init__(self, config=None):
|
|
|
super(MyConfigurable, self).__init__(config=config)
|
|
|
# Then any other code you need to finish initialization.
|
|
|
|
|
|
This ensures that instances will be configured properly.
|
|
|
"""
|
|
|
parent = kwargs.pop('parent', None)
|
|
|
if parent is not None:
|
|
|
# config is implied from parent
|
|
|
if kwargs.get('config', None) is None:
|
|
|
kwargs['config'] = parent.config
|
|
|
self.parent = parent
|
|
|
|
|
|
config = kwargs.pop('config', None)
|
|
|
|
|
|
# load kwarg traits, other than config
|
|
|
super(Configurable, self).__init__(**kwargs)
|
|
|
|
|
|
# load config
|
|
|
if config is not None:
|
|
|
# We used to deepcopy, but for now we are trying to just save
|
|
|
# by reference. This *could* have side effects as all components
|
|
|
# will share config. In fact, I did find such a side effect in
|
|
|
# _config_changed below. If a config attribute value was a mutable type
|
|
|
# all instances of a component were getting the same copy, effectively
|
|
|
# making that a class attribute.
|
|
|
# self.config = deepcopy(config)
|
|
|
self.config = config
|
|
|
else:
|
|
|
# allow _config_default to return something
|
|
|
self._load_config(self.config)
|
|
|
|
|
|
# Ensure explicit kwargs are applied after loading config.
|
|
|
# This is usually redundant, but ensures config doesn't override
|
|
|
# explicitly assigned values.
|
|
|
for key, value in kwargs.items():
|
|
|
setattr(self, key, value)
|
|
|
|
|
|
#-------------------------------------------------------------------------
|
|
|
# Static trait notifiations
|
|
|
#-------------------------------------------------------------------------
|
|
|
|
|
|
@classmethod
|
|
|
def section_names(cls):
|
|
|
"""return section names as a list"""
|
|
|
return [c.__name__ for c in reversed(cls.__mro__) if
|
|
|
issubclass(c, Configurable) and issubclass(cls, c)
|
|
|
]
|
|
|
|
|
|
def _find_my_config(self, cfg):
|
|
|
"""extract my config from a global Config object
|
|
|
|
|
|
will construct a Config object of only the config values that apply to me
|
|
|
based on my mro(), as well as those of my parent(s) if they exist.
|
|
|
|
|
|
If I am Bar and my parent is Foo, and their parent is Tim,
|
|
|
this will return merge following config sections, in this order::
|
|
|
|
|
|
[Bar, Foo.bar, Tim.Foo.Bar]
|
|
|
|
|
|
With the last item being the highest priority.
|
|
|
"""
|
|
|
cfgs = [cfg]
|
|
|
if self.parent:
|
|
|
cfgs.append(self.parent._find_my_config(cfg))
|
|
|
my_config = Config()
|
|
|
for c in cfgs:
|
|
|
for sname in self.section_names():
|
|
|
# Don't do a blind getattr as that would cause the config to
|
|
|
# dynamically create the section with name Class.__name__.
|
|
|
if c._has_section(sname):
|
|
|
my_config.merge(c[sname])
|
|
|
return my_config
|
|
|
|
|
|
def _load_config(self, cfg, section_names=None, traits=None):
|
|
|
"""load traits from a Config object"""
|
|
|
|
|
|
if traits is None:
|
|
|
traits = self.traits(config=True)
|
|
|
if section_names is None:
|
|
|
section_names = self.section_names()
|
|
|
|
|
|
my_config = self._find_my_config(cfg)
|
|
|
|
|
|
# hold trait notifications until after all config has been loaded
|
|
|
with self.hold_trait_notifications():
|
|
|
for name, config_value in iteritems(my_config):
|
|
|
if name in traits:
|
|
|
if isinstance(config_value, LazyConfigValue):
|
|
|
# ConfigValue is a wrapper for using append / update on containers
|
|
|
# without having to copy the initial value
|
|
|
initial = getattr(self, name)
|
|
|
config_value = config_value.get_value(initial)
|
|
|
# We have to do a deepcopy here if we don't deepcopy the entire
|
|
|
# config object. If we don't, a mutable config_value will be
|
|
|
# shared by all instances, effectively making it a class attribute.
|
|
|
setattr(self, name, deepcopy(config_value))
|
|
|
|
|
|
def _config_changed(self, name, old, new):
|
|
|
"""Update all the class traits having ``config=True`` as metadata.
|
|
|
|
|
|
For any class trait with a ``config`` metadata attribute that is
|
|
|
``True``, we update the trait with the value of the corresponding
|
|
|
config entry.
|
|
|
"""
|
|
|
# Get all traits with a config metadata entry that is True
|
|
|
traits = self.traits(config=True)
|
|
|
|
|
|
# We auto-load config section for this class as well as any parent
|
|
|
# classes that are Configurable subclasses. This starts with Configurable
|
|
|
# and works down the mro loading the config for each section.
|
|
|
section_names = self.section_names()
|
|
|
self._load_config(new, traits=traits, section_names=section_names)
|
|
|
|
|
|
def update_config(self, config):
|
|
|
"""Fire the traits events when the config is updated."""
|
|
|
# Save a copy of the current config.
|
|
|
newconfig = deepcopy(self.config)
|
|
|
# Merge the new config into the current one.
|
|
|
newconfig.merge(config)
|
|
|
# Save the combined config as self.config, which triggers the traits
|
|
|
# events.
|
|
|
self.config = newconfig
|
|
|
|
|
|
@classmethod
|
|
|
def class_get_help(cls, inst=None):
|
|
|
"""Get the help string for this class in ReST format.
|
|
|
|
|
|
If `inst` is given, it's current trait values will be used in place of
|
|
|
class defaults.
|
|
|
"""
|
|
|
assert inst is None or isinstance(inst, cls)
|
|
|
final_help = []
|
|
|
final_help.append(u'%s options' % cls.__name__)
|
|
|
final_help.append(len(final_help[0])*u'-')
|
|
|
for k, v in sorted(cls.class_traits(config=True).items()):
|
|
|
help = cls.class_get_trait_help(v, inst)
|
|
|
final_help.append(help)
|
|
|
return '\n'.join(final_help)
|
|
|
|
|
|
@classmethod
|
|
|
def class_get_trait_help(cls, trait, inst=None):
|
|
|
"""Get the help string for a single trait.
|
|
|
|
|
|
If `inst` is given, it's current trait values will be used in place of
|
|
|
the class default.
|
|
|
"""
|
|
|
assert inst is None or isinstance(inst, cls)
|
|
|
lines = []
|
|
|
header = "--%s.%s=<%s>" % (cls.__name__, trait.name, trait.__class__.__name__)
|
|
|
lines.append(header)
|
|
|
if inst is not None:
|
|
|
lines.append(indent('Current: %r' % getattr(inst, trait.name), 4))
|
|
|
else:
|
|
|
try:
|
|
|
dvr = repr(trait.get_default_value())
|
|
|
except Exception:
|
|
|
dvr = None # ignore defaults we can't construct
|
|
|
if dvr is not None:
|
|
|
if len(dvr) > 64:
|
|
|
dvr = dvr[:61]+'...'
|
|
|
lines.append(indent('Default: %s' % dvr, 4))
|
|
|
if 'Enum' in trait.__class__.__name__:
|
|
|
# include Enum choices
|
|
|
lines.append(indent('Choices: %r' % (trait.values,)))
|
|
|
|
|
|
help = trait.get_metadata('help')
|
|
|
if help is not None:
|
|
|
help = '\n'.join(wrap_paragraphs(help, 76))
|
|
|
lines.append(indent(help, 4))
|
|
|
return '\n'.join(lines)
|
|
|
|
|
|
@classmethod
|
|
|
def class_print_help(cls, inst=None):
|
|
|
"""Get the help string for a single trait and print it."""
|
|
|
print(cls.class_get_help(inst))
|
|
|
|
|
|
@classmethod
|
|
|
def class_config_section(cls):
|
|
|
"""Get the config class config section"""
|
|
|
def c(s):
|
|
|
"""return a commented, wrapped block."""
|
|
|
s = '\n\n'.join(wrap_paragraphs(s, 78))
|
|
|
|
|
|
return '# ' + s.replace('\n', '\n# ')
|
|
|
|
|
|
# section header
|
|
|
breaker = '#' + '-'*78
|
|
|
s = "# %s configuration" % cls.__name__
|
|
|
lines = [breaker, s, breaker, '']
|
|
|
# get the description trait
|
|
|
desc = cls.class_traits().get('description')
|
|
|
if desc:
|
|
|
desc = desc.default_value
|
|
|
else:
|
|
|
# no description trait, use __doc__
|
|
|
desc = getattr(cls, '__doc__', '')
|
|
|
if desc:
|
|
|
lines.append(c(desc))
|
|
|
lines.append('')
|
|
|
|
|
|
parents = []
|
|
|
for parent in cls.mro():
|
|
|
# only include parents that are not base classes
|
|
|
# and are not the class itself
|
|
|
# and have some configurable traits to inherit
|
|
|
if parent is not cls and issubclass(parent, Configurable) and \
|
|
|
parent.class_traits(config=True):
|
|
|
parents.append(parent)
|
|
|
|
|
|
if parents:
|
|
|
pstr = ', '.join([ p.__name__ for p in parents ])
|
|
|
lines.append(c('%s will inherit config from: %s'%(cls.__name__, pstr)))
|
|
|
lines.append('')
|
|
|
|
|
|
for name, trait in iteritems(cls.class_traits(config=True)):
|
|
|
help = trait.get_metadata('help') or ''
|
|
|
lines.append(c(help))
|
|
|
lines.append('# c.%s.%s = %r'%(cls.__name__, name, trait.get_default_value()))
|
|
|
lines.append('')
|
|
|
return '\n'.join(lines)
|
|
|
|
|
|
|
|
|
|
|
|
class SingletonConfigurable(Configurable):
|
|
|
"""A configurable that only allows one instance.
|
|
|
|
|
|
This class is for classes that should only have one instance of itself
|
|
|
or *any* subclass. To create and retrieve such a class use the
|
|
|
:meth:`SingletonConfigurable.instance` method.
|
|
|
"""
|
|
|
|
|
|
_instance = None
|
|
|
|
|
|
@classmethod
|
|
|
def _walk_mro(cls):
|
|
|
"""Walk the cls.mro() for parent classes that are also singletons
|
|
|
|
|
|
For use in instance()
|
|
|
"""
|
|
|
|
|
|
for subclass in cls.mro():
|
|
|
if issubclass(cls, subclass) and \
|
|
|
issubclass(subclass, SingletonConfigurable) and \
|
|
|
subclass != SingletonConfigurable:
|
|
|
yield subclass
|
|
|
|
|
|
@classmethod
|
|
|
def clear_instance(cls):
|
|
|
"""unset _instance for this class and singleton parents.
|
|
|
"""
|
|
|
if not cls.initialized():
|
|
|
return
|
|
|
for subclass in cls._walk_mro():
|
|
|
if isinstance(subclass._instance, cls):
|
|
|
# only clear instances that are instances
|
|
|
# of the calling class
|
|
|
subclass._instance = None
|
|
|
|
|
|
@classmethod
|
|
|
def instance(cls, *args, **kwargs):
|
|
|
"""Returns a global instance of this class.
|
|
|
|
|
|
This method create a new instance if none have previously been created
|
|
|
and returns a previously created instance is one already exists.
|
|
|
|
|
|
The arguments and keyword arguments passed to this method are passed
|
|
|
on to the :meth:`__init__` method of the class upon instantiation.
|
|
|
|
|
|
Examples
|
|
|
--------
|
|
|
|
|
|
Create a singleton class using instance, and retrieve it::
|
|
|
|
|
|
>>> from IPython.config.configurable import SingletonConfigurable
|
|
|
>>> class Foo(SingletonConfigurable): pass
|
|
|
>>> foo = Foo.instance()
|
|
|
>>> foo == Foo.instance()
|
|
|
True
|
|
|
|
|
|
Create a subclass that is retrived using the base class instance::
|
|
|
|
|
|
>>> class Bar(SingletonConfigurable): pass
|
|
|
>>> class Bam(Bar): pass
|
|
|
>>> bam = Bam.instance()
|
|
|
>>> bam == Bar.instance()
|
|
|
True
|
|
|
"""
|
|
|
# Create and save the instance
|
|
|
if cls._instance is None:
|
|
|
inst = cls(*args, **kwargs)
|
|
|
# Now make sure that the instance will also be returned by
|
|
|
# parent classes' _instance attribute.
|
|
|
for subclass in cls._walk_mro():
|
|
|
subclass._instance = inst
|
|
|
|
|
|
if isinstance(cls._instance, cls):
|
|
|
return cls._instance
|
|
|
else:
|
|
|
raise MultipleInstanceError(
|
|
|
'Multiple incompatible subclass instances of '
|
|
|
'%s are being created.' % cls.__name__
|
|
|
)
|
|
|
|
|
|
@classmethod
|
|
|
def initialized(cls):
|
|
|
"""Has an instance been created?"""
|
|
|
return hasattr(cls, "_instance") and cls._instance is not None
|
|
|
|
|
|
|
|
|
class LoggingConfigurable(Configurable):
|
|
|
"""A parent class for Configurables that log.
|
|
|
|
|
|
Subclasses have a log trait, and the default behavior
|
|
|
is to get the logger from the currently running Application.
|
|
|
"""
|
|
|
|
|
|
log = Instance('logging.Logger')
|
|
|
def _log_default(self):
|
|
|
from IPython.utils import log
|
|
|
return log.get_logger()
|
|
|
|
|
|
|
|
|
|
