def _check_against_schema(self):
for key, subschema in six.iteritems(self._schema):
_, default, required = util.get_properties(subschema)
if key not in self._data and default:
setattr(self, util.as_attr(key), default)
if key not in self._data and required:
raise util.ConfigError('Attribute {} is required.'.format(key))
def update(self, newer_config, merge=False):
"""Create a fresh config combining the new and old configs.
It does this by iterating over the 'config_properties' class
attribute which contains names of property attributes for the config.
Two methods of combining configs are possible, an 'update' and
a 'merge', the latter set by the keyword argument 'merge=True'.
An update overrides older values with new values -- even if those
new values are None. Update will remove values that are present in
the old config if they are not present in the new config.
A merge by comparison will allow old values to persist if they are
not specified in the new config. This can be used for end-user
customizations to override specific settings without having to re-create
large portions of a config to override it.
Arguments:
newer_config: A config object to combine with the current config.
merge: Allows old values not overridden to survive into the fresh config.
Returns:
A config object of the same sort as called upon.
"""
# removed 'merge' kw arg - and it was passed to constructor
# make a note to not do that, consume it on the param list
fresh_config = self.__class__(schema=self._schema)
logger.debug('from parent update merge %s', merge)
if not isinstance(newer_config, MergableConfig):
raise util.ConfigError('Attempting to update a %s with a %s' %
(self.__class__, newer_config.__class__))
for prop_name in self._schema.keys():
# get the specified property off of the current class
prop = self.__class__.__dict__.get(util.as_attr(prop_name))
assert prop
new_value = prop.fget(newer_config)
old_value = prop.fget(self)
if merge and new_value is not None:
if isinstance(new_value, dict) and isinstance(old_value, dict):
new_value = old_value.update(new_value)
elif isinstance(new_value, list) and isinstance(
old_value, list):
new_value = old_value.extend(new_value)
if new_value is not None:
prop.fset(fresh_config, new_value)
elif merge and old_value is not None:
prop.fset(fresh_config, old_value)
return fresh_config
def load_from_dict(self, dict_):
""" Sets Config attributes from key/values in dict_ """
for key, value in six.iteritems(dict_):
setattr(self, util.as_attr(key), value)
self._check_against_schema()