bcceff368d
This patch is one in a series to re-enable H306 style check rule (imports are in alphabetical order). It touches engine files (without resources). Implements: blueprint reduce-flake8-ignored-rules (partial) Change-Id: Ifd36fc49199c48af891bd8e7cc2d2262a53032eb
115 lines
4.2 KiB
Python
115 lines
4.2 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import collections
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import itertools
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import sys
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from oslo.config import cfg
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from heat.common import plugin_loader
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from heat.openstack.common import log
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logger = log.getLogger(__name__)
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class PluginManager(object):
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'''A class for managing plugin modules.'''
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def __init__(self, *extra_packages):
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'''Initialise the Heat Engine plugin package, and any others.
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The heat.engine.plugins package is always created, if it does not
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exist, from the plugin directories specified in the config file, and
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searched for modules. In addition, any extra packages specified are
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also searched for modules. e.g.
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>>> PluginManager('heat.engine.resources')
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will load all modules in the heat.engine.resources package as well as
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any user-supplied plugin modules.
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'''
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def packages():
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for package_name in extra_packages:
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yield sys.modules[package_name]
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cfg.CONF.import_opt('plugin_dirs', 'heat.common.config')
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yield plugin_loader.create_subpackage(cfg.CONF.plugin_dirs,
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'heat.engine')
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def modules():
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pkg_modules = itertools.imap(plugin_loader.load_modules,
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packages())
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return itertools.chain.from_iterable(pkg_modules)
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self.modules = list(modules())
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def map_to_modules(self, function):
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'''Iterate over the results of calling a function on every module.'''
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return itertools.imap(function, self.modules)
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class PluginMapping(object):
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'''A class for managing plugin mappings.'''
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def __init__(self, names, *args, **kwargs):
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'''Initialise with the mapping name(s) and arguments.
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`names` can be a single name or a list of names. The first name found
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in a given module is the one used. Each module is searched for a
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function called <name>_mapping() which is called to retrieve the
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mappings provided by that module. Any other arguments passed will be
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passed to the mapping functions.
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'''
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if isinstance(names, basestring):
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names = [names]
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self.names = ['%s_mapping' % name for name in names]
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self.args = args
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self.kwargs = kwargs
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def load_from_module(self, module):
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'''Return the mapping specified in the given module.
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If no such mapping is specified, an empty dictionary is returned.
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'''
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for mapping_name in self.names:
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mapping_func = getattr(module, mapping_name, None)
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if callable(mapping_func):
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fmt_data = {'mapping_name': mapping_name, 'module': module}
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try:
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mapping_dict = mapping_func(*self.args, **self.kwargs)
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except Exception:
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logger.error(_('Failed to load %(mapping_name)s '
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'from %(module)s') % fmt_data)
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raise
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else:
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if isinstance(mapping_dict, collections.Mapping):
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return mapping_dict
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elif mapping_dict is not None:
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logger.error(_('Invalid type for %(mapping_name)s '
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'from %(module)s') % fmt_data)
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return {}
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def load_all(self, plugin_manager):
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'''Iterate over the mappings from all modules in the plugin manager.
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Mappings are returned as a list of (key, value) tuples.
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'''
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mod_dicts = plugin_manager.map_to_modules(self.load_from_module)
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return itertools.chain.from_iterable(d.iteritems() for d in mod_dicts)
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