class StackResolver(object):
def __init__(self):
self.registered = MergedOptions()
def register(self, stack_kls, extra_aliases=None):
"""Register a stack type"""
aliases = list(getattr(stack_kls, "aliases", []))
if extra_aliases:
aliases.extend(extra_aliases)
if not aliases:
raise BadStackKls("No alias provided", kls=stack_kls)
self.registered.update({alias: stack_kls for alias in aliases})
def register_import(self, import_line, extra_aliases=None):
"""Register a kls from an import string"""
if ":" not in import_line:
raise BadImport("Expecting '<path>:<obj>'", got=import_line)
path, obj = import_line.split(":")
if not valid_python_path(path):
raise BadImport("Path portion of import is not a valid python name", path=path)
if not valid_python_name(obj):
raise BadImport("obj portion of import is not a valid python name", obj=obj)
obj = do_import(path, obj)
self.register(obj, extra_aliases)
def register_defaults(self):
self.register_import("cloudcity.resolution.types.config:ConfigStack")
def resolve(self, name, options):
the_type = options.get("type", "config")
if the_type not in self.registered:
raise UnknownStackType(name=name, only_have=self.registered.keys(), wanted=the_type)
return self.registered[the_type](name, options)
