From ef5c9e11595a00de468783adbb60cfbc2cbbf13d Mon Sep 17 00:00:00 2001 From: termie Date: Thu, 24 Mar 2011 12:42:46 -0700 Subject: add Limited, an API limiting/versioning wrapper --- nova/api/direct.py | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'nova/api') diff --git a/nova/api/direct.py b/nova/api/direct.py index dfca250e0..1011091a6 100644 --- a/nova/api/direct.py +++ b/nova/api/direct.py @@ -211,6 +211,42 @@ class ServiceWrapper(wsgi.Controller): return result +class Limited(object): + __notdoc = """Limit the available methods on a given object. + + (Not a docstring so that the docstring can be conditionally overriden.) + + Useful when defining a public API that only exposes a subset of an + internal API. + + Expected usage of this class is to define a subclass that lists the allowed + methods in the 'allowed' variable. + + Additionally where appropriate methods can be added or overwritten, for + example to provide backwards compatibility. + + """ + + _allowed = None + + def __init__(self, proxy): + self._proxy = proxy + if not self.__doc__: + self.__doc__ = proxy.__doc__ + if not self._allowed: + self._allowed = [] + + def __getattr__(self, key): + """Only return methods that are named in self._allowed.""" + if key not in self._allowed: + raise AttributeError() + return getattr(self._proxy, key) + + def __dir__(self): + """Only return methods that are named in self._allowed.""" + return [x for x in dir(self._proxy) if x in self._allowed] + + class Proxy(object): """Pretend a Direct API endpoint is an object.""" def __init__(self, app, prefix=None): -- cgit