qubes/admin: Add listing of API methods

qubes/api/__init__.py

@@ -41,7 +41,7 @@ class PermissionDenied(Exception):
     pass
 
 
-def method(name, *, no_payload=False, endpoints=None):
+def method(name, *, no_payload=False, endpoints=None, **classifiers):
     '''Decorator factory for methods intended to appear in API.
 
     The decorated method can be called from public API using a child of
@@ -75,11 +75,14 @@ def method(name, *, no_payload=False, endpoints=None):
 
         # pylint: disable=protected-access
         if endpoints is None:
-            func._rpcname = ((name, None),)
+            func.rpcnames = ((name, None),)
         else:
-            func._rpcname = tuple(
+            func.rpcnames = tuple(
                 (name.format(endpoint=endpoint), endpoint)
                 for endpoint in endpoints)
+
+        func.classifiers = classifiers
+
         return func
 
     return decorator
@@ -133,43 +136,45 @@ class AbstractQubesAPI(object):
         #: is this operation cancellable?
         self.cancellable = False
 
-        untrusted_candidates = []
-        for attr in dir(self):
-            func = getattr(self, attr)
+        candidates = list(self.list_methods(self.method))
+
+        if not candidates:
+            raise ProtocolError('no such method: {!r}'.format(self.method))
+
+        assert len(candidates) == 1, \
+            'multiple candidates for method {!r}'.format(self.method)
 
+        #: the method to execute
+        self._handler = candidates[0]
+        self._running_handler = None
+
+    @classmethod
+    def list_methods(cls, select_method=None):
+        for attr in dir(cls):
+            func = getattr(cls, attr)
             if not callable(func):
                 continue
 
             try:
                 # pylint: disable=protected-access
-                for mname, endpoint in func._rpcname:
-                    if mname != self.method:
-                        continue
-                    untrusted_candidates.append((func, endpoint))
+                rpcnames = func.rpcnames
             except AttributeError:
                 continue
 
-        if not untrusted_candidates:
-            raise ProtocolError('no such method: {!r}'.format(self.method))
-
-        assert len(untrusted_candidates) == 1, \
-            'multiple candidates for method {!r}'.format(self.method)
-
-        #: the method to execute
-        self._handler = untrusted_candidates[0]
-        self._running_handler = None
-        del untrusted_candidates
+            for mname, endpoint in rpcnames:
+                if select_method is None or mname == select_method:
+                    yield (func, mname, endpoint)
 
     def execute(self, *, untrusted_payload):
         '''Execute management operation.
 
         This method is a coroutine.
         '''
-        handler, endpoint = self._handler
+        handler, _, endpoint = self._handler
         kwargs = {}
         if endpoint is not None:
             kwargs['endpoint'] = endpoint
-        self._running_handler = asyncio.ensure_future(handler(
+        self._running_handler = asyncio.ensure_future(handler(self,
             untrusted_payload=untrusted_payload, **kwargs))
         return self._running_handler