[feature] pluggable backends and api registry

the idea behind this mechanism (partially implemented for that) is to be
able to check the backend output against some type annotations.

We want to be able to detect if a given backend (real services or
authoritative mocks) have diverged from what's specified in the API
annotations.

1 files changed, 54 insertions, 0 deletions

diff --git a/src/leap/bitmask/core/api.py b/src/leap/bitmask/core/api.py
new file mode 100644
index 00000000..9f3725dc
--- /dev/null
+++ b/src/leap/bitmask/core/api.py
@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -*-
+# api.py
+# Copyright (C) 2016 LEAP Encryption Acess Project
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Registry for the public API for the Bitmask Backend.
+"""
+from collections import OrderedDict
+
+registry = OrderedDict()
+
+
+class APICommand(type):
+    """
+    A metaclass to keep a global registry of all the methods that compose the
+    public API for the Bitmask Backend.
+    """
+    def __init__(cls, name, bases, attrs):
+        for key, val in attrs.iteritems():
+            properties = getattr(val, 'register', None)
+            label = getattr(cls, 'label', None)
+            if label:
+                name = label
+            if properties is not None:
+                registry['%s.%s' % (name, key)] = properties
+
+
+def register_method(*args):
+    """
+    This method gathers info about all the methods that are supposed to
+    compose the public API to communicate with the backend.
+
+    It sets up a register property for any method that uses it.
+    A type annotation is supposed to be in this property.
+    The APICommand metaclass collects these properties of the methods and
+    stores them in the global api_registry object, where they can be
+    introspected at runtime.
+    """
+    def decorator(f):
+        f.register = tuple(args)
+        return f
+    return decorator