Driver registry

Uses automatic dependency injection to provide controllers with driver
interfaces (identity_api, token_api, etc).

See tests/test_injection.py for a self-contained example.

Change-Id: I255087de534292fbf57a45b19f97488f831f607c

2 files changed, 144 insertions, 11 deletions

diff --git a/tests/test_auth.py b/tests/test_auth.py
index c0dbbd2c..75f06174 100644
--- a/tests/test_auth.py
+++ b/tests/test_auth.py
@@ -17,13 +17,9 @@ import uuid
 
 import default_fixtures
 
-from keystone import catalog
 from keystone import config
 from keystone import exception
-from keystone import identity
-from keystone.identity.backends import kvs as kvs_identity
 from keystone.openstack.common import timeutils
-from keystone import policy
 from keystone import test
 from keystone import token
 
@@ -56,15 +52,11 @@ class AuthTest(test.TestCase):
     def setUp(self):
         super(AuthTest, self).setUp()
 
-        # load_fixtures checks for 'identity_api' to be defined
-        self.identity_api = kvs_identity.Identity()
+        CONF.identity.driver = 'keystone.identity.backends.kvs.Identity'
+        self.load_backends()
         self.load_fixtures(default_fixtures)
 
-        self.api = token.controllers.Auth(
-            catalog_api=catalog.Manager(),
-            identity_api=identity.Manager(),
-            policy_api=policy.Manager(),
-            token_api=token.Manager())
+        self.api = token.controllers.Auth()
 
     def assertEqualTokens(self, a, b):
         """Assert that two tokens are equal.
diff --git a/tests/test_injection.py b/tests/test_injection.py
new file mode 100644
index 00000000..4953cfca
--- /dev/null
+++ b/tests/test_injection.py
@@ -0,0 +1,141 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2012 OpenStack LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import unittest2 as unittest
+import uuid
+
+from keystone.common import dependency
+
+
+class TestDependencyInjection(unittest.TestCase):
+    def test_dependency_injection(self):
+        class Interface(object):
+            def do_work(self):
+                assert False
+
+        @dependency.provider('first_api')
+        class FirstImplementation(Interface):
+            def do_work(self):
+                return True
+
+        @dependency.provider('second_api')
+        class SecondImplementation(Interface):
+            def do_work(self):
+                return True
+
+        @dependency.requires('first_api', 'second_api')
+        class Consumer(object):
+            def do_work_with_dependencies(self):
+                assert self.first_api.do_work()
+                assert self.second_api.do_work()
+
+        # initialize dependency providers
+        first_api = FirstImplementation()
+        second_api = SecondImplementation()
+
+        # ... sometime later, initialize a dependency consumer
+        consumer = Consumer()
+
+        # the expected dependencies should be available to the consumer
+        self.assertIs(consumer.first_api, first_api)
+        self.assertIs(consumer.second_api, second_api)
+        self.assertIsInstance(consumer.first_api, Interface)
+        self.assertIsInstance(consumer.second_api, Interface)
+        consumer.do_work_with_dependencies()
+
+    def test_dependency_configuration(self):
+        @dependency.provider('api')
+        class Configurable(object):
+            def __init__(self, value=None):
+                self.value = value
+
+            def get_value(self):
+                return self.value
+
+        @dependency.requires('api')
+        class Consumer(object):
+            def get_value(self):
+                return self.api.get_value()
+
+        # initialize dependency providers
+        api = Configurable(value=True)
+
+        # ... sometime later, initialize a dependency consumer
+        consumer = Consumer()
+
+        # the expected dependencies should be available to the consumer
+        self.assertIs(consumer.api, api)
+        self.assertIsInstance(consumer.api, Configurable)
+        self.assertTrue(consumer.get_value())
+
+    def test_inherited_dependency(self):
+        class Interface(object):
+            def do_work(self):
+                assert False
+
+        @dependency.provider('first_api')
+        class FirstImplementation(Interface):
+            def do_work(self):
+                return True
+
+        @dependency.provider('second_api')
+        class SecondImplementation(Interface):
+            def do_work(self):
+                return True
+
+        @dependency.requires('first_api')
+        class ParentConsumer(object):
+            def do_work_with_dependencies(self):
+                assert self.first_api.do_work()
+
+        @dependency.requires('second_api')
+        class ChildConsumer(ParentConsumer):
+            def do_work_with_dependencies(self):
+                assert self.second_api.do_work()
+                super(ChildConsumer, self).do_work_with_dependencies()
+
+        # initialize dependency providers
+        first_api = FirstImplementation()
+        second_api = SecondImplementation()
+
+        # ... sometime later, initialize a dependency consumer
+        consumer = ChildConsumer()
+
+        # dependencies should be naturally inherited
+        self.assertEqual(
+            ParentConsumer._dependencies,
+            set(['first_api']))
+        self.assertEqual(
+            ChildConsumer._dependencies,
+            set(['first_api', 'second_api']))
+        self.assertEqual(
+            consumer._dependencies,
+            set(['first_api', 'second_api']))
+
+        # the expected dependencies should be available to the consumer
+        self.assertIs(consumer.first_api, first_api)
+        self.assertIs(consumer.second_api, second_api)
+        self.assertIsInstance(consumer.first_api, Interface)
+        self.assertIsInstance(consumer.second_api, Interface)
+        consumer.do_work_with_dependencies()
+
+    def test_unresolvable_dependency(self):
+        @dependency.requires(uuid.uuid4().hex)
+        class Consumer(object):
+            pass
+
+        with self.assertRaises(dependency.UnresolvableDependencyException):
+            Consumer()