Find context arg by type rather than by name.

This requires changes to all the tests that were passing
in a string as a bogus context; that seems like an improvement.

Change-Id: Ib8fc83cbda25a1cfa8794b72dc13f666549ef892

nova/exception.py

@@ -25,7 +25,7 @@ SHOULD include dedicated exception logging.
 """
 
 import functools
-import inspect
+import itertools
 import sys
 
 import webob.exc
@@ -1073,19 +1073,17 @@ class CouldNotFetchImage(NovaException):
 
 
 def get_context_from_function_and_args(function, args, kwargs):
-    """Find an arg named 'context' and return the value.
+    """Find an arg of type RequestContext and return it.
 
        This is useful in a couple of decorators where we don't
        know much about the function we're wrapping.
     """
-    context = None
-    if 'context' in kwargs.keys():
-        context = kwargs['context']
-    else:
-        (iargs, _iva, _ikw, _idf) = inspect.getargspec(function)
-        if 'context' in iargs:
-            index = iargs.index('context')
-            if len(args) > index:
-                context = args[index]
 
-    return context
+    # import here to avoid circularity:
+    from nova import context
+
+    for arg in itertools.chain(kwargs.values(), args):
+        if isinstance(arg, context.RequestContext):
+            return arg
+
+    return None

nova/tests/test_notifier.py

@@ -14,6 +14,7 @@
 #    under the License.
 
 import nova
+from nova import context
 from nova import flags
 from nova import log
 import nova.notifier.no_op_notifier
@@ -21,6 +22,10 @@ from nova.notifier import api as notifier_api
 from nova import test
 
 
+ctxt = context.get_admin_context()
+ctxt2 = context.get_admin_context()
+
+
 class NotifierTestCase(test.TestCase):
     """Test case for notifications"""
     def setUp(self):
@@ -36,7 +41,7 @@ class NotifierTestCase(test.TestCase):
         self.stubs.Set(nova.notifier.no_op_notifier, 'notify',
                 mock_notify)
 
-        notifier_api.notify('contextarg', 'publisher_id', 'event_type',
+        notifier_api.notify(ctxt, 'publisher_id', 'event_type',
                             nova.notifier.api.WARN, dict(a=3))
         self.assertEqual(self.notify_called, True)
 
@@ -53,11 +58,11 @@ class NotifierTestCase(test.TestCase):
                 self.assertEqual(message[k], v)
             self.assertTrue(len(message['message_id']) > 0)
             self.assertTrue(len(message['timestamp']) > 0)
-            self.assertEqual(context, 'contextarg')
+            self.assertEqual(context, ctxt)
 
         self.stubs.Set(nova.notifier.no_op_notifier, 'notify',
                 message_assert)
-        notifier_api.notify('contextarg', 'publisher_id', 'event_type',
+        notifier_api.notify(ctxt, 'publisher_id', 'event_type',
                             nova.notifier.api.WARN, dict(a=3))
 
     def test_send_rabbit_notification(self):
@@ -69,14 +74,14 @@ class NotifierTestCase(test.TestCase):
             self.mock_notify = True
 
         self.stubs.Set(nova.rpc, 'notify', mock_notify)
-        notifier_api.notify('contextarg', 'publisher_id', 'event_type',
+        notifier_api.notify(ctxt, 'publisher_id', 'event_type',
                             nova.notifier.api.WARN, dict(a=3))
 
         self.assertEqual(self.mock_notify, True)
 
     def test_invalid_priority(self):
         self.assertRaises(nova.notifier.api.BadPriorityException,
-                notifier_api.notify, 'contextarg', 'publisher_id',
+                notifier_api.notify, ctxt, 'publisher_id',
                 'event_type', 'not a priority', dict(a=3))
 
     def test_rabbit_priority_queue(self):
@@ -92,7 +97,7 @@ class NotifierTestCase(test.TestCase):
             self.test_topic = topic
 
         self.stubs.Set(nova.rpc, 'notify', mock_notify)
-        notifier_api.notify('contextarg', 'publisher_id',
+        notifier_api.notify(ctxt, 'publisher_id',
                             'event_type', 'DEBUG', dict(a=3))
         self.assertEqual(self.test_topic, 'testnotify.debug')
 
@@ -161,17 +166,17 @@ class NotifierTestCase(test.TestCase):
                 mock_notify)
 
         # Test positional context
-        self.assertEqual(3, example_api(1, 2, "contextname"))
+        self.assertEqual(3, example_api(1, 2, ctxt))
         self.assertEqual(self.notify_called, True)
-        self.assertEqual(self.context_arg, "contextname")
+        self.assertEqual(self.context_arg, ctxt)
 
         self.notify_called = False
         self.context_arg = None
 
         # Test named context
-        self.assertEqual(3, example_api2(1, 2, context="contextname2"))
+        self.assertEqual(3, example_api2(1, 2, context=ctxt2))
         self.assertEqual(self.notify_called, True)
-        self.assertEqual(self.context_arg, "contextname2")
+        self.assertEqual(self.context_arg, ctxt2)
 
         # Test missing context
         self.assertEqual(3, example_api2(1, 2, bananas="delicious"))