Add base for notifier plugins

OSprofiler will support notifers for different collectors.

So add base for plugins.

In next patch we will add osprofiler oslo.messaging based notifier

Change-Id: Iad14c67f1e7cdbd0f4bcc64200fecf048316e385

osprofiler/_notifiers/base.py

@@ -0,0 +1,34 @@
+# Copyright 2014 Mirantis Inc.
+# All Rights Reserved.
+#
+#    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.
+
+from osprofiler import _utils as utils
+
+
+class Notifier(object):
+
+    def notify(self, info):
+        """This method will be called on each notifier.notify() call.
+
+        To add new drivers you should, create new subclass of this class and
+        implement notify method.
+        """
+
+    @staticmethod
+    def factory(name, *args, **kwargs):
+        for driver in utils.itersubclasses(Notifier):
+            if name == driver.__name__:
+                return driver(*args, **kwargs).notify
+
+        raise TypeError("There is no driver, with name: %s" % name)

osprofiler/_notifiers/messaging.py

@@ -0,0 +1,14 @@
+# Copyright 2014 Mirantis Inc.
+# All Rights Reserved.
+#
+#    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.

osprofiler/_utils.py

@@ -89,3 +89,24 @@ def signed_unpack(data, hmac_data, hmac_key):
         return json.loads(binary_decode(base64.urlsafe_b64decode(data)))
     except Exception:
         return None
+
+
+def itersubclasses(cls, _seen=None):
+    """Generator over all subclasses of a given class in depth first order."""
+
+    if not isinstance(cls, type):
+        raise TypeError("itersubclasses must be called with "
+                        "new-style classes, not %.100r" % cls)
+
+    _seen = _seen or set()
+    try:
+        subs = cls.__subclasses__()
+    except TypeError:   # fails only when cls is type
+        subs = cls.__subclasses__(cls)
+    subs = cls.__subclasses__()
+    for sub in subs:
+        if sub not in _seen:
+            _seen.add(sub)
+            yield sub
+            for sub in itersubclasses(sub, _seen):
+                yield sub

osprofiler/notifier.py

@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from osprofiler._notifiers import base
+
 
 def _noop_notifier(info):
     """Do nothing on notify()."""
@@ -45,3 +47,15 @@ def set(notifier):
     """
     global __notifier
     __notifier = notifier
+
+
+def create(plugin_name, *args, **kwargs):
+    """Create notifier based on specified plugin_name
+
+    :param plugin_name: Name of plugin that creates notifier
+    :param *args: args that will be passed to plugin init method
+    :param **kwargs: kwargs that will be passed to plugin init method
+    :returns: Callable notifier method
+    :raise TypeError: In case of invalid name of plugin raises TypeError
+    """
+    return base.Notifier.factory(plugin_name, *args, **kwargs)

tests/notifiers/test_base.py

@@ -0,0 +1,48 @@
+# Copyright 2014 Mirantis Inc.
+# All Rights Reserved.
+#
+#    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.
+
+from osprofiler._notifiers import base
+from tests import test
+
+
+class NotifierBaseTestCase(test.TestCase):
+
+    def test_factory(self):
+
+        class A(base.Notifier):
+
+            def notify(self, a):
+                return a
+
+        self.assertEqual(base.Notifier.factory("A")(10), 10)
+
+    def test_factory_with_args(self):
+
+        class B(base.Notifier):
+
+            def __init__(self, a, b=10):
+                self.a = a
+                self.b = b
+
+            def notify(self, c):
+                return self.a + self.b + c
+
+        self.assertEqual(base.Notifier.factory("B", 5, b=7)(10), 22)
+
+    def test_factory_not_found(self):
+        self.assertRaises(TypeError, base.Notifier.factory, "non existing")
+
+    def test_notify(self):
+        base.Notifier().notify("")

tests/test_notifier.py

@@ -13,8 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from osprofiler import notifier
+import mock
 
+from osprofiler import notifier
 from tests import test
 
 
@@ -34,3 +35,17 @@ class NotifierTestCase(test.TestCase):
 
     def test_get_default_notifier(self):
         self.assertEqual(notifier.get(), notifier._noop_notifier)
+
+    def test_notify(self):
+        m = mock.MagicMock()
+        notifier.set(m)
+        notifier.notify(10)
+
+        m.assert_called_once_with(10)
+
+    @mock.patch("osprofiler.notifier.base.Notifier.factory")
+    def test_create(self, mock_factory):
+
+        result = notifier.create("test", 10, b=20)
+        mock_factory.assert_called_once_with("test", 10, b=20)
+        self.assertEqual(mock_factory.return_value, result)

tests/test_utils.py

@@ -76,3 +76,19 @@ class UtilsTestCase(test.TestCase):
         hmac_data = utils.generate_hmac(data, hmac)
 
         self.assertIsNone(utils.signed_unpack(data, hmac_data, hmac))
+
+    def test_itersubclasses(self):
+
+        class A(object):
+            pass
+
+        class B(A):
+            pass
+
+        class C(A):
+            pass
+
+        class D(C):
+            pass
+
+        self.assertEqual([B, C, D], list(utils.itersubclasses(A)))