Check subnetpool extension support

This fix is to add support for checking subnetpool extension support
at Kuryr server startup time. If required extension is found missing,
startup script will exit and kuryr driver server will not start.

Change-Id: I264be36c1b3b23517f4f2ff741f51a5a86b2ae9f
Closes-Bug: #1498393

kuryr/common/exceptions.py

@@ -26,8 +26,16 @@ class BindingFailure(KuryrException):
 class DuplicatedResourceException(KuryrException):
     """Exception represents there're multiple resources for the ID.
 
-    This exception is thrown when you query the Neutron resouce associated with
-    the ID and you get multiple resources.
+    For example, this exception is thrown when you query the Neutron resource
+    associated with the ID and you get multiple resources.
+    """
+
+
+class MandatoryApiMissing(KuryrException):
+    """Exception represents that mandatory api is not found.
+
+    For example, this exception is thrown when expected neutron
+    extension(subnetpools) APIs are not found.
     """
 
 

kuryr/controllers.py

@@ -24,6 +24,8 @@ from kuryr.common import exceptions
 from kuryr import schemata
 from kuryr import utils
 
+MANDATORY_NEUTRON_EXTENSION = "subnet_allocation"
+
 cfg.CONF.import_group('neutron_client', 'kuryr.common.config')
 cfg.CONF.import_group('keystone_client', 'kuryr.common.config')
 
@@ -45,6 +47,19 @@ else:
     app.neutron = utils.get_neutron_client_simple(
         url=neutron_uri, token=auth_token)
 
+
+def check_for_neutron_ext_support():
+    """Validates for mandatory extension support availability in neutron.
+    """
+    try:
+        app.neutron.show_extension(MANDATORY_NEUTRON_EXTENSION)
+    except n_exceptions.NeutronClientException as e:
+        if e.status_code == n_exceptions.NotFound.status_code:
+            raise exceptions.MandatoryApiMissing(
+                            "Neutron extension with alias '{0}' not found"
+                            .format(MANDATORY_NEUTRON_EXTENSION))
+
+
 # TODO(tfukushima): Retrieve the following subnet names from the config file.
 SUBNET_POOLS_V4 = [
     p.strip() for p in os.environ.get('SUBNET_POOLS_V4', 'kuryr').split(',')]

kuryr/tests/test_config.py

@@ -12,11 +12,15 @@
 
 import os
 
+from neutronclient.common import exceptions as n_exceptions
+
 from kuryr.common import config
+from kuryr.common import exceptions
+from kuryr import controllers
 from kuryr.tests import base
 
 
-class ConfigurationTest(base.TestCase):
+class ConfigurationTest(base.TestKuryrBase):
 
     def test_defaults(self):
         basepath = os.path.abspath(os.path.join(os.path.dirname(__file__),
@@ -33,3 +37,15 @@ class ConfigurationTest(base.TestCase):
 
         self.assertEqual('http://127.0.0.1:35357',
                          config.CONF.keystone_client.auth_uri)
+
+    def test_check_for_neutron_ext_support_with_ex(self):
+        ext_alias = "subnet_allocation"
+        self.mox.StubOutWithMock(controllers.app.neutron, "show_extension")
+        err = n_exceptions.NotFound.status_code
+        ext_not_found_ex = n_exceptions.NeutronClientException(status_code=err,
+                                                               message="")
+        neutron = controllers.app.neutron
+        neutron.show_extension(ext_alias).AndRaise(ext_not_found_ex)
+        self.mox.ReplayAll()
+        ex = exceptions.MandatoryApiMissing
+        self.assertRaises(ex, controllers.check_for_neutron_ext_support)

scripts/run_server.py

@@ -12,6 +12,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from kuryr import controllers
 from kuryr import server
 
+controllers.check_for_neutron_ext_support()
 server.start()