Handle missing endpoint, region, service

SDK will not return 'ResourceNotFound' for a list operation (like
'services'): it will only do that for a fetch operation (like
'get_service'):

  >>> import openstack
  >>> conn = openstack.connect(cloud='devstack-admin')
  >>> set(conn.identity.services(name='foo'))
  []
  >>> conn.identity.get_service('foo')
  Traceback (most recent call last):
    ...
  openstack.exceptions.NotFoundException: No Service found for foo: Client Error for url: http://example.com/identity/v3/services/foo, Could not find service: foo.

Correct our assumptions here.

Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
Change-Id: I21bfa283c95ace092bc154e28f5d584d027c29f9

oslo_limit/limit.py

@@ -366,57 +366,70 @@ class _EnforcerUtils:
             endpoint = self.connection.get_endpoint(endpoint_id)  # type: ignore
         except os_exceptions.ResourceNotFound:
             raise ValueError(f"Can't find endpoint for {endpoint_id}")
+
         return cast(_endpoint.Endpoint, endpoint)
 
     def _get_endpoint_by_service_lookup(self) -> _endpoint.Endpoint:
         service_type = CONF.oslo_limit.endpoint_service_type
         service_name = CONF.oslo_limit.endpoint_service_name
+
         if not service_type and not service_name:
             raise ValueError(
                 "Either service_type or service_name should be set"
             )
 
-        try:
+        # find service
+
         services = self.connection.services(  # type: ignore
             type=service_type, name=service_name
         )
         services = list(services)
+
         if len(services) > 1:
             raise ValueError("Multiple services found")
-            service_id = services[0].id
-        except os_exceptions.ResourceNotFound:
+
+        if len(services) == 0:
             raise ValueError("Service not found")
 
+        service_id = services[0].id
+
+        # find region (if any)
+
         if CONF.oslo_limit.endpoint_region_name is not None:
-            try:
             regions = self.connection.regions(  # type: ignore
                 name=CONF.oslo_limit.endpoint_region_name
             )
             regions = list(regions)
+
             if len(regions) > 1:
                 raise ValueError("Multiple regions found")
-                region_id = regions[0].id
-            except os_exceptions.ResourceNotFound:
+
+            if len(regions) == 0:
                 raise ValueError("Region not found")
+
+            region_id = regions[0].id
         else:
             region_id = None
 
+        # find endpoint
+
         interface = CONF.oslo_limit.endpoint_interface
         if interface.endswith('URL'):
             interface = interface[:-3]
-        try:
+
         endpoints = self.connection.endpoints(  # type: ignore
             service_id=service_id,
             region_id=region_id,
             interface=interface,
         )
         endpoints = list(endpoints)
-        except os_exceptions.ResourceNotFound:
-            raise ValueError("Endpoint not found")
 
         if len(endpoints) > 1:
             raise ValueError("Multiple endpoints found")
 
+        if len(endpoints) == 0:
+            raise ValueError("Endpoint not found")
+
         return cast(_endpoint.Endpoint, endpoints[0])
 
     @staticmethod

oslo_limit/tests/test_limit.py

@@ -468,7 +468,7 @@ class TestEnforcerUtils(base.BaseTestCase):
         )
         fake_service = service.Service(id='SERVICE_ID')
         self.mock_conn.services.return_value = [fake_service]
-        self.mock_conn.endpoints.side_effect = os_exceptions.ResourceNotFound
+        self.mock_conn.endpoints.return_value = []
 
         self.assertRaises(ValueError, limit._EnforcerUtils)
 
@@ -509,7 +509,7 @@ class TestEnforcerUtils(base.BaseTestCase):
         self.config_fixture.config(
             group='oslo_limit', endpoint_service_name='SERVICE_NAME'
         )
-        self.mock_conn.services.side_effect = os_exceptions.ResourceNotFound
+        self.mock_conn.services.return_value = []
 
         self.assertRaises(ValueError, limit._EnforcerUtils)
 
@@ -564,7 +564,7 @@ class TestEnforcerUtils(base.BaseTestCase):
         self.mock_conn.services.return_value = [fake_service]
         fake_endpoint = endpoint.Endpoint()
         self.mock_conn.endpoints.return_value = [fake_endpoint]
-        self.mock_conn.regions.side_effect = os_exceptions.ResourceNotFound
+        self.mock_conn.regions.return_value = []
 
         self.assertRaises(ValueError, limit._EnforcerUtils)