Add support for passing optional `requested_roles` attribute

When passing ``requested_roles`` down the ``identity-service``
relation the Keystone charm will create the listed roles for you.

Useful for charm authors implementing charms with specific role
requirements.

Change-Id: I7c1eedb1e78ffc53ac3e0df81f6b52358dd8dfa5
Closes-Bug: #1813602

requires.py

@@ -119,7 +119,7 @@ class KeystoneRequires(RelationBase):
         return True
 
     def register_endpoints(self, service, region, public_url, internal_url,
-                           admin_url):
+                           admin_url, requested_roles=None):
         """
         Register this service with keystone
         """
@@ -130,6 +130,9 @@ class KeystoneRequires(RelationBase):
             'admin_url': admin_url,
             'region': region,
         }
+        if requested_roles:
+            relation_info.update(
+                {'requested_roles': ','.join(requested_roles)})
         self.set_local(**relation_info)
         self.set_remote(**relation_info)
 

unit_tests/test_requires.py

@@ -224,6 +224,22 @@ class TestKeystoneRequires(unittest.TestCase):
         self.set_local.assert_called_once_with(**result)
         self.set_remote.assert_called_once_with(**result)
 
+    def test_register_endpoints_requested_roles(self):
+        self.patch_kr('set_local')
+        self.patch_kr('set_remote')
+        self.kr.register_endpoints('s', 'r', 'p_url', 'i_url', 'a_url',
+                                   requested_roles=['role1', 'role2'])
+        result = {
+            'service': 's',
+            'public_url': 'p_url',
+            'internal_url': 'i_url',
+            'admin_url': 'a_url',
+            'region': 'r',
+            'requested_roles': 'role1,role2',
+        }
+        self.set_local.assert_called_once_with(**result)
+        self.set_remote.assert_called_once_with(**result)
+
     def test_request_keystone_endpoint_information(self):
         self.patch_kr('set_local')
         self.patch_kr('set_remote')