Always update existing matching endpoints

There is no usecase for having 2 endpoints that have the same Region,
interface, service_name and service_type.

The keystone module should default to update these endpoints if the url
is different, but the Region, interface, service_name and service_type
match.

This will make the default behaviour of state "present" to match that of
state "update".

Change-Id: I0ade538e20f2a926b33c1637446c2d4f650cd13d

library/keystone

@@ -200,7 +200,8 @@ options:
         default: True
     state:
         description:
-            - Ensuring the endpoint is either present, absent, or update
+            - Ensuring the endpoint is either present, absent.
+            - It always ensures endpoint is updated to latest url.
         required: False
         default: 'present'
     command:
@@ -1118,9 +1119,24 @@ class ManageKeystone(object):
             )
             if state == 'present':
                 ''' Creating an endpoint for this url
-                    (if it does not exist)
+                    (if it does not exist) or updating
+                    an existing endpoint that matches
+                    the service type, name, interface
+                    and region.
                 '''
-                if endpoint is None:
+                similar_endpoint = self._get_endpoint_by_details(
+                    region=region,
+                    service_id=service.id,
+                    interface=interface
+                )
+                if similar_endpoint is not None:
+                    if similar_endpoint.url != url:
+                        self.state_change = True
+                        endpoint = self.keystone.endpoints.update(
+                            endpoint=similar_endpoint,
+                            url=url
+                        )
+                elif endpoint is None:
                     self.state_change = True
                     endpoint = self.keystone.endpoints.create(
                         region=region,
@@ -1128,10 +1144,13 @@ class ManageKeystone(object):
                         url=url,
                         interface=interface
                     )
+            # The update state is deprecated and should be removed in Q
             elif state == 'update':
                 ''' Checking if there is a similar endpoint with a
                     different url. Update it if there is one, create
-                    if there is none.
+                    if there is none. Update is deprecated and will
+                    be removed in Q. "Present" achieves the same
+                    result.
                 '''
                 similar_endpoint = self._get_endpoint_by_details(
                     region=region,
@@ -1263,6 +1282,7 @@ class ManageKeystone(object):
         )
 
 
+# TODO(evrardjp): Deprecate state=update in Q.
 def main():
     module = AnsibleModule(
         argument_spec=dict(

releasenotes/notes/keystone_plugin_default_update-c025bd5508069df3.yaml

@@ -0,0 +1,12 @@
+---
+features:
+  - The default behaviour of ``ensure_endpoint`` in the
+    keystone module has changed to update an existing
+    endpoint, if one exists that matches the service
+    name, type, region and interface. This ensures that
+    no duplicate service entries can exist per region.
+deprecations:
+  - The ``update`` state for the ``ensure_endpoint``
+    method of the ``keystone`` module is now deprecated,
+    and will be removed in the Queens cycle. Setting
+    state to ``present`` will achieve the same result.