Handle old status-less placement service

Older versions of placement didn't include the status field
in their version discovery documents. This was fixed in
placement in https://review.opendev.org/575117, but there
are clouds out there in the wild running this version
and SDK bombs out trying to talk to them.

Change-Id: I152f0c626b358328cedd404c8fc8d0bee46d2991

openstack/config/cloud_region.py

@@ -321,6 +321,10 @@ class CloudRegion(object):
         else:
             return 'unknown'
 
+    def set_service_value(self, key, service_type, value):
+        key = _make_key(key, service_type)
+        self.config[key] = value
+
     def set_session_constructor(self, session_constructor):
         """Sets the Session constructor."""
         self._session_constructor = session_constructor
@@ -645,7 +649,7 @@ class CloudRegion(object):
             self.get_interface(service_type), {})
         return interface_versions.get(service_type, [])
 
-    def _get_hardcoded_endpoint(self, service_type, constructor):
+    def _get_endpoint_from_catalog(self, service_type, constructor):
         adapter = constructor(
             session=self.get_session(),
             service_type=self.get_service_type(service_type),
@@ -653,7 +657,11 @@ class CloudRegion(object):
             interface=self.get_interface(service_type),
             region_name=self.get_region_name(service_type),
         )
-        endpoint = adapter.get_endpoint()
+        return adapter.get_endpoint()
+
+    def _get_hardcoded_endpoint(self, service_type, constructor):
+        endpoint = self._get_endpoint_from_catalog(
+            service_type, constructor)
         if not endpoint.rstrip().rsplit('/')[-1] == 'v2.0':
             if not endpoint.endswith('/'):
                 endpoint += '/'

openstack/service_description.py

@@ -89,13 +89,38 @@ class ServiceDescription(object):
                 # The keystone proxy has a method called get_endpoint
                 # that is about managing keystone endpoints. This is
                 # unfortunate.
-                endpoint = proxy_mod.Proxy.get_endpoint(proxy)
+                try:
+                    endpoint = proxy_mod.Proxy.get_endpoint(proxy)
+                except IndexError:
+                    # It's best not to look to closely here. This is
+                    # to support old placement.
+                    # There was a time when it had no status entry
+                    # in its version discovery doc (OY) In this case,
+                    # no endpoints get through version discovery
+                    # filtering. In order to deal with that, catch
+                    # the IndexError thrown by keystoneauth and
+                    # set an endpoint_override for the user to the
+                    # url in the catalog and try again.
+                    self._set_override_from_catalog(instance.config)
+                    proxy = self._make_proxy(instance)
+                    endpoint = proxy_mod.Proxy.get_endpoint(proxy)
                 if instance._strict_proxies:
                     self._validate_proxy(proxy, endpoint)
                 proxy._connection = instance
             instance._proxies[self.service_type] = proxy
         return instance._proxies[self.service_type]
 
+    def _set_override_from_catalog(self, config):
+        override = config._get_endpoint_from_catalog(
+            self.service_type,
+            proxy_mod.Proxy,
+        )
+        config.set_service_value(
+            'endpoint_override',
+            self.service_type,
+            override,
+        )
+
     def _validate_proxy(self, proxy, endpoint):
         exc = None
         service_url = getattr(proxy, 'skip_discovery', None)

openstack/tests/unit/base.py

@@ -532,9 +532,10 @@ class TestCase(base.TestCase):
             uri=compute_discovery_url,
             text=open(discovery_fixture, 'r').read())
 
-    def get_placement_discovery_mock_dict(self):
+    def get_placement_discovery_mock_dict(
+            self, discovery_fixture='placement.json'):
         discovery_fixture = os.path.join(
-            self.fixtures_directory, "placement.json")
+            self.fixtures_directory, discovery_fixture)
         return dict(method='GET', uri="https://placement.example.com/",
                     text=open(discovery_fixture, 'r').read())
 
@@ -580,9 +581,9 @@ class TestCase(base.TestCase):
         self.__do_register_uris([
             self.get_cinder_discovery_mock_dict()])
 
-    def use_placement(self):
+    def use_placement(self, **kwargs):
         self.__do_register_uris([
-            self.get_placement_discovery_mock_dict()])
+            self.get_placement_discovery_mock_dict(**kwargs)])
 
     def use_designate(self):
         # NOTE(slaweq): This method is only meant to be used in "setUp"

openstack/tests/unit/fixtures/bad-placement.json

@@ -0,0 +1,10 @@
+{
+    "versions": [
+        {
+            "id": "v1.0",
+            "links": [{"href": "", "rel": "self"}],
+            "max_version": "1.17",
+            "min_version": "1.0"
+        }
+    ]
+}

openstack/tests/unit/test_placement_rest.py

@@ -69,3 +69,35 @@ class TestPlacementRest(base.TestCase):
             (1, 17),
             self.cloud.placement.get_endpoint_data().max_microversion)
         self.assert_calls()
+
+
+class TestBadPlacementRest(base.TestCase):
+
+    def setUp(self):
+        super(TestBadPlacementRest, self).setUp()
+        # The bad-placement.json is for older placement that was
+        # missing the status field from its discovery doc. This
+        # lets us show that we can talk to such a placement.
+        self.use_placement(discovery_fixture='bad-placement.json')
+
+    def _register_uris(self, status_code=None):
+        uri = dict(
+            method='GET',
+            uri=self.get_mock_url(
+                'placement', 'public', append=['allocation_candidates']),
+            json={})
+        if status_code is not None:
+            uri['status_code'] = status_code
+        self.register_uris([uri])
+
+    def _validate_resp(self, resp, status_code):
+        self.assertEqual(status_code, resp.status_code)
+        self.assertEqual(
+            'https://placement.example.com/allocation_candidates',
+            resp.url)
+        self.assert_calls()
+
+    def test_discovery(self):
+        self._register_uris()
+        rs = self.cloud.placement.get('/allocation_candidates')
+        self._validate_resp(rs, 200)

releasenotes/notes/old-placement-4b3c34abb8fe7b81.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Workaround an issue using openstacksdk with older versions of
+    the placement service that are missing a status field in
+    their version discovery doc.