Bail earlier on a version mismatch for a supported service

When we can't find a version for a service we do know about, the
behavior of falling through to an empty Proxy just leads to
massive end-user confusion. Throw an error.

Change-Id: I7625a2b076fcebe2d66c412503fe3e7681f26918

openstack/service_description.py

@@ -177,7 +177,15 @@ class ServiceDescription(object):
             **version_kwargs
         )
         found_version = temp_adapter.get_api_major_version()
-        if found_version is None:
+        if found_version is None and version_kwargs:
+            raise exceptions.NotSupported(
+                "The {service_type} service for {cloud}:{region_name}"
+                " exists but does not have any supported versions.".format(
+                    service_type=self.service_type,
+                    cloud=instance.name,
+                    region_name=instance.config.region_name))
+        proxy_class = self.supported_versions.get(str(found_version[0]))
+        if not proxy_class:
             # Maybe openstacksdk is being used for the passthrough
             # REST API proxy layer for an unknown service in the
             # service catalog that also doesn't have any useful

openstack/tests/unit/fixtures/bad-glance-version.json

@@ -0,0 +1,15 @@
+{
+  "versions": [
+    {
+      "status": "CURRENT",
+      "updated": "2013-07-23T11:33:21Z",
+      "links": [
+        {
+          "href": "https://example.com/image/v7/",
+          "rel": "self"
+        }
+      ],
+      "id": "v7"
+    }
+  ]
+}

openstack/tests/unit/fixtures/catalog-bogus-glance.json

@@ -0,0 +1,52 @@
+{
+  "token": {
+    "audit_ids": [
+      "Rvn7eHkiSeOwucBIPaKdYA"
+    ],
+    "catalog": [
+      {
+        "endpoints": [
+          {
+            "id": "32466f357f3545248c47471ca51b0d3a",
+            "interface": "public",
+            "region": "RegionOne",
+            "url": "https://example.com/image/"
+          }
+        ],
+        "name": "glance",
+        "type": "image"
+      }
+    ],
+    "expires_at": "9999-12-31T23:59:59Z",
+    "issued_at": "2016-12-17T14:25:05.000000Z",
+    "methods": [
+      "password"
+    ],
+    "project": {
+      "domain": {
+        "id": "default",
+        "name": "default"
+      },
+      "id": "1c36b64c840a42cd9e9b931a369337f0",
+      "name": "Default Project"
+    },
+    "roles": [
+      {
+        "id": "9fe2ff9ee4384b1894a90878d3e92bab",
+        "name": "_member_"
+      },
+      {
+        "id": "37071fc082e14c2284c32a2761f71c63",
+        "name": "swiftoperator"
+      }
+    ],
+    "user": {
+      "domain": {
+        "id": "default",
+        "name": "default"
+      },
+      "id": "c17534835f8f42bf98fc367e0bf35e09",
+      "name": "mordred"
+    }
+  }
+}

openstack/tests/unit/test_missing_version.py

@@ -0,0 +1,40 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import testtools
+
+from openstack import exceptions
+from openstack import proxy
+from openstack.tests.unit import base
+
+
+class TestMissingVersion(base.TestCase):
+
+    def setUp(self):
+        super(TestMissingVersion, self).setUp()
+        self.use_keystone_v3(catalog='catalog-bogus-glance.json')
+        self.use_glance(
+            image_version_json='bad-glance-version.json',
+            image_discovery_url='https://example.com/image/')
+
+    def test_unsupported_version(self):
+
+        with testtools.ExpectedException(exceptions.NotSupported):
+            self.cloud.image.get('/')
+
+        self.assert_calls()
+
+    def test_unsupported_version_override(self):
+        self.cloud.config.config['image_api_version'] = '7'
+        self.assertTrue(isinstance(self.cloud.image, proxy.Proxy))
+
+        self.assert_calls()

releasenotes/notes/bail-on-failed-service-cf299c37d5647b08.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    When a known service cannot be resolved to a supported version,
+    an exception is now thrown instead of just returning a blank
+    Proxy object. This allows returning sane errors to users.