Check volume endpoint availability in the same order

cinder microversion check (api.cinder.get_microversion) checks
volume endpoint availability in a different order as cinderclient()
does. It does not API_VERSIONS setting in horizon.
As a result, when multiple volume endpoints are configured,
get_microversion() accesses a volume endpoint with a different API
version. At the moment cinder v2 and v3 APIs returns the same info,
so it only affects when cinder v1 endpoint is configured.

This commit introduces a new function _find_cinder_url() to
retrieve a volume endpoint considering API_VERSIONS.

get_auth_params_from_request() is no longer needed and the variable
substitutions are now backed to cinderclient(). It was introduced
so that the memoized decorator worked but the memoized decorator
was improved and we no longer need it.

Change-Id: I69b1fc11caf8a78c49e98aba6c538e5f344b14f2
Closes-Bug: #1864133

openstack_dashboard/api/cinder.py

@@ -201,78 +201,56 @@ class GroupType(base.APIResourceWrapper):
     _attrs = ['id', 'name', 'description', 'is_public', 'group_specs']
 
 
-def get_auth_params_from_request(request):
-    auth_url = base.url_for(request, 'identity')
-    cinder_urls = []
-    for service_name in ('volumev3', 'volumev2', 'volume'):
+def _find_cinder_url(request, version=None):
+    if version is None:
+        api_version = VERSIONS.get_active_version()
+        version = api_version['version']
+    version = base.Version(version)
+
+    # We support only cinder v2 and v3.
+    if version.major == 3:
+        candidates = ['volumev3', 'volume']
+    else:
+        candidates = ['volumev2', 'volume']
+
+    for service_name in candidates:
         try:
-            cinder_url = base.url_for(request, service_name)
-            cinder_urls.append((service_name, cinder_url))
+            return version, base.url_for(request, service_name)
         except exceptions.ServiceCatalogException:
             pass
-    if not cinder_urls:
+    else:
         raise exceptions.ServiceCatalogException(
-            "no volume service configured")
-    cinder_urls = tuple(cinder_urls)  # need to make it cacheable
-    return(
-        request.user.username,
-        request.user.token.id,
-        request.user.tenant_id,
-        cinder_urls,
-        auth_url,
-    )
+            ("Cinder %(version)s requested but no '%(service)s' service "
+             "type available in Keystone catalog.") %
+            {'version': version, 'service': candidates})
 
 
 @memoized
 def cinderclient(request, version=None):
-    if version is None:
-        api_version = VERSIONS.get_active_version()
-        version = api_version['version']
+    version, cinder_url = _find_cinder_url(request, version)
+
     insecure = settings.OPENSTACK_SSL_NO_VERIFY
     cacert = settings.OPENSTACK_SSL_CACERT
 
-    (username, token_id, tenant_id, cinder_urls,
-        auth_url) = get_auth_params_from_request(request)
-    version = base.Version(version)
-    if version.major == 2:
-        service_names = ('volumev2', 'volume')
-    elif version.major == 3:
-        service_names = ('volumev3', 'volume')
-    else:
-        service_names = ('volume',)
-    for name, _url in cinder_urls:
-        if name in service_names:
-            cinder_url = _url
-            break
-    else:
-        raise exceptions.ServiceCatalogException(
-            "Cinder {version} requested but no '{service}' service "
-            "type available in Keystone catalog.".format(version=version,
-                                                         service=service_names)
-        )
     c = cinder_client.Client(
         version,
-        username,
-        token_id,
-        project_id=tenant_id,
-        auth_url=auth_url,
+        request.user.username,
+        request.user.token.id,
+        project_id=request.user.tenant_id,
+        auth_url=base.url_for(request, 'identity'),
         insecure=insecure,
         cacert=cacert,
         http_log_debug=settings.DEBUG,
     )
-    c.client.auth_token = token_id
+    c.client.auth_token = request.user.token.id
     c.client.management_url = cinder_url
     return c
 
 
 def get_microversion(request, features):
-    for service_name in ('volume', 'volumev2', 'volumev3'):
-        try:
-            cinder_url = base.url_for(request, service_name)
-            break
-        except exceptions.ServiceCatalogException:
-            continue
-    else:
+    try:
+        version, cinder_url = _find_cinder_url(request)
+    except exceptions.ServiceCatalogException:
         return None
 
     insecure = settings.OPENSTACK_SSL_NO_VERIFY