Add warning log when deprecated v2 and v3 code get used

This patch adds warning log when deprecated v2 and v3 wsgi stack
running. It is good for notify user update their environment.

Change-Id: Ifce7ee1c97ef908bae56dbb72f79c39e3c8aa65e

nova/api/openstack/compute/__init__.py

@@ -19,6 +19,7 @@
 """
 
 from oslo_config import cfg
+from oslo_log import log as logging
 
 import nova.api.openstack
 from nova.api.openstack.compute import extension_info
@@ -35,6 +36,7 @@
 from nova.api.openstack.compute.legacy_v2 import servers as v2_servers
 from nova.api.openstack.compute.legacy_v2 import versions \
         as legacy_v2_versions
+from nova.i18n import _LW
 
 allow_instance_snapshots_opt = cfg.BoolOpt('allow_instance_snapshots',
         default=True,
@@ -43,13 +45,26 @@
 CONF = cfg.CONF
 CONF.register_opt(allow_instance_snapshots_opt)
 
+LOG = logging.getLogger(__name__)
+
 
 class APIRouter(nova.api.openstack.APIRouter):
     """Routes requests on the OpenStack API to the appropriate controller
     and method.
     """
     ExtensionManager = v2_extensions.ExtensionManager
 
+    def __init__(self, ext_mgr=None, init_only=None):
+        LOG.warning(_LW(
+            "Deprecated: Starting with the Liberty release, the v2 API was "
+            "already deprecated and the v2.1 API is set as the default. Nova "
+            "also supports v2.1 API legacy v2 compatible mode for switching "
+            "to v2.1 API smoothly. For more information on how to configure "
+            "v2.1 API and legacy v2 compatible mode, please refer Nova "
+            "api-paste.ini sample file."))
+        super(APIRouter, self).__init__(ext_mgr=ext_mgr,
+                                        init_only=init_only)
+
     def _setup_routes(self, mapper, ext_mgr, init_only):
         if init_only is None or 'versions' in init_only:
             self.resources['versions'] = legacy_v2_versions.create_resource()
@@ -155,6 +170,10 @@ class APIRouterV3(nova.api.openstack.APIRouterV21):
     and method.
     """
     def __init__(self, init_only=None):
+        LOG.warning(_LW(
+            "Deprecated: The v3 API was deprecated. The v2.1 API replaces it "
+            "as the Nova API, please refer Nova api-paste.ini sample file for "
+            "how to configure v2.1 API."))
         self._loaded_extension_info = extension_info.LoadedExtensionInfo()
         super(APIRouterV3, self).__init__(init_only, v3mode=True)