Added ability to load specific extensions.

For example, the following nova.conf configuration file:

--osapi_compute_extension=nova.api.openstack.compute.contrib.select_extensions
--osapi_compute_ext_list=Createserverext,Extended_status

Would load only the Createserverext and Extended_status extensions.

Change-Id: I8c2a444683c6e4114875827b44ef01e457eb94ac

3 files changed, 25 insertions, 6 deletions

diff --git a/nova/api/openstack/compute/contrib/__init__.py b/nova/api/openstack/compute/contrib/__init__.py
index 2713a82f4..eaa9557af 100644
--- a/nova/api/openstack/compute/contrib/__init__.py
+++ b/nova/api/openstack/compute/contrib/__init__.py
@@ -21,12 +21,19 @@ It can't be called 'extensions' because that causes namespacing problems.
 
 """
 
+from nova import flags
 from nova import log as logging
 from nova.api.openstack import extensions
 
 
+FLAGS = flags.FLAGS
 LOG = logging.getLogger('nova.api.openstack.compute.contrib')
 
 
 def standard_extensions(ext_mgr):
     extensions.load_standard_extensions(ext_mgr, LOG, __path__, __package__)
+
+
+def select_extensions(ext_mgr):
+    extensions.load_standard_extensions(ext_mgr, LOG, __path__, __package__,
+                                        FLAGS.osapi_compute_ext_list)
diff --git a/nova/api/openstack/extensions.py b/nova/api/openstack/extensions.py
index b55c05d7c..33cd0bf57 100644
--- a/nova/api/openstack/extensions.py
+++ b/nova/api/openstack/extensions.py
@@ -309,7 +309,7 @@ def wrap_errors(fn):
     return wrapped
 
 
-def load_standard_extensions(ext_mgr, logger, path, package):
+def load_standard_extensions(ext_mgr, logger, path, package, ext_list=None):
     """Registers all standard API extensions."""
 
     # Walk through all the modules in our directory...
@@ -331,13 +331,18 @@ def load_standard_extensions(ext_mgr, logger, path, package):
                 continue
 
             # Try loading it
-            classname = ("%s%s.%s.%s%s" %
-                         (package, relpkg, root,
-                          root[0].upper(), root[1:]))
+            classname = "%s%s" % (root[0].upper(), root[1:])
+            classpath = ("%s%s.%s.%s" %
+                         (package, relpkg, root, classname))
+
+            if ext_list is not None and classname not in ext_list:
+                logger.debug("Skipping extension: %s" % classpath)
+                continue
+
             try:
-                ext_mgr.load_extension(classname)
+                ext_mgr.load_extension(classpath)
             except Exception as exc:
-                logger.warn(_('Failed to load extension %(classname)s: '
+                logger.warn(_('Failed to load extension %(classpath)s: '
                               '%(exc)s') % locals())
 
         # Now, let's consider any subdirectories we may have...
diff --git a/nova/api/openstack/volume/contrib/__init__.py b/nova/api/openstack/volume/contrib/__init__.py
index 58c0413ab..01b585c69 100644
--- a/nova/api/openstack/volume/contrib/__init__.py
+++ b/nova/api/openstack/volume/contrib/__init__.py
@@ -21,12 +21,19 @@ It can't be called 'extensions' because that causes namespacing problems.
 
 """
 
+from nova import flags
 from nova import log as logging
 from nova.api.openstack import extensions
 
 
+FLAGS = flags.FLAGS
 LOG = logging.getLogger('nova.api.openstack.volume.contrib')
 
 
 def standard_extensions(ext_mgr):
     extensions.load_standard_extensions(ext_mgr, LOG, __path__, __package__)
+
+
+def select_extensions(ext_mgr):
+    extensions.load_standard_extensions(ext_mgr, LOG, __path__, __package__,
+                                        FLAGS.osapi_volume_ext_list)