This is the groundwork for the upcoming distributed scheduler changes. Nothing is actually wired up here, so it shouldn't break any existing code (and all tests pass).

The goals were to:

1. Define the basic distributed scheduler communication mechanism:
   a. call_zone_method - how each zone can communicate with its children

   b. encrypted child-blobs - how child zones an securely and statelessly report back weight and build-plan info

2. Put in hooks for advanced-filtering (hard-requirements, capabilities) as well as preferences (least-cost-scheduling)

3. Create a base set of dist-scheduler tests that we can extend as we add more functionality.

Next up will be to:

1. Add in a filtering driver

2. Add in a cost-scheduler driver

2 files changed, 45 insertions, 1 deletions

diff --git a/nova/api/openstack/__init__.py b/nova/api/openstack/__init__.py
index 348b70d5b..5b7f080ad 100644
--- a/nova/api/openstack/__init__.py
+++ b/nova/api/openstack/__init__.py
@@ -98,7 +98,8 @@ class APIRouter(wsgi.Router):
             server_members['inject_network_info'] = 'POST'
 
             mapper.resource("zone", "zones", controller=zones.Controller(),
-                        collection={'detail': 'GET', 'info': 'GET'}),
+                        collection={'detail': 'GET', 'info': 'GET',
+                                    'select': 'GET'})
 
             mapper.resource("user", "users", controller=users.Controller(),
                         collection={'detail': 'GET'})
diff --git a/nova/api/openstack/zones.py b/nova/api/openstack/zones.py
index 227ffecdc..af73d8f6d 100644
--- a/nova/api/openstack/zones.py
+++ b/nova/api/openstack/zones.py
@@ -13,7 +13,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import json
+import urlparse
+
+from nova import crypto
 from nova import db
+from nova import exception
 from nova import flags
 from nova import log as logging
 from nova.api.openstack import common
@@ -21,6 +26,12 @@ from nova.scheduler import api
 
 
 FLAGS = flags.FLAGS
+flags.DEFINE_string('build_plan_encryption_key',
+        None,
+        '128bit (hex) encryption key for scheduler build plans.')
+
+
+LOG = logging.getLogger('nova.api.openstack.zones')
 
 
 def _filter_keys(item, keys):
@@ -97,3 +108,35 @@ class Controller(common.OpenstackController):
         zone_id = int(id)
         zone = api.zone_update(context, zone_id, env["zone"])
         return dict(zone=_scrub_zone(zone))
+
+    def select(self, req):
+        """Returns a weighted list of costs to create instances
+           of desired capabilities."""
+        ctx = req.environ['nova.context']
+        qs = req.environ['QUERY_STRING']
+        param_dict = urlparse.parse_qs(qs)
+        param_dict.pop("fresh", None)
+        # parse_qs returns a dict where the values are lists,
+        # since query strings can have multiple values for the
+        # same key. We need to convert that to single values.
+        for key in param_dict:
+            param_dict[key] = param_dict[key][0]
+        build_plan = api.select(ctx, specs=param_dict)
+        cooked = self._scrub_build_plan(build_plan)
+        return {"weights": cooked}
+
+    def _scrub_build_plan(self, build_plan):
+        """Remove all the confidential data and return a sanitized
+        version of the build plan. Include an encrypted full version
+        of the weighting entry so we can get back to it later."""
+        if not FLAGS.build_plan_encryption_key:
+            raise exception.FlagNotSet(flag='build_plan_encryption_key')
+
+        encryptor = crypto.encryptor(FLAGS.build_plan_encryption_key)
+        cooked = []
+        for entry in build_plan:
+            json_entry = json.dumps(entry)
+            cipher_text = encryptor(json_entry)
+            cooked.append(dict(weight=entry['weight'],
+                blob=cipher_text))
+        return cooked