First attempt to rewrite reroute_compute

nova/scheduler/api.py

@@ -24,6 +24,7 @@ from nova import exception
 from nova import flags
 from nova import log as logging
 from nova import rpc
+from nova import utils
 
 from eventlet import greenpool
 
@@ -224,32 +225,57 @@ class reroute_compute(object):
     def __init__(self, method_name):
         self.method_name = method_name
 
+
+    def _route_local():
+        pass
+
+    def _route_to_child_zones(context, collection, item_uuid):
+        if not FLAGS.enable_zone_routing:
+            raise InstanceNotFound(instance_id=item_uuid)
+
+        zones = db.zone_get_all(context)
+        if not zones:
+            raise InstanceNotFound(instance_id=item_uuid)
+
+        # Ask the children to provide an answer ...
+        LOG.debug(_("Asking child zones ..."))
+        result = self._call_child_zones(zones,
+                    wrap_novaclient_function(_issue_novaclient_command,
+                           collection, self.method_name, item_uuid))
+        # Scrub the results and raise another exception
+        # so the API layers can bail out gracefully ...
+        raise RedirectResult(self.unmarshall_result(result))
+
     def __call__(self, f):
         def wrapped_f(*args, **kwargs):
-            collection, context, item_id = \
+            collection, context, item_id_or_uuid = \
                             self.get_collection_context_and_id(args, kwargs)
-            try:
-                # Call the original function ...
+
+            attempt_reroute = False  
+            if utils.is_uuid_like(item_id_or_uuid):
+                item_uuid = item_id_or_uuid
+                try:
+                    instance = self.db.instance_get_by_uuid(
+                                            context, item_uuid)
+                except exception.InstanceNotFound, e:
+                    # NOTE(sirp): since a UUID was passed in, we can attempt
+                    # to reroute to a child zone
+                    attempt_reroute = True
+                    LOG.debug(_("Instance %(item_uuid)s not found "
+                                        "locally: '%(e)s'" % locals()))
+                else:
+                    # NOTE(sirp): since we're not re-routing in this case, and we
+                    # we were passed a UUID, we need to replace that UUID with an
+                    # integer ID in the argument list so that the zone-local code
+                    # can continue to use integer IDs.
+                    item_id = instance['id']
+                    self.replace_uuid_with_id(args, kwargs, replacement_id)
+
+            if attempt_reroute:
+                self._route_to_child_zones(context, collection, item_uuid)
+            else:
                 return f(*args, **kwargs)
-            except exception.InstanceNotFound, e:
-                LOG.debug(_("Instance %(item_id)s not found "
-                                    "locally: '%(e)s'" % locals()))
 
-                if not FLAGS.enable_zone_routing:
-                    raise
-
-                zones = db.zone_get_all(context)
-                if not zones:
-                    raise
-
-                # Ask the children to provide an answer ...
-                LOG.debug(_("Asking child zones ..."))
-                result = self._call_child_zones(zones,
-                            wrap_novaclient_function(_issue_novaclient_command,
-                                   collection, self.method_name, item_id))
-                # Scrub the results and raise another exception
-                # so the API layers can bail out gracefully ...
-                raise RedirectResult(self.unmarshall_result(result))
         return wrapped_f
 
     def _call_child_zones(self, zones, function):
@@ -268,6 +294,18 @@ class reroute_compute(object):
             instance_id = args[2]
         return ("servers", context, instance_id)
 
+    @staticmethod
+    def replace_uuid_with_id(args, kwargs, replacement_id):
+        """
+        Extracts the UUID parameter from the arg or kwarg list and replaces
+        it with an integer ID.
+        """
+        if 'instance_id' in kwargs:
+            kwargs['instance_id'] = replacement_id
+        elif len(args) > 1:
+            args.pop(2)
+            args.insert(2, replacement_id)
+
     def unmarshall_result(self, zone_responses):
         """Result is a list of responses from each child zone.
         Each decorator derivation is responsible to turning this