Add existing_network context

This context lets you use existing networks that have already been
created instead of creating new networks with Rally. This is useful
when, for instance, you are using Neutron with a dumb router that is
not capable of creating new networks on the fly.

Change-Id: I3718dba57145c3e64237dcb758cdcf3505e000dd

rally/plugins/openstack/wrappers/network.py

@@ -112,6 +112,21 @@ class NovaNetworkWrapper(NetworkWrapper):
             cidr = generate_cidr(start_cidr=self.start_cidr)
         return cidr
 
+    def _marshal_network_object(self, net_obj):
+        """Convert a Network object to a dict.
+
+        This helps keep return values from the NovaNetworkWrapper
+        compatible with those from NeutronWrapper.
+
+        :param net_obj: The Network object to convert to a dict
+        """
+        return {"id": net_obj.id,
+                "cidr": net_obj.cidr,
+                "name": net_obj.label,
+                "status": "ACTIVE",
+                "external": False,
+                "tenant_id": net_obj.project_id}
+
     def create_network(self, tenant_id, **kwargs):
         """Create network.
 
@@ -123,18 +138,14 @@ class NovaNetworkWrapper(NetworkWrapper):
         label = utils.generate_random_name("rally_net_")
         network = self.client.networks.create(
             tenant_id=tenant_id, cidr=cidr, label=label)
-        return {"id": network.id,
-                "cidr": network.cidr,
-                "name": network.label,
-                "status": "ACTIVE",
-                "external": False,
-                "tenant_id": tenant_id}
+        return self._marshal_network_object(network)
 
     def delete_network(self, network):
         return self.client.networks.delete(network["id"])
 
     def list_networks(self):
-        return self.client.networks.list()
+        return [self._marshal_network_object(n)
+                for n in self.client.networks.list()]
 
     def create_floating_ip(self, ext_network=None, **kwargs):
         """Allocate a floating ip from the given nova-network pool

tests/unit/plugins/openstack/wrappers/test_network.py

@@ -30,6 +30,8 @@ class NovaNetworkWrapperTestCase(test.TestCase):
 
     class Net(object):
         def __init__(self, **kwargs):
+            if "tenant_id" in kwargs:
+                kwargs["project_id"] = kwargs.pop("tenant_id")
             self.__dict__.update(kwargs)
 
     def get_wrapper(self, *skip_cidrs, **kwargs):
@@ -88,9 +90,18 @@ class NovaNetworkWrapperTestCase(test.TestCase):
 
     def test_list_networks(self):
         service = self.get_wrapper()
-        service.client.networks.list.return_value = "foo_list"
         service.client.networks.list.reset_mock()
-        self.assertEqual(service.list_networks(), "foo_list")
+        service.client.networks.list.return_value = [
+            self.Net(id="foo_id", project_id="foo_tenant", cidr="foo_cidr",
+                     label="foo_label"),
+            self.Net(id="bar_id", project_id="bar_tenant", cidr="bar_cidr",
+                     label="bar_label")]
+        expected = [
+            {"id": "foo_id", "cidr": "foo_cidr", "name": "foo_label",
+             "status": "ACTIVE", "external": False, "tenant_id": "foo_tenant"},
+            {"id": "bar_id", "cidr": "bar_cidr", "name": "bar_label",
+             "status": "ACTIVE", "external": False, "tenant_id": "bar_tenant"}]
+        self.assertEqual(expected, service.list_networks())
         service.client.networks.list.assert_called_once_with()
 
     def test__get_floating_ip(self):