Improve NSB Standalone XML generation

Delayed the generation of the XML file until the last step. The
following functions will return a XML string insted:
- Libvirt.build_vm_xml
- SriovContext._enable_interfaces
- OvsDpdkContext._enable_interfaces

The XML file will be written just before copying the file to the
compute hosting the VMs.

JIRA: YARDSTICK-939

Change-Id: Icc80f4741903bbe335db4ebccab395b72fa87e82
Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>

3 files changed, 54 insertions, 49 deletions

diff --git a/yardstick/benchmark/contexts/standalone/model.py b/yardstick/benchmark/contexts/standalone/model.py
index ac81ee742..7eab1c9c8 100644
--- a/yardstick/benchmark/contexts/standalone/model.py
+++ b/yardstick/benchmark/contexts/standalone/model.py
@@ -29,7 +29,7 @@ from yardstick.common import exceptions
 from yardstick.common.yaml_loader import yaml_load
 from yardstick.network_services.utils import PciAddress
 from yardstick.network_services.helpers.cpu import CpuSysCores
-from yardstick.common.utils import write_file
+
 
 LOG = logging.getLogger(__name__)
 
@@ -132,7 +132,7 @@ class Libvirt(object):
         return vm_pci
 
     @classmethod
-    def add_ovs_interface(cls, vpath, port_num, vpci, vports_mac, xml):
+    def add_ovs_interface(cls, vpath, port_num, vpci, vports_mac, xml_str):
         """Add a DPDK OVS 'interface' XML node in 'devices' node
 
         <devices>
@@ -156,7 +156,7 @@ class Libvirt(object):
 
         vhost_path = ('{0}/var/run/openvswitch/dpdkvhostuser{1}'.
                       format(vpath, port_num))
-        root = ET.parse(xml)
+        root = ET.fromstring(xml_str)
         pci_address = PciAddress(vpci.strip())
         device = root.find('devices')
 
@@ -181,10 +181,10 @@ class Libvirt(object):
 
         cls._add_interface_address(interface, pci_address)
 
-        root.write(xml)
+        return ET.tostring(root)
 
     @classmethod
-    def add_sriov_interfaces(cls, vm_pci, vf_pci, vf_mac, xml):
+    def add_sriov_interfaces(cls, vm_pci, vf_pci, vf_mac, xml_str):
         """Add a SR-IOV 'interface' XML node in 'devices' node
 
         <devices>
@@ -207,7 +207,7 @@ class Libvirt(object):
             -sr_iov-how_sr_iov_libvirt_works
         """
 
-        root = ET.parse(xml)
+        root = ET.fromstring(xml_str)
         device = root.find('devices')
 
         interface = ET.SubElement(device, 'interface')
@@ -224,7 +224,7 @@ class Libvirt(object):
         pci_vm_address = PciAddress(vm_pci.strip())
         cls._add_interface_address(interface, pci_vm_address)
 
-        root.write(xml)
+        return ET.tostring(root)
 
     @staticmethod
     def create_snapshot_qemu(connection, index, vm_image):
@@ -237,7 +237,8 @@ class Libvirt(object):
         return image
 
     @classmethod
-    def build_vm_xml(cls, connection, flavor, cfg, vm_name, index):
+    def build_vm_xml(cls, connection, flavor, vm_name, index):
+        """Build the XML from the configuration parameters"""
         memory = flavor.get('ram', '4096')
         extra_spec = flavor.get('extra_specs', {})
         cpu = extra_spec.get('hw:cpu_cores', '2')
@@ -261,9 +262,7 @@ class Libvirt(object):
             socket=socket, threads=threads,
             vm_image=image, cpuset=cpuset, cputune=cputune)
 
-        write_file(cfg, vm_xml)
-
-        return [vcpu, mac]
+        return vm_xml, mac
 
     @staticmethod
     def update_interrupts_hugepages_perf(connection):
@@ -283,6 +282,13 @@ class Libvirt(object):
         cpuset = "%s,%s" % (cores, threads)
         return cpuset
 
+    @classmethod
+    def write_file(cls, file_name, xml_str):
+        """Dump a XML string to a file"""
+        root = ET.fromstring(xml_str)
+        et = ET.ElementTree(element=root)
+        et.write(file_name, encoding='utf-8', method='xml')
+
 
 class StandaloneContextHelper(object):
     """ This class handles all the common code for standalone
diff --git a/yardstick/benchmark/contexts/standalone/ovs_dpdk.py b/yardstick/benchmark/contexts/standalone/ovs_dpdk.py
index ee0eb9e0d..30b685eec 100644
--- a/yardstick/benchmark/contexts/standalone/ovs_dpdk.py
+++ b/yardstick/benchmark/contexts/standalone/ovs_dpdk.py
@@ -359,7 +359,7 @@ class OvsDpdkContext(Context):
         self.networks = portlist
         LOG.info("Ports %s", self.networks)
 
-    def _enable_interfaces(self, index, vfs, cfg):
+    def _enable_interfaces(self, index, vfs, xml_str):
         vpath = self.ovs_properties.get("vpath", "/usr/local")
         vf = self.networks[vfs[0]]
         port_num = vf.get('port_num', 0)
@@ -368,8 +368,8 @@ class OvsDpdkContext(Context):
         slot = index + port_num + 10
         vf['vpci'] = \
             "{}:{}:{:02x}.{}".format(vpci.domain, vpci.bus, slot, vpci.function)
-        model.Libvirt.add_ovs_interface(
-            vpath, port_num, vf['vpci'], vf['mac'], str(cfg))
+        return model.Libvirt.add_ovs_interface(
+            vpath, port_num, vf['vpci'], vf['mac'], xml_str)
 
     def setup_ovs_dpdk_context(self):
         nodes = []
@@ -384,17 +384,16 @@ class OvsDpdkContext(Context):
             # 1. Check and delete VM if already exists
             model.Libvirt.check_if_vm_exists_and_delete(vm_name,
                                                         self.connection)
+            xml_str, mac = model.Libvirt.build_vm_xml(
+                self.connection, self.vm_flavor, vm_name, index)
 
-            _, mac = model.Libvirt.build_vm_xml(
-                self.connection, self.vm_flavor, cfg, vm_name, index)
             # 2: Cleanup already available VMs
-            for vkey, vfs in collections.OrderedDict(
-                    vnf["network_ports"]).items():
-                if vkey == "mgmt":
-                    continue
-                self._enable_interfaces(index, vfs, cfg)
+            for vfs in [vfs for vfs_name, vfs in vnf["network_ports"].items()
+                        if vfs_name != 'mgmt']:
+                xml_str = self._enable_interfaces(index, vfs, xml_str)
 
             # copy xml to target...
+            model.Libvirt.write_file(cfg, xml_str)
             self.connection.put(cfg, cfg)
 
             # NOTE: launch through libvirt
diff --git a/yardstick/benchmark/contexts/standalone/sriov.py b/yardstick/benchmark/contexts/standalone/sriov.py
index d7620552b..5db419e6a 100644
--- a/yardstick/benchmark/contexts/standalone/sriov.py
+++ b/yardstick/benchmark/contexts/standalone/sriov.py
@@ -16,15 +16,12 @@ from __future__ import absolute_import
 import os
 import logging
 import collections
-from collections import OrderedDict
 
 from yardstick import ssh
 from yardstick.network_services.utils import get_nsb_option
 from yardstick.network_services.utils import provision_tool
 from yardstick.benchmark.contexts.base import Context
-from yardstick.benchmark.contexts.standalone.model import Libvirt
-from yardstick.benchmark.contexts.standalone.model import StandaloneContextHelper
-from yardstick.benchmark.contexts.standalone.model import Server
+from yardstick.benchmark.contexts.standalone import model
 from yardstick.network_services.utils import PciAddress
 
 LOG = logging.getLogger(__name__)
@@ -49,8 +46,8 @@ class SriovContext(Context):
         self.attrs = {}
         self.vm_flavor = None
         self.servers = None
-        self.helper = StandaloneContextHelper()
-        self.vnf_node = Server()
+        self.helper = model.StandaloneContextHelper()
+        self.vnf_node = model.Server()
         self.drivers = []
         super(SriovContext, self).__init__()
 
@@ -87,15 +84,14 @@ class SriovContext(Context):
             os.path.join(get_nsb_option("bin_path"), "dpdk-devbind.py"))
 
         #    Todo: NFVi deploy (sriov, vswitch, ovs etc) based on the config.
-        StandaloneContextHelper.install_req_libs(self.connection)
-        self.networks = StandaloneContextHelper.get_nic_details(
+        model.StandaloneContextHelper.install_req_libs(self.connection)
+        self.networks = model.StandaloneContextHelper.get_nic_details(
             self.connection, self.networks, self.dpdk_devbind)
         self.nodes = self.setup_sriov_context()
 
         LOG.debug("Waiting for VM to come up...")
-        self.nodes = StandaloneContextHelper.wait_for_vnfs_to_start(self.connection,
-                                                                    self.servers,
-                                                                    self.nodes)
+        self.nodes = model.StandaloneContextHelper.wait_for_vnfs_to_start(
+            self.connection, self.servers, self.nodes)
 
     def undeploy(self):
         """don't need to undeploy"""
@@ -105,7 +101,7 @@ class SriovContext(Context):
 
         # Todo: NFVi undeploy (sriov, vswitch, ovs etc) based on the config.
         for vm in self.vm_names:
-            Libvirt.check_if_vm_exists_and_delete(vm, self.connection)
+            model.Libvirt.check_if_vm_exists_and_delete(vm, self.connection)
 
         # Bind nics back to kernel
         for ports in self.networks.values():
@@ -136,8 +132,8 @@ class SriovContext(Context):
         except StopIteration:
             pass
         else:
-            raise ValueError("Duplicate nodes!!! Nodes: %s %s" %
-                             (node, duplicate))
+            raise ValueError("Duplicate nodes!!! Nodes: %s %s"
+                             % (node, duplicate))
 
         node["name"] = attr_name
         return node
@@ -179,7 +175,7 @@ class SriovContext(Context):
             self.connection.execute(build_vfs.format(ports.get('phy_port')))
 
             # configure VFs...
-            mac = StandaloneContextHelper.get_mac_address()
+            mac = model.StandaloneContextHelper.get_mac_address()
             interface = ports.get('interface')
             if interface is not None:
                 self.connection.execute(vf_cmd.format(interface, mac))
@@ -201,7 +197,7 @@ class SriovContext(Context):
         slot = index + idx + 10
         vf['vpci'] = \
             "{}:{}:{:02x}.{}".format(vpci.domain, vpci.bus, slot, vpci.function)
-        Libvirt.add_sriov_interfaces(
+        model.Libvirt.add_sriov_interfaces(
             vf['vpci'], vf['vf_pci']['vf_pci'], vf['mac'], str(cfg))
         self.connection.execute("ifconfig %s up" % vf['interface'])
         self.connection.execute(vf_spoofchk.format(vf['interface']))
@@ -212,34 +208,37 @@ class SriovContext(Context):
         #   1 : modprobe host_driver with num_vfs
         self.configure_nics_for_sriov()
 
-        for index, (key, vnf) in enumerate(OrderedDict(self.servers).items()):
+        for index, (key, vnf) in enumerate(collections.OrderedDict(
+                self.servers).items()):
             cfg = '/tmp/vm_sriov_%s.xml' % str(index)
             vm_name = "vm_%s" % str(index)
 
             # 1. Check and delete VM if already exists
-            Libvirt.check_if_vm_exists_and_delete(vm_name, self.connection)
+            model.Libvirt.check_if_vm_exists_and_delete(vm_name,
+                                                        self.connection)
+            xml_str, mac = model.Libvirt.build_vm_xml(
+                self.connection, self.vm_flavor, vm_name, index)
 
-            _, mac = Libvirt.build_vm_xml(self.connection, self.vm_flavor, cfg, vm_name, index)
             # 2: Cleanup already available VMs
-            for idx, (vkey, vfs) in enumerate(OrderedDict(vnf["network_ports"]).items()):
-                if vkey == "mgmt":
-                    continue
+            network_ports = collections.OrderedDict(
+                {k: v for k, v in vnf["network_ports"].items() if k != 'mgmt'})
+            for idx, vfs in enumerate(network_ports.values()):
                 self._enable_interfaces(index, idx, vfs, cfg)
 
             # copy xml to target...
+            model.Libvirt.write_file(cfg, xml_str)
             self.connection.put(cfg, cfg)
 
             # NOTE: launch through libvirt
             LOG.info("virsh create ...")
-            Libvirt.virsh_create_vm(self.connection, cfg)
+            model.Libvirt.virsh_create_vm(self.connection, cfg)
 
             self.vm_names.append(vm_name)
 
             # build vnf node details
-            nodes.append(self.vnf_node.generate_vnf_instance(self.vm_flavor,
-                                                             self.networks,
-                                                             self.host_mgmt.get('ip'),
-                                                             key, vnf, mac))
+            nodes.append(self.vnf_node.generate_vnf_instance(
+                self.vm_flavor, self.networks, self.host_mgmt.get('ip'),
+                key, vnf, mac))
 
         return nodes
 
@@ -248,7 +247,8 @@ class SriovContext(Context):
             "mac": vfmac,
             "pf_if": pfif
         }
-        vfs = StandaloneContextHelper.get_virtual_devices(self.connection, value)
+        vfs = model.StandaloneContextHelper.get_virtual_devices(
+            self.connection, value)
         for k, v in vfs.items():
             m = PciAddress(k.strip())
             m1 = PciAddress(value.strip())