Set network bridge names manually

- libvirt bridge name generator allows to create only 256 names
  so this patch returns some logic for manual generation of
  bridge names.
- Node network interface names are still generated by libvirt
  (and limited to 65536 names)

Change-Id: Ife31acd300466f660f7525e8f4fd6927ae1e2158
Related-Bug: #1590419
Implements: blueprint fuel-devops-multiple-databases

devops/driver/libvirt/libvirt_driver.py

@@ -14,6 +14,7 @@
 
 from __future__ import division
 import datetime
+import itertools
 import os
 from time import sleep
 import xml.etree.ElementTree as ET
@@ -121,6 +122,8 @@ class Snapshot(object):
 
 class DevopsDriver(object):
 
+    _device_name_generators = {}
+
     def __init__(self,
                  connection_string="qemu:///system",
                  storage_pool_name="default",
@@ -274,7 +277,7 @@ class DevopsDriver(object):
             else:
                 raise
 
-    @retry()
+    @retry(delay=3)
     def network_define(self, network):
         """Define network
 
@@ -1071,3 +1074,42 @@ class DevopsDriver(object):
         else:
             logger.warning("Can't close tray: no cdrom devices "
                            "found for Node {!r}".format(node.name))
+
+    def get_allocated_device_names(self):
+        """Get list of existing bridge names and network devices
+
+        :rtype : List
+        """
+        names = []
+
+        # Local Network Devices
+        for dev in self.conn.listAllDevices():
+            xml = ET.fromstring(dev.XMLDesc())
+            name_el = xml.find('./capability/interface')
+            if name_el is None:
+                continue
+            name = name_el.text
+            names.append(name)
+
+        # Network Bridges
+        for net in self.conn.listAllNetworks():
+            names.append(net.bridgeName())
+
+        return names
+
+    def get_available_device_name(self, prefix):
+        """Get available name for bridge
+
+        :type prefix: str
+        :rtype : String
+        """
+        allocated_names = self.get_allocated_device_names()
+        if prefix not in self._device_name_generators:
+            self._device_name_generators[prefix] = (
+                '{}{}'.format(prefix, i) for i in itertools.count())
+        all_names = self._device_name_generators[prefix]
+
+        for name in all_names:
+            if name in allocated_names:
+                continue
+            return name

devops/driver/libvirt/libvirt_xml_builder.py

@@ -51,8 +51,9 @@ class LibvirtXMLBuilder(object):
         stp_val = 'off'
         if self.driver.stp:
             stp_val = 'on'
-        # bridge_name will be generated by libvirt with prefix 'virbr'
+
         network_xml.bridge(
+            name=self.driver.get_available_device_name(br_prefix),
             stp=stp_val, delay="0")
 
         if network.forward is not None:

devops/tests/test_libvirt_xml_builder.py

@@ -28,7 +28,8 @@ class BaseTestXMLBuilder(TestCase):
     def setUp(self):
         # TODO(prmtl): make it fuzzy
         self.volume_path = "volume_path_mock"
-        self.xml_builder = LibvirtXMLBuilder(mock.Mock())
+        self.driver_mock = mock.Mock()
+        self.xml_builder = LibvirtXMLBuilder(self.driver_mock)
         self.xml_builder.driver.volume_path = mock.Mock(
             return_value=self.volume_path
         )
@@ -104,12 +105,15 @@ class TestNetworkXml(BaseTestXMLBuilder):
         self.net.has_dhcp_server = False
 
     def test_net_name_bridge_name(self):
+        self.driver_mock.get_available_device_name.return_value = 'fuelbr0'
         xml = self.xml_builder.build_network_xml(self.net)
         self.assertXMLIn(
             '<name>{0}_{1}</name>'
             ''.format(self.net.environment.name, self.net.name),
             xml)
-        self.assertXMLIn('<bridge delay="0" stp="on" />', xml)
+        self.assertXMLIn('<bridge delay="0" name="fuelbr0" stp="on" />', xml)
+        self.driver_mock.get_available_device_name.assert_called_once_with(
+            'fuelbr')
 
     def test_forward(self):
         self.net.forward = "nat"