Better static network configuration support

When matching metadata network interface details with
the actual existing instance network adapters, keep
a valid alignment between their names by using their indexes.
This will be used if and only if the hardware address
is missing and the trivial name matching will fail.

Change-Id: I32b1efece3eb0a43432315ac6516561ef6ccbe37

cloudbaseinit/plugins/common/networkconfig.py

@@ -13,6 +13,8 @@
 #    under the License.
 
 
+import re
+
 from cloudbaseinit import exception
 from cloudbaseinit.metadata.services import base as service_base
 from cloudbaseinit.openstack.common import log as logging
@@ -34,18 +36,30 @@ NET_REQUIRE = {
 }
 
 
+def _name2idx(name):
+    """Get the position of a network interface by its name."""
+    match = re.search(r"eth(\d+)", name, re.I)
+    if not match:
+        raise exception.CloudbaseInitException(
+            "invalid NetworkDetails name {!r}"
+            .format(name)
+        )
+    return int(match.group(1))
+
+
 def _preprocess_nics(network_details, network_adapters):
     """Check NICs and fill missing data if possible."""
-    # initial checks
+    # Initial checks.
     if not network_adapters:
         raise exception.CloudbaseInitException(
             "no network adapters available")
     # Sort VM adapters by name (assuming that those
     # from the context are in correct order).
+    # Do this for a better matching by order
+    # if hardware address is missing.
     network_adapters = sorted(network_adapters, key=lambda arg: arg[0])
-    _network_details = []    # store here processed data
+    _network_details = []    # store here processed interfaces
-    # check and update every NetworkDetails object
+    # Check and update every NetworkDetails object.
-    ind = 0
     total = len(network_adapters)
     for nic in network_details:
         if not isinstance(nic, service_base.NetworkDetails):
@@ -53,7 +67,7 @@ def _preprocess_nics(network_details, network_adapters):
                 "invalid NetworkDetails object {!r}"
                 .format(type(nic))
             )
-        # check requirements
+        # Check requirements.
         final_status = True
         for fields, status in NET_REQUIRE.items():
             if not status:
@@ -68,14 +82,14 @@ def _preprocess_nics(network_details, network_adapters):
             # Complete hardware address if missing by selecting
             # the corresponding MAC in terms of naming, then ordering.
             if not nic.mac:
-                mac = None
+                # By name...
-                # by name
                 macs = [adapter[1] for adapter in network_adapters
                         if adapter[0] == nic.name]
                 mac = macs[0] if macs else None
-                # or by order
+                # ...or by order.
-                if not mac and ind < total:
+                idx = _name2idx(nic.name)
-                    mac = network_adapters[ind][1]
+                if not mac and idx < total:
+                    mac = network_adapters[idx][1]
                 nic = service_base.NetworkDetails(
                     nic.name,
                     mac,
@@ -86,7 +100,6 @@ def _preprocess_nics(network_details, network_adapters):
                     nic.dnsnameservers
                 )
             _network_details.append(nic)
-        ind += 1
     return _network_details
 
 

cloudbaseinit/tests/plugins/common/test_networkconfig.py

@@ -87,15 +87,13 @@ class TestNetworkConfigPlugin(unittest.TestCase):
         reboot = len(missed_adapters) != self._count
         self.assertEqual((plugin_base.PLUGIN_EXECUTION_DONE, reboot), ret)
 
-    def _setUp(self, same_names=True):
+    def _setUp(self, same_names=True, wrong_names=False, no_macs=False):
         # Generate fake pairs of NetworkDetails objects and
         # local ethernet network adapters.
+        iface_name = "Ethernet" if wrong_names else "eth"
         self._count = 3
-        details_names = [
+        details_names = ["{}{}".format(iface_name, idx)
-            "eth0",
+                         for idx in range(self._count)]
-            "eth1",
-            "eth2"
-        ]
         if same_names:
             adapters_names = details_names[:]
         else:
@@ -120,7 +118,7 @@ class TestNetworkConfigPlugin(unittest.TestCase):
             "192.168.255.255",
             "192.168.122.127",
         ]
-        gateway = [
+        gateways = [
             "192.168.122.1",
             "192.168.122.16",
             "192.168.122.32",
@@ -136,11 +134,11 @@ class TestNetworkConfigPlugin(unittest.TestCase):
             adapter = (adapters_names[ind], macs[ind])
             nic = service_base.NetworkDetails(
                 details_names[ind],
-                macs[ind],
+                None if no_macs else macs[ind],
                 addresses[ind],
                 netmasks[ind],
                 broadcasts[ind],
-                gateway[ind],
+                gateways[ind],
                 dnsnses[ind].split()
             )
             self._network_adapters.append(adapter)
@@ -166,6 +164,10 @@ class TestNetworkConfigPlugin(unittest.TestCase):
         self._network_details.append([None] * 6)
         self._partial_test_execute(invalid_details=True)
 
+    def test_execute_invalid_network_details_name(self):
+        self._setUp(wrong_names=True, no_macs=True)
+        self._partial_test_execute(invalid_details=True)
+
     def test_execute_single(self):
         for _ in range(self._count - 1):
             self._network_adapters.pop()