Add mapping option to influence nicN mapping order

Currently there's a fixed mapping between abstracted interface
names (nic1, nic2 etc) and the underlying biosdevname for the
device.

In many cases, this mapping based on system enumeration is
sufficient, but in some cases, particularly when you perform
detailed pre-deployment discovery of interfaces, you may wish
to alter the mapping independently of the config (e.g if the
config is in a heat template, and the discovery data is
provided at runtime).

So this adds a -m option to os-net-config, which enables a
mapping file to be provided, such that specific interfaces
may be mapped to their abstract names based on knowledge of
the devices or the networks they are connected to.

The mapping file has the following format, where em1 and em2 are
device names as detected by the OS (e.g biosdevname):

interface_mapping:
    nic1: em2
    nic2: em1

Or you can use the device MAC instead:

interface_mapping:
    nic1: 12:34:56:78:9a:bc
    nic2: 12:34:56:de:f0:12

Change-Id: I93e6d3ed733244834bb3c2126c91db705b4d9167

1 files changed, 63 insertions, 23 deletions

diff --git a/os_net_config/objects.py b/os_net_config/objects.py
index 4a43528..929bcab 100644
--- a/os_net_config/objects.py
+++ b/os_net_config/objects.py
@@ -51,16 +51,45 @@ def _get_required_field(json, name, object_name):
     return field
 
 
-def _numbered_nics():
+def _numbered_nics(nic_mapping=None):
+    mapping = nic_mapping or {}
     global _NUMBERED_NICS
     if _NUMBERED_NICS:
         return _NUMBERED_NICS
     _NUMBERED_NICS = {}
     count = 0
-    for nic in utils.ordered_active_nics():
+    active_nics = utils.ordered_active_nics()
+    for nic in active_nics:
         count += 1
-        _NUMBERED_NICS["nic%i" % count] = nic
-        logger.info("nic%i mapped to: %s" % (count, nic))
+        nic_alias = "nic%i" % count
+        nic_mapped = mapping.get(nic_alias, nic)
+
+        # The mapping is either invalid, or specifies a mac
+        if nic_mapped not in active_nics:
+            for active in active_nics:
+                try:
+                    active_mac = utils.interface_mac(active)
+                except IOError:
+                    continue
+                if nic_mapped == active_mac:
+                    logger.debug("%s matches device %s" % (nic_mapped, active))
+                    nic_mapped = active
+                    break
+            else:
+                # The mapping can't specify a non-active or non-existent nic
+                logger.warning('interface %s is not in an active nic (%s)'
+                               % (nic_mapped, ', '.join(active_nics)))
+                continue
+
+        # Duplicate mappings are not allowed
+        if nic_mapped in _NUMBERED_NICS.values():
+            msg = ('interface %s already mapped, '
+                   'check mapping file for duplicates'
+                   % nic_mapped)
+            raise InvalidConfigException(msg)
+
+        _NUMBERED_NICS[nic_alias] = nic_mapped
+        logger.info("%s mapped to: %s" % (nic_alias, nic_mapped))
     return _NUMBERED_NICS
 
 
@@ -100,8 +129,8 @@ class _BaseOpts(object):
     """Base abstraction for logical port options."""
 
     def __init__(self, name, use_dhcp=False, use_dhcpv6=False, addresses=[],
-                 routes=[], mtu=1500, primary=False):
-        numbered_nic_names = _numbered_nics()
+                 routes=[], mtu=1500, primary=False, nic_mapping=None):
+        numbered_nic_names = _numbered_nics(nic_mapping)
         if name in numbered_nic_names:
             self.name = numbered_nic_names[name]
         else:
@@ -162,19 +191,23 @@ class _BaseOpts(object):
                 msg = 'Routes must be a list.'
                 raise InvalidConfigException(msg)
 
+        nic_mapping = json.get('nic_mapping')
+
         if include_primary:
-            return (use_dhcp, use_dhcpv6, addresses, routes, mtu, primary)
+            return (use_dhcp, use_dhcpv6, addresses, routes, mtu, primary,
+                    nic_mapping)
         else:
-            return (use_dhcp, use_dhcpv6, addresses, routes, mtu)
+            return (use_dhcp, use_dhcpv6, addresses, routes, mtu,
+                    nic_mapping)
 
 
 class Interface(_BaseOpts):
     """Base class for network interfaces."""
 
     def __init__(self, name, use_dhcp=False, use_dhcpv6=False, addresses=[],
-                 routes=[], mtu=1500, primary=False):
+                 routes=[], mtu=1500, primary=False, nic_mapping=None):
         super(Interface, self).__init__(name, use_dhcp, use_dhcpv6, addresses,
-                                        routes, mtu, primary)
+                                        routes, mtu, primary, nic_mapping)
 
     @staticmethod
     def from_json(json):
@@ -191,13 +224,14 @@ class Vlan(_BaseOpts):
     """
 
     def __init__(self, device, vlan_id, use_dhcp=False, use_dhcpv6=False,
-                 addresses=[], routes=[], mtu=1500, primary=False):
+                 addresses=[], routes=[], mtu=1500, primary=False,
+                 nic_mapping=None):
         name = 'vlan%i' % vlan_id
         super(Vlan, self).__init__(name, use_dhcp, use_dhcpv6, addresses,
-                                   routes, mtu, primary)
+                                   routes, mtu, primary, nic_mapping)
         self.vlan_id = int(vlan_id)
 
-        numbered_nic_names = _numbered_nics()
+        numbered_nic_names = _numbered_nics(nic_mapping)
         if device in numbered_nic_names:
             self.device = numbered_nic_names[device]
         else:
@@ -217,9 +251,9 @@ class OvsBridge(_BaseOpts):
 
     def __init__(self, name, use_dhcp=False, use_dhcpv6=False, addresses=[],
                  routes=[], mtu=1500, members=[], ovs_options=None,
-                 ovs_extra=[]):
+                 ovs_extra=[], nic_mapping=None):
         super(OvsBridge, self).__init__(name, use_dhcp, use_dhcpv6, addresses,
-                                        routes, mtu, False)
+                                        routes, mtu, False, nic_mapping)
         self.members = members
         self.ovs_options = ovs_options
         self.ovs_extra = ovs_extra
@@ -238,7 +272,8 @@ class OvsBridge(_BaseOpts):
     @staticmethod
     def from_json(json):
         name = _get_required_field(json, 'name', 'OvsBridge')
-        opts = _BaseOpts.base_opts_from_json(json, include_primary=False)
+        (use_dhcp, use_dhcpv6, addresses, routes, mtu, nic_mapping
+         ) = _BaseOpts.base_opts_from_json(json, include_primary=False)
         ovs_options = json.get('ovs_options')
         ovs_extra = json.get('ovs_extra', [])
         members = []
@@ -253,8 +288,10 @@ class OvsBridge(_BaseOpts):
                 msg = 'Members must be a list.'
                 raise InvalidConfigException(msg)
 
-        return OvsBridge(name, *opts, members=members, ovs_options=ovs_options,
-                         ovs_extra=ovs_extra)
+        return OvsBridge(name, use_dhcp=use_dhcp, use_dhcpv6=use_dhcpv6,
+                         addresses=addresses, routes=routes, mtu=mtu,
+                         members=members, ovs_options=ovs_options,
+                         ovs_extra=ovs_extra, nic_mapping=nic_mapping)
 
 
 class OvsBond(_BaseOpts):
@@ -262,9 +299,9 @@ class OvsBond(_BaseOpts):
 
     def __init__(self, name, use_dhcp=False, use_dhcpv6=False, addresses=[],
                  routes=[], mtu=1500, primary=False, members=[],
-                 ovs_options=None, ovs_extra=[]):
+                 ovs_options=None, ovs_extra=[], nic_mapping=None):
         super(OvsBond, self).__init__(name, use_dhcp, use_dhcpv6, addresses,
-                                      routes, mtu, primary)
+                                      routes, mtu, primary, nic_mapping)
         self.members = members
         self.ovs_options = ovs_options
         self.ovs_extra = ovs_extra
@@ -281,7 +318,8 @@ class OvsBond(_BaseOpts):
     @staticmethod
     def from_json(json):
         name = _get_required_field(json, 'name', 'OvsBond')
-        opts = _BaseOpts.base_opts_from_json(json)
+        (use_dhcp, use_dhcpv6, addresses, routes, mtu, nic_mapping
+         ) = _BaseOpts.base_opts_from_json(json, include_primary=False)
         ovs_options = json.get('ovs_options')
         ovs_extra = json.get('ovs_extra', [])
         members = []
@@ -296,5 +334,7 @@ class OvsBond(_BaseOpts):
                 msg = 'Members must be a list.'
                 raise InvalidConfigException(msg)
 
-        return OvsBond(name, *opts, members=members, ovs_options=ovs_options,
-                       ovs_extra=ovs_extra)
+        return OvsBond(name, use_dhcp=use_dhcp, use_dhcpv6=use_dhcpv6,
+                       addresses=addresses, routes=routes, mtu=mtu,
+                       members=members, ovs_options=ovs_options,
+                       ovs_extra=ovs_extra, nic_mapping=nic_mapping)