ConfigDrive: write 'injected' files and legacy networking

Previous commit disabled the consumption of 'injected' files in 
configdrive (openstack server boot --file=/target/file=local-file)
unless the datasource was in 'pass' mode.  The default mode is 'net'
so that would never happen.

Also here are:
a.) a fix for 'links_path_prefix' string from debian, to finally
    disable the rendering of systemd.link files (LP: #1594546)
b.) some comments to apply_network_config
c.) implement a backwards compatibility for for distros that do
    not yet implement apply_network_config by converting the network
    config into ENI format and calling apply_network.

    This is required because prior to the previous commit, those distros
    would have had 'apply_network' called with the openstack provided
    ENI file.  But after this change they will have apply_network_config
    called by cloudinit's main.
d.) a network_state_to_eni helper for converting net config to eni
    it supports the not-actually-correct 'hwaddress' field in ENI.

LP: #1602373

4 files changed, 64 insertions, 15 deletions

diff --git a/cloudinit/distros/__init__.py b/cloudinit/distros/__init__.py
index 14b500f8..006a7062 100644
--- a/cloudinit/distros/__init__.py
+++ b/cloudinit/distros/__init__.py
@@ -32,6 +32,8 @@ import stat
 from cloudinit import importer
 from cloudinit import log as logging
 from cloudinit import net
+from cloudinit.net import eni
+from cloudinit.net import network_state
 from cloudinit import ssh_util
 from cloudinit import type_utils
 from cloudinit import util
@@ -138,9 +140,30 @@ class Distro(object):
             return self._bring_up_interfaces(dev_names)
         return False
 
+    def _apply_network_from_network_config(self, netconfig, bring_up=True):
+        LOG.warn("apply_network_config is not currently implemented "
+                 "for distribution '%s'.  Attempting to use "
+                 "apply_network", self.__class__)
+        header = '\n'.join([
+            "# Converted from network_config for distro %s" % self.__class__,
+            "# Implmentation of _write_network_config is needed."
+        ])
+        ns = network_state.parse_net_config_data(netconfig)
+        contents = eni.network_state_to_eni(
+            ns, header=header, render_hwaddress=True)
+        self.apply_network(contents, bring_up=bring_up)
+
     def apply_network_config(self, netconfig, bring_up=False):
-        # Write it out
-        dev_names = self._write_network_config(netconfig)
+        # apply network config netconfig
+        # This method is preferred to apply_network which only takes
+        # a much less complete network config format (interfaces(5)).
+        try:
+            dev_names = self._write_network_config(netconfig)
+        except NotImplementedError:
+            # backwards compat until all distros have apply_network_config
+            return self._apply_network_from_network_config(
+                netconfig, bring_up=bring_up)
+
         # Now try to bring them up
         if bring_up:
             return self._bring_up_interfaces(dev_names)
diff --git a/cloudinit/distros/debian.py b/cloudinit/distros/debian.py
index 5ae9a509..4d336b5b 100644
--- a/cloudinit/distros/debian.py
+++ b/cloudinit/distros/debian.py
@@ -67,7 +67,7 @@ class Distro(distros.Distro):
         self._net_renderer = eni.Renderer({
             'eni_path': self.network_conf_fn,
             'eni_header': ENI_HEADER,
-            'links_prefix_path': None,
+            'links_path_prefix': None,
             'netrules_path': None,
         })
 
diff --git a/cloudinit/net/eni.py b/cloudinit/net/eni.py
index e5ed10fd..419e7a74 100644
--- a/cloudinit/net/eni.py
+++ b/cloudinit/net/eni.py
@@ -352,7 +352,7 @@ class Renderer(renderer.Renderer):
             content += down + route_line + eol
         return content
 
-    def _render_interfaces(self, network_state):
+    def _render_interfaces(self, network_state, render_hwaddress=False):
         '''Given state, emit etc/network/interfaces content.'''
 
         content = ""
@@ -397,6 +397,8 @@ class Renderer(renderer.Renderer):
                         iface['mode'] = 'dhcp'
 
                     content += _iface_start_entry(iface, index)
+                    if render_hwaddress and iface.get('mac_address'):
+                        content += "    hwaddress %s" % iface['mac_address']
                     content += _iface_add_subnet(iface, subnet)
                     content += _iface_add_attrs(iface)
                     for route in subnet.get('routes', []):
@@ -411,8 +413,6 @@ class Renderer(renderer.Renderer):
         for route in network_state.iter_routes():
             content += self._render_route(route)
 
-        # global replacements until v2 format
-        content = content.replace('mac_address', 'hwaddress')
         return content
 
     def render_network_state(self, target, network_state):
@@ -448,3 +448,21 @@ class Renderer(renderer.Renderer):
                     ""
                 ])
                 util.write_file(fname, content)
+
+
+def network_state_to_eni(network_state, header=None, render_hwaddress=False):
+    # render the provided network state, return a string of equivalent eni
+    eni_path = 'etc/network/interfaces'
+    renderer = Renderer({
+        'eni_path': eni_path,
+        'eni_header': header,
+        'links_path_prefix': None,
+        'netrules_path': None,
+    })
+    if not header:
+        header = ""
+    if not header.endswith("\n"):
+        header += "\n"
+    contents = renderer._render_interfaces(
+        network_state, render_hwaddress=render_hwaddress)
+    return header + contents
diff --git a/cloudinit/sources/DataSourceConfigDrive.py b/cloudinit/sources/DataSourceConfigDrive.py
index 3130e618..91d6ff13 100644
--- a/cloudinit/sources/DataSourceConfigDrive.py
+++ b/cloudinit/sources/DataSourceConfigDrive.py
@@ -107,12 +107,19 @@ class DataSourceConfigDrive(openstack.SourceMixin, sources.DataSource):
         if self.dsmode == sources.DSMODE_DISABLED:
             return False
 
-        # This is legacy and sneaky.  If dsmode is 'pass' then write
-        # 'injected files' and apply legacy ENI network format.
         prev_iid = get_previous_iid(self.paths)
         cur_iid = md['instance-id']
-        if prev_iid != cur_iid and self.dsmode == sources.DSMODE_PASS:
-            on_first_boot(results, distro=self.distro)
+        if prev_iid != cur_iid:
+            # better would be to handle this centrally, allowing
+            # the datasource to do something on new instance id
+            # note, networking is only rendered here if dsmode is DSMODE_PASS
+            # which means "DISABLED, but render files and networking"
+            on_first_boot(results, distro=self.distro,
+                          network=self.dsmode == sources.DSMODE_PASS)
+
+        # This is legacy and sneaky.  If dsmode is 'pass' then do not claim
+        # the datasource was used, even though we did run on_first_boot above.
+        if self.dsmode == sources.DSMODE_PASS:
             LOG.debug("%s: not claiming datasource, dsmode=%s", self,
                       self.dsmode)
             return False
@@ -184,15 +191,16 @@ def get_previous_iid(paths):
         return None
 
 
-def on_first_boot(data, distro=None):
+def on_first_boot(data, distro=None, network=True):
     """Performs any first-boot actions using data read from a config-drive."""
     if not isinstance(data, dict):
         raise TypeError("Config-drive data expected to be a dict; not %s"
                         % (type(data)))
-    net_conf = data.get("network_config", '')
-    if net_conf and distro:
-        LOG.warn("Updating network interfaces from config drive")
-        distro.apply_network(net_conf)
+    if network:
+        net_conf = data.get("network_config", '')
+        if net_conf and distro:
+            LOG.warn("Updating network interfaces from config drive")
+            distro.apply_network(net_conf)
     write_injected_files(data.get('files'))