Merge ~jocave/checkbox-support:add-netplan-parser into checkbox-support:master

[Jonathan Cave]

Add a netplan config file parser taken from the upstream project. This is a simple read-only parser at the moment that collates information as it reads the files in order of precedence.

It may be necessary in the future to expand on this so we can support reading a configuration hierarchy, modify and then write out.

[Maciej Kisielewski (kissiel)]

+1

review: Approve

diff --git a/checkbox_support/parsers/netplan.py b/checkbox_support/parsers/netplan.py
new file mode 100644
index 0000000..ff49cbf
--- /dev/null
+++ b/checkbox_support/parsers/netplan.py
@@ -0,0 +1,159 @@
+# This file is based on the parser from the netplan project:
+# https://github.com/CanonicalLtd/netplan/blob/master/netplan/configmanager.py
+#
+# Copyright 2019 Canonical Ltd.
+#
+# Authors:
+#   Mathieu Trudel-Lapierre <[e-mail]>
+#   Jonathan Cave <[e-mail]>
+#
+# Checkbox is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3,
+# as published by the Free Software Foundation.
+#
+# Checkbox is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Checkbox.  If not, see <http://www.gnu.org/licenses/>.
+
+import glob
+import logging
+import os
+import yaml
+
+
+class Netplan():
+
+    def __init__(self, prefix="/"):
+        self.prefix = prefix
+        self.config = {}
+
+    @property
+    def network(self):
+        return self.config['network']
+
+    @property
+    def interfaces(self):
+        interfaces = {}
+        interfaces.update(self.ethernets)
+        interfaces.update(self.wifis)
+        interfaces.update(self.bridges)
+        interfaces.update(self.bonds)
+        interfaces.update(self.vlans)
+        return interfaces
+
+    @property
+    def physical_interfaces(self):
+        interfaces = {}
+        interfaces.update(self.ethernets)
+        interfaces.update(self.wifis)
+        return interfaces
+
+    @property
+    def ethernets(self):
+        return self.network['ethernets']
+
+    @property
+    def wifis(self):
+        return self.network['wifis']
+
+    @property
+    def bridges(self):
+        return self.network['bridges']
+
+    @property
+    def bonds(self):
+        return self.network['bonds']
+
+    @property
+    def vlans(self):
+        return self.network['vlans']
+
+    @property
+    def renderer(self):
+        return self.network['renderer']
+
+    def parse(self):
+        """
+        Parse all our config files to return an object that describes the
+        system's entire configuration, so that it can later be interrogated.
+        Returns a dict that contains the entire, collated and merged YAML.
+        """
+
+        # /run/netplan shadows /etc/netplan/, which shadows /lib/netplan
+        names_to_paths = {}
+        for yaml_dir in ['lib', 'etc', 'run']:
+            for yaml_file in glob.glob(os.path.join(
+                    self.prefix, yaml_dir, 'netplan', '*.yaml')):
+                names_to_paths[os.path.basename(yaml_file)] = yaml_file
+
+        files = [names_to_paths[name]
+                 for name in sorted(names_to_paths.keys())]
+
+        self.config['network'] = {
+            'ethernets': {},
+            'wifis': {},
+            'bridges': {},
+            'bonds': {},
+            'vlans': {},
+            'renderer': None
+        }
+        for yaml_file in files:
+            self._merge_yaml_config(yaml_file)
+
+    def _merge_interface_config(self, orig, new):
+        new_interfaces = set()
+        changed_ifaces = list(new.keys())
+
+        for ifname in changed_ifaces:
+            iface = new.pop(ifname)
+            if ifname in orig:
+                logging.debug("{} exists in {}".format(ifname, orig))
+                orig[ifname].update(iface)
+            else:
+                logging.debug("{} not found in {}".format(ifname, orig))
+                orig[ifname] = iface
+                new_interfaces.add(ifname)
+
+        return new_interfaces
+
+    def _merge_yaml_config(self, yaml_file):
+        new_interfaces = set()
+
+        try:
+            with open(yaml_file) as f:
+                yaml_data = yaml.load(f, Loader=yaml.CSafeLoader)
+                network = None
+                if yaml_data is not None:
+                    network = yaml_data.get('network')
+                if network:
+                    if 'ethernets' in network:
+                        new = self._merge_interface_config(
+                            self.ethernets, network.get('ethernets'))
+                        new_interfaces |= new
+                    if 'wifis' in network:
+                        new = self._merge_interface_config(
+                            self.wifis, network.get('wifis'))
+                        new_interfaces |= new
+                    if 'bridges' in network:
+                        new = self._merge_interface_config(
+                            self.bridges, network.get('bridges'))
+                        new_interfaces |= new
+                    if 'bonds' in network:
+                        new = self._merge_interface_config(
+                            self.bonds, network.get('bonds'))
+                        new_interfaces |= new
+                    if 'vlans' in network:
+                        new = self._merge_interface_config(
+                            self.vlans, network.get('vlans'))
+                        new_interfaces |= new
+                    if 'renderer' in network:
+                        self.config['network']['renderer'] = network.get(
+                            'renderer')
+            return new_interfaces
+        except (IOError, yaml.YAMLError):
+            logging.error('Error while loading {}'.format(yaml_file))
+            self.config = {}