nocloud: add configurable meta/user data paths

In some cases, the NoCloud config drive is built using
`_` instead of `-` characters for the metadata and userdata paths.

This commit adds two configuration options to be able to set custom
values to those paths:

```ini
[nocloud]
metadata_file = "meta-data"
userdata_file = "user-data"
```

Fixes: #89

Change-Id: I312aa26ed9be6f22156ac238f456c3906d93760d
Signed-off-by: Adrian Vladu <avladu@cloudbasesolutions.com>

Author: ader1990

cloudbaseinit/conf/factory.py

@@ -26,6 +26,7 @@
     'cloudbaseinit.conf.packet.PacketOptions',
     'cloudbaseinit.conf.vmwareguestinfo.VMwareGuestInfoConfigOptions',
     'cloudbaseinit.conf.gce.GCEOptions',
+    'cloudbaseinit.conf.nocloud.NoCloudOptions',
 )
 
 

cloudbaseinit/conf/nocloud.py

@@ -0,0 +1,47 @@
+# Copyright 2024 Cloudbase Solutions Srl
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""Config options available for the OpenStack metadata service."""
+
+from oslo_config import cfg
+
+from cloudbaseinit.conf import base as conf_base
+
+
+class NoCloudOptions(conf_base.Options):
+
+    """Config options available for the OpenStack metadata service."""
+
+    def __init__(self, config):
+        super(NoCloudOptions, self).__init__(config, group="nocloud")
+        self._options = [
+            cfg.StrOpt(
+                "metadata_file", default="meta-data",
+                help="The file name where the service looks for"
+                     "metadata"),
+            cfg.StrOpt(
+                "userdata_file", default="user-data",
+                help="The file name where the service looks for"
+                     "userdata"),
+        ]
+
+    def register(self):
+        """Register the current options to the global ConfigOpts object."""
+        group = cfg.OptGroup(self.group_name, title='NoCloud Options')
+        self._config.register_group(group)
+        self._config.register_opts(self._options, group=group)
+
+    def list(self):
+        """Return a list which contains all the available options."""
+        return self._options

cloudbaseinit/metadata/services/baseconfigdrive.py

@@ -32,10 +32,12 @@
 
 class BaseConfigDriveService(base.BaseMetadataService):
 
-    def __init__(self, drive_label, metadata_file):
+    def __init__(self, drive_label, metadata_file,
+                 userdata_file='user-data'):
         super(BaseConfigDriveService, self).__init__()
         self._drive_label = drive_label
         self._metadata_file = metadata_file
+        self._userdata_file = userdata_file
         self._metadata_path = None
         self._searched_types = set()
         self._searched_locations = set()

cloudbaseinit/metadata/services/nocloudservice.py

@@ -276,17 +276,19 @@ class NoCloudConfigDriveService(baseconfigdrive.BaseConfigDriveService):
 
     def __init__(self):
         super(NoCloudConfigDriveService, self).__init__(
-            'cidata', 'meta-data')
+            'cidata', CONF.nocloud.metadata_file,
+            CONF.nocloud.userdata_file)
         self._meta_data = {}
 
     def get_user_data(self):
-        return self._get_cache_data("user-data")
+        return self._get_cache_data(self._userdata_file)
 
     def _get_meta_data(self):
         if self._meta_data:
             return self._meta_data
 
-        raw_meta_data = self._get_cache_data("meta-data", decode=True)
+        raw_meta_data = self._get_cache_data(
+            self._metadata_file, decode=True)
         try:
             self._meta_data = (
                 serialization.parse_json_yaml(raw_meta_data))

doc/source/services.rst

@@ -128,13 +128,15 @@ similar to the EC2 metadata in terms of how the metadata files are named and str
 
 The metadata is provided on a config-drive (vfat or iso9660) with the label cidata or CIDATA.
 
-The folder structure for NoCloud is:
+The default folder structure for NoCloud is:
 
   * /user-data
   * /meta-data
 
 The user-data and meta-data files respect the EC2 metadata service format.
 
+The names of the meta-data and user-data files can be configured.
+
 Capabilities:
 
     * instance id
@@ -153,6 +155,11 @@ Config options for `config_drive` section:
     * types (list: ["vfat", "iso"])
     * locations (list: ["cdrom", "hdd", "partition"])
 
+Config options for `nocloud` section:
+
+    * metadata_file (string: "meta-data")
+    * userdata_file (string: "user-data")
+
 Example metadata:
 
 .. code-block:: yaml