LXDProfileGenerator

A simple python script to populate YAML profiles for LXD

User guide

The script takes a YAML template as input, updates it using a YAML file (-u UPDATE), and outputs a YAML file (-p PROFILE).

Type $python3 lxd_profile_generator.py -h to get this short help :

usage: lxd_profile_generator.py [-h] [-u UPDATE] [-p PROFILE] [-c] [-V] [-s] template

Script to generate LXD profiles from templates

positional arguments:
  template              YAML template used to generate the profile

optional arguments:
  -h, --help            show this help message and exit
  -u UPDATE, --update UPDATE
                        YAML values applied to the template
  -p PROFILE, --profile PROFILE
                        YAML profile generated
  -c, --cloud-init      parse cloud-init data
  -V, --verbose         make script verbose
  -s, --skip-errors     skip errors

Update rules

The script compares the template and the update dictionaries according to the following rules, which are applied recursively :

dicts are compared to find matching keys :
- keys missing in template are added using updatevalues
- keys present in both dicts lead to a recursive search
- keys missing in update remain untouched
template lists are extended by counterpart updatelists
other templatevalues are updated by their update counterpart if their type is identical (None value match any value).

Cloud-init data dicts, which are stored as plain strings in LXD profile YAML, are also compared with update dict, but their top key (data.<something>) must be inserted in the top dict of update. The required comment #cloud-config is also added at the required place in the output YAML file.

Dependencies

This script should run on python3.5 and later. However, it has only be tested on python3.9

The PyYAML module is required. Credits and documentation may be found at https://pyyaml.org.
The module may be installed easily using pip : python3 -m pip install pyyaml
A C backend can also be used to speed up PyYAML, but it is not mandatory and requires to modify YAML_LOADER and YAML_DUMPER constants in the script.

License

This repository and its content are licensed under the EUPL-1.2-or-later.

Check https://joinup.ec.europa.eu/collection/eupl/eupl-text-eupl-12

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