Ansible Nested Facts

Ansible supports having a directory of variables which are loaded for every task. These facts cannot be nested in any way, limiting their usefullness.

To combat this, nestedfacts implements loading a nested directory structure containing yml files. A quick example is show below. Refer to "Usage" for a deeper explaination and more ways to integrate this library with ansible.

$ tree scratch
scratch
└── someone
    ├── ports.yml
    └── webserver
        └── domains.yml

$ pip install nestedfacts
$ python -m 'nestedfacts' scratch
{
  "someone": {
    "webserver": {
      "domains": [
        "google.com",
        "yolo.org"
      ]
    }, 
    "ports": {
      "55552": "both",
      "62250": "tcp"
    }
  }
}

This project supports and is tested on both, python 2 and 3. Since ansible just calls the file as an exectuable, the usual python2- restriction does not apply.

Usage

By default the script loads yml from the current directory. There are two ways to influence this: a) pass a directory to the module, as show above. b) the more interesting way: use the script as a library.

For this purpose, a new python script in /etc/ansible/facts.d/ needs to be created:

#!/usr/bin/env python
from nestedfacts import dump_yml_filedir
dump_yml_filedir('/etc/ansible/fancyfacts')

Please note that the file needs to be named <something>.fact and needs executable-rights for ansible to include it.

Invalid Input

There are a few scenarios where a file cannot be loaded.

• It contains invalid yml. In this case, the key is present, but set to null:

$ tree invalid_file
invalid_file
├── foo.yml
└── invalid.yml

$ cat invalid_file/invalid.yml
{{{{{

$ python -m 'nestedfacts' invalid_file
{
  "foo": 42,
  "invalid": null
}

• non-yml-files. When the script encounters something, that does not end in .yml, the file is ignored completely:

$ tree nonyaml_dir/
nonyaml_dir/
├── foo.yml
└── somethingelse

$ python -m 'nestedfacts' nonyaml_dir/
{
  "foo": 43
}

• In case the provided root is missing {} is returned.

• In case a non-yml-file is provided as the root null is returned.

Development

Setup

virtualenv  venv --python python2
source venv/bin/activate
pip install -r requirements-dev.txt

You are free to play around in the scratch-directory, which is ignored by git. See the example above for directory structure and invocation. If you add or change something, you probably want to write a test for that.

Tests

Tests are managed by tox and tested by the pytest-module. You can run them using the tox-command.

Deployment

The only file in this directory needed in production is userfacts.py. Copy, clone or simlink it into your /etc/ansible/facts.d/preferences.fact- directory using your favourte deployment tool. Please note that this script needs the pyyaml-module to work.

PyPI

Assuming you have been handed the required credentials, the package on PyPI can be updated like this:

rm dist/*
python setup.py sdist bdist_wheel
twine upload dist/*