kayobe/doc/source/contributor/development.rst
Mark Goddard af3b719b73 Move group_vars to an inventory directory
The group variables originally in ansible/group_vars/ were playbook
group variables, due to being adjacent to the playbooks. Typically they
provided default values for global variables in the all group, as well
as some more specific groups. This has worked fairly well, but results
in (at least) a couple of problems.

1. The default variable precedence rules mean that these playbook group
   variables have a higher precedence than inventory group variables
   (for a given group). This can make it challenging to override
   playbook group variables in the inventory in Kayobe configuration.

2. Any playbook run by Kayobe must be in the same directory as the
   playbook group variables in order to use them. Given that they
   include variables required for connectivity such as ansible_host and
   ansible_user, this is quite critical. For Kayobe custom playbooks, we
   work around this by symlinking to the group_vars directory from the
   directory containing the custom playbook. This is not an elegant
   workaround, and has assumptions about the relative paths of the
   Kayobe configuration and virtual environment in which Kayobe is
   installed.

Story: 2010280
Task: 46233

Change-Id: Ifea5c7e73f6f410f96a7398bfd349d1f631d9fc0
2022-09-08 10:11:23 +01:00

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2.8 KiB
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===========
Development
===========
Source Code Orientation
=======================
There are a number of layers to Kayobe, so here we provide a few pointers to
the major parts.
CLI
---
The Command Line Interface (CLI) is built using the `cliff
<https://pypi.org/project/cliff/>`__ library. Commands are exposed as Python
entry points in `setup.cfg
<https://opendev.org/openstack/kayobe/src/branch/master/setup.cfg>`__. These
entry points map to classes in `kayobe/cli/commands.py
<https://opendev.org/openstack/kayobe/src/branch/master/kayobe/cli/commands.py>`__.
The helper modules `kayobe/ansible.py
<https://opendev.org/openstack/kayobe/src/branch/master/kayobe/ansible.py>`__
and `kayobe/kolla_ansible.py
<https://opendev.org/openstack/kayobe/src/branch/master/kayobe/kolla_ansible.py>`__
are used to execute Kayobe playbooks and Kolla Ansible commands respectively.
Ansible
-------
Kayobe's Ansible playbooks live in `ansible/*.yml
<https://opendev.org/openstack/kayobe/src/branch/master/ansible>`__, and these
typically execute roles in `ansible/roles/
<https://opendev.org/openstack/kayobe/src/branch/master/ansible/roles>`__.
Global variable defaults are defined in group variable files in
`ansible/inventory/group_vars/all/
<https://opendev.org/openstack/kayobe/src/branch/master/ansible/group_vars/>`__
and these typically map to commented out variables in the configuration files
in `etc/kayobe/*.yml
<https://opendev.org/openstack/kayobe/src/branch/master/etc/kayobe/>`__.
A number of custom Jinja filters exist in `ansible/filter_plugins/*.py
<https://opendev.org/openstack/kayobe/src/branch/master/ansible/filter_plugins>`__.
Kayobe depends on roles and collections hosted on Ansible Galaxy, and these and
their version requirements are defined in `requirements.yml
<https://opendev.org/openstack/kayobe/src/branch/master/requirements.yml>`__.
Ansible Galaxy
==============
Kayobe uses a number of Ansible roles and collections hosted on Ansible Galaxy.
The role dependencies are tracked in ``requirements.yml``, and specify required
versions. The process for changing a Galaxy role or collection is as follows:
#. If required, develop changes for the role or collection. This may be done
outside of Kayobe, or by modifying the code in place during development. If
upstream changes to the code have already been made, this step can be
skipped.
#. Commit changes to the role or collection, typically via a Github pull
request.
#. Request that a tagged release of the role or collection be made, or make one
if you have the necessary privileges.
#. Ensure that automatic imports are configured for the repository using e.g. a
webhook notification, or perform a manual import of the role on Ansible
Galaxy.
#. Modify the version in ``requirements.yml`` to match the new release of the
role or collection.