This role ensures that a specific pip-installable command is
available.
Example usage:
- role: ensure-python-command
vars:
ensure_python_command_name: poetry
ensure_python_command_version: ==1.8.5 # omit to install latest
In this case, if the `poetry` command is not already available, pip will
install it in a new venv. Either way, after running this role, the
`ensure_python_command_executable` variable will hold the full path to
the command.
We already have similar roles for specific commands:
- ensure-nox
- ensure-poetry
- ensure-pyproject-build
- ensure-tox
- ensure-twine
- ensure-uv
These roles are essentially copies of each other with different command
names. This new role consolidates that code. The existing roles now act
as wrappers that just set variables and call the new role.
> Note: The `ensure-tox` role has not been refactored due to exclusive
> legacy code related to Python 2, which must be removed first.
The new role introduces three variables to replace the overloaded
`ensure_<command>_executable` variable from the other roles:
- `ensure_python_command_name` (input, command name)
- `ensure_python_command_existing` (input, existing path for the command)
- `ensure_python_command_executable` (output, detected/installed path)
This separation avoids using the same variable as both input and output,
which can cause issues due to Ansible's variable precedence rules:
https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_variables.html
Understanding variable precedence
...
19. set_facts / registered vars
20. role (and include_role) params
...
Since we use `set_fact` inside the role, it is ineffective when the same
variable is also passed as a role parameter :/
I'm not adding tests for the new role because its functionality is
already covered by the existing tests for all the refactored roles:
- test-playbooks/ensure-nox.yaml
- test-playbooks/ensure-poetry.yaml
- test-playbooks/ensure-pyproject-build.yaml
- test-playbooks/ensure-twine.yaml
- test-playbooks/ensure-uv.yaml
Change-Id: Idd970cb31bd928576bca3602ce96fbc491ecdb60
34c30b9fa5