Add ensure-poetry role

Poetry (https://python-poetry.org) is not declared as a dependency for a
Python project, it must be available somehow in the system. This role
installs it if missing.

- Latest version is installed, unless `ensure_poetry_version` is
  informed.

- The installed executable path is set as the `poetry_executable` fact.

- The `/usr/local/bin/poetry` symlink can also be created if
  `ensure_poetry_global_symlink: true`.

This new role is basically a copy of the `ensure-nox` role with the
symlink creation snippet taken from the `ensure-tox` role.

The commit adding `ensure-nox` (77b1b24) has been taken as an example of
the necessary changes when adding a new role.

Change-Id: I5592d38d415a9d74055348406653b69f110541ae

doc/source/python-roles.rst

@@ -7,6 +7,7 @@ Python Roles
 .. zuul:autorole:: ensure-if-python
 .. zuul:autorole:: ensure-nox
 .. zuul:autorole:: ensure-pip
+.. zuul:autorole:: ensure-poetry
 .. zuul:autorole:: ensure-python
 .. zuul:autorole:: ensure-sphinx
 .. zuul:autorole:: ensure-tox

roles/ensure-poetry/README.rst

@@ -0,0 +1,42 @@
+Ensure Poetry is installed
+
+Look for ``poetry``, and if not found, install it via ``pip`` into a
+virtual environment for the current user.
+
+**Role Variables**
+
+.. zuul:rolevar:: ensure_poetry_version
+   :default: ''
+
+   Version specifier to select the version of Poetry.  The default is the
+   latest version.
+
+.. zuul:rolevar:: ensure_poetry_venv_path
+   :default: {{ ansible_user_dir }}/.local/poetry
+
+   Directory for the Python venv where Poetry will be installed.
+
+.. zuul:rolevar:: ensure_poetry_global_symlink
+   :default: False
+
+   Install a symlink to the poetry executable into ``/usr/local/bin/poetry``.
+   This can be useful when scripts need to be run that expect to find
+   Poetry in a more standard location and plumbing through the value
+   of ``ensure_poetry_executable`` would be onerous.
+
+   Setting this requires root access, so should only be done in
+   circumstances where root access is available.
+
+**Output Variables**
+
+.. zuul:rolevar:: ensure_poetry_executable
+   :default: poetry
+
+   After running this role, ``ensure_poetry_executable`` will be set as the path
+   to a valid ``poetry``.
+
+   At role runtime, look for an existing ``poetry`` at this specific
+   path.  Note the default (``poetry``) effectively means to find poetry in
+   the current ``$PATH``.  For example, if your base image
+   pre-installs poetry in an out-of-path environment, set this so the
+   role does not attempt to install the user version.

roles/ensure-poetry/defaults/main.yaml

@@ -0,0 +1,4 @@
+ensure_poetry_global_symlink: false
+ensure_poetry_version: ""
+ensure_poetry_executable: poetry
+ensure_poetry_venv_path: "{{ ansible_user_dir }}/.local/poetry"

roles/ensure-poetry/tasks/main.yaml

@@ -0,0 +1,44 @@
+- name: Install pip
+  include_role:
+    name: ensure-pip
+
+- name: Check if poetry is installed
+  shell: |
+    command -v {{ ensure_poetry_executable }} {{ ensure_poetry_venv_path }}/bin/poetry || exit 1
+  args:
+    executable: /bin/bash
+  register: poetry_preinstalled
+  failed_when: false
+
+- name: Export preinstalled ensure_poetry_executable
+  set_fact:
+    ensure_poetry_executable: "{{ poetry_preinstalled.stdout_lines[0] }}"
+    cacheable: true
+  when: poetry_preinstalled.rc == 0
+
+- name: Install poetry to local env
+  when: poetry_preinstalled.rc != 0
+  block:
+    - name: Create local venv
+      command: "{{ ensure_pip_virtualenv_command }} {{ ensure_poetry_venv_path }}"
+
+    - name: Install poetry to local venv
+      command: "{{ ensure_poetry_venv_path }}/bin/pip install poetry{{ ensure_poetry_version }}"
+
+    - name: Export installed ensure_poetry_executable path
+      set_fact:
+        ensure_poetry_executable: "{{ ensure_poetry_venv_path }}/bin/poetry"
+        cacheable: true
+
+- name: Output poetry version
+  command: "{{ ensure_poetry_executable }} --version"
+
+- name: Make global symlink
+  when:
+    - ensure_poetry_global_symlink
+    - ensure_poetry_executable != '/usr/local/bin/poetry'
+  file:
+    state: link
+    src: "{{ ensure_poetry_executable }}"
+    dest: /usr/local/bin/poetry
+  become: yes

test-playbooks/ensure-poetry.yaml

@@ -0,0 +1,35 @@
+- hosts: all
+  name: Test ensure-poetry installs into user environment
+  tasks:
+    - name: Verify poetry is not installed
+      command: "poetry --version"
+      register: result
+      failed_when: result.rc == 0
+    - name: Run ensure-poetry with poetry not installed
+      include_role:
+        name: ensure-poetry
+    - name: Verify ensure_poetry_executable is set
+      assert:
+        that:
+          - ensure_poetry_executable == ansible_user_dir + '/.local/poetry/bin/poetry'
+    - name: Verify poetry is installed
+      command: "{{ ensure_poetry_executable }} --version"
+      register: result
+      failed_when: result.rc != 0
+
+- hosts: all
+  name: Test ensure-poetry when ensure_poetry_executable is set to an already installed poetry
+  tasks:
+    - name: Create a virtualenv
+      command: '{{ ensure_pip_virtualenv_command }} {{ ansible_user_dir }}/poetry-venv'
+    - name: Install poetry to local venv
+      command: '{{ ansible_user_dir }}/poetry-venv/bin/pip install poetry'
+    - name: Run ensure-poetry pointing to an already installed poetry
+      include_role:
+        name: ensure-poetry
+      vars:
+        ensure_poetry_executable: "{{ ansible_user_dir }}/poetry-venv/bin/poetry"
+    - name: Verify ensure_poetry_executable is set to the virtualenv poetry
+      assert:
+        that:
+          - ensure_poetry_executable == ansible_user_dir + '/poetry-venv/bin/poetry'

zuul-tests.d/python-jobs.yaml

@@ -144,6 +144,75 @@
     nodeset:
       nodes: []
 
+- job:
+    name: zuul-jobs-test-ensure-poetry
+    description: Test the ensure-poetry role
+    files:
+      - roles/ensure-poetry/.*
+      - test-playbooks/ensure-poetry.yaml
+    run: test-playbooks/ensure-poetry.yaml
+    tags: all-platforms
+
+- job:
+    name: zuul-jobs-test-ensure-poetry-centos-9-stream
+    description: Test the ensure-poetry role on centos-9-stream
+    parent: zuul-jobs-test-ensure-poetry
+    tags: auto-generated
+    nodeset:
+      nodes:
+        - name: centos-9-stream
+          label: centos-9-stream
+
+- job:
+    name: zuul-jobs-test-ensure-poetry-debian-bookworm
+    description: Test the ensure-poetry role on debian-bookworm
+    parent: zuul-jobs-test-ensure-poetry
+    tags: auto-generated
+    nodeset:
+      nodes:
+        - name: debian-bookworm
+          label: debian-bookworm
+
+- job:
+    name: zuul-jobs-test-ensure-poetry-debian-bullseye
+    description: Test the ensure-poetry role on debian-bullseye
+    parent: zuul-jobs-test-ensure-poetry
+    tags: auto-generated
+    nodeset:
+      nodes:
+        - name: debian-bullseye
+          label: debian-bullseye
+
+- job:
+    name: zuul-jobs-test-ensure-poetry-ubuntu-focal
+    description: Test the ensure-poetry role on ubuntu-focal
+    parent: zuul-jobs-test-ensure-poetry
+    tags: auto-generated
+    nodeset:
+      nodes:
+        - name: ubuntu-focal
+          label: ubuntu-focal
+
+- job:
+    name: zuul-jobs-test-ensure-poetry-ubuntu-jammy
+    description: Test the ensure-poetry role on ubuntu-jammy
+    parent: zuul-jobs-test-ensure-poetry
+    tags: auto-generated
+    nodeset:
+      nodes:
+        - name: ubuntu-jammy
+          label: ubuntu-jammy
+
+- job:
+    name: zuul-jobs-test-ensure-poetry-ubuntu-noble
+    description: Test the ensure-poetry role on ubuntu-noble
+    parent: zuul-jobs-test-ensure-poetry
+    tags: auto-generated
+    nodeset:
+      nodes:
+        - name: ubuntu-noble
+          label: ubuntu-noble
+
 - job:
     name: zuul-jobs-test-ensure-sphinx
     description: Test the ensure-sphinx role
@@ -420,6 +489,12 @@
         - zuul-jobs-test-ensure-pip-ubuntu-jammy
         - zuul-jobs-test-ensure-pip-ubuntu-noble
         - zuul-jobs-test-ensure-pip-localhost
+        - zuul-jobs-test-ensure-poetry-centos-9-stream
+        - zuul-jobs-test-ensure-poetry-debian-bookworm
+        - zuul-jobs-test-ensure-poetry-debian-bullseye
+        - zuul-jobs-test-ensure-poetry-ubuntu-focal
+        - zuul-jobs-test-ensure-poetry-ubuntu-jammy
+        - zuul-jobs-test-ensure-poetry-ubuntu-noble
         - zuul-jobs-test-ensure-sphinx
         - zuul-jobs-test-ensure-tox-centos-9-stream
         - zuul-jobs-test-ensure-tox-debian-bookworm