Use the virtualenv's pip to build the wheels

Instead of requiring pip installed on the host, we can
use the pip in the virtualenv instead. This keeps the
host cleaner.

Change-Id: I8d6c77e2cfa2cbcd81df21c7ed22a0a344d3b55c

README.rst

@@ -15,9 +15,9 @@ This Ansible role prepares a python venv for use in OpenStack-Ansible.
 
 The role requires the following to be present prior to execution:
 
-* pip >= 7.1 (to support using the constraints option)
-* virtualenv >= 13.0.0 (to support using the no-pip, no-setuptools, no-wheels
-  options)
+* virtualenv >= 1.10 (to support using the never-download option)
+* pip >= 7.1 (to support using the constraints option) in the virtualenv
+  once it has been created.
 
 Use-cases
 ~~~~~~~~~

tasks/python_venv_build.yml

@@ -41,11 +41,15 @@
   with_items:
     - "{{ venv_build_archive_path }}"
     - "{{ venv_build_wheel_path }}"
-    - "{{ venv_install_destination_path }}"
+
+- name: Create the virtualenv (if it does not exist)
+  command: "virtualenv --no-site-packages {{ _venv_create_no_download }} {{ venv_install_destination_path }}"
+  args:
+    creates: "{{ venv_install_destination_path }}/bin/activate"
 
 - name: Build wheels for the packages to be installed into the venv
   command: >-
-    pip wheel
+    {{ venv_install_destination_path }}/bin/pip wheel
     --wheel-dir {{ venv_build_wheel_path }}/
     --find-links {{ venv_build_wheel_path }}/
     --log /var/log/python_wheel_build.log
@@ -54,13 +58,6 @@
   when:
     - venv_build_wheels | bool
 
-#TODO(odyssey4me):
-# Split the venv build into multiple parts:
-# 1. Create the venv without pip, setuptools, wheel
-# 2. Use get-pip.py to install the right versions
-#    of pip, setuptools, wheel into the venv
-# 3. Install the packages into the venv
-
 - name: Build venv
   pip:
     name: "{{ venv_pip_packages }}"

tasks/python_venv_preflight.yml

@@ -30,34 +30,20 @@
   failed_when: false
   register: _virtualenv_version
 
-- name: Collect the version of pip
-  shell: |
-    pip --version 2>/dev/null | awk '{print $2}' || echo 'none'
-  args:
-    executable: /bin/bash
-  changed_when: false
-  failed_when: false
-  register: _pip_version
-
 - name: Fail when required virtualenv version is not present
   fail:
     msg: >-
       The required virtualenv version is not present.
-      The minimum version of 13.0.0 is required, but
+      The minimum version of 1.10 is required, but
       {{ _virtualenv_version.stdout }} is installed.
   when:
     - ((_virtualenv_version.stdout | trim) == 'none') or
-      ((_virtualenv_version.stdout | trim) is version_compare('13.0.0', '<'))
+      ((_virtualenv_version.stdout | trim) is version_compare('1.10', '<'))
 
-- name: Fail when required pip version is not present
-  fail:
-    msg: >-
-      The required virtualenv version is not present.
-      The minimum version of 7.1 is required, but
-      {{ _pip_version.stdout }} is installed.
-  when:
-    - ((_pip_version.stdout | trim) == 'none') or
-      ((_pip_version.stdout | trim) is version_compare('7.1', '<'))
+- name: Set the correct virtualenv parameter to prevent downloads when creating
+  set_fact:
+    _venv_create_no_download: >-
+      {{ ((_virtualenv_version.stdout | trim) is version_compare('14.0.0', '<')) | ternary('--never-download', '--no-download') }}
 
 - name: Check whether the venv_install_source_path is a URL or a file path
   set_fact: