From 6dce7ba60594f871cc07627ea40d80d82cc544b1 Mon Sep 17 00:00:00 2001
From: Ian Wienand <iwienand@redhat.com>
Date: Wed, 8 Apr 2020 06:26:47 +1000
Subject: [PATCH] ensure-pip: export ensure_pip_virtualenv_command

This makes ensure-pip export something that should be sensible for
users of pip: to put in their 'virtualenv_command' for their host.

The theory of operation is fairly simple; see if "python3 -m venv"
looks like it works, and set that as the command if it does.  If not,
set "virtualenv".  For sanity, we check if it works.

We pull in virtualenv in the Python 2 case, but for Python 3 we are
deliberately do not bring it as it is an unnecessary dependency.  If
jobs do require the actual `virtualenv` package, they should provision
it themselves ... except for Xenial, which, as described inline, has
issues.

Follow-on changes will convert existing zuul-jobs roles that install
tools into virtualenvs to use this argument.

Change-Id: Idad14c0e77eed5bf8df2c8f84f52fbdea2236a9f
---
 roles/ensure-pip/tasks/Debian.yaml |  1 +
 roles/ensure-pip/tasks/RedHat.yaml |  1 +
 roles/ensure-pip/tasks/main.yaml   | 32 ++++++++++++++++++++++++++++++
 roles/ensure-pip/tasks/xenial.yaml | 20 +++++++++++++++++++
 test-playbooks/ensure-pip.yaml     | 15 ++++++++++++++
 5 files changed, 69 insertions(+)
 create mode 100644 roles/ensure-pip/tasks/xenial.yaml

diff --git a/roles/ensure-pip/tasks/Debian.yaml b/roles/ensure-pip/tasks/Debian.yaml
index ad7c4163d..d70a07552 100644
--- a/roles/ensure-pip/tasks/Debian.yaml
+++ b/roles/ensure-pip/tasks/Debian.yaml
@@ -3,6 +3,7 @@
     name:
       - python3-pip
       - python3-setuptools
+      - python3-venv
   become: yes
 
 - name: Install Python 2 pip
diff --git a/roles/ensure-pip/tasks/RedHat.yaml b/roles/ensure-pip/tasks/RedHat.yaml
index 33fb01f77..4f9021baf 100644
--- a/roles/ensure-pip/tasks/RedHat.yaml
+++ b/roles/ensure-pip/tasks/RedHat.yaml
@@ -34,6 +34,7 @@
     name:
       - python-pip
       - python-setuptools
+      - python-virtualenv
     state: present
   become: yes
   when: (ensure_pip_from_packages_with_python2) or
diff --git a/roles/ensure-pip/tasks/main.yaml b/roles/ensure-pip/tasks/main.yaml
index 3c6e72f22..74df1d9c0 100644
--- a/roles/ensure-pip/tasks/main.yaml
+++ b/roles/ensure-pip/tasks/main.yaml
@@ -29,6 +29,7 @@
 - name: Install pip from packages
   include: "{{ item }}"
   with_first_found:
+    - "{{ ansible_distribution_release }}.yaml"
     - "{{ ansible_distribution }}.yaml"
     - "{{ ansible_os_family }}.yaml"
     - "default.yaml"
@@ -41,3 +42,34 @@
   when:
     - ensure_pip_from_upstream
     - pip_preinstalled.rc != 0
+
+#
+# virtualenv setup
+#
+- name: Probe for venv
+  command: /usr/bin/python3 -m venv --help
+  no_log: True
+  failed_when: false
+  register: _venv_probe
+
+- name: Set host default
+  set_fact:
+    _host_virtualenv: '{{ (_venv_probe.rc == 0) | ternary("/usr/bin/python3 -m venv", "virtualenv") }}'
+  when: ansible_distribution_release != 'xenial'
+
+# The pip included with Xenial (version ~8) has issues with our wheel
+# mirrors; it will not correctly look to upstream pypi when it can't
+# find the wheel in the configured mirror, so virutalenv creation
+# fails.  venv uses the system pip version; for this reason we need to
+# use virtualenv which does upgrade pip in the environment; but note
+# that on Xenial "virtualenv" is owned by the python2 package; so we
+# specify the command to python3 directly.
+- name: Set host default (Xenial)
+  set_fact:
+    _host_virtualenv: '/usr/bin/python3 -m virtualenv'
+  when: ansible_distribution_release == 'xenial'
+
+- name: Set ensure_pip_virtualenv_cmd
+  set_fact:
+    ensure_pip_virtualenv_command: '{{ ensure_pip_virtualenv_command | default(_host_virtualenv) }}'
+    cacheable: true
diff --git a/roles/ensure-pip/tasks/xenial.yaml b/roles/ensure-pip/tasks/xenial.yaml
new file mode 100644
index 000000000..1b4b63b70
--- /dev/null
+++ b/roles/ensure-pip/tasks/xenial.yaml
@@ -0,0 +1,20 @@
+# See notes in main.yaml about the virtualenv requirements
+
+- name: Install Python 3 pip
+  package:
+    name:
+      - python3-pip
+      - python3-setuptools
+      - python3-venv
+      - python3-virtualenv
+  become: yes
+
+- name: Install Python 2 pip
+  package:
+    name:
+      - python-setuptools
+      - python-pip
+      - python-virtualenv
+  become: yes
+  when: (ensure_pip_from_packages_with_python2) or
+        (ansible_python.version.major == 2)
diff --git a/test-playbooks/ensure-pip.yaml b/test-playbooks/ensure-pip.yaml
index 6b83580e6..8fb39a02c 100644
--- a/test-playbooks/ensure-pip.yaml
+++ b/test-playbooks/ensure-pip.yaml
@@ -1,6 +1,21 @@
 - hosts: all
   roles:
     - ensure-pip
+  tasks:
+    - name: Sanity check provided virtualenv command works
+      shell: |
+        tmp_venv=$(mktemp -d -t venv-XXXXXXXXXX)
+        trap "rm -rf $tmp_venv" EXIT
+        {{ ensure_pip_virtualenv_command }} $tmp_venv
+        $tmp_venv/bin/pip install tox
+      failed_when: false
+      register: _venv_sanity
+
+    - name: Assert sanity check
+      fail:
+        msg: 'The virtualenv_command: "{{ ensure_pip_virtualenv_command }}" does not appear to work!'
+      when:
+        - _venv_sanity.rc != 0
 
 # NOTE(ianw) : this does not play nicely with pip-and-virtualenv which
 # has already installed from source.  We might be able to test this