Run wheels build for each unique distro/arch

There may be multiple architecures and OS versions in
ansible_play_hosts. However, with run_once we build wheels only
for one selected distro and do not repsect multi-arch/multi-distro
setups.
Instead of run_once we need to select single (and first in play)
host of each architecture and distro and delegate wheels building
from it. That is needed, because venv_build_host is selected based
on the facts gathered for current inventory_hostname and will
depend on it's arch/distro.

Change-Id: I492d17169538ad2768e28f7c48314bdec407ab36
Closes-Bug: #1964535

releasenotes/notes/fix_respect_multiarch_setup-6e4d0b2c48ff3a18.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Wheels build for multi-arch and multi-distro setups is fixed. For that
+    you still need to have set of venv_build_targets that will define targets
+    for each operating system and architecture.

tasks/main.yml

@@ -63,8 +63,9 @@
     apply:
       tags:
         - build
-  when: venv_wheel_build_enable | bool
-  run_once: yes
+  when:
+    - venv_wheel_build_enable | bool
+    - inventory_hostname in _venv_wheels_first_play_hosts
   tags:
     - always
 

vars/main.yml

@@ -56,6 +56,18 @@ venv_build_targets: |-
   {% endfor %}
   {{ targets }}
 
+_venv_wheels_first_play_hosts: |
+  {% set first_hosts = {} %}
+  {% for host in ansible_play_hosts %}
+  {%   set arch = hostvars[host]['ansible_facts']['architecture'] %}
+  {%   set distro = hostvars[host]['ansible_facts']['distribution_version'] %}
+  {%   set distro_arch = [distro, arch] | join('_') %}
+  {%   if distro_arch not in first_hosts %}
+  {%     set _ = first_hosts.update({distro_arch: host}) %}
+  {%   endif %}
+  {% endfor %}
+  {{ first_hosts.values() }}
+
 _venv_pip_packages: "{{ (venv_default_pip_packages | union(venv_pip_packages)) | sort | select | list }}"
 
 _venv_build_dist_arch: "{{ (ansible_facts['distribution'] | lower) | replace(' ', '_') }}-{{ ansible_facts['distribution_version'].split('.')[:2] | join('.') }}-{{ ansible_facts['architecture'] | lower }}"