Make pre-molecule tox playbook platform agnostic

This change updates the tox molecule playbook to make it platform
agnostic by moving the OS specific package lists into var files
that will be dynamically loaded based on the operating system
the playbook is being executed against. This is being done so
that we can use molecule on OS's like CentOS, Ubuntu, SUSE,
Debian, etc. While the only platforms supported at this time
are Red Hat based, this change will allow additional var files
to be added enabling additional platforms without needing any
chanages to our task structure.

> The linters job has been updated to exclude vars files from the
  ansible lint playbook commands. This is done because the playbook
  commands assume all found files are playbooks.

Change-Id: I88f3551838e3676374d0a795631c8769ba40fbf4
Signed-off-by: Kevin Carter <kecarter@redhat.com>

playbooks/tox/pre-molecule.yaml

@@ -1,29 +1,27 @@
 - hosts: all
+  vars:
+    tox_molecule_packages: "{{ _tox_molecule_packages | default([]) }}"
   tasks:
+  - name: Gather variables for each operating system
+    include_vars: "{{ item }}"
+    with_first_found:
+      - skip: true
+        files:
+          - "vars/{{ ansible_distribution | lower }}-{{ ansible_distribution_version | lower }}.yaml"
+          - "vars/{{ ansible_distribution | lower }}-{{ ansible_distribution_major_version | lower }}.yaml"
+          - "vars/{{ ansible_os_family | lower }}-{{ ansible_distribution_major_version | lower }}.yaml"
+          - "vars/{{ ansible_distribution | lower }}.yaml"
+          - "vars/{{ ansible_os_family | lower }}-{{ ansible_distribution_version.split('.')[0] }}.yaml"
+          - "vars/{{ ansible_os_family | lower }}.yaml"
+    tags:
+      - always
 
-  # psutil->python-devel
-  # psutil->gcc
-  # ansible->selinux
-  - name: install packages needed by molecule
-    when: ansible_os_family == "RedHat" and ansible_lsb.major_release|int >= 8
+  - name: Install packages needed by molecule
     become: true
     package:
-      name:
-        - python2-devel
-        - python2-libselinux
-        - python3-devel
-        - python3-libselinux
-        - gcc
+      name: "{{ tox_molecule_packages }}"
+    when:
+      - (tox_molecule_packages | length) > 0
 
-  - name: install packages needed by molecule
-    when: ansible_os_family == "RedHat" and ansible_lsb.major_release|int < 8
-    become: true
-    package:
-      name:
-        - python-devel
-        - libselinux-python
-        - gcc
-
-  - name: install docker
-    include_role:
-      name: install-docker
+  roles:
+    - role: install-docker

playbooks/tox/vars/redhat-7.yaml

@@ -0,0 +1,6 @@
+---
+
+_tox_molecule_packages:
+  - python-devel
+  - libselinux-python
+  - gcc

playbooks/tox/vars/redhat-8.yaml

@@ -0,0 +1,6 @@
+---
+
+_tox_molecule_packages:
+  - python3-devel
+  - python3-libselinux
+  - gcc

tox.ini

@@ -43,12 +43,12 @@ commands =
   # Ansible lint
   # [ANSIBLE0012] Commands should not change things if nothing needs doing
   # [204] Lines should be no longer than 160 chars
-  bash -c "find playbooks -type f -regex '.*.ya?ml' -print0 | \
+  bash -c "find playbooks -type f -regex '.*.ya?ml' ! -regex '.*vars\/.*' -print0 | \
     xargs -t -n1 -0 ansible-lint -xANSIBLE0012,204"
   bash -c 'find roles -maxdepth 1 -mindepth 1 -type d -printf "%p/\n" | \
     xargs -t -n1 ansible-lint -xANSIBLE0012,204'
   # Ansible Syntax Check
-  bash -c "find playbooks -type f -regex '.*.ya?ml' -exec \
+  bash -c "find playbooks -type f -regex '.*.ya?ml' ! -regex '.*vars\/.*' -exec \
     ansible-playbook --syntax-check -i {toxinidir}/tests/inventory \{\} + > /dev/null"
   {toxinidir}/tools/check_jobs_documented.py