Require minimum version of Ansible

[grasmash]

It would be great if Drupal VM asserted that a minimum version of Ansible is in use.

You could use the assert module for this.

Something like:

- hosts: all
  tasks:
    - name: Get current Ansible version on local host
      local_action: command ansible --version
      register: local_ansible_version
    - assert:
        that:
          - "'2.1' in local_ansible_version.stdout"

[geerlingguy]

+1 to this; There are a number of people who have run into issues like #891, #890, #771, and #713... would help stomp out those errors in the future.

This would need to run prior to anything else.

[smiller171]

I think I may spend some time later turning this into a module, but here's a python script that will fail if the installed version of Ansible isn't at least 2.1.0:

# -*- encoding:utf-8 -*-
from distutils.version import LooseVersion

import sys

import ansible

def print_red_bold(text):
    print('\x1b[31;1m' + text + '\x1b[0m')

def __init__(self):
    # Can't use `on_X` because this isn't forwards compatible with Ansible 2.0+
    required_version = '2.1.0'
    installed_version = ansible.__version__
    if LooseVersion(installed_version) < LooseVersion(required_version):
        print_red_bold(
            "drupal-vm restriction: only Ansible version greater than {version} is supported.\n"
            .format(version=required_version)
        )
        sys.exit(1)

[geerlingguy]

For easier maintenance (e.g. when 2.2+ comes out), to test a minimum version, we can use version_compare... I hope :)

[geerlingguy]

Nice... looks like there's already a globally-accessible ansible_version variable that lets us do this more easily than string comparisons.

Test playbook:

---
- hosts: localhost
  pre_tasks:
    - debug: var=ansible_version

Output:

TASK [debug] *******************************************************************
ok: [localhost] => {
    "ansible_version": {
        "full": "2.1.1.0", 
        "major": 2, 
        "minor": 1, 
        "revision": 1, 
        "string": "2.1.1.0"
    }
}

[geerlingguy]

I'll be adding a new variable for this and for vagrant min version (was going to hardcode it in playbook, but it's nicer to use a var):

drupalvm_vagrant_version_min: '1.8.5'
drupalvm_ansible_version_min: '2.1'

[smiller171]

@geerlingguy nice catch. I looked for both a version_compare function and an ansible_version var and couldn't find either. ansible_version wasn't listed when I ran setup ad-hoc

[smiller171]

One thing to note is that if someone has a really old version of Ansible, it's likely to fail on a syntax check before it ever gets to running your version check task. The only way I know to get around this is to write something as a callback module that is compatible with both pre and post 2.0

[geerlingguy]

@smiller171 - True, mentioned in blog post here: http://www.jeffgeerling.com/blog/2016/require-minimum-ansible-version-your-playbook

I'd rather Ansible solves this upstream... everyone adding their own callback plugin for a version check seems a bit crazy.

[smiller171]

Agreed. I wonder if Ansible would accept a pull request to add in that functionality. Having it as a top-level parameter for a play seems to make sense:

- hosts: all
   minimum_ansible_version: 1.9.2
   tasks:
.....

Of course this isn't helpful for users of old versions, since the old versions wouldn't support the minimum_ansible_version parameter. Perhaps you could also ship a callback plugin with instructions on how to include it with your playbooks.