version

Recently, to automate building, tagging, and pushing my geerlingguy/php-apache Docker Hub image (see this issue), I needed to find a way to reliably determine the PHP major.minor.release version string. You'd think this would be simple.

Well, using Docker, I would run the image and then try:

That's great; it outputs the version right at the start. But there are a few problems here:

It's helpful to be able to enforce a minimum required Ansible version in Ansible playbooks. Ansible Roles have long been able to specify a minimum Ansible version—but only for Ansible Galaxy and ansible-galaxy-related dependency management.

I've found more and more that users who installed Ansible further in the past (in the 1.7.x or 1.8.x era) are now using some of my newer projects that require Ansible 2.0 (there are so many nice new shiny things!), and they're running into errors like:

The problem, as it turns out, is that these users are running a version < 2.0, but it's not very obvious based on that error message!