Conditional task if a variable is set

I have a playbook with the interpreter (ansible_python_interpreter) set manually.

Then I have 2 tasks (foo, bar) as an example.

I only want bar executed if the interpreter is set to python2. How can I make that happen?

hosts: "{{ ansible_limit | default (omit) }}"
  vars:
    ansible_python_interpreter: "/usr/bin/python3"
  tasks:
  - name: foo
    shell: /home/test/foo
  - name: bar
    shell: /home/test/bar

I tried when but did not get the access to the variable right I think.

when: ansible_python_interpreter.find('python2') != -1

Solution

The setup module provides you with the option to gather python_version

    - setup:
        gather_subset: python_version
    - debug:
        var: ansible_python_version

gives for example,

  ansible_python_version: 3.8.18

Then, test the version. For example,

    - debug:
        msg: foo
      when: ansible_python_version is version('3.8', '>')
    - debug:
        msg: bar
      when: ansible_python_version is version('3.8', '<')

gives

  msg: foo

^{Example of a complete playbook for testing
- hosts: all

vars:

ansible_python_interpreter: /usr/local/bin/python3.8

tasks:

- setup:
gather_subset: python_version

- debug:
var: ansible_python_version

- debug:
msg: foo
when: ansible_python_version is version('3.8', '>')

- debug:
msg: bar
when: ansible_python_version is version('3.8', '<')}