backwards compatibility - How to suppress "Unsupported parameters" error in Ansible?

Question

I am using a the quiet parameter in the assert module for tasks where the output is too verbose. The quiet parameter was introduced in Ansible 2.8, but unfortunately, my code sometimes needs to run on Debian Buster, which still comes with Ansible 2.7.

In that case, Ansible fails with the fatal error "Unsupported parameters for (assert) module: quiet". Since this is only a cosmetic parameter, I want Ansible 2.7 to ignore this parameter and continue.

Is there a way to add this parameter in my task so that Ansible 2.8 is nice and quiet, but the task still runs in Ansible 2.7?

- name: Silent assert
  assert:
    that:
      - true
    quiet: yes

question from:https://stackoverflow.com/questions/65910893/how-to-suppress-unsupported-parameters-error-in-ansible

Answer 1

There is an omit filter which can help in bypassing some parameters if they are not applicable. For this purpose, we can define a variable that will be set to true for Ansible version 2.8 or greater. Then this variable can be passed to the quiet parameter of assert module in combination with omit.

Example:

  - set_fact:
      quiet_assert: true
    when: ansible_version.full is version('2.8', '>=')
  - assert:
      that:
      - true
      quiet: "{{ quiet_assert|default(omit) }}"