I trying to figure out how to determine if a ssh keyfile is encrypted or not. This is documented here.
So I developed a simple ansible-playbook using the two examples in the document.

# site2.yml

- name: site playbook (dummy site)
  hosts: localhost
  gather_facts: no

  vars:
    thisisfalse: '{{ "any string" is ansible_vault }}'
    thisistrue: '{{ "$ANSIBLE_VAULT;1.2;AES256;dev...." is ansible_vault }}'    
    
  tasks:

    - name:  show example1
      ansible.builtin.debug:
        var: thisisfalse

    - name:  show example2
      ansible.builtin.debug:
        var: thisistrue

# Results:
# 
# fatal: [localhost]: FAILED! => 
#   msg: 'An unhandled exception occurred while templating ''{{ "any string" is ansible_vault }}''. 
#   Error was a <class ''ansible.errors.AnsibleError''>, original message: template error while templating string: 
#   Could not load "ansible_vault": ''ansible_vault''. 
#   String: {{ "any string" is ansible_vault }}. 
#   Could not load "ansible_vault": ''ansible_vault'''

So, as can be seen above, it doesn’t seem to like “ansible_vault”.
I thought it strange that the content was referring to “ansible.builtin.vault_encrypted”, but the examples were using “ansible_vault”. So I changed “ansible_vault” references to “ansible.builtin.vault_encrypted” and this is the new playbook.

# site3.yml

- name: site playbook (dummy site)
  hosts: localhost
  gather_facts: no

  vars:
    thisisfalse: '{{ "any string" is ansible.builtin.vault_encrypted }}'
    thisistrue: '{{ "$ANSIBLE_VAULT;1.2;AES256;dev...." is ansible.builtin.vault_encrypted }}'    
    
  tasks:

    - name:  show example1
      ansible.builtin.debug:
        var: thisisfalse

    - name:  show example2
      ansible.builtin.debug:
        var: thisistrue

# Results:

# PLAYBOOK: site3.yml ***********************************************************************************************************************************************************************************************************************
# 1 plays in site3.yml

# PLAY [site playbook (dummy site)] *********************************************************************************************************************************************************************************************************

# TASK [show example1] **********************************************************************************************************************************************************************************************************************
# task path: /home/sjf/tick/site3.yml:13
# Tuesday 30 July 2024  18:42:47 +0000 (0:00:00.005)       0:00:00.005 ********** 
# ok: [localhost] => 
#   thisisfalse: false

# TASK [show example2] **********************************************************************************************************************************************************************************************************************
# task path: /home/sjf/tick/site3.yml:17
# Tuesday 30 July 2024  18:42:47 +0000 (0:00:00.019)       0:00:00.025 ********** 
# ok: [localhost] => 
#   thisistrue: false

As can be seen in the results, it no longer errors out, but unfortunately BOTH the ‘thisisfalse’ variable and ‘thisistrue’ variables are false. So it still isn’t working. Does anybody see what I am doing wrong?

Thanks for any assistance.