Ansible Jinja2 evaluate string as template

Question

I have a sort of configuration vars file through which I'm looping,

checks:
  - name: "x"
    setting: "y"
    eval: "{{ 'OK' if var == 'x' else 'NOK' }}"

main.yml

- hosts: all
  tasks:
  - name: Loop
    include_tasks: do.yml
    loop: "{{ checks }}"

Now the issue is that the eval gets templated/expanded as it's entering the loop...

inside do.yml

---
- debug:
    var: item

(shows eval as NOK)

- name: Do stuff
  shell:
  register: var

- name: Save stuff
  set_fact
    result: "{{ result | d([]) + [ res ] }}"
  vars:
    res:
      name: "{{ item.name }}"
      setting: "{{ item.setting }}"
      result: "{{ item.eval }}"

How do I make it so that the item.eval is re-evaluated after var is registered? What I'd like even more is if I just provided the string, without the curly brackets in checks.yml file and that would get templated inside the loop. I just can't make it work.

Answer 1

The case you describe is not complete. Without the variable var defined you have to see the error message:

'var'' is undefined

The below play

- hosts: localhost

  vars:

    checks:
      - name: "x"
        setting: "y"
        eval: "{{ 'OK' if var == 'x' else 'NOK' }}"

  tasks:

    - include_tasks: do.yml
      loop: "{{ checks }}"

fails

fatal: [localhost]: FAILED! => 
  msg: '[{''name'': ''x'', ''setting'': ''y'', ''eval'': "{{ ''OK'' if var == ''x'' else ''NOK'' }}"}]: ''var'' is undefined'

---

To answer your question: "How do I make it so that the item.eval is re-evaluated after var is registered?"

It is not possible to reevaluate item.eval

---

The solution might be to restructure the data. For example,

    checks:
      - eval:
          x: OK
          default: NOK
      - eval:
          y: OK
          default: NOK

Then, evaluate the dictionary in the loop. For example,

shell> cat do.yml
- command: echo x
  register: out

- set_fact:
    result: "{{ result | d([]) + [ res ] }}"
  vars:
    res:
      result: "{{ item.eval[out.stdout] if  out.stdout in item.eval else item.eval.default }}"

gives

  result:
  - result: OK
  - result: NOK

---

Example of a complete playbook for testing

- hosts: localhost

  vars:

    checks:
      - eval:
          x: OK
          default: NOK
      - eval:
          y: OK
          default: NOK

  tasks:

    - include_tasks: do.yml
      loop: "{{ checks }}"

    - debug:
        var: result