Evaluation of (Python) expressions only in "only_if" and not in "vars" section of a playbook?

Archives Ansible Project
1

Hi,

I'm playing around with Ansible for few hours - it is very interesting
(and feature list is exactly what I was looking for), but it seams to
be a bit inflexible to me. Maybe, I just don't understand the concepts
correctly. Therefore, here and in following posts I will ask some
questions ...

Do I understand it correctly that (Python) expressions are only
evaluated as the "only_if" value? I would prefer to have evaluation in
the "vars" section of a playbook to make it more modular. Similar toi
this example:

- hosts: foo
  vars:
    is_correct_platform: "'{{ansible_product_name}}' == 'VMware
Virtual Platform'"
    tmp_dir: "/tmp/foo"
    tmp_file: "{{tmp_dir}}/myfile"
    file_exists: "os.path.isfile('{{tmp_file}}')"
    do_action: "{{is_correct_platform}} and not({{file_exists}})"
  tasks
  - name: foo1
    action: ...
    only_if: "{{do_action}}"
  - name: foo2
    action: ...
    only_if: "{{do_action}}"

Can I do this in a different way? Are changes scheduled for future
releases?

Thanks,

Frank

2

You can save expressions in vars and use them in only_if statements, I included this in previous emails to the list, in fact.

3

Also, I believe you can use jinja expressions (subset of python, basically), inside {{ }} tags, e.g., {{ var1 == var2 }}.

4

For only_if, yes, as long as they are quoted.