How to divide and multiply Ansible facts queried by json_query?

Question

"{{ ansible_facts | json_query('mounts[*].size_available') }} / {{ ansible_facts | json_query('mounts[*].size_total') }} * 100"

I am trying to get size available and divide it by size total and Multiply it by 100 to give me the percentage disc usage. This current code gives me the output something like this:

"msg": "[238273] / [483298433] * 100"

It completely ignores the / and the *.
How can I resolve this issue?

Answer 1

json_query is not needed. Simply map the attributes, e.g.

    - debug:
        msg: "{{ (item.0 / item.1 * 100)|round }}"
      with_together:
        - "{{ ansible_mounts|map(attribute='size_available')|list }}"
        - "{{ ansible_mounts|map(attribute='size_total')|list }}"

gives

ok: [localhost] => (item=[2085240832, 41015336960]) => 
  msg: '5.0'
ok: [localhost] => (item=[30278656, 100663296]) => 
  msg: '30.0'
ok: [localhost] => (item=[21565116416, 109899771904]) => 
  msg: '20.0'

---

A simpler option is to iterate the list of mounts, e.g.

    - debug:
        msg: "{{ (item.size_available / item.size_total * 100)|round }}"
      loop: "{{ ansible_mounts }}"
      loop_control:
        label: "{{ item.mount }}"

gives

ok: [localhost] => (item=/) => 
  msg: '5.0'
ok: [localhost] => (item=/boot/efi) => 
  msg: '30.0'
ok: [localhost] => (item=/export) => 
  msg: '20.0'