set interface name in a variable with jinja loop on ansible - ansible

Question

i want to set inside a variable interface name if is equals to a variable pass on command line so i'm using jinja like this :
- name: Inizializzo la rete
hosts: all
gather_facts: true
become: yes
become_user: root
tasks:
- name: stampo interfacce
set_fact:
privata: "{% for interfacce in ansible_interfaces %} {% set int_tmp = 'ansible_facts.' ~ interfacce ~ '.macaddress' %} {% if {{int_tmp}}==mac_privata %} {{interfacce}} {% endif %} {% endfor %}"
- name: Stampo
debug:
msg: "{{privata}}"
but it doesn't works
i call this :
ansible-playbook test.yml --extra-vars "mac_privata=00:50:56:b7:bc:f1"
i do this because i've more than three interface
where i'm wrong?
EDIT:
#mdaniel
Thanks for your answer but it seems that it doesn't substitute hostvars['ansible_' ~ interfacce ~ '.macaddress'] with content of ansible_ens32.macaddress.
For example i do this :
- name: Stampo
debug:
msg: "{{ ansible_ens32.macaddress }}"
i've this output :
TASK [Stampo] **********************************************************************************************************************************************
ok: [10.150.20.130] => {
"msg": "00:50:56:b7:bb:f1"
}
but if i do this :
- name: stampo interfacce
set_fact:
privata: >-
{%- for interfacce in ansible_interfaces -%}
{%- if interfacce != 'lo' -%}
{%- set int_tmp = hostvars['ansible_' ~ interfacce ~ '.macaddress'] -%}
{%- if int_tmp == mac_privata -%}
{{ interfacce }}
{%- endif -%}
{%- endif -%}
{%- endfor -%}
- name: Stampo
debug:
msg: "{{privata}}"
I'm expecting name of interface with mac_privata macaddress in privata variable if i do this :
ansible-playbook test.yml --extra-vars "mac_privata=00:50:56:b7:bb:f1"
i've ens_32 but it's empty:
TASK [stampo interfacce] ***********************************************************************************************************************************
task path: /mnt/c/Users/francesco.ferraro/ansible_test/test.yml:7
ok: [10.150.20.130] => {
"ansible_facts": {
"privata": ""
},
"changed": false
}

Answer 1

Any time one sees {{ inside another jinja2 context, it's almost certainly not what you what to happen. To dynamically look up a variable, use either vars[""] or hostvars[""], or if you prefer the lookup("vars", "")
privata: >-
{%- for interfacce in ansible_interfaces -%}
{%- set int_tmp = vars['ansible_facts.' ~ interfacce ~ '.macaddress'] -%}
{%- if int_tmp == mac_privata -%}
{{ interfacce }}
{%- endif -%}
{%- endfor -%}
Most cases support the conditional for loop, which can make the snippet a little shorter
privata: >-
{%- for interfacce in ansible_interfaces
if mac_privata == vars['ansible_facts.' ~ interfacce ~ '.macaddress'] -%}
{{ interfacce }}
{%- endfor -%}