如何在ansible中的when语句中动态构造变量名

Question

我有以下变量文件：

node1_interface;
  - name: eth1
    ip: 10.234.10.21    mask: 255.255.255.0

我有以下剧本，我想在when条件下动态构造ansible事实变量名

vars_files:
  vars/variables.ym
tasks:
  - name: create interface
    command: /sbin/nmcli connection create conn-name "{{ item.name }}" ifname "{{ item.name }}" ipv4 "{{ item.ip }}"
    with_item: {{ vars[inventory_hostname + '_interface'] }}
    when: ansible_{{ item.name }}.ipv4.address is not defined

But I am getting an error where it cannot construct the ansible fact dynamically in the when statement (It is working without the when)