Ansible：如何检查Playbook中是否加载了变量？

Question

---
- hosts: "{{ target }}"
  roles:
    - app

  tasks:
  - name: alert if variable does not exist
    fail:
      msg: "{{ item }} is not defined"
    when: "{{ item }}" is not defined
    with_items:
      - country
      - city
      - street
...

[app]
ansible-slave1
ansible-slave2

[db]
ansible-db

[multi:children]
app
db

country: "France"
city: "Paris"

[vagrant@ansible-master vagrant]$ ansible-playbook --inventory-file=ansible_master_hosts test_variables.yml --extra-vars "target=ansible-slave1" --syntax-check
ERROR! Syntax Error while loading YAML.

The error appears to have been in '/vagrant/test_variables.yml': line 10, column 24, but may be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

  msg: "{{ item }} is not defined"
when: "{{ item }}" is not defined
                   ^ here
We could be wrong, but this one looks like it might be an issue with
missing quotes.  Always quote template expression brackets when they
start a value. For instance:

    with_items:
      - {{ foo }}

Should be written as:

    with_items:
      - "{{ foo }}"

我很乐意得到任何暗示。

谢谢

Answer 1

存在on open问题条件被定义，无法捕获未定义的var。

作为解决办法，我建议将where条件更改为以下内容：

何时：“{{item}}”==“