Ansible subelements循环处理用户密钥报错，求解决方案

问题场景 #

尝试运行以下测试代码，使用Ansible的subelements过滤器循环处理users变量中的用户名称、授权密钥文件及对应密钥：

- hosts: localhost
  gather_facts: no
  vars:
    users:
      - name: user1
        authorized_keys_file: authorized_keys_file_1.log
        authorized_keys:
          - key1
          - key2
      - name: user2
        authorized_keys_file: authorized_keys_file_2.log
        authorized_keys:
          - key1
  tasks:
    - name: List keys to add to authorized_key_file
      debug:
        msg: "User={{ item.0.name }} File={{ item.0.authorized_keys_file }} key={{ item.1 }}"
      loop:
        - "{{ users | subelements('authorized_keys') }}"

报错信息 #

The task includes an option with an undefined variable. The error was: 'list object' has no attribute 'name'

期望输出 #

User=user1 File=authorized_keys_file_1 key=key1
User=user1 File=authorized_keys_file_1 key=key2
User=user2 File=authorized_keys_file_2 key=key1

解决方案 #

错误原因是loop参数里多套了一层列表（- "{{ users | subelements('authorized_keys') }}"），导致item变成了整个subelements返回的列表，而非预期的元组。

修正后的代码只需去掉loop下的列表符号，直接使用subelements的结果：

- hosts: localhost
  gather_facts: no
  vars:
    users:
      - name: user1
        authorized_keys_file: authorized_keys_file_1.log
        authorized_keys:
          - key1
          - key2
      - name: user2
        authorized_keys_file: authorized_keys_file_2.log
        authorized_keys:
          - key1
  tasks:
    - name: List keys to add to authorized_key_file
      debug:
        msg: "User={{ item.0.name }} File={{ item.0.authorized_keys_file }} key={{ item.1 }}"
      loop: "{{ users | subelements('authorized_keys') }}"

运行修正后的代码，就能得到预期的循环输出，后续也可以直接把这个逻辑迁移到ansible.posix.authorized_key模块中使用。

内容的提问来源于stack exchange，提问作者Gryphus71