使用Ansible yedit修改YAML字典列表失败，求正确实现方式

问题背景 #

你有一个包含字典列表的YAML文件，结构如下：

INSTANCES:
  - NAME: hosttype1
    HOST_NAME: mysevername1
  - NAME: hosttype2
    HOST_NAME: myservername2
  - NAME: hosttype2
    HOST_NAME: myservername3

尝试用Ansible的yedit模块修改其中的NAME和HOST_NAME字段，编写的任务代码如下：

- name: Update property file {{ environment_env_property_file }} 
  yedit:
    src: "{{ environment_env_property_file }}"
    state: present
    edits:
    - key: INSTANCES.NAME[0]
      value: "CM01"
    - key: INSTANCES.NAME[0].HOST_NAME
      value: "ap-2001c.domain.net"
    - key: INSTANCES.NAME[1]
      value: "BP01"
    - key: INSTANCES.NAME[1].HOST_NAME
      value: "ap-2002c.domain.net"
    - key: INSTANCES.NAME[2]
      value: "BP01"
    - key: INSTANCES.NAME[2].HOST_NAME
      value: "ap-2003c.domain.net"

执行任务时出现报错：

An exception occurred during task execution. To see the full traceback, use -vvv. The error was: main.YeditException: Unexpected item type found while going through key path: INSTANCES.NAME[0] (at key: NAME)

你疑问：修改该字典列表的正确方式是什么？自己猜测的以下写法是否正确？

- key: INSTANCES[0].NAME
  value: "hosttype1"
- key: INSTANCES[0].HOST_NAME
  value: "myservername1"
- key: INSTANCES[1].NAME
  value: "hosttype2"
- key: INSTANCES[1].HOST_NAME
  value: "myservername2"
- key: INSTANCES[2].NAME
  value: "hosttype3"
- key: INSTANCES[2].HOST_NAME
  value: "myservername3"

解答 #

你猜测的写法是完全正确的。

错误原因解析 #

之前的代码路径逻辑错误：INSTANCES是一个列表类型，列表中的每个元素才是包含NAME和HOST_NAME的字典。你试图用INSTANCES.NAME[0]直接访问，但INSTANCES本身并没有NAME这个顶层键，yedit模块无法解析这种错误路径，因此抛出类型异常。

正确的任务代码 #

修正路径后的完整Ansible任务如下：

- name: Update property file {{ environment_env_property_file }} 
  yedit:
    src: "{{ environment_env_property_file }}"
    state: present
    edits:
    - key: INSTANCES[0].NAME
      value: "CM01"
    - key: INSTANCES[0].HOST_NAME
      value: "ap-2001c.domain.net"
    - key: INSTANCES[1].NAME
      value: "BP01"
    - key: INSTANCES[1].HOST_NAME
      value: "ap-2002c.domain.net"
    - key: INSTANCES[2].NAME
      value: "BP01"
    - key: INSTANCES[2].HOST_NAME
      value: "ap-2003c.domain.net"

内容的提问来源于stack exchange，提问作者Anders Jansson