Question

我有以下测试手册来遍历列表字典。

- hosts: localhost

  connection: local

  vars:

    machine_roles:

      masters: ["master1","master2"]
      workers: ["worker1","worker2"]

  tasks:

    - name: toto
      debug:
       msg: "{{ item.0.role}} --- {{ item.1 }}"

      loop:
        - "{{ machine_roles | dict2items(key_name='role', value_name='machine') | subelements('machine') }}"

我想获得以下输出：

masters --- master1
masters --- master2
workers --- worker1
workers --- worker2

根据我对文档和类似文章的理解，我希望我的剧本能够胜任这项工作。但是，运行它时出现以下错误：

fatal: [localhost]: FAILED! => {"msg": "The task includes an option with an undefined variable. The error was: 'list object' has no attribute 'role'\n\nThe error appears to be in '/root/git/visa-jupyter/jupyterhub-kubespawner/test.yml': line 14, column 7, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n    - name: toto\n      ^ here\n"}

令人惊讶的是，在调试{{ machine_roles | dict2items(key_name='role', value_name='machine') | subelements('machine') }}的结果时，我得到了：

    [
        [
            {
                "machine": [
                    "master1", 
                    "master2"
                ], 
                "role": "masters"
            }, 
            "master1"
        ], 
        [
            {
                "machine": [
                    "master1", 
                    "master2"
                ], 
                "role": "masters"
            }, 
            "master2"
        ], 
        [
            {
                "machine": [
                    "worker1", 
                    "worker2"
                ], 
                "role": "workers"
            }, 
            "worker1"
        ], 
        [
            {
                "machine": [
                    "worker1", 
                    "worker2"
                ], 
                "role": "workers"
            }, 
            "worker2"
        ]
    ]

在我看来，结合使用dict2items和subelements时，文档中将说明预期的结果。

为什么在此数据结构上应用loop命令会失败，或者至少不会产生我期望的结果？

[编辑和答复] 我终于可以找到错误。我自己是通过以下方法引入另一个循环级别来使自己感到震惊：

loop:
  - "{{ machine_roles | dict2items(key_name='role', value_name='machine') | subelements('machine') }}"

正确的语法是（出于我的目的）

loop: "{{ machine_roles | dict2items(key_name='role', value_name='machine') | subelements('machine') }}"

Answer 1

这一定是一些奇怪的格式/缩进问题。您的代码工作正常

"msg": "masters --- master1"
"msg": "masters --- master2"
"msg": "workers --- worker1"
"msg": "workers --- worker2"

FWIW。这是经过测试的code的链接。

遍历带有ansible循环的列表字典

1 个答案: