ansible - 有条件地连接 jinja2 列表

Question

ansible角色中使用的一些数据:

list1:
  - foo
  - bar
list2:             # sometimes this is empty

此 ansible 任务失败:

- name: hello
  somemodule:
    dosomething: "{{ list1 + list2 }}"

错误:

fatal: [localhost]: FAILED! => {"msg": "Unexpected templating type error occurred on ({{list1 + list2}}): can only concatenate list (not \"NoneType\") to list"}

是否有办法仅在 list2 不为空时有条件连接？

Answer 1

您可以使用none bulitin 测试结合 inline if expression为此:

- debug:
    msg: "{{ list1 + (list2 if list2 is not none else []) }}" 

鉴于剧本

- hosts: local
  gather_facts: no
  vars:
    list1:
      - foo
      - bar
    list2:

  tasks:
    - debug:
        msg: "{{ list1 + (list2 if list2 is not none else [])  }}"

一场比赛将导致以下回顾:

PLAY [local] **************************************************************************************

TASK [debug] **************************************************************************************
ok: [local] => {
    "msg": [
        "foo",
        "bar"
    ]
}

PLAY RECAP ****************************************************************************************
local                      : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0