在Ansible中解析字典键或参数变量

Question

在Ansible中,如果我尝试将变量用作参数名称或键名,则永远不会解析它.例如,如果我有{{ some_var }}: true,或者:

template: "{{ resolve_me_to_src }}": "some_src"

变量只是字面上使用而永远不会解决.我的具体用例是使用ec2模块,其中我的一些标签名称存储为变量:

- name: Provision a set of instances
  ec2:
    group: "{{ aws_security_group }}"
    instance_type: "{{ aws_instance_type }}"
    image: "{{ aws_ami_id }}"
    region: "{{ aws_region }}"
    vpc_subnet_id: "{{ aws_vpc_subnet_id }}"
    key_name: "{{ aws_key_name }}"
    wait: true
    count: "{{ num_machines }}"
    instance_tags: { "{{ some_tag }}": "{{ some_value }}", "{{ other_tag }}": "{{ other_value }}" }

有没有办法解决？我可以标记我想以某种方式强制进行评估吗？

Answer 1

这对你有用吗？

(rc=0)$ cat training.yml
- hosts: localhost
  tags: so5
  gather_facts: False
  vars: [
      k1: 'key1',
      k2: 'key2',
      d1: "{
        '{{k1}}': 'value1',
        '{{k2}}': 'value2',
      }",
    ]
  tasks:
  - debug: msg="{{item}}"
    with_dict: "{{d1}}"


(rc=0)$ ansible-playbook training.yml -t so5

PLAY [localhost] **************************************************************** 

PLAY [localhost] **************************************************************** 

TASK: [debug msg="{{item}}"] ************************************************** 
ok: [localhost] => (item={'key': 'key2', 'value': 'value2'}) => {
    "item": {
        "key": "key2", 
        "value": "value2"
    }, 
    "msg": "{'value': 'value2', 'key': 'key2'}"
}
ok: [localhost] => (item={'key': 'key1', 'value': 'value1'}) => {
    "item": {
        "key": "key1", 
        "value": "value1"
    }, 
    "msg": "{'value': 'value1', 'key': 'key1'}"
}

PLAY RECAP ******************************************************************** 
localhost                    : ok=1    changed=0    unreachable=0    failed=0   

(rc=0)$

Trick是用双引号包装dict声明.Ansible将这个未记录的(但是一致的)和糟糕的翻译(ansible相当于shell变量扩展)应用于剧本中的大多数(并非所有)YAML值(RHS的所有内容':').这是通过Jinja2引擎,Python解释器和ansible-engine以某种未知顺序放置这些字符串的一些组合.