resolve dictionary key or parameter variable in Ansible

Question

In Ansible, if I try to use a variable as a parameter name, or a key name, it is never resolved. For example, if I have {{ some_var }}: true, or:

Answer 1

Another option - you can try something like:

  module_name: "{{ item.key }}={{ item.value }}"
  with_items:
  - { key: "option", value: "{{ any_value }}" }

Please note that everything is inline and I'm using an equal (=) and everything is wrapped with double quotes.

Answer 2

Will this work for you?

(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 is to wrap dict declaration with double quotes. Ansible applies this undocumented (but consistant) and crappy translation (ansible's equivalent of shell variable expantion) to most (not all) YAML values (everything RHS of ':') in the playbook. It is some combination putting these strings through Jinja2-engine, Python-interpreter and ansible-engine in some unknown order.