ansible json_query How to define default value to missing key

Question

I've got some variables:

  vars:
    foo:
      - {name: "bar", path: "/tmp"}
      - {name: "zob" }
    default: "/home"

I'd like to make json_query that extracts name and path, and when path is not defined takes a default value.

The result I would like is

  - {name: "bar", path: "/tmp"}
  - {name: "zob", path: "/home"}

Is there a possiblity in json_query to defined a default value when the key is not defined?

Thanks, Raoul

Instead of defining the default in the variables part, you can use define it in the code part, using defaullt values. but depends of the use-case, which is not fully explained here. If you want specific answer, edit the question and provide more information. Best — Baptiste Mille-Mathias, Jun 26 '20 at 17:13

Zeitounator · Accepted Answer · 2020-06-26T17:29:11.627

The following will merge every elements of your list with a default hash map overiding existing values if redefined using the merge jmespath function. This works for the path in the example but you can add more mappings if needed.

---
- hosts: localhost
  gather_facts: false

  vars:
    foo:
      - {name: "bar", path: "/tmp"}
      - {name: "zob" }
    foo_defaults:
      path: "/home"

  tasks:
    - debug:
        msg: "{{ foo | json_query(query) }}"
      vars:
        query: >-
          [].merge(`{{ foo_defaults | to_json }}`, @)

Which gives

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

TASK [debug] ***************************************************************************************************************************************************************************************************************************
ok: [localhost] => {
    "msg": [
        {
            "name": "bar",
            "path": "/tmp"
        },
        {
            "name": "zob",
            "path": "/home"
        }
    ]
}

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

ansible json_query How to define default value to missing key

1 Answers1