ansible – join pairs of attributes from list of dictionaries

January 5, 2022

I have a list of dictionaries

myhosts:
  - {hostname:aaa, port:1111}
  - {hostname:bbb, port:2222}

And I want to get a single string containing the joined host:port pairs, like this

result = "aaa:1111, bbb:2222"

Thanks

>Solution :

NB: You need a space between the key and value (hostname: aaa
instead of hostname:aaa) to get the data structure you expect.

You could do something like this:

- hosts: localhost
  vars:
    myhosts:
      - {hostname: aaa, port: 1111}
      - {hostname: bbb, port: 2222}

  tasks:
    - set_fact:
        mylist: >-
          {{ mylist + ["{hostname}:{port}".format(**item)] }}
      vars:
        mylist: []
      loop: "{{ myhosts }}"

    - debug:
        var: mylist

The above playbook produces the following output:


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

TASK [Gathering Facts] *********************************************************
ok: [localhost]

TASK [set_fact] ****************************************************************
ok: [localhost] => (item={'hostname': 'aaa', 'port': 1111})
ok: [localhost] => (item={'hostname': 'bbb', 'port': 2222})

TASK [debug] *******************************************************************
ok: [localhost] => {
    "mylist": [
        "aaa:1111",
        "bbb:2222"
    ]
}

PLAY RECAP *********************************************************************
localhost                  : ok=3    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0