Ansible, with_nested, How to asign dynamic variables in loop

Question

I'm trying to iterate through the number of entries dynamically in an array and use the output as an index.

Pretty sure I'm doing something wrong.

How can I assign a variable to the sequence end that represents the count of my current array?

ansible-playbook 2.9.6

run.yml:

---
- hosts: localhost

  tasks:
  - name: Import config
    include_vars: 
      file: ./config.yml

  - name: DEBUG
    debug: msg="{{ item[0].team_name }}: {{ item[0].applications.name }}: index: {{ item[1] }}"
    with_nested:
      - "{{ teams }}"
      - "{{ lookup('sequence', 'start=1 end='+(item[0].applications|length))|string }}"

config.yml:

teams:
  - team_name: Name-of-Team_A
    applications:
      - name: app_name_a
      - name: app_name_b
  - team_name: Name-of-Team_B
    applications:
      - name: app_name_c
      - name: app_name_d

Execution:

ansible-playbook run.yml

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

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

TASK [Import config] ****************************************************************************************************************************************************************
ok: [localhost]

TASK [DEBUG] ************************************************************************************************************************************************************************
fatal: [localhost]: FAILED! => {"msg": "'item' is undefined"}

PLAY RECAP **************************************************************************************************************************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0

Desired outcome:

msg: 'Name-of-Team_A: app_name_a: index: 1' 
msg: 'Name-of-Team_A: app_name_b: index: 2' 
msg: 'Name-of-Team_B: app_name_c: index: 1' 
msg: 'Name-of-Team_B: app_name_d: index: 2'

What is the expected result? – Vladimir Botka Oct 19 '20 at 08:55 — Vladimir Botka, Oct 19 '20 at 08:55

Vladimir Botka · Answer 1 · 2020-10-19T23:23:59.090

A: For example, the task below

- debug:
    msg: "{{ item.0.team_name }}: {{ item.1.name }}: {{ index1|int + 1 }}"
  with_subelements:
    - "{{ teams }}"
    - applications
  vars:
    team_names: "{{ teams|
                    map(attribute='team_name')|
                    list }}"
    index0: "{{ team_names.index(item.0.team_name) }}"
    applications: "{{ teams|
                      map(attribute='applications')|
                      list }}"
    application_names: "{{ applications[index0|int]|
                           map(attribute='name')|
                           list }}"
    index1: "{{ application_names.index(item.1.name) }}"

gives

  msg: 'Name-of-Team_A: app_name_a: 1'
  msg: 'Name-of-Team_A: app_name_b: 2'
  msg: 'Name-of-Team_B: app_name_c: 1'
  msg: 'Name-of-Team_B: app_name_d: 2'

This solution is limited to unique lists.

A better structure for this use-case is a dictionary. For example, the task below gives the same results

- debug:
    msg: "{{ item.0.key }}: {{ item.1 }}: {{ teams[item.0.key].index(item.1) + 1 }}"
  with_subelements:
    - "{{ teams|dict2items }}"
    - value
  vars:
    teams:
      Name-of-Team_A:
        - app_name_a
        - app_name_b
      Name-of-Team_B:
        - app_name_c
        - app_name_d

The lists must be unique. The method index will find the first match.

Thanks a million Vladimir, I knew it's going to be complicated. — Malan, Oct 19 '20 at 14:50

Ansible, with_nested, How to asign dynamic variables in loop

1 Answers1