Score:1

Server

Accessing dict subelement value

azk

1/7/23, 2:17 AM

Here's my playbook

- name: Host's luns
  debug:
    msg: "{{ luns }}"
  vars:
    luns: "{{ ansible_facts.lvm.pvs }}"

And the output for this is

TASK [Luns del vg] ************************************************************
ok: [awxworker_rhel6] => {
    "msg": {
        "/dev/sda2": {
            "free_g": "20.72",
            "size_g": "79.72",
            "vg": "vg00"
        },
        "/dev/sdb1": {
            "free_g": "3.99",
            "size_g": "4.99",
            "vg": "vg01"
        },
        "/dev/sdc1": {
            "free_g": "0.99",
            "size_g": "4.99",
            "vg": "vg02"
        },
        "/dev/sdd1": {
            "free_g": "4.99",
            "size_g": "4.99",
            "vg": "vg01"
        }
    }
}

I need to get the luns of a matched vg

Ej: "The vg01 luns are: /dev/sdb1 /dev/sdd1"

I have tried this beetwen other ways

- name: Luns del VG
  set_fact:
    vg_luns: "{{ item }}"
  with_items: "{{ ansible_facts.lvm.pvs }}"
    vars:
      VGname: "{{ VG }}"
  when: ansible_facts.lvm.pvs.vg_luns.vg == VGname
  
- name: Print VG's luns
  debug:
    msg:
      - "The {{ VGname }} luns are: {{ vg_luns }}"

VG is an extravariable where I put the matched VGname

$ ansible-playbook -i proyects/Inventory/awx_hosts -l testhost getvgluns.yml -e VG=vg01

Hope you can help

Thanks in advance!

207

2 + 0

ansible

ansible-playbook

Score:1

Server

flowerysong

1/7/23, 7:37 AM

There's no need for set_fact or Ansible loops. Convert the dictionary to a list and use normal Jinja operations on it.

- debug:
    msg: "The {{ VG }} luns are: {{ ansible_facts.lvm.pvs | dict2items | selectattr('value.vg', 'equalto', VG) | map(attribute='key') | join(' ') }}"

0 + 1

azk

1/7/23, 12:52 PM

Thank you very much! That points directly to what I need.

Score:0

Server

Vladimir Botka

1/7/23, 5:08 AM

Create a dictionary of the groups. For example

  - set_fact:
      vgs: "{{ vgs|d({})|
               combine({item.0: item.1|
                                map(attribute='key')|
                                list}) }}"
    loop: "{{ luns|dict2items|groupby('value.vg') }}"

gives

  vgs:
    vg00:
    - /dev/sda2
    vg01:
    - /dev/sdb1
    - /dev/sdd1
    vg02:
    - /dev/sdc1

Then the selection is trivial

    - debug:
        msg: "The {{ VG }} luns are: {{ vgs[VG]|join(' ') }}"

gives the message

shell> ansible-playbook playbook.yml -e VG=vg01

  msg: 'The vg01 luns are: /dev/sdb1 /dev/sdd1'

0 + 3

azk

1/7/23, 1:44 PM

This is an attractive solution too. Perhaps there's a syntax problem because it gives me an error: ``` FAILED! => {"msg": "|combine expects dictionaries, got \"{'vg00': <generator object do_map at 0x7fd9fdd3c888>}\""} ``` I'll try to find out what it is.

Vladimir Botka

1/7/23, 2:13 PM

Add the *list* filter. I updated the answer. Actually, both solutions use the same procedure. The *list* is not needed in the solution you accepted because of the filter *join* right after *map*. Here, the *join* filter is used after the group was selected.

azk

1/7/23, 6:25 PM

Perfect. I accept your solution too. It works well. Thank you very much!

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Accessing dict subelement value

TH: การเข้าถึงค่าองค์ประกอบย่อย dict

RO: Accesarea valorii subelementului dict

RU: Доступ к значению подэлемента dict

VI: Accessing dict subelement value

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