Json - Syntax to check if var

BILKAM
February 19, 2023
243 views
3 votes
3 Answers

I have a playbook to get all disks letter configured on my server and I need a task to verify if extra var letter is on the list.
For example I need to check if "F" is on the json data below.
Could you please help me on the best best syntax?

Thanks

 {
        "disks_drives_letter": [
            [
                "C"
            ],
            [
                "D"
            ],
            [
                "E"
            ],
            []
        ]
    }

Tags: ansible json

Answers

Chosen as BEST ANSWER

| flatten help me thanks @vladimir-botka

- name: Get all disks letter from the disks infos
      set_fact:
        disks_drives_letters: "{{ win_disk_facts | json_query(query) | flatten  }}"     
    
- name: Check if disk_letter is used on server    fail:
    msg: "The disk letter already exist on the VM"   when:  '"{{ drive_letter }}" in "{{ disks_drives_letters}}"'

(Edit)

You can use setup module to get your host information like disks. For more information about the setup module https://docs.ansible.com/ansible/latest/collections/ansible/builtin/setup_module.html

Example of playbook:

- hosts: localhost
  tasks:
  gather_facts: false
  vars:
    my_disk_drives: ['sda', 'sdb']
  tasks:
    - name: Collect host hardware information
      setup:
        gather_subset:
          - hardware

    - name: Output if disk exist
      debug:
        msg: "{{ item }} exists" 
      loop: "{{ my_disk_drives }}"
      when: item in hostvars[inventory_hostname].ansible_devices.keys() | list

    - name: Output if disks does not exist
      debug:
        msg: "{{ item }} does not exist" 
      loop: "{{ my_disk_drives }}"
      when: not item in hostvars[inventory_hostname].ansible_devices.keys() | list

Output:

TASK [Output if disk exist] 
ok: [localhost] => (item=sda) => {
    "msg": "sda exists"
}
skipping: [localhost] => (item=sdb) 

TASK [Output if disks does not exist] 
skipping: [localhost] => (item=sda) 
ok: [localhost] => (item=sdb) => {
    "msg": "sdb does not exist"
}

Use filters intersect and difference, and declare the lists

  my_disks_exist: "{{ ansible_devices.keys()|intersect(my_disks) }}"
  my_disks_not_exist: "{{ my_disks|difference(my_disks_exist) }}"

Example of a complete playbook for testing

- hosts: localhost

  vars:

    my_disks: [sda, sdb, sdc]
    my_disks_exist: "{{ ansible_devices.keys()|intersect(my_disks) }}"
    my_disks_not_exist: "{{ my_disks|difference(my_disks_exist) }}"
    

  tasks:

    - setup:
        gather_subset: devices
    - debug:
        var: ansible_devices.keys()
    - debug:
        var: my_disks_exist
    - debug:
        var: my_disks_not_exist

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Json – Syntax to check if var

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