We will be using passwordless ssh access to the switch, so ssh-rsa key has to be configured on the target switch.
All we need to do here is to ssh to the switch, run the command: "show interfaces vlan terse | match inet" and get vlan interface IDs from the output.
If the switch has vlan interfaces configured, the output will look like this:

vlan.501upup inet 10.5.5.10/24
vlan.601upup inet 10.6.6.10/24

The following python regex will be used to get vlan interface numbers:

pulled_vlans = re.findall(r'vlan.(\d{3})', cli_output)

We need to write a simple custom Python ansible module that will be called from the playbook.

**TIP: To make a custom module available to Ansible, you can either specify the path to your custom module in an environment variable, ANSIBLE_LIBRARY; use the --module-path command-line option, or drop the modules in a ./library directory alongside your top-level playbooks.

I chose to follow the last option.

Here is module library/get_vlan_iface:

#!/usr/local/bin/python

from jnpr.junos import Device
import re
import sys
import json
import os



def main():
    module = AnsibleModule(
        argument_spec=dict(
            host=dict(required=True),
            console=dict(required=False, default=None),
            user=dict(required=False, default=os.getenv('USER')),
            passwd=dict(required=False, default=None),
            port=dict(required=False, default=830)),
        supports_check_mode=True)

    m_args = module.params
    m_results = dict(changed=False)

    if m_args['console'] is None:
        try:
            from jnpr.junos import Device
            from jnpr.junos.version import VERSION
            if not float(re.match('\d+.\d+', VERSION).group()) >= 1.1:
                module.fail_json(msg='junos-eznc >= 1.1.x is required for this module')
        except ImportError:
            module.fail_json(msg='junos-eznc >= 1.1.x is required for this module')
        # -----------
        # via NETCONF
        # -----------
        dev = Device(m_args['host'], user=m_args['user'], passwd=m_args['passwd'], port=m_args['port'])
        try:
            dev.open()
        except Exception as err:
            msg = 'unable to connect to {0}: {1}'.format(m_args['host'], str(err))
            module.fail_json(msg=msg)
            return
        else:
            pulled_vlan = []
            vlan_interfaces = dev.cli('show interfaces vlan terse  | match inet', warning=False)
            pulled_vlans = re.findall(r'vlan.(\d{3})', vlan_interfaces)
            pulled_vlans = map(int, pulled_vlans)
            m_results['vlan_iface'] = pulled_vlans
            dev.close()

    module.exit_json(**m_results)



#---------------------------------------------------------------
# MAIN
#---------------------------------------------------------------
from ansible.module_utils.basic import *

main()
  
  

Next - we will create an inventory file network_inventory.corp:

[corp_switches]
nyc-sw1.nets.net ipaddr=10.5.5.10

and a playbook file get_swi.yml:

---
- hosts: corp_switches
  connection: local
  gather_facts: no

  tasks:
    - name: running command
      get_vlan_iface: user='Username' host={{ inventory_hostname  }}
      register: get_vlan_out

    - name: set var
      set_fact:
        vlan_iface: "{{ get_vlan_out.vlan_iface }}"

    - name: debug_vlans
      debug: var=get_vlan_out
  
  

To tset this module, we can use test-module script:

  
root@command-box]  (master) # ./hacking/test-module -m library/get_vlan_iface  -a "user='Username' host='10.5.5.10'"
* including generated source, if any, saving to: /root/.ansible_module_generated
* this may offset any line numbers in tracebacks/debuggers!
***********************************
RAW OUTPUT
{"changed": false, "vlan_iface": [501, 601]}


***********************************
PARSED OUTPUT
{
    "changed": false,
    "vlan_iface": [
        501,
        601
    ]
}
  
  

And finally, we run the playbook:

  
root@command-box]  (master) # ansible-playbook -i network-inventory.corp get_swi.yml

PLAY [voip_switch] ************************************************************

TASK: [running command] *******************************************************
ok: [nyc-sw1.nets.net]

TASK: [set var] ***************************************************************
ok: [nyc-sw1.nets.net]

TASK: [debug_vlans] ***********************************************************
ok: [nyc-sw1.nets.net] => {
    "get_vlan_out": {
        "changed": false,
        "invocation": {
            "module_args": "user='Automate' host=port-corp-sw1.squarespace.net",
            "module_name": "get_vlan_iface"
        },
        "vlan_iface": [
            501,
            601
        ]
    }
}

PLAY RECAP ********************************************************************
nyc-sw1.nets.net : ok=3    changed=0    unreachable=0    failed=0
  
  

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