Here’s my playbook snippet:

- name: Get switch configuration
  uri:
    url: https://{{ ansible_host }}/api/v1/sites/{{ site_id }}/devices/{{ switch }}
    method: GET
    return_content: yes
    headers:
      Content-Type: "application/json"
      Authorization: "Token {{ mist_token }}"
    validate_certs: no
  ignore_errors: yes
  register: switch_configuration_response

- name: print switch_configuration_response
  debug:
    var: switch_configuration_response

- name: Parse JSON response
  set_fact:
    switch_configuration: "{{ switch_configuration_response.json }}"

- name: Define the target description
  set_fact:
    target_description: "INET_{{ link }}"

- name: Find the port key with the specified description
  set_fact:
    interface_name: "{{ item.key }}"
  loop: "{{ switch_configuration.port_config | dict2items }}"
  when: item.value.description == target_description

- name: print interface_name
  debug:
    var: interface_name

- name: Update the fact
  ansible.utils.update_fact:
    updates:
      - path: switch_configuration.port_config.{{ interface_name }}.usage
        value: disabled
  register: updated_switch_configuration

- name: print switch_configuration
  debug:
    var: switch_configuration

- name: print switch_configuration
  debug:
    var: updated_switch_configuration

Pay atention on this block:

- name: Update the fact
  ansible.utils.update_fact:
    updates:
      - path: switch_configuration.port_config.{{ interface_name }}.usage
        value: disabled
  register: updated_switch_configuration

- name: print switch_configuration
  debug:
    var: switch_configuration

- name: print updated switch_configuration
  debug:
    var: updated_switch_configuration 

When I run the playbook I expect that only the specific “usage” field is updated and the rest of the json remains untouched, but instead, it is creating a new key “switch_configuration” and putting all the values inside of it, as a redundance.

Output snippet:

TASK [print switch_configuration] **********************************************
ok: [JUNIPER_MIST] => {
    "switch_configuration": {
        "additional_config_cmds": [
            ""
        ],
        "bgp_config": null,
        "changed": true,
        "created_time": 1706718685,
        "deviceprofile_id": null,
        "disable_auto_config": false,
        "evpn_scope": null,
        "evpntopo_id": null,
        "failed": false,
        "hw_rev": "D",
        "id": "00000000-0000-0000-1000-bc0ffef85364",
        "ip_config": {
            "network": "default",
            "type": "dhcp"
        },
        "mac": "bc0ffef85364",
        "managed": true,
        "map_id": null,
        "model": "EX2300-24P",
        "modified_time": 1720131177,
        "name": "SW-MAG036-CORE1-TESTE2",
        "networks": {},
        "notes": "TESTE2",
        "oob_ip_config": {
            "type": "dhcp",
            "use_mgmt_vrf": false
        },
        "org_id": "5d568cec-dcd9-4fe9-ad1a-65c93640f9ad",
        "port_config": {
            "ge-0/0/0": {
                "critical": false,
                "description": "INET_EBT",
                "dynamic_usage": null,
                "no_local_overwrite": true,
                "usage": "vlan_52"
            },
            "ge-0/0/1": {
                "critical": false,
                "description": "INET_ALGAR",
                "dynamic_usage": null,
                "no_local_overwrite": true,
                "usage": "vlan_51"
            }
        },
        "port_usages": {},
        "role": "",
        "routing_policies": {},
        "serial": "JY4823370892",
        "site_id": "29ca1e1c-8958-4159-9568-f5070be1239a",
        "st_ip_base": "",
        "switch_config": {},
        "tag_id": 3452277,
        "tag_uuid": "5d568cec-dcd9-4fe9-ad1a-65c93640f9ad",
        "type": "switch"
    }
}

TASK [print updated switch_configuration] **********************************************
ok: [JUNIPER_MIST] => {
    "updated_switch_configuration": {
        "changed": true,
        "failed": false,
        "switch_configuration": {
            "additional_config_cmds": [
                ""
            ],
            "bgp_config": null,
            "changed": true,
            "created_time": 1706718685,
            "deviceprofile_id": null,
            "disable_auto_config": false,
            "evpn_scope": null,
            "evpntopo_id": null,
            "failed": false,
            "hw_rev": "D",
            "id": "00000000-0000-0000-1000-bc0ffef85364",
            "ip_config": {
                "network": "default",
                "type": "dhcp"
            },
            "mac": "bc0ffef85364",
            "managed": true,
            "map_id": null,
            "model": "EX2300-24P",
            "modified_time": 1720131177,
            "name": "SW-MAG036-CORE1-TESTE2",
            "networks": {},
            "notes": "TESTE2",
            "oob_ip_config": {
                "type": "dhcp",
                "use_mgmt_vrf": false
            },
            "org_id": "5d568cec-dcd9-4fe9-ad1a-65c93640f9ad",
            "port_config": {
                "ge-0/0/0": {
                    "critical": false,
                    "description": "INET_EBT",
                    "dynamic_usage": null,
                    "no_local_overwrite": true,
                    "usage": "vlan_52"
                },
                "ge-0/0/1": {
                    "critical": false,
                    "description": "INET_ALGAR",
                    "dynamic_usage": null,
                    "no_local_overwrite": true,
                    "usage": "disabled"
                }
            },
            "port_usages": {},
            "role": "",
            "routing_policies": {},
            "serial": "JY4823370892",
            "site_id": "29ca1e1c-8958-4159-9568-f5070be1239a",
            "st_ip_base": "",
            "switch_config": {},
            "tag_id": 3452277,
            "tag_uuid": "5d568cec-dcd9-4fe9-ad1a-65c93640f9ad",
            "type": "switch"
        }
    }
}

Pay attention on the new key “switch_configuration” created inside updated_switch_configuration. Any guesses on why is that happening?