@metadata_reactor
def add_vlan_infos_to_interface(metadata):
    interfaces = {}

    for iface, config in metadata.get('interfaces', {}).items():
        if not '.' in iface:
            continue

        interface,vlan = iface.split('.')

        interfaces.setdefault(interface, {}).setdefault('vlans', set())
        interfaces[interface]['vlans'].add(vlan)

    return {
        'interfaces': interfaces,
    }