Azure Bicep - How to get the ip address of a Site for the main domain?

I am using bicep to configure the site and DNS. Currently, I can configure it when using the subdomain (e.g www.foilen-lab.me) by using a CNANE, but for the main (e.g foilen-lab.me), I cannot use a CNAME and must use the IP. How can I get the IP?

Currently for the "www":

resource siteWww 'Microsoft.Web/sites@2021-03-01' = {
  name: 'www-foilen-lab-me'
  location: location
  kind: 'app,linux,container'
  properties: {
    serverFarmId: serverFarmsId
    reserved: true
    httpsOnly: true
    siteConfig: {
      alwaysOn: true
      numberOfWorkers: 1
      linuxFxVersion: 'DOCKER|foilen/az-docker-apache_php:7.4.9-3'
    }
  }
}

resource dnsWww 'Microsoft.Network/dnsZones/CNAME@2018-05-01' = {
  parent: dnsZone
  name: 'www'
  properties: {
    TTL: 3600
    CNAMERecord: {
      cname: '${siteWww.name}.azurewebsites.net'
    }
  }
}

And I would like to create something like:

resource dns 'Microsoft.Network/dnsZones/A@2018-05-01' = {
  parent: dnsZone
  name: '@'
  properties: {
    TTL: 3600
    ARecords: [
      {
        ipv4Address: '${siteWww.xxxxxxxx}'
      }
    ]
  }
}

thanks

You should be able to use siteWww.properties.inboundIpAddress to get the current ipAddress.

As a general rule of thumb you can retrieve any property on a resource in bicep by using it's symbolic name and the JSON path of the GET from the REST api.

So for example, if you go to the portal for any resource and select the JSON View from the overview page... you can see what's possible to return via that syntax. e.g. siteWww.properties.customDomainVerificationId is also handy.