//reference: https://lucian.blog/terraform-csvs-netflix/

locals {
  dns_records = csvdecode(file("mydomaincom_dns_records.csv"))
  // csv needs the columns: name, proxied, type, record_data, mx_priority
}

resource "cloudflare_record" "dns_records" {
    for_each = { for records in local.dns_records  : records.name => records }
  name = each.value.name
  proxied = each.value.proxied
  ttl = 1
  type = each.value.type
  value = each.value.record_data
  zone_id = var.zone_id
  // If record type is MX then add the MX priority
  priority = (each.value.type == "MX") == true ? each.value.mx_priority : null
}

name: the name of the record i.e. www proxied: (true or false) whether to proxy the record via cloudflare or if its a DNS only record type: cname, A, AAAA, MX, TXT etc the type of record record data: the IP address, or hostname, or TXT data priority: the record priority, for MX records only

That last line in the above snippet will check if the record type being added is an MX record, if it is a MX record, it will then add the priority to the record.