netbox-ddns/netbox_ddns/utils.py

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import dns.rdatatype
import dns.resolver
def normalize_fqdn(dns_name: str) -> str:
if not dns_name:
return ''
return dns_name.lower().rstrip('.') + '.'
def get_soa(dns_name: str) -> str:
parts = dns_name.rstrip('.').split('.')
for i in range(len(parts)):
zone_name = normalize_fqdn('.'.join(parts[i:]))
try:
dns.resolver.query(zone_name, dns.rdatatype.SOA)
return zone_name
except dns.resolver.NoAnswer:
# The name exists, but has no SOA. Continue one level further up
continue
except dns.resolver.NXDOMAIN as e:
# Look for a SOA record in the authority section
for query, response in e.responses().items():
for rrset in response.authority:
if rrset.rdtype == dns.rdatatype.SOA:
return rrset.name.to_text()