dns

DNS module.

exception wmflib.dns.DnsError[source]

Bases: WmflibError

Custom exception class for errors of the Dns class.

exception wmflib.dns.DnsNotFound[source]

Bases: DnsError

Custom exception class to indicate the record was not found.

One or more resource records might exist for this domain but no record matches the resource record type requested.

class wmflib.dns.Dns(*, nameserver_addresses: Sequence[str] | None = None, port: int | None = None)[source]

Bases: object

Class to interact with the DNS.

Initialize the instance optionally specifying the nameservers to use.

Examples

Using the host’s default DNS resolvers:

>>> from wmflib.dns import Dns
>>> dns = Dns()

Using a specific set of resolvers and port:

>>> from wmflib.dns import Dns
>>> dns = Dns(nameserver_addresses=['10.0.0.1', '10.0.0.2'], port=5353)

Parameters:

nameserver_addresses (Sequence, optional) – the nameserveres address to use, if not set uses the OS configuration.
port (int, optional) – the port the nameserver_addresses nameserveres is listening to, if different from the default 53. This applies only if a nameserveres is explicitelyes specified.

resolve_ipv4(name: str) → List[str][source]

Perform a DNS lookup for an A record for the given name.

Examples

>>> dns.resolve_ipv4('api.svc.eqiad.wmnet')
['10.2.2.22']

Parameters:: name (str) – the name to resolve.
Returns:: the list of IPv4 addresses as strings returned by the DNS response.
Return type:: list

resolve_ipv6(name: str) → List[str][source]

Perform a DNS lookup for an AAAA record for the given name.

Examples

>>> dns.resolve_ipv6('wikimedia.org')
['2620:0:861:ed1a::1']

Parameters:: name (str) – the name to resolve.
Returns:: the list of IPv6 addresses as strings returned by the DNS response.
Return type:: list

resolve_ips(name: str) → List[str][source]

Perform a DNS lookup for A and AAAA records for the given name.

Examples

>>> dns.resolve_ips('wikimedia.org')
['208.80.154.224', '2620:0:861:ed1a::1']

Parameters:: name (str) – the name to resolve.
Returns:: the list of IPv4 and IPv6 addresses as strings returned by the DNS response.
Return type:: list
Raises:: wmflib.dns.DnsNotFound – when no address is found.

resolve_ptr(address: str) → List[str][source]

Perform a DNS lookup for PTR record for the given address.

Examples

>>> dns.resolve_ptr('208.80.154.224')
['text-lb.eqiad.wikimedia.org']

Parameters:: address (str) – the IPv4 or IPv6 address to resolve.
Returns:: the list of absolute target PTR records as strings, without the trailing dot.
Return type:: list

resolve_cname(name: str) → str[source]

Perform a DNS lookup for CNAME record for the given name.

Examples

>>> dns.resolve_cname('puppet.codfw.wmnet')
'puppetmaster2001.codfw.wmnet'

Parameters:: name (str) – the name to resolve.
Returns:: the absolute target name for this CNAME, without the trailing dot.
Return type:: str

resolve(qname: str | Name, record_type: str) → Answer[source]

Perform a DNS lookup for the given qname and record type.

Examples

>>> response = dns.resolve('wikimedia.org', 'MX')
>>> [rdata.to_text() for rdata in response.rrset]
['10 mx1001.wikimedia.org.', '50 mx2001.wikimedia.org.']

Parameters:

qname (str) – the name or address to resolve.
record_type (str) – the DNS record type to lookup for, like ‘A’, ‘AAAA’, ‘PTR’, etc.

Returns:

the DNS response.

Return type:

dns.resolver.Answer

Raises:

wmflib.dns.DnsNotFound – if there are no records for the given record type but the qname has records for different record type(s).
wmflib.dns.DnsError – on generic error.

class wmflib.dns.PublicAuthDns[source]

Bases: Dns

Class to interact with the DNS using the wikimedia foundation authoritative servers.

Initialize the instance with the WMF public authoritative namerservers.

It uses the nameservers defined in wmflib.constants.PUBLIC_AUTHDNS.

Examples

>>> from wmflib.dns import PublicAuthDns
>>> dns = PublicAuthDns()