def _verify_ipaddress(self):
if not self._ipaddress:
raise MKIPAddressLookupError("Host as no IP address configured.")
if self._ipaddress in ["0.0.0.0", "::"]:
raise MKIPAddressLookupError(
"Failed to lookup IP address and no explicit IP address configured")
def cached_dns_lookup(hostname, family):
# type: (str, int) -> Optional[str]
cache = cmk_base.config_cache.get_dict("cached_dns_lookup")
cache_id = hostname, family
# Address has already been resolved in prior call to this function?
try:
return cache[cache_id]
except KeyError:
pass
# Prepare file based fall-back DNS cache in case resolution fails
# TODO: Find a place where this only called once!
ip_lookup_cache = _initialize_ip_lookup_cache()
cached_ip = ip_lookup_cache.get(cache_id)
if cached_ip and config.use_dns_cache:
cache[cache_id] = cached_ip
return cached_ip
host_config = config.get_config_cache().get_host_config(hostname)
if host_config.is_no_ip_host:
cache[cache_id] = None
return None
# Now do the actual DNS lookup
try:
ipa = socket.getaddrinfo(
hostname, None, family == 4 and socket.AF_INET
or socket.AF_INET6)[0][4][0]
# Update our cached address if that has changed or was missing
if ipa != cached_ip:
console.verbose("Updating IPv%d DNS cache for %s: %s\n" %
(family, hostname, ipa))
_update_ip_lookup_cache(cache_id, ipa)
cache[cache_id] = ipa # Update in-memory-cache
return ipa
except (MKTerminate, MKTimeout):
# We should be more specific with the exception handler below, then we
# could drop this special handling here
raise
except Exception as e:
# DNS failed. Use cached IP address if present, even if caching
# is disabled.
if cached_ip:
cache[cache_id] = cached_ip
return cached_ip
else:
cache[cache_id] = None
raise MKIPAddressLookupError(
"Failed to lookup IPv%d address of %s via DNS: %s" %
(family, hostname, e))