def _ip_to_hostname(config_cache, ip):
# type: (config.ConfigCache, Optional[HostAddress]) -> Optional[HostName]
if not _config_cache.exists("ip_to_hostname"):
cache = _config_cache.get_dict("ip_to_hostname")
for host in config_cache.all_active_realhosts():
try:
cache[ip_lookup.lookup_ipv4_address(host)] = host
except Exception:
pass
else:
cache = _config_cache.get_dict("ip_to_hostname")
return cache.get(ip)
def update_timeperiods_cache() -> None:
# { "last_update": 1498820128, "timeperiods": [{"24x7": True}] }
# The value is store within the config cache since we need a fresh start on reload
tp_cache = _config_cache.get_dict("timeperiods_cache")
if not tp_cache:
response = livestatus.LocalConnection().query(
"GET timeperiods\nColumns: name in")
for tp_name, tp_active in response:
tp_cache[tp_name] = bool(tp_active)
def timeperiod_active(timeperiod: TimeperiodName) -> Optional[bool]:
"""Returns
True : active
False: inactive
None : unknown timeperiod
Raises an exception if e.g. a timeout or connection error appears.
This way errors can be handled upstream."""
update_timeperiods_cache()
return _config_cache.get_dict("timeperiods_cache").get(timeperiod)
def cached_dns_lookup(hostname, family):
# type: (HostName, int) -> Optional[str]
cache = _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
ip_lookup_cache = _get_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))
ip_lookup_cache.update_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
cache[cache_id] = None
raise MKIPAddressLookupError(
"Failed to lookup IPv%d address of %s via DNS: %s" %
(family, hostname, e))
def check_timeperiod(timeperiod: TimeperiodName) -> bool:
"""Check if a timeperiod is currently active. We have no other way than
doing a Livestatus query. This is not really nice, but if you have a better
idea, please tell me..."""
# Let exceptions happen, they will be handled upstream.
try:
update_timeperiods_cache()
except MKTimeout:
raise
except Exception:
if cmk.utils.debug.enabled():
raise
# If the query is not successful better skip this check then fail
return True
# Note: This also returns True when the timeperiod is unknown
# The following function timeperiod_active handles this differently
return _config_cache.get_dict("timeperiods_cache").get(timeperiod, True)
def cleanup_timeperiod_caches() -> None:
_config_cache.get_dict("timeperiods_cache").clear()
