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Code Issues Releases Wiki Activity

make dns resolver retrying explicit

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github@kiekerjan.isdronken.nl 2022-04-18 21:40:20 +02:00
parent 1b0f7991db
commit aaa7702d9d
2 changed files with 29 additions and 36 deletions
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30
management/dns_update.py
View File

@ -1110,35 +1110,33 @@ def set_secondary_dns(hostnames, env):
if len(hostnames) > 0:
# Validate that all hostnames are valid and that all zone-xfer IP addresses are valid.
resolver = dns.resolver.get_default_resolver()
resolver.timeout = 3
resolver.lifetime = 3
resolver.timeout = 5
resolver.lifetime = 5
for item in hostnames:
if not item.startswith("xfr:"):
# Resolve hostname.
tries = 2
while tries > 0:
tries = tries - 1
try:
response = resolver.resolve(item, "A")
tries = 0
except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
logging.debug('Error on resolving ipv4 address, trying ipv6')
try:
response = resolver.resolve(item, "AAAA")
tries = 0
except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
raise ValueError("Could not resolve the IP address of %s." % item)
except (dns.resolver.Timeout):
resolver.timeout = 5
resolver.lifetime = 5
logging.debug('Timeout on resolving ipv4 address re-trying')
try:
response = resolver.resolve(item, "A")
except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
logging.debug('Error on resolving ipv4 address, trying ipv6 (2)')
try:
response = resolver.resolve(item, "AAAA")
except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
raise ValueError("Could not resolve the IP address of %s." % item)
except (dns.resolver.Timeout):
logging.debug('Timeout on resolving ipv6 address')
if tries < 1:
raise ValueError("Could not resolve the IP address of %s due to timeout." % item)
except (dns.resolver.Timeout):
logging.debug('Timeout on resolving ipv4 address')
if tries < 1:
raise ValueError("Could not resolve the IP address of %s due to timeout." % item)
resolver.timeout = 3
resolver.lifetime = 3
else:
# Validate IP address.
try:

25
management/status_checks.py
View File

@ -801,30 +801,25 @@ def query_dns(qname, rtype, nxdomain='[Not Set]', at=None, as_list=False):
resolver.nameservers = [at]
# Set a timeout so that a non-responsive server doesn't hold us back.
resolver.timeout = 3
resolver.lifetime = 3
# Do the query.
try:
response = resolver.resolve(qname, rtype, search=True)
except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
# Host did not have an answer for this query; not sure what the
# difference is between the two exceptions.
logging.debug("No result for dns lookup %s, %s", qname, rtype)
return nxdomain
except dns.exception.Timeout:
logging.debug("Timeout on dns lookup %s, %s. Retrying", qname, rtype)
resolver.timeout = 5
resolver.lifetime = 5
tries = 2
# Do the query.
while tries > 0:
tries = tries - 1
try:
response = resolver.resolve(qname, rtype, search=True)
tries = 0
except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
# Host did not have an answer for this query; not sure what the
# difference is between the two exceptions.
logging.debug("No result for dns lookup %s, %s (2)", qname, rtype)
logging.debug("No result for dns lookup %s, %s (%d)", qname, rtype, tries)
if tries < 1:
return nxdomain
except dns.exception.Timeout:
logging.debug("Timeout on dns lookup %s, %s.", qname, rtype)
logging.debug("Timeout on dns lookup %s, %s (%d)", qname, rtype, tries)
if tries < 1:
return "[timeout]"
# Normalize IP addresses. IP address --- especially IPv6 addresses --- can