diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py
index 241b17f2cb..a97532162f 100644
--- a/synapse/http/endpoint.py
+++ b/synapse/http/endpoint.py
@@ -354,16 +354,28 @@ def _get_hosts_for_srv_record(dns_client, host):
return res[0]
- def eb(res):
- res.trap(DNSNameError)
- return []
+ def eb(res, record_type):
+ if res.check(DNSNameError):
+ return []
+ logger.warn("Error looking up %s for %s: %s",
+ record_type, host, res, res.value)
+ return res
# no logcontexts here, so we can safely fire these off and gatherResults
d1 = dns_client.lookupAddress(host).addCallbacks(cb, eb)
d2 = dns_client.lookupIPV6Address(host).addCallbacks(cb, eb)
- results = yield defer.gatherResults([d1, d2], consumeErrors=True)
+ results = yield defer.DeferredList(
+ [d1, d2], consumeErrors=True)
+
+ # if all of the lookups failed, raise an exception rather than blowing out
+ # the cache with an empty result.
+ if results and all(s == defer.FAILURE for (s, _) in results):
+ defer.returnValue(results[0][1])
+
+ for (success, result) in results:
+ if success == defer.FAILURE:
+ continue
- for result in results:
for answer in result:
if not answer.payload:
continue
|
