diff options
| -rw-r--r-- | synapse/http/endpoint.py | 41 | ||||
| -rw-r--r-- | tests/test_dns.py | 34 |
2 files changed, 56 insertions, 19 deletions
diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py index 4775f6707d..bc28a2959a 100644 --- a/synapse/http/endpoint.py +++ b/synapse/http/endpoint.py @@ -22,6 +22,7 @@ from twisted.names.error import DNSNameError, DomainError import collections import logging import random +import time logger = logging.getLogger(__name__) @@ -31,7 +32,7 @@ SERVER_CACHE = {} _Server = collections.namedtuple( - "_Server", "priority weight host port" + "_Server", "priority weight host port expires" ) @@ -92,7 +93,8 @@ class SRVClientEndpoint(object): host=domain, port=default_port, priority=0, - weight=0 + weight=0, + expires=0, ) else: self.default_server = None @@ -153,7 +155,13 @@ class SRVClientEndpoint(object): @defer.inlineCallbacks -def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE): +def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE, clock=time): + cache_entry = cache.get(service_name, None) + if cache_entry: + if all(s.expires > int(clock.time()) for s in cache_entry): + servers = list(cache_entry) + defer.returnValue(servers) + servers = [] try: @@ -173,27 +181,26 @@ def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE): continue payload = answer.payload - host = str(payload.target) + srv_ttl = answer.ttl try: answers, _, _ = yield dns_client.lookupAddress(host) except DNSNameError: continue - ips = [ - answer.payload.dottedQuad() - for answer in answers - if answer.type == dns.A and answer.payload - ] - - for ip in ips: - servers.append(_Server( - host=ip, - port=int(payload.port), - priority=int(payload.priority), - weight=int(payload.weight) - )) + for answer in answers: + if answer.type == dns.A and answer.payload: + ip = answer.payload.dottedQuad() + host_ttl = min(srv_ttl, answer.ttl) + + servers.append(_Server( + host=ip, + port=int(payload.port), + priority=int(payload.priority), + weight=int(payload.weight), + expires=int(clock.time()) + host_ttl, + )) servers.sort() cache[service_name] = list(servers) diff --git a/tests/test_dns.py b/tests/test_dns.py index 637b1606f8..c394c57ee7 100644 --- a/tests/test_dns.py +++ b/tests/test_dns.py @@ -21,6 +21,8 @@ from mock import Mock from synapse.http.endpoint import resolve_service +from tests.utils import MockClock + class DnsTestCase(unittest.TestCase): @@ -63,14 +65,17 @@ class DnsTestCase(unittest.TestCase): self.assertEquals(servers[0].host, ip_address) @defer.inlineCallbacks - def test_from_cache(self): + def test_from_cache_expired_and_dns_fail(self): dns_client_mock = Mock() dns_client_mock.lookupService.return_value = defer.fail(error.DNSServerError()) service_name = "test_service.examle.com" + entry = Mock(spec_set=["expires"]) + entry.expires = 0 + cache = { - service_name: [object()] + service_name: [entry] } servers = yield resolve_service( @@ -83,6 +88,31 @@ class DnsTestCase(unittest.TestCase): self.assertEquals(servers, cache[service_name]) @defer.inlineCallbacks + def test_from_cache(self): + clock = MockClock() + + dns_client_mock = Mock(spec_set=['lookupService']) + dns_client_mock.lookupService = Mock(spec_set=[]) + + service_name = "test_service.examle.com" + + entry = Mock(spec_set=["expires"]) + entry.expires = 999999999 + + cache = { + service_name: [entry] + } + + servers = yield resolve_service( + service_name, dns_client=dns_client_mock, cache=cache, clock=clock, + ) + + self.assertFalse(dns_client_mock.lookupService.called) + + self.assertEquals(len(servers), 1) + self.assertEquals(servers, cache[service_name]) + + @defer.inlineCallbacks def test_empty_cache(self): dns_client_mock = Mock() |