def test_disabled_service(self):
"""
test the behaviour when there is a single record which is ".".
"""
service_name = b"test_service.example.com"
lookup_deferred = Deferred()
dns_client_mock = Mock()
dns_client_mock.lookupService.return_value = lookup_deferred
cache = {}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
# Old versions of Twisted don't have an ensureDeferred in failureResultOf.
resolve_d = defer.ensureDeferred(resolver.resolve_service(service_name))
# returning a single "." should make the lookup fail with a ConenctError
lookup_deferred.callback(
(
[dns.RRHeader(type=dns.SRV, payload=dns.Record_SRV(target=b"."))],
None,
None,
)
)
self.failureResultOf(resolve_d, ConnectError)
def test_non_srv_answer(self):
"""
test the behaviour when the dns server gives us a spurious non-SRV response
"""
service_name = b"test_service.example.com"
lookup_deferred = Deferred()
dns_client_mock = Mock()
dns_client_mock.lookupService.return_value = lookup_deferred
cache = {}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
resolve_d = resolver.resolve_service(service_name)
self.assertNoResult(resolve_d)
lookup_deferred.callback((
[
dns.RRHeader(type=dns.A, payload=dns.Record_A()),
dns.RRHeader(type=dns.SRV,
payload=dns.Record_SRV(target=b"host")),
],
None,
None,
))
servers = self.successResultOf(resolve_d)
self.assertEquals(len(servers), 1)
self.assertEquals(servers, cache[service_name])
self.assertEquals(servers[0].host, b"host")
def test_from_cache(self):
clock = MockClock()
dns_client_mock = Mock(spec_set=["lookupService"])
dns_client_mock.lookupService = Mock(spec_set=[])
service_name = b"test_service.example.com"
entry = Mock(spec_set=["expires", "priority", "weight"])
entry.expires = 999999999
entry.priority = 0
entry.weight = 0
cache = {service_name: [entry]}
resolver = SrvResolver(dns_client=dns_client_mock,
cache=cache,
get_time=clock.time)
servers = yield defer.ensureDeferred(
resolver.resolve_service(service_name))
self.assertFalse(dns_client_mock.lookupService.called)
self.assertEquals(len(servers), 1)
self.assertEquals(servers, cache[service_name])
def test_non_srv_answer(self):
"""
test the behaviour when the dns server gives us a spurious non-SRV response
"""
service_name = b"test_service.example.com"
lookup_deferred = Deferred()
dns_client_mock = Mock()
dns_client_mock.lookupService.return_value = lookup_deferred
cache = {}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
resolve_d = resolver.resolve_service(service_name)
self.assertNoResult(resolve_d)
lookup_deferred.callback(
(
[
dns.RRHeader(type=dns.A, payload=dns.Record_A()),
dns.RRHeader(type=dns.SRV, payload=dns.Record_SRV(target=b"host")),
],
None,
None,
)
)
servers = self.successResultOf(resolve_d)
self.assertEquals(len(servers), 1)
self.assertEquals(servers, cache[service_name])
self.assertEquals(servers[0].host, b"host")
def test_disabled_service(self):
"""
test the behaviour when there is a single record which is ".".
"""
service_name = b"test_service.example.com"
lookup_deferred = Deferred()
dns_client_mock = Mock()
dns_client_mock.lookupService.return_value = lookup_deferred
cache = {}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
resolve_d = resolver.resolve_service(service_name)
self.assertNoResult(resolve_d)
# returning a single "." should make the lookup fail with a ConenctError
lookup_deferred.callback(
(
[dns.RRHeader(type=dns.SRV, payload=dns.Record_SRV(target=b"."))],
None,
None,
)
)
self.failureResultOf(resolve_d, ConnectError)
def test_empty_cache(self):
dns_client_mock = Mock()
dns_client_mock.lookupService.return_value = defer.fail(error.DNSServerError())
service_name = b"test_service.example.com"
cache = {}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
with self.assertRaises(error.DNSServerError):
yield defer.ensureDeferred(resolver.resolve_service(service_name))
def test_empty_cache(self):
dns_client_mock = Mock()
dns_client_mock.lookupService.return_value = defer.fail(error.DNSServerError())
service_name = b"test_service.example.com"
cache = {}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
with self.assertRaises(error.DNSServerError):
yield resolver.resolve_service(service_name)
def test_name_error(self):
dns_client_mock = Mock()
dns_client_mock.lookupService.return_value = defer.fail(error.DNSNameError())
service_name = b"test_service.example.com"
cache = {}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
servers = yield defer.ensureDeferred(resolver.resolve_service(service_name))
self.assertEqual(len(servers), 0)
self.assertEqual(len(cache), 0)
def test_name_error(self):
dns_client_mock = Mock()
dns_client_mock.lookupService.return_value = defer.fail(error.DNSNameError())
service_name = b"test_service.example.com"
cache = {}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
servers = yield resolver.resolve_service(service_name)
self.assertEquals(len(servers), 0)
self.assertEquals(len(cache), 0)
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 = b"test_service.example.com"
entry = Mock(spec_set=["expires"])
entry.expires = 0
cache = {service_name: [entry]}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
servers = yield resolver.resolve_service(service_name)
dns_client_mock.lookupService.assert_called_once_with(service_name)
self.assertEquals(len(servers), 1)
self.assertEquals(servers, cache[service_name])
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 = b"test_service.example.com"
entry = Mock(spec_set=["expires"])
entry.expires = 0
cache = {service_name: [entry]}
resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
servers = yield resolver.resolve_service(service_name)
dns_client_mock.lookupService.assert_called_once_with(service_name)
self.assertEquals(len(servers), 1)
self.assertEquals(servers, cache[service_name])
def test_from_cache(self):
clock = MockClock()
dns_client_mock = Mock(spec_set=['lookupService'])
dns_client_mock.lookupService = Mock(spec_set=[])
service_name = b"test_service.example.com"
entry = Mock(spec_set=["expires"])
entry.expires = 999999999
cache = {service_name: [entry]}
resolver = SrvResolver(dns_client=dns_client_mock,
cache=cache,
get_time=clock.time)
servers = yield resolver.resolve_service(service_name)
self.assertFalse(dns_client_mock.lookupService.called)
self.assertEquals(len(servers), 1)
self.assertEquals(servers, cache[service_name])
def test_from_cache(self):
clock = MockClock()
dns_client_mock = Mock(spec_set=['lookupService'])
dns_client_mock.lookupService = Mock(spec_set=[])
service_name = b"test_service.example.com"
entry = Mock(spec_set=["expires"])
entry.expires = 999999999
cache = {service_name: [entry]}
resolver = SrvResolver(
dns_client=dns_client_mock, cache=cache, get_time=clock.time
)
servers = yield resolver.resolve_service(service_name)
self.assertFalse(dns_client_mock.lookupService.called)
self.assertEquals(len(servers), 1)
self.assertEquals(servers, cache[service_name])