Convert sydent.http.srvresolver and associated modules to async/awai…

…t. (#365)

changelog.d/365.misc

@@ -0,0 +1 @@
+Convert inlineCallbacks to async/await.

sydent/http/matrixfederationagent.py

@@ -268,7 +268,9 @@ def _route_matrix_uri(
 
         # try a SRV lookup
         service_name = b"_matrix._tcp.%s" % (parsed_uri.host,)
-        server_list = yield self._srv_resolver.resolve_service(service_name)
+        server_list = yield defer.ensureDeferred(
+            self._srv_resolver.resolve_service(service_name)
+        )
 
         if not server_list:
             target_host = parsed_uri.host

sydent/http/srvresolver.py

@@ -16,10 +16,9 @@
 import logging
 import random
 import time
-from typing import Callable, Dict, Generator, List, SupportsInt, Tuple
+from typing import Callable, Dict, List, SupportsInt, Tuple
 
 import attr
-from twisted.internet import defer
 from twisted.internet.error import ConnectError
 from twisted.internet.interfaces import IResolver
 from twisted.names import client, dns
@@ -107,8 +106,7 @@ def __init__(
         self._cache = cache
         self._get_time = get_time
 
-    @defer.inlineCallbacks
-    def resolve_service(self, service_name: bytes) -> "Generator":
+    async def resolve_service(self, service_name: bytes) -> List["Server"]:
         """Look up a SRV record
 
         :param service_name: The record to look up.
@@ -129,7 +127,7 @@ def resolve_service(self, service_name: bytes) -> "Generator":
                 return servers
 
         try:
-            answers, _, _ = yield self._dns_client.lookupService(service_name)
+            answers, _, _ = await self._dns_client.lookupService(service_name)
         except DNSNameError:
             # TODO: cache this. We can get the SOA out of the exception, and use
             # the negative-TTL value.

tests/test_blacklisting.py

@@ -11,18 +11,16 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 
-
 from unittest.mock import patch
 
-from twisted.internet import defer
 from twisted.internet.error import DNSLookupError
 from twisted.test.proto_helpers import StringTransport
 from twisted.trial.unittest import TestCase
 from twisted.web.client import Agent
 
 from sydent.http.blacklisting_reactor import BlacklistingReactorWrapper
 from sydent.http.srvresolver import Server
-from tests.utils import make_request, make_sydent
+from tests.utils import AsyncMock, make_request, make_sydent
 
 
 class BlacklistingAgentTest(TestCase):
@@ -92,7 +90,9 @@ def test_reactor(self):
                 _bindAddress,
             ) = self.reactor.tcpClients.pop()
 
-    @patch("sydent.http.srvresolver.SrvResolver.resolve_service")
+    @patch(
+        "sydent.http.srvresolver.SrvResolver.resolve_service", new_callable=AsyncMock
+    )
     def test_federation_client_allowed_ip(self, resolver):
         self.sydent.run()
 
@@ -108,17 +108,15 @@ def test_federation_client_allowed_ip(self, resolver):
             },
         )
 
-        resolver.return_value = defer.succeed(
-            [
-                Server(
-                    host=self.allowed_domain,
-                    port=443,
-                    priority=1,
-                    weight=1,
-                    expires=100,
-                )
-            ]
-        )
+        resolver.return_value = [
+            Server(
+                host=self.allowed_domain,
+                port=443,
+                priority=1,
+                weight=1,
+                expires=100,
+            )
+        ]
 
         request.render(self.sydent.servlets.registerServlet)
 
@@ -144,7 +142,9 @@ def test_federation_client_allowed_ip(self, resolver):
 
         self.assertEqual(channel.code, 200)
 
-    @patch("sydent.http.srvresolver.SrvResolver.resolve_service")
+    @patch(
+        "sydent.http.srvresolver.SrvResolver.resolve_service", new_callable=AsyncMock
+    )
     def test_federation_client_safe_ip(self, resolver):
         self.sydent.run()
 
@@ -160,17 +160,15 @@ def test_federation_client_safe_ip(self, resolver):
             },
         )
 
-        resolver.return_value = defer.succeed(
-            [
-                Server(
-                    host=self.safe_domain,
-                    port=443,
-                    priority=1,
-                    weight=1,
-                    expires=100,
-                )
-            ]
-        )
+        resolver.return_value = [
+            Server(
+                host=self.safe_domain,
+                port=443,
+                priority=1,
+                weight=1,
+                expires=100,
+            )
+        ]
 
         request.render(self.sydent.servlets.registerServlet)
 
@@ -210,17 +208,15 @@ def test_federation_client_unsafe_ip(self, resolver):
             },
         )
 
-        resolver.return_value = defer.succeed(
-            [
-                Server(
-                    host=self.unsafe_domain,
-                    port=443,
-                    priority=1,
-                    weight=1,
-                    expires=100,
-                )
-            ]
-        )
+        resolver.return_value = [
+            Server(
+                host=self.unsafe_domain,
+                port=443,
+                priority=1,
+                weight=1,
+                expires=100,
+            )
+        ]
 
         request.render(self.sydent.servlets.registerServlet)
 

tests/utils.py

@@ -3,6 +3,7 @@
 import os
 from io import BytesIO
 from typing import Dict
+from unittest.mock import MagicMock
 
 import attr
 import twisted.logger
@@ -298,3 +299,8 @@ def getHostByName(self, name, timeout=None):
 
     def installNameResolver(self, resolver: IHostnameResolver) -> IHostnameResolver:
         raise NotImplementedError()
+
+
+class AsyncMock(MagicMock):
+    async def __call__(self, *args, **kwargs):
+        return super().__call__(*args, **kwargs)