Remove redundant WrappedConnection (#4409)

* Remove redundant WrappedConnection

The matrix federation client uses an HTTP connection pool, which times out its
idle HTTP connections, so there is no need for any of this business.

changelog.d/4409.misc

+Remove redundant federation connection wrapping code

synapse/http/endpoint.py

@@ -140,82 +140,15 @@ def matrix_federation_endpoint(reactor, destination, tls_client_options_factory=
         default_port = 8448
 
     if port is None:
-        return _WrappingEndpointFac(SRVClientEndpoint(
+        return SRVClientEndpoint(
             reactor, "matrix", domain, protocol="tcp",
             default_port=default_port, endpoint=transport_endpoint,
             endpoint_kw_args=endpoint_kw_args
-        ), reactor)
+        )
     else:
-        return _WrappingEndpointFac(transport_endpoint(
+        return transport_endpoint(
             reactor, domain, port, **endpoint_kw_args
-        ), reactor)
-
-
-class _WrappingEndpointFac(object):
-    def __init__(self, endpoint_fac, reactor):
-        self.endpoint_fac = endpoint_fac
-        self.reactor = reactor
-
-    @defer.inlineCallbacks
-    def connect(self, protocolFactory):
-        conn = yield self.endpoint_fac.connect(protocolFactory)
-        conn = _WrappedConnection(conn, self.reactor)
-        defer.returnValue(conn)
-
-
-class _WrappedConnection(object):
-    """Wraps a connection and calls abort on it if it hasn't seen any action
-    for 2.5-3 minutes.
-    """
-    __slots__ = ["conn", "last_request"]
-
-    def __init__(self, conn, reactor):
-        object.__setattr__(self, "conn", conn)
-        object.__setattr__(self, "last_request", time.time())
-        self._reactor = reactor
-
-    def __getattr__(self, name):
-        return getattr(self.conn, name)
-
-    def __setattr__(self, name, value):
-        setattr(self.conn, name, value)
-
-    def _time_things_out_maybe(self):
-        # We use a slightly shorter timeout here just in case the callLater is
-        # triggered early. Paranoia ftw.
-        # TODO: Cancel the previous callLater rather than comparing time.time()?
-        if time.time() - self.last_request >= 2.5 * 60:
-            self.abort()
-            # Abort the underlying TLS connection. The abort() method calls
-            # loseConnection() on the TLS connection which tries to
-            # shutdown the connection cleanly. We call abortConnection()
-            # since that will promptly close the TLS connection.
-            #
-            # In Twisted >18.4; the TLS connection will be None if it has closed
-            # which will make abortConnection() throw. Check that the TLS connection
-            # is not None before trying to close it.
-            if self.transport.getHandle() is not None:
-                self.transport.abortConnection()
-
-    def request(self, request):
-        self.last_request = time.time()
-
-        # Time this connection out if we haven't send a request in the last
-        # N minutes
-        # TODO: Cancel the previous callLater?
-        self._reactor.callLater(3 * 60, self._time_things_out_maybe)
-
-        d = self.conn.request(request)
-
-        def update_request_time(res):
-            self.last_request = time.time()
-            # TODO: Cancel the previous callLater?
-            self._reactor.callLater(3 * 60, self._time_things_out_maybe)
-            return res
-
-        d.addCallback(update_request_time)
-
-        return d
+        )
 
 
 class SRVClientEndpoint(object):

synapse/http/matrixfederationclient.py

@@ -321,23 +321,23 @@ class MatrixFederationHttpClient(object):
                         url_str,
                     )
 
-                    # we don't want all the fancy cookie and redirect handling that
-                    # treq.request gives: just use the raw Agent.
-                    request_deferred = self.agent.request(
-                        method_bytes,
-                        url_bytes,
-                        headers=Headers(headers_dict),
-                        bodyProducer=producer,
-                    )
-
-                    request_deferred = timeout_deferred(
-                        request_deferred,
-                        timeout=_sec_timeout,
-                        reactor=self.hs.get_reactor(),
-                    )
-
                     try:
                         with Measure(self.clock, "outbound_request"):
+                            # we don't want all the fancy cookie and redirect handling
+                            # that treq.request gives: just use the raw Agent.
+                            request_deferred = self.agent.request(
+                                method_bytes,
+                                url_bytes,
+                                headers=Headers(headers_dict),
+                                bodyProducer=producer,
+                            )
+
+                            request_deferred = timeout_deferred(
+                                request_deferred,
+                                timeout=_sec_timeout,
+                                reactor=self.hs.get_reactor(),
+                            )
+
                             response = yield make_deferred_yieldable(
                                 request_deferred,
                             )

tests/http/test_fedclient.py

@@ -17,6 +17,7 @@ from mock import Mock
 
 from twisted.internet.defer import TimeoutError
 from twisted.internet.error import ConnectingCancelledError, DNSLookupError
+from twisted.test.proto_helpers import StringTransport
 from twisted.web.client import ResponseNeverReceived
 from twisted.web.http import HTTPChannel
 
@@ -44,7 +45,7 @@ class FederationClientTests(HomeserverTestCase):
 
     def test_dns_error(self):
         """
-        If the DNS raising returns an error, it will bubble up.
+        If the DNS lookup returns an error, it will bubble up.
         """
         d = self.cl.get_json("testserv2:8008", "foo/bar", timeout=10000)
         self.pump()
@@ -63,7 +64,7 @@ class FederationClientTests(HomeserverTestCase):
         self.pump()
 
         # Nothing happened yet
-        self.assertFalse(d.called)
+        self.assertNoResult(d)
 
         # Make sure treq is trying to connect
         clients = self.reactor.tcpClients
@@ -72,7 +73,7 @@ class FederationClientTests(HomeserverTestCase):
         self.assertEqual(clients[0][1], 8008)
 
         # Deferred is still without a result
-        self.assertFalse(d.called)
+        self.assertNoResult(d)
 
         # Push by enough to time it out
         self.reactor.advance(10.5)
@@ -94,7 +95,7 @@ class FederationClientTests(HomeserverTestCase):
         self.pump()
 
         # Nothing happened yet
-        self.assertFalse(d.called)
+        self.assertNoResult(d)
 
         # Make sure treq is trying to connect
         clients = self.reactor.tcpClients
@@ -107,7 +108,7 @@ class FederationClientTests(HomeserverTestCase):
         client.makeConnection(conn)
 
         # Deferred is still without a result
-        self.assertFalse(d.called)
+        self.assertNoResult(d)
 
         # Push by enough to time it out
         self.reactor.advance(10.5)
@@ -135,7 +136,7 @@ class FederationClientTests(HomeserverTestCase):
         client.makeConnection(conn)
 
         # Deferred does not have a result
-        self.assertFalse(d.called)
+        self.assertNoResult(d)
 
         # Send it the HTTP response
         client.dataReceived(b"HTTP/1.1 200 OK\r\nServer: Fake\r\n\r\n")
@@ -159,7 +160,7 @@ class FederationClientTests(HomeserverTestCase):
         client.makeConnection(conn)
 
         # Deferred does not have a result
-        self.assertFalse(d.called)
+        self.assertNoResult(d)
 
         # Send it the HTTP response
         client.dataReceived(
@@ -195,3 +196,42 @@ class FederationClientTests(HomeserverTestCase):
         request = server.requests[0]
         content = request.content.read()
         self.assertEqual(content, b'{"a":"b"}')
+
+    def test_closes_connection(self):
+        """Check that the client closes unused HTTP connections"""
+        d = self.cl.get_json("testserv:8008", "foo/bar")
+
+        self.pump()
+
+        # there should have been a call to connectTCP
+        clients = self.reactor.tcpClients
+        self.assertEqual(len(clients), 1)
+        (_host, _port, factory, _timeout, _bindAddress) = clients[0]
+
+        # complete the connection and wire it up to a fake transport
+        client = factory.buildProtocol(None)
+        conn = StringTransport()
+        client.makeConnection(conn)
+
+        # that should have made it send the request to the connection
+        self.assertRegex(conn.value(), b"^GET /foo/bar")
+
+        # Send the HTTP response
+        client.dataReceived(
+            b"HTTP/1.1 200 OK\r\n"
+            b"Content-Type: application/json\r\n"
+            b"Content-Length: 2\r\n"
+            b"\r\n"
+            b"{}"
+        )
+
+        # We should get a successful response
+        r = self.successResultOf(d)
+        self.assertEqual(r, {})
+
+        self.assertFalse(conn.disconnecting)
+
+        # wait for a while
+        self.pump(120)
+
+        self.assertTrue(conn.disconnecting)