Fix connection pooling

aiohttp/client.py

@@ -134,7 +134,7 @@ def request(self, method, url, *,
                 try:
                     yield from resp.start(conn, read_until_eof)
                 except:
-                    resp.close()
+                    resp.close(force=True)
                     conn.close()
                     raise
             except (aiohttp.HttpProcessingError,

aiohttp/connector.py

@@ -291,12 +291,6 @@ def connect(self, req):
                 else:
                     transport, proto = yield from self._create_connection(req)
 
-                if not self._force_close:
-                    if self._conns.get(key, None) is None:
-                        self._conns[key] = []
-
-                    self._conns[key].append((transport, proto,
-                                            self._loop.time()))
             except asyncio.TimeoutError as exc:
                 raise ClientTimeoutError(
                     'Connection timeout to host %s:%s ssl:%s' % key) from exc
@@ -309,7 +303,10 @@ def connect(self, req):
         return conn
 
     def _get(self, key):
-        conns = self._conns.get(key)
+        try:
+            conns = self._conns[key]
+        except KeyError:
+            return None, None
         t1 = self._loop.time()
         while conns:
             transport, proto, t0 = conns.pop()
@@ -318,8 +315,12 @@ def _get(self, key):
                     transport.close()
                     transport = None
                 else:
+                    if not conns:
+                        # The very last connection was reclaimed: drop the key
+                        del self._conns[key]
                     return transport, proto
-
+        # No more connections: drop the key
+        del self._conns[key]
         return None, None
 
     def _release(self, key, req, transport, protocol, *, should_close=False):
@@ -357,15 +358,6 @@ def _release(self, key, req, transport, protocol, *, should_close=False):
 
         reader = protocol.reader
         if should_close or (reader.output and not reader.output.at_eof()):
-            conns = self._conns.get(key)
-            if conns is not None and len(conns) >= 0:
-                # Issue #253: An empty array will eventually be
-                # removed by cleanup, but it's better to pop straight
-                # away, because cleanup might not get called (e.g. if
-                # keepalive is False).
-                if not acquired:
-                    self._conns.pop(key, None)
-
             transport.close()
         else:
             conns = self._conns.get(key)

tests/test_connector.py

@@ -239,7 +239,7 @@ def test_get_expired(self):
         tr, proto = unittest.mock.Mock(), unittest.mock.Mock()
         conn._conns[1] = [(tr, proto, self.loop.time() - 1000)]
         self.assertEqual(conn._get(1), (None, None))
-        self.assertEqual(conn._conns[1], [])
+        self.assertFalse(conn._conns)
         conn.close()
 
     def test_release(self):
@@ -278,8 +278,17 @@ def test_release_close(self):
         self.assertFalse(conn._conns)
         self.assertTrue(tr.close.called)
 
-    def test_release_pop_empty_conns(self):
-        # see issue #253
+    def test_get_pop_empty_conns(self):
+        # see issue #473
+        conn = aiohttp.BaseConnector(loop=self.loop)
+        key = ('127.0.0.1', 80, False)
+        conn._conns[key] = []
+        tr, proto = conn._get(key)
+        self.assertEqual((None, None), (tr, proto))
+        self.assertFalse(conn._conns)
+
+    def test_release_close_do_not_add_to_pool(self):
+        # see issue #473
         conn = aiohttp.BaseConnector(loop=self.loop)
         req = unittest.mock.Mock()
         resp = unittest.mock.Mock()
@@ -288,13 +297,10 @@ def test_release_pop_empty_conns(self):
 
         key = ('127.0.0.1', 80, False)
 
-        conn._conns[key] = []
-
         tr, proto = unittest.mock.Mock(), unittest.mock.Mock()
         conn._acquired[key].append(tr)
         conn._release(key, req, tr, proto)
-        self.assertEqual({}, conn._conns)
-        self.assertTrue(tr.close.called)
+        self.assertFalse(conn._conns)
 
     def test_release_close_do_not_delete_existing_connections(self):
         key = ('127.0.0.1', 80, False)