Prevent gthread connection reset on max-requests restart

Author: aszubarev

gunicorn/config.py

@@ -125,6 +125,10 @@ def worker_class(self):
             worker_class.setup()
         return worker_class
 
+    @property
+    def worker_connections_enqueue_async(self):
+        return self.settings['worker_connections_enqueue_async'].get()
+
     @property
     def address(self):
         s = self.settings['bind'].get()
@@ -737,6 +741,30 @@ class WorkerConnections(Setting):
         """
 
 
+class WorkerConnectionsEnqueueAsync(Setting):
+    name = "worker_connections_enqueue_async"
+    section = "Worker Processes"
+    cli = ["--worker-connections-enqueue-async"]
+    validator = validate_bool
+    action = 'store_true'
+    default = False
+    desc = """\
+        Enqueue accepted connections to worker asynchronously.
+
+        It helps to use Gunicorn without reverse proxy.
+        When clients connect to Gunicorn, the server will start read data only when clients sent data.
+        If clients keep connections without sending data, server only accept the connections and no block the worker;
+
+        .. note::
+           If you're enable ``max-requests`` and it option, the worker can restart with accepted connections.
+
+           When clients send data via connections after restart the worker,
+           clients may have error ``Connection reset by peer``
+
+        This setting only affects the ``gthread`` worker types.
+        """
+
+
 class MaxRequests(Setting):
     name = "max_requests"
     section = "Worker Processes"

gunicorn/workers/gthread.py

@@ -123,10 +123,18 @@ def accept(self, server, listener):
             conn = TConn(self.cfg, sock, client, server)
 
             self.nr_conns += 1
-            # wait until socket is readable
-            with self._lock:
-                self.poller.register(conn.sock, selectors.EVENT_READ,
-                                     partial(self.on_client_socket_readable, conn))
+
+            if not self.cfg.worker_connections_enqueue_async:
+                # submit the connection to a worker
+                self.enqueue_req(conn)
+            else:
+                # wait until socket is readable
+                with self._lock:
+                    self.poller.register(
+                        conn.sock,
+                        selectors.EVENT_READ,
+                        partial(self.on_client_socket_readable, conn),
+                    )
         except OSError as e:
             if e.errno not in (errno.EAGAIN, errno.ECONNABORTED,
                                errno.EWOULDBLOCK):
@@ -137,7 +145,7 @@ def on_client_socket_readable(self, conn, client):
             # unregister the client from the poller
             self.poller.unregister(client)
 
-            if conn.initialized:
+            if not self.cfg.worker_connections_enqueue_async or conn.initialized:
                 # remove the connection from keepalive
                 try:
                     self._keep.remove(conn)