Add default grpc keepalive value

Author: vgvoleg

ydb/connection.py

@@ -26,6 +26,7 @@
 YDB_REQUEST_TYPE_HEADER = "x-ydb-request-type"
 
 _DEFAULT_MAX_GRPC_MESSAGE_SIZE = 64 * 10**6
+_DEFAULT_KEEPALIVE_TIMEOUT = 10000
 
 
 def _message_to_string(message):
@@ -185,15 +186,18 @@ def _construct_channel_options(driver_config, endpoint_options=None):
             getattr(driver_config, "grpc_lb_policy_name", "round_robin"),
         ),
     ]
-    if driver_config.grpc_keep_alive_timeout is not None:
-        _default_connect_options.extend(
-            [
-                ("grpc.keepalive_time_ms", driver_config.grpc_keep_alive_timeout >> 3),
-                ("grpc.keepalive_timeout_ms", driver_config.grpc_keep_alive_timeout),
-                ("grpc.http2.max_pings_without_data", 0),
-                ("grpc.keepalive_permit_without_calls", 0),
-            ]
-        )
+    if driver_config.grpc_keep_alive_timeout is None:
+        driver_config.grpc_keep_alive_timeout = _DEFAULT_KEEPALIVE_TIMEOUT
+
+    _default_connect_options.extend(
+        [
+            ("grpc.keepalive_time_ms", driver_config.grpc_keep_alive_timeout >> 3),
+            ("grpc.keepalive_timeout_ms", driver_config.grpc_keep_alive_timeout),
+            ("grpc.http2.max_pings_without_data", 0),
+            ("grpc.keepalive_permit_without_calls", 0),
+        ]
+    )
+
     if endpoint_options is not None:
         if endpoint_options.ssl_target_name_override:
             _default_connect_options.append(