CDRIVER-2218 Only topology scanner performs MongoDB Handshake

Author: bjori

src/mongoc/mongoc-cluster.c

@@ -668,7 +668,7 @@ _mongoc_stream_run_ismaster (mongoc_cluster_t *cluster,
                              const char *address,
                              uint32_t server_id)
 {
-   bson_t command = BSON_INITIALIZER;
+   const bson_t *command;
    mongoc_cmd_parts_t parts;
    bson_t reply;
    bson_error_t error = {0};
@@ -682,8 +682,10 @@ _mongoc_stream_run_ismaster (mongoc_cluster_t *cluster,
    BSON_ASSERT (cluster);
    BSON_ASSERT (stream);
 
-   bson_append_int32 (&command, "ismaster", 8, 1);
-   mongoc_cmd_parts_init (&parts, "admin", MONGOC_QUERY_SLAVE_OK, &command);
+   command = _mongoc_topology_scanner_get_ismaster (
+      cluster->client->topology->scanner);
+
+   mongoc_cmd_parts_init (&parts, "admin", MONGOC_QUERY_SLAVE_OK, command);
 
    start = bson_get_monotonic_time ();
    mongoc_cluster_run_command_private (
@@ -698,7 +700,6 @@ _mongoc_stream_run_ismaster (mongoc_cluster_t *cluster,
    /* send the error from run_command IN to handle_ismaster */
    mongoc_server_description_handle_ismaster (sd, &reply, rtt_msec, &error);
 
-   bson_destroy (&command);
    bson_destroy (&reply);
 
    r = _mongoc_topology_update_from_handshake (cluster->client->topology, sd);

src/mongoc/mongoc-topology-scanner-private.h

@@ -150,6 +150,9 @@ mongoc_topology_scanner_node_setup (mongoc_topology_scanner_node_t *node,
 mongoc_topology_scanner_node_t *
 mongoc_topology_scanner_get_node (mongoc_topology_scanner_t *ts, uint32_t id);
 
+bson_t *
+_mongoc_topology_scanner_get_ismaster (mongoc_topology_scanner_t *ts);
+
 bool
 mongoc_topology_scanner_has_node_for_host (mongoc_topology_scanner_t *ts,
                                            mongoc_host_list_t *host);

src/mongoc/mongoc-topology-scanner.c

@@ -106,15 +106,9 @@ _build_ismaster_with_handshake (mongoc_topology_scanner_t *ts)
    return res;
 }
 
-static bson_t *
-_get_ismaster_doc (mongoc_topology_scanner_t *ts,
-                   mongoc_topology_scanner_node_t *node)
+bson_t *
+_mongoc_topology_scanner_get_ismaster (mongoc_topology_scanner_t *ts)
 {
-   if (node->last_used != -1 && node->last_failed == -1) {
-      /* The node's been used before and not failed recently */
-      return &ts->ismaster_cmd;
-   }
-
    /* If this is the first time using the node or if it's the first time
     * using it after a failure, build handshake doc */
    if (bson_empty (&ts->ismaster_cmd_with_handshake)) {
@@ -137,14 +131,22 @@ _begin_ismaster_cmd (mongoc_topology_scanner_t *ts,
                      mongoc_topology_scanner_node_t *node,
                      int64_t timeout_msec)
 {
-   const bson_t *ismaster_cmd_to_send = _get_ismaster_doc (ts, node);
+   const bson_t *command;
+
+   if (node->last_used != -1 && node->last_failed == -1) {
+      /* The node's been used before and not failed recently */
+      command = &ts->ismaster_cmd;
+   } else {
+      command = _mongoc_topology_scanner_get_ismaster (ts);
+   }
+
 
    node->cmd = mongoc_async_cmd_new (ts->async,
                                      node->stream,
                                      ts->setup,
                                      node->host.host,
                                      "admin",
-                                     ismaster_cmd_to_send,
+                                     command,
                                      &mongoc_topology_scanner_ismaster_handler,
                                      node,
                                      timeout_msec);

tests/test-mongoc-client.c

@@ -2371,7 +2371,6 @@ test_mongoc_client_select_server_retry_fail (void)
 }
 
 
-
 /* CDRIVER-2172: in single mode, if the selected server has a socket that's been
  * idle for socketCheckIntervalMS, check it with ping. If it fails, retry once.
  */
@@ -2728,6 +2727,56 @@ _respond_to_ping (future_t *future, mock_server_t *server)
    request_destroy (request);
 }
 
+static void
+test_mongoc_handshake_pool (void)
+{
+   mock_server_t *server;
+   request_t *request1;
+   request_t *request2;
+   mongoc_uri_t *uri;
+   mongoc_client_t *client1;
+   mongoc_client_t *client2;
+   mongoc_client_pool_t *pool;
+   const char *const server_reply = "{'ok': 1, 'ismaster': true}";
+   future_t *future;
+
+   server = mock_server_new ();
+   mock_server_run (server);
+
+   uri = mongoc_uri_copy (mock_server_get_uri (server));
+   mongoc_uri_set_appname (uri, BSON_FUNC);
+
+   pool = mongoc_client_pool_new (uri);
+
+   client1 = mongoc_client_pool_pop (pool);
+   request1 = mock_server_receives_ismaster (server);
+   _assert_ismaster_valid (request1, true);
+   mock_server_replies_simple (request1, server_reply);
+   request_destroy (request1);
+
+   client2 = mongoc_client_pool_pop (pool);
+   future = future_client_command_simple (
+      client2, "test", tmp_bson ("{'ping': 1}"), NULL, NULL, NULL);
+
+   request2 = mock_server_receives_ismaster (server);
+   _assert_ismaster_valid (request2, true);
+   mock_server_replies_simple (request2, server_reply);
+   request_destroy (request2);
+
+   request2 = mock_server_receives_command (
+      server, "test", MONGOC_QUERY_SLAVE_OK, NULL);
+   mock_server_replies_ok_and_destroys (request2);
+   ASSERT (future_get_bool (future));
+   future_destroy (future);
+
+   mongoc_client_pool_push (pool, client1);
+   mongoc_client_pool_push (pool, client2);
+
+   mongoc_client_pool_destroy (pool);
+   mongoc_uri_destroy (uri);
+   mock_server_destroy (server);
+}
+
 static void
 _test_client_sends_handshake (bool pooled)
 {
@@ -2762,9 +2811,8 @@ _test_client_sends_handshake (bool pooled)
 
    request = mock_server_receives_ismaster (server);
 
-   /* Make sure the isMaster request has a "meta" field: */
+   /* Make sure the isMaster request has a "client" field: */
    _assert_ismaster_valid (request, true);
-
    mock_server_replies_simple (request, server_reply);
    request_destroy (request);
 
@@ -3179,6 +3227,8 @@ test_client_install (TestSuite *suite)
    TestSuite_AddMockServerTest (
       suite, "/Client/mismatched_me", test_mongoc_client_mismatched_me);
 
+   TestSuite_AddMockServerTest (
+      suite, "/Client/handshake/pool", test_mongoc_handshake_pool);
    TestSuite_Add (suite,
                   "/Client/application_handshake",
                   test_mongoc_client_application_handshake);