Fix rviz crash issue if run later

nav2_rviz_plugins/include/nav2_rviz_plugins/docking_panel.hpp

@@ -110,7 +110,6 @@ private Q_SLOTS:
 
   // Flags to indicate if the plugins have been loaded
   bool plugins_loaded_ = false;
-  bool server_failed_ = false;
 
   QVBoxLayout * main_layout_{nullptr};
   QHBoxLayout * info_layout_{nullptr};

nav2_rviz_plugins/include/nav2_rviz_plugins/selector.hpp

@@ -43,8 +43,7 @@ class Selector : public rviz_common::Panel
   ~Selector();
 
 private:
-  // The (non-spinning) client node used to invoke the action client
-  void timerEvent(QTimerEvent * event) override;
+  void loadPlugins();
 
   rclcpp::Node::SharedPtr client_node_;
   rclcpp::Publisher<std_msgs::msg::String>::SharedPtr pub_controller_;
@@ -54,9 +53,7 @@ class Selector : public rviz_common::Panel
   rclcpp::Publisher<std_msgs::msg::String>::SharedPtr pub_progress_checker_;
   rclcpp::TimerBase::SharedPtr rclcpp_timer_;
 
-  bool plugins_loaded_ = false;
-  bool server_failed_ = false;
-  bool tried_once_ = false;
+  std::thread load_plugins_thread_;
 
   QBasicTimer timer_;
   QVBoxLayout * main_layout_;

nav2_rviz_plugins/include/nav2_rviz_plugins/utils.hpp

@@ -35,7 +35,7 @@ namespace nav2_rviz_plugins
    * @param combo_box The combo box to add the loaded plugins to
    */
 void pluginLoader(
-  rclcpp::Node::SharedPtr node, bool & server_failed, const std::string & server_name,
+  rclcpp::Node::SharedPtr node, const std::string & server_name,
   const std::string & plugin_type, QComboBox * combo_box);
 
 // Create label string from goal status msg

nav2_rviz_plugins/src/docking_panel.cpp

@@ -245,9 +245,10 @@ DockingPanel::DockingPanel(QWidget * parent)
     [this] {
       // Load the plugins if not already loaded
       if (!plugins_loaded_) {
+        dock_type_->addItem("Default");
         RCLCPP_INFO(client_node_->get_logger(), "Loading dock plugins");
         nav2_rviz_plugins::pluginLoader(
-        client_node_, server_failed_, "docking_server", "dock_plugins", dock_type_);
+        client_node_, "docking_server", "dock_plugins", dock_type_);
         plugins_loaded_ = true;
       }
     });

nav2_rviz_plugins/src/selector.cpp

@@ -69,8 +69,15 @@ Selector::Selector(QWidget * parent)
   main_layout_->addLayout(row_3_label_layout_);
   main_layout_->addLayout(row_3_layout_);
 
+  controller_->addItem("Default");
+  planner_->addItem("Default");
+  goal_checker_->addItem("Default");
+  smoother_->addItem("Default");
+  progress_checker_->addItem("Default");
+
+
   setLayout(main_layout_);
-  timer_.start(200, this);
+  loadPlugins();
 
   connect(
     controller_, QOverload<int>::of(&QComboBox::activated), this,
@@ -95,16 +102,15 @@ Selector::Selector(QWidget * parent)
 
 Selector::~Selector()
 {
+  if (load_plugins_thread_.joinable()) {
+    load_plugins_thread_.join();
+  }
 }
 
 // Publish the selected controller or planner
 void Selector::setSelection(
   QComboBox * combo_box, rclcpp::Publisher<std_msgs::msg::String>::SharedPtr publisher)
 {
-  // If "default" option is selected, it gets removed and the next item is selected
-  if (combo_box->findText("Default") != -1) {
-    combo_box->removeItem(0);
-  }
 
   // if there are no plugins available, return
   if (combo_box->count() == 0) {
@@ -115,7 +121,6 @@ void Selector::setSelection(
   msg.data = combo_box->currentText().toStdString();
 
   publisher->publish(msg);
-  timer_.start(200, this);
 }
 
 // Call setSelection() for controller
@@ -148,37 +153,21 @@ void Selector::setProgressChecker()
 }
 
 void
-Selector::timerEvent(QTimerEvent * event)
+Selector::loadPlugins()
 {
-  if (event->timerId() == timer_.timerId()) {
-    if (!plugins_loaded_) {
-      nav2_rviz_plugins::pluginLoader(
-        client_node_, server_failed_, "controller_server", "controller_plugins", controller_);
-      nav2_rviz_plugins::pluginLoader(
-        client_node_, server_failed_, "planner_server", "planner_plugins", planner_);
-      nav2_rviz_plugins::pluginLoader(
-        client_node_, server_failed_, "controller_server", "goal_checker_plugins", goal_checker_);
-      nav2_rviz_plugins::pluginLoader(
-        client_node_, server_failed_, "smoother_server", "smoother_plugins", smoother_);
-      nav2_rviz_plugins::pluginLoader(
-        client_node_, server_failed_, "controller_server", "progress_checker_plugins",
-        progress_checker_);
-
-      plugins_loaded_ = true;
-    }
-
-    // Restart the timer if the one of the server fails
-    if (server_failed_ && !tried_once_) {
-      RCLCPP_INFO(client_node_->get_logger(), "Retrying to connect to the failed server.");
-      server_failed_ = false;
-      plugins_loaded_ = false;
-      tried_once_ = true;
-      timer_.start(200, this);
-      return;
-    }
-
-    timer_.stop();
-  }
+  load_plugins_thread_ = std::thread([this]() {
+    nav2_rviz_plugins::pluginLoader(
+      client_node_, "controller_server", "controller_plugins", controller_);
+    nav2_rviz_plugins::pluginLoader(
+      client_node_, "planner_server", "planner_plugins", planner_);
+    nav2_rviz_plugins::pluginLoader(
+      client_node_, "controller_server", "goal_checker_plugins", goal_checker_);
+    nav2_rviz_plugins::pluginLoader(
+      client_node_, "smoother_server", "smoother_plugins", smoother_);
+    nav2_rviz_plugins::pluginLoader(
+      client_node_, "controller_server", "progress_checker_plugins",
+      progress_checker_);
+  });
 }
 
 }  // namespace nav2_rviz_plugins

nav2_rviz_plugins/src/utils.cpp

@@ -21,35 +21,19 @@ namespace nav2_rviz_plugins
 {
 
 void pluginLoader(
-  rclcpp::Node::SharedPtr node, bool & server_failed, const std::string & server_name,
+  rclcpp::Node::SharedPtr node, const std::string & server_name,
   const std::string & plugin_type, QComboBox * combo_box)
 {
   auto parameter_client = std::make_shared<rclcpp::SyncParametersClient>(node, server_name);
 
-  // Do not load the plugins if the combo box is already populated
-  if (combo_box->count() > 0) {
-    return;
-  }
-
   // Wait for the service to be available before calling it
-  bool server_unavailable = false;
   while (!parameter_client->wait_for_service(std::chrono::seconds(1))) {
     if (!rclcpp::ok()) {
       RCLCPP_ERROR(node->get_logger(), "Interrupted while waiting for the service. Exiting.");
       rclcpp::shutdown();
     }
-    RCLCPP_INFO(node->get_logger(), "%s service not available", server_name.c_str());
-    server_unavailable = true;
-    server_failed = true;
-    break;
   }
 
-  // Loading the plugins into the combo box
-  // If server unavaialble, let the combo box be empty
-  if (server_unavailable) {
-    return;
-  }
-  combo_box->addItem("Default");
   auto parameters = parameter_client->get_parameters({plugin_type});
   auto str_arr = parameters[0].as_string_array();
   for (auto str : str_arr) {