Async params (#927)

* add is_async param to controller manager

* handle is_async param for hw components

* Remove std::terminate() call used for debugging

* Remove whitespace

* Remove empty line

* use strcasecmp

Author: VX792

controller_interface/include/controller_interface/controller_interface_base.hpp

@@ -153,6 +153,9 @@ class ControllerInterfaceBase : public rclcpp_lifecycle::node_interfaces::Lifecy
   CONTROLLER_INTERFACE_PUBLIC
   unsigned int get_update_rate() const;
 
+  CONTROLLER_INTERFACE_PUBLIC
+  bool is_async() const;
+
   /// Declare and initialize a parameter with a type.
   /**
    *
@@ -220,6 +223,7 @@ class ControllerInterfaceBase : public rclcpp_lifecycle::node_interfaces::Lifecy
   std::vector<hardware_interface::LoanedCommandInterface> command_interfaces_;
   std::vector<hardware_interface::LoanedStateInterface> state_interfaces_;
   unsigned int update_rate_ = 0;
+  bool is_async_ = false;
 
 private:
   std::shared_ptr<rclcpp_lifecycle::LifecycleNode> node_;

controller_interface/src/controller_interface_base.cpp

@@ -34,6 +34,7 @@ return_type ControllerInterfaceBase::init(
   try
   {
     auto_declare<int>("update_rate", 0);
+    auto_declare<bool>("is_async", false);
   }
   catch (const std::exception & e)
   {
@@ -84,6 +85,7 @@ const rclcpp_lifecycle::State & ControllerInterfaceBase::configure()
   if (get_state().id() == lifecycle_msgs::msg::State::PRIMARY_STATE_UNCONFIGURED)
   {
     update_rate_ = get_node()->get_parameter("update_rate").as_int();
+    is_async_ = get_node()->get_parameter("is_async").as_bool();
   }
 
   return get_node()->configure();

hardware_interface/include/hardware_interface/hardware_component_info.hpp

@@ -42,6 +42,9 @@ struct HardwareComponentInfo
   /// Component pluginlib plugin name.
   std::string plugin_name;
 
+  /// Component is async
+  bool is_async;
+
   /// Component current state.
   rclcpp_lifecycle::State state;
 

hardware_interface/include/hardware_interface/hardware_info.hpp

@@ -54,6 +54,7 @@ struct ComponentInfo
   std::string name;
   /// Type of the component: sensor, joint, or GPIO.
   std::string type;
+
   /**
    * Name of the command interfaces that can be set, e.g. "position", "velocity", etc.
    * Used by joints and GPIOs.
@@ -106,6 +107,8 @@ struct HardwareInfo
   std::string name;
   /// Type of the hardware: actuator, sensor or system.
   std::string type;
+  /// Component is async
+  bool is_async;
   /// Name of the pluginlib plugin of the hardware that will be loaded.
   std::string hardware_plugin_name;
   /// (Optional) Key-value pairs for hardware parameters.

hardware_interface/src/component_parser.cpp

@@ -47,6 +47,8 @@ constexpr const auto kTypeAttribute = "type";
 constexpr const auto kRoleAttribute = "role";
 constexpr const auto kReductionAttribute = "mechanical_reduction";
 constexpr const auto kOffsetAttribute = "offset";
+constexpr const auto kIsAsyncAttribute = "is_async";
+
 }  // namespace
 
 namespace hardware_interface
@@ -211,6 +213,20 @@ std::string parse_data_type_attribute(const tinyxml2::XMLElement * elem)
   return data_type;
 }
 
+/// Parse is_async attribute
+/**
+ * Parses an XMLElement and returns the value of the is_async attribute.
+ * Defaults to "false" if not specified.
+ *
+ * \param[in] elem XMLElement that has the data_type attribute.
+ * \return boolean specifying the if the value read was true or false.
+ */
+bool parse_is_async_attribute(const tinyxml2::XMLElement * elem)
+{
+  const tinyxml2::XMLAttribute * attr = elem->FindAttribute(kIsAsyncAttribute);
+  return attr ? strcasecmp(attr->Value(), "true") == 0 : false;
+}
+
 /// Search XML snippet from URDF for parameters.
 /**
  * \param[in] params_it pointer to the iterator where parameters info should be found
@@ -499,6 +515,7 @@ HardwareInfo parse_resource_from_xml(
   HardwareInfo hardware;
   hardware.name = get_attribute_value(ros2_control_it, kNameAttribute, kROS2ControlTag);
   hardware.type = get_attribute_value(ros2_control_it, kTypeAttribute, kROS2ControlTag);
+  hardware.is_async = parse_is_async_attribute(ros2_control_it);
 
   // Parse everything under ros2_control tag
   hardware.hardware_plugin_name = "";

hardware_interface/src/resource_manager.cpp

@@ -97,6 +97,7 @@ class ResourceStorage
     component_info.name = hardware_info.name;
     component_info.type = hardware_info.type;
     component_info.plugin_name = hardware_info.hardware_plugin_name;
+    component_info.is_async = hardware_info.is_async;
 
     hardware_info_map_.insert(std::make_pair(component_info.name, component_info));
     hardware_used_by_controllers_.insert(