Gazebo | Ignition | Community
Ask Your Question

ROS2 Subscriber not triggering callback when more than 3 subscribers in plugin

asked 2022-09-20 06:19:28 -0600

Sam_Prt gravatar image

Hello !

I have been writing a plugin to control 4 joints on my model. Each joint command is obtained from a ros2 topic through a subscriber. Everything works as expected when there is only 3 subscribers. However, when I setup all 4 subscribers, the callbacks are not triggered.

Here is a minimal example (ROS2 foxy and Gazebo 11):

#include <gazebo/common/Plugin.hh>
#include <gazebo/physics/Model.hh>
#include <gazebo_ros/node.hpp>
#include <rclcpp/rclcpp.hpp>
#include <std_msgs/msg/float32.hpp>

namespace gazebo_plugins {

class TestPlugin : public gazebo::ModelPlugin {
    TestPlugin() = default;

    void Load(gazebo::physics::ModelPtr model, sdf::ElementPtr sdf) {

        // Store the model pointer for convenience.
        this->model_ = model;

        // Initialize ROS node
        this->node_ = gazebo_ros::Node::Get(sdf);

        // Get QoS profiles
        const gazebo_ros::QoS &qos = this->node_->get_qos();

        // Create a topic name
        std::string topic_1 = "topic_1";
        std::string topic_2 = "topic_2";
        std::string topic_3 = "topic_3";
        std::string topic_4 = "topic_4";

        // Create subscribers
        this->topic_1_subscriber_ = this->node_->create_subscription<std_msgs::msg::Float32>(
                qos.get_subscription_qos(topic_1, rclcpp::QoS(1)),
                std::bind(&TestPlugin::OnTopic1CmdMsg, this, std::placeholders::_1));
        this->topic_2_subscriber_ = this->node_->create_subscription<std_msgs::msg::Float32>(
                qos.get_subscription_qos(topic_2, rclcpp::QoS(1)),
                std::bind(&TestPlugin::OnTopic2CmdMsg, this, std::placeholders::_1));
        this->topic_3_subscriber_ = this->node_->create_subscription<std_msgs::msg::Float32>(
                qos.get_subscription_qos(topic_3, rclcpp::QoS(1)),
                std::bind(&TestPlugin::OnTopic3CmdMsg, this, std::placeholders::_1));
        this->topic_4_subscriber_ = this->node_->create_subscription<std_msgs::msg::Float32>(
                qos.get_subscription_qos(topic_4, rclcpp::QoS(1)),
                std::bind(&TestPlugin::OnTopic4CmdMsg, this, std::placeholders::_1));

        // Listen to the update event. This event is broadcast every
        // simulation iteration.
        this->updateConnection_ = gazebo::event::Events::ConnectWorldUpdateBegin(
                std::bind(&TestPlugin::OnUpdate, this));

        RCLCPP_INFO(this->node_->get_logger(), "Plugin loaded successfully.");

    void OnUpdate() {

        RCLCPP_INFO_THROTTLE(this->node_->get_logger(), *this->node_->get_clock(), 1000, "Update");

    void OnTopic1CmdMsg(const std_msgs::msg::Float32::SharedPtr msg) {
        RCLCPP_INFO_THROTTLE(this->node_->get_logger(), *this->node_->get_clock(), 1000, "Received topic 1 : %f", msg->data);

    void OnTopic2CmdMsg(const std_msgs::msg::Float32::SharedPtr msg) {
        RCLCPP_INFO_THROTTLE(this->node_->get_logger(), *this->node_->get_clock(), 1000, "Received topic 2 : %f", msg->data);


    void OnTopic3CmdMsg(const std_msgs::msg::Float32::SharedPtr msg) {
        RCLCPP_INFO_THROTTLE(this->node_->get_logger(), *this->node_->get_clock(), 1000, "Received topic 3 : %f", msg->data);


    void OnTopic4CmdMsg(const std_msgs::msg::Float32::SharedPtr msg) {
        RCLCPP_INFO_THROTTLE(this->node_->get_logger(), *this->node_->get_clock(), 1000, "Received topic 4 : %f", msg->data);


    // Pointer to the update event connection
    gazebo::event::ConnectionPtr updateConnection_;

    gazebo_ros::Node::SharedPtr node_;
    gazebo::physics::ModelPtr model_;

    rclcpp::Subscription<std_msgs::msg::Float32>::SharedPtr topic_1_subscriber_;
    rclcpp::Subscription<std_msgs::msg::Float32>::SharedPtr topic_2_subscriber_;
    rclcpp::Subscription<std_msgs::msg::Float32>::SharedPtr topic_3_subscriber_;
    rclcpp::Subscription<std_msgs::msg::Float32>::SharedPtr topic_4_subscriber_;
    // Tell Gazebo about this plugin, so that Gazebo can call Load on this plugin.

This code does not trigger the callbacks, however, by simply commenting any one of the subscriber definition, the callbacks are triggered.

I find this very puzzling... Any help would be most welcome, thank you !

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2022-09-21 02:45:13 -0600

Sam_Prt gravatar image

After some testing I have found that I am able to use 4 subscribers if I launch Gazebo 11 with this command :

gazebo -s

However, if I use the launch file from the gazebo_ros package (ROS foxy), the subscribers do not work all together. I modified my launch file to take this into account and it works now.

I am still interested in knowing why the gazebo launch file creates this problem, if anyone has more information...

edit flag offensive delete link more

Question Tools

1 follower


Asked: 2022-09-20 06:19:28 -0600

Seen: 54 times

Last updated: Sep 20