QOS (Message queue depth) for topics

[Akuva2001]

Configurable queue size for topics

Motivation

https://design.ros2.org/articles/qos.html

Sensor data
For sensor data, in most cases it’s more important to receive readings in a timely fashion, rather than ensuring that all of them arrive. That is, developers want the latest samples as soon as they are captured, at the expense of maybe losing some. For that reason the sensor data profile uses best effort reliability and a smaller queue depth.

In some cases we need shorter or longer queue size.

Examples:

• C++
  https://docs.ros.org/en/humble/Tutorials/Beginner-Client-Libraries/Writing-A-Simple-Cpp-Publisher-And-Subscriber.html

publisher_ = this->create_publisher<std_msgs::msg::String>("topic", 10);

subscription_ = this->create_subscription<std_msgs::msg::String>(
      "topic", 10, std::bind(&MinimalSubscriber::topic_callback, this, _1));

• Python
  https://docs.ros.org/en/humble/Tutorials/Beginner-Client-Libraries/Writing-A-Simple-Py-Publisher-And-Subscriber.html

self.publisher_ = self.create_publisher(String, 'topic', 10)

self.subscription = self.create_subscription(
            String,
            'topic',
            self.listener_callback,
            10)

In all examples 10 is a QOS parameter. I haven't found any option to set this parameter in goroslib library. Maybe I missed smth.

Is it planned to add this behaviour to the library?

Best Regards