.. _microros_subscriber_performance_test:

Microros Subscriber Performance Test
========================================================================

Overview
--------

The subscriber example demonstrates the message subscription function of microros nodes through XRCE-Client.

Board Setting
-------------

- One ubuntu host with ROS2 foxy version installed.

- Connect the host to the development board using a USB to serial port. The serial port number used by the development board can be found in board.h.

Environment Setup
-----------------

ros2 foxy install:

1. Installation steps on the official website [https://docs.ros.org/en/foxy/Installation/Alternatives/Ubuntu-Development-Setup.html].

2. Installing through APT(If necessary，change the source of ubuntu)

.. code-block:: bash

   sudo apt update
   sudo apt install ros-foxy-desktop


After installing ROS2 foxy, it is necessary to install the agent on the host side, which is installed through Docker

.. code-block:: bash

   docker run -it --rm --net=host -v /dev/shm:/dev/shm -v /dev:/dev --privileged microros/micro-ros-agent:foxy serial --dev ${serial}

If you encounter a situation where the serial port cannot be opened, please change the permissions for the serial port

.. code-block:: bash

   sudo chmod -R 777 ${serial}

After running the agent, reset the board.

.. note::

   - Currently, the static library linked by microros is compiled by GCC 11.1.0 and Andes Toolchain v520.

Running the example
-------------------

Open a new terminal

.. code-block:: bash

   source /opt/ros/foxy/setup.bash

- type `ros2 node list` You can see the 'subscriber' node.
- type `ros2 topic list` You can see/int32_subscriber topic name.
- type `ros2 node info /subscriber` You can query the functions and message types of nodes.
- type `ros2 topic echo /int32_subscriber` Print out /int32_subscriber messages.

Open a new terminal type

.. code-block:: bash

   source /opt/ros/foxy/setup.bash

   ros2 topic pub /int32_subscriber std_msgs/msg/Int32 "{data: 1234}"

The agent starts publishing messages under/int32_subscriber topics, and you can see the nodes that subscribe to /int32_subscriber topic printing out.

.. code-block:: bash

   data: 1234
   ---
   data: 1234
   ---
   data: 1234
   ---
   data: 1234
   ---
   data: 1234
   ---