robotis_dds_python

A Python SDK for publishing and subscribing to topics using CycloneDDS without importing rclpy. This library provides a lightweight alternative to ROS 2 Python API while maintaining compatibility with ROS 2 message types.

Features

• Lightweight: No ROS 2 runtime dependencies
• Compatible: Works with standard ROS 2 message types
• Easy to use: Simple publisher/subscriber API
• Extensible: Support for custom message types

Installation

Prerequisites

• Python 3.8 or higher
• CycloneDDS 0.10.2

Install from source

1. Before using this package, you need to have CycloneDDS installed on your system. You can build it from source as follows:

# Install build dependencies
sudo apt update
sudo apt install -y git build-essential cmake libssl-dev

# Clone CycloneDDS source
git clone https://github.com/eclipse-cyclonedds/cyclonedds.git
cd cyclonedds
git checkout 0.10.2

# Create a build directory
mkdir build && cd build

# Build and install CycloneDDS
cmake -DCMAKE_INSTALL_PREFIX=$HOME/cyclonedds/install -DBUILD_EXAMPLES=ON ..
cmake --build .
cmake --install .

• Note: You can change $HOME/cyclonedds/install to any directory you prefer.

2. After installation, make sure to set the environment variables so that Python can locate the CycloneDDS libraries:

# For bash
echo 'export CYCLONEDDS_HOME=$HOME/cyclonedds/install' >> ~/.bashrc
echo 'export CMAKE_PREFIX_PATH=$CYCLONEDDS_HOME:$CMAKE_PREFIX_PATH' >> ~/.bashrc
echo 'export LD_LIBRARY_PATH=$CYCLONEDDS_HOME/lib:$LD_LIBRARY_PATH' >> ~/.bashrc
echo 'export PATH=$CYCLONEDDS_HOME/bin:$PATH' >> ~/.bashrc

source ~/.bashrc

# For zsh
echo 'export CYCLONEDDS_HOME=$HOME/cyclonedds/install' >> ~/.zshrc
echo 'export CMAKE_PREFIX_PATH=$CYCLONEDDS_HOME:$CMAKE_PREFIX_PATH' >> ~/.zshrc
echo 'export LD_LIBRARY_PATH=$CYCLONEDDS_HOME/lib:$LD_LIBRARY_PATH' >> ~/.zshrc
echo 'export PATH=$CYCLONEDDS_HOME/bin:$PATH' >> ~/.zshrc

source ~/.zshrc

Finally, install robotis_dds_python:

# Clone the repository
git clone https://github.com/robotis-git/robotis_dds_python.git

# Install the package
cd robotis_dds_python
pip install -e .

Examples

Check the example/ directory for complete working examples:

• trajectory_publisher.py - Publishing joint trajectory messages
• trajectory_subscriber.py - Subscribing to joint trajectory messages

Creating Custom Messages

To add support for new ROS 2 message types:

1. Navigate to the IDL directory:

   cd robotis_dds_python/robotis_dds_python/idl

2. Generate Python bindings from IDL:

   idlc -l py -I /opt/ros/jazzy/share/ /opt/ros/jazzy/share/{your_package}/msg/{YourMessage}.idl

3. Update the generated files and __init__.py as needed.

API Reference

topic_manager

topic_writer(topic_name, topic_type, qos)

Creates a DDS DataWriter for publishing messages.

Parameters:

• topic_name (str): Name of the topic
• topic_type (Type): Message type class
• qos (Qos, optional): Quality of Service settings

Returns: DataWriter instance

topic_reader(domain_id, topic_name, topic_type, qos)

Creates a DDS DataReader for subscribing to messages.

Parameters:

• topic_name (str): Name of the topic
• topic_type (Type): Message type class
• qos (Qos, optional): Quality of Service settings

Returns: DataReader instance

Contributing

We welcome contributions! Please see our Contributing Guidelines for details.

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.