Eclipse Zenoh

The Eclipse Zenoh: Zero Overhead Pub/sub, Store/Query and Compute.

Zenoh (pronounce /zeno/) unifies data in motion, data at rest and computations. It carefully blends traditional pub/sub with geo-distributed storages, queries and computations, while retaining a level of time and space efficiency that is well beyond any of the mainstream stacks.

Check the website zenoh.io and the roadmap for more detailed information.

A Zenoh bridge for ROS 2 over DDS

ROS (the Robot Operating System) is a set of software libraries and tools allowing to build robotic applications. In its version 2, ROS 2 relies mostly on O.M.G. DDS as a middleware for communications. This plugin bridges all ROS 2 communications using DDS over Zenoh.

While a Zenoh bridge for DDS already exists and helped lot of robotic use cases to overcome some wireless connectivity, bandwidth and integration issues, using a bridge dedicated to ROS 2 brings the following advantages:

• A better integration of the ROS graph (all ROS topics/services/actions can be seen across bridges)
• A better support of ROS toolings (ros2, rviz2…)
• Configuration of a ROS namespace on the bridge, instead of on each ROS Nodes
• Easier integration with Zenoh native applications (services and actions are mapped to Zenoh Queryables)
• More compact exchanges of discovery information between the bridges

Plugin or bridge ?

This software is built in 2 ways to choose from:

• zenoh-plugin-ros2dds: a Zenoh plugin - a dynamic library that can be loaded by a Zenoh router
• zenoh-bridge-ros2dds: a standalone executable

The features and configurations described in this document applies to both. Meaning the “plugin” and “bridge” words are interchangeables in the rest of this document.

How to install it

To install the latest release of either the DDS plugin for the Zenoh router, either the zenoh-bridge-ros2dds standalone executable, you can do as follows:

Manual installation (all platforms)

All release packages can be downloaded from:

• https://download.eclipse.org/zenoh/zenoh-plugin-ros2dds/latest/

Each subdirectory has the name of the Rust target. See the platforms each target corresponds to on https://doc.rust-lang.org/stable/rustc/platform-support.html

Choose your platform and download:

• the zenoh-plugin-ros2dds-<version>-<platform>.zip file for the plugin.
  Then unzip it in the same directory than zenohd or to any directory where it can find the plugin library (e.g. /usr/lib)
• the zenoh-bridge-ros2dds-<version>-<platform>.zip file for the standalone executable.
  Then unzip it where you want, and run the extracted zenoh-bridge-ros2dds binary.

Linux Debian

Add Eclipse Zenoh private repository to the sources list:

echo "deb [trusted=yes] https://download.eclipse.org/zenoh/debian-repo/ /" | sudo tee -a /etc/apt/sources.list > /dev/null
sudo apt update

Then either:

• install the plugin with: sudo apt install zenoh-plugin-ros2dds.
• install the standalone executable with: sudo apt install zenoh-bridge-ros2dds.

Docker images

The zenoh-bridge-ros2dds standalone executable is also available as a Docker images for both amd64 and arm64. To get it, do:

• docker pull eclipse/zenoh-bridge-ros2dds:latest for the latest release
• docker pull eclipse/zenoh-bridge-ros2dds:nightly for the main branch version (nightly build)

Nightly builds

The “Release” action builds packages for most most of OSes. You can download those from the “Artifacts” section in each build.
Just download the package for your OS and unzip it. You’ll get 3 zips: 1 for the plugin, 1 for the plugin as debian package and 1 for the bridge. Unzip the zenoh-bridge-ros2dds-<platform>.zip file, and you can run ./zenoh-bridge-ros2dds

How to build it

:warning: WARNING :warning: : As Rust doesn’t have a stable ABI, the plugins should be built with the exact same Rust version than zenohd, and using for zenoh dependency the same version (or commit number) than ‘zenohd’. Otherwise, incompatibilities in memory mapping of shared types between zenohd and the library can lead to a "SIGSEV" crash.

In order to build the zenoh bridge for DDS you need first to install the following dependencies:

• Rust. If you already have the Rust toolchain installed, make sure it is up-to-date with:

  rustup update
  

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