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.

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ROS1 to Zenoh Bridge plugin

👉 Install latest release: see below

👉 Docker image: see below

👉 Build "main" branch: see below

Background

ROS1 is a well-known mature platform for building robotic systems. Despite the fact that next generation of ROS - ROS2 is released long time ago, many developers still prefer using ROS1. In order to integrate ROS1 systems to Zenoh infrastructure, as it was done for DDS/ROS2, ROS1 to Zenoh Bridge was designed.

How to install it

To install the latest release of either the ROS1 plugin for the Zenoh router, either the zenoh-bridge-ros1 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-ros1/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-ros1-<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-ros1-<version>-<platform>.zip file for the standalone executable.
  Then unzip it where you want, and run the extracted zenoh-bridge-ros1 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-ros1.
• install the standalone executable with: sudo apt install zenoh-bridge-ros1.

How to build it

⚠️ WARNING ⚠️ : Zenoh and its ecosystem are under active development. When you build from git, make sure you also build from git any other Zenoh repository you plan to use (e.g. binding, plugin, backend, etc.). It may happen that some changes in git are not compatible with the most recent packaged Zenoh release (e.g. deb, docker, pip). We put particular effort in mantaining compatibility between the various git repositories in the Zenoh project.

⚠️ 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.

⚠️ WARNING ⚠️ : We failed to build the plugin's tests on the system with 2(1)GB of RAM(swap) as ld ran out of memory, please pay attention to this fact!

In order to build the ROS1 to Zenoh Bridge, 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

• On Linux, make sure the llvm and clang development packages are installed:

  • on Debians do: sudo apt install llvm-dev libclang-dev
  • on CentOS or RHEL do: sudo yum install llvm-devel clang-devel
  • on Alpine do: apk install llvm11-dev clang-dev

Once these dependencies are in place, you may clone the repository on your machine:

git clone https://github.com/eclipse-zenoh/zenoh-plugin-ros1.git
cd zenoh-plugin-ros1
cargo build --release

The standalone executable binary zenoh-bridge-ros1 and a plugin shared library (*.so on Linux, *.dylib on Mac OS, *.dll on Windows) to be dynamically loaded by the zenoh router zenohd will be generated in the target/release subdirectory.

Docker image

The zenoh-bridge-ros1 standalone executable is also available as a Docker images for both amd64 and arm64. To get it, do:

• docker pull eclipse/zenoh-bridge-ros1:latest for the latest release
• docker pull eclipse/zenoh-bridge-ros1:main for the main branch version (nightly build)

Usage: docker run --init --net host eclipse/zenoh-bridge-ros1
It supports the same command line arguments than the zenoh-bridge-ros1 (see below or check with -h argument).

A quick test with built-in examples

If you want to run examples or tests, you need to install ROS1:

sudo apt install -y ros-base

There is a set of example utilities illustarating bridge in operation. Here is a description on how to configure the following schema:

_____________________________                           ________________________________
|                           |                           |                              |
|        rosmaster_1        |                           |         rosmaster_2          |
|                           |                           |                              |
| ros1_publisher -> zenoh-bridge-ros1 -> zenoh -> zenoh-bridge-ros1 -> ros1_subscriber |
|___________________________|                           |______________________________|

# build the bridge from source
cargo build -p zenoh-bridge-ros1
cd target/debug/
# terminal 1:
./zenoh-bridge-ros1 --with_rosmaster true --ros_master_uri http://localhost:10000
# terminal 2:
./zenoh-bridge-ros1 --with_rosmaster true --ros_master_uri http://localhost:10001
# terminal 3:
ROS_MASTER_URI=http://localhost:10000 rostopic pub /topic std_msgs/String -r 1 test_message
# terminal 4:
ROS_MASTER_URI=http://localhost:10001 rostopic echo /topic

Once completed, you will see the following exchange between ROS1 publisher and subscriber:

Implementation

Currently, ROS1 to Zenoh Bridge is based on rosrust library fork. Some limitations are applied due to rosrust's implementation details, and we are re-engineering rosrust to overcome this

Limitations

• all topic names are bridged as-is
• there is a performance impact coming from rosrust