ROS-Z

Making ROS 2 Zenoh-Native

_{Built by the Zenoh team at ZettaScale}

Overview

ROS 2 was designed to be independent from the underlying communication middleware. This is a nice architectural property, yet it does not come for free. What if we were to streamline ROS 2 and implement it natively on Zenoh? ROS-Z, a Zenoh-native ROS 2 stack, answers this question. ROS-Z preserves portability for RCL-C/CPP/Py-based applications and provides an extremely optimised stack for Rust users that interoperates with any Zenoh RMW-based ROS 2.

Goals

ROS-Z was started as an experiment to understand what we could gain from verticalisation while at the same time providing (1) a pure-Rust stack to ROS2 users, and (2) zenoh-native implementation of RCL-C. We hope that the lesson learned through this experiment will help the ROS community making ROS 2 even better.

Status

ROS-Z is experimental software. It is tested with ROS 2 Jazzy and should be interoperable with ROS 2 Rolling, but we make no guarantees with respect to official distributions.

Building

ROS-Z is designed to work without ROS dependencies by default. ROS-dependent features are opt-in.

Default Build (No ROS Dependencies)

The default workspace build includes only the core library and works without ROS 2:

# Build the workspace (ros-z + ros-z-codegen)
cargo build

# Run tests
cargo test

# Build example with custom Rust-defined messages (no ros-z-msgs required)
cargo build -p ros-z --example z_custom_message

Building with ros-z-msgs (still no ROS required)

The ros-z-msgs package includes bundled message definitions (std_msgs, geometry_msgs, sensor_msgs, nav_msgs) and can be built without ROS:

# Build ros-z-msgs with bundled messages (default, no ROS required)
cargo build -p ros-z-msgs

# Build examples that use bundled ros-z-msgs types
cargo build -p ros-z --example z_pubsub       # Uses std_msgs
cargo build -p ros-z --example z_pingpong     # Uses std_msgs
cargo build -p ros-z --example twist_pub      # Uses geometry_msgs
cargo build -p ros-z --example battery_state_sub  # Uses sensor_msgs
cargo build -p ros-z --example laser_scan     # Uses sensor_msgs

With ROS 2 Installation (Optional)

Only needed for RCL bindings or external message packages not bundled with roslibrust:

# Build RCL bindings (requires ROS 2)
cargo build -p rcl-z

# Build ros-z-msgs with external message packages (requires ROS 2)
cargo build -p ros-z-msgs --features external_msgs

# Build example that uses external messages (requires ROS 2)
cargo build --example z_srvcli --features external_msgs

Using Nix (Optional)

If you're using Nix, we provide development shells with all dependencies pre-configured:

# Default development environment (with ROS 2 Jazzy)
nix develop

# Specific ROS distros
nix develop .#jazzy      # ROS 2 Jazzy
nix develop .#rolling    # ROS 2 Rolling

# Without ROS dependencies
nix develop .#noRos

# CI environments (minimal, no dev tools)
nix develop .#jazzy-ci
nix develop .#rolling-ci
nix develop .#noRos-ci

Note on ros-z-msgs: This package can build without ROS installed! When ROS is not available, it automatically falls back to using bundled message definitions from the roslibrust git dependency. The build system searches for ROS packages in this order:

1. System ROS installation (via AMENT_PREFIX_PATH or CMAKE_PREFIX_PATH)
2. Common ROS installation paths (/opt/ros/{rolling,jazzy,iron,humble})
3. Roslibrust git dependency (~/.cargo/git/checkouts/roslibrust-*/assets/)

This allows ros-z-msgs to generate message types even in environments without ROS 2 installed. The default common_interfaces feature includes std_msgs, geometry_msgs, and sensor_msgs which are all available in roslibrust assets. Note that example_interfaces is not included in the default build as it requires a ROS 2 installation.

Workspace Structure

Default workspace members (no ROS dependencies):

• ros-z: Core Zenoh-native ROS 2 library
• ros-z-codegen: Message and service code generation utilities

Optional packages (excluded from default build):

• ros-z-msgs: Auto-generated ROS 2 message types (default features work without ROS; external message packages require ROS 2)
• ros-z-tests: Integration tests (requires ros-z-msgs)

ROS-dependent packages (excluded from default build):

• rcl-z: RCL C bindings (requires ROS 2 RCL libraries)

Examples

Examples are categorized by their dependencies:

• Custom Rust messages (no ros-z-msgs required):

  • z_custom_message - Demonstrates pub/sub and service with custom Rust-defined messages

• Bundled messages (no ROS required, uses roslibrust assets):

  • z_pubsub - Publisher/subscriber using std_msgs
  • z_pingpong - Ping-pong latency benchmark using std_msgs
  • twist_pub - Twist publisher using geometry_msgs
  • battery_state_sub - Battery state subscriber using sensor_msgs
  • laser_scan - Laser scan publisher using sensor_msgs

• External messages (requires ROS 2 installation):

  • z_srvcli - Service client/server using example_interfaces
    • Build with: cargo build --example z_srvcli --features external_msgs

• Advanced (requires protobuf feature):

  • protobuf_demo - Demonstrates protobuf serialization with both ROS messages and custom protobuf messages
    • Build with: cargo build -p protobuf_demo

Feature Flags

ros-z

• protobuf - Enable protobuf serialization support (requires prost)
• rcl-z - Enable RCL integration features
• external_msgs - Enable examples that require external ROS message packages (propagates to ros-z-msgs/external_msgs)

ros-z-msgs

Messages are organized into two categories:

Bundled messages (no ROS installation required):

• bundled_msgs (default) - All bundled message packages
• std_msgs, geometry_msgs, sensor_msgs, nav_msgs - Individual bundled packages
• common_interfaces - Convenience feature for std_msgs, geometry_msgs, sensor_msgs

External messages (require ROS 2 installation):

• external_msgs - All external message packages
• example_interfaces - Individual external package

Other features:

• all_msgs - Enable both bundled and external messages (requires ROS 2)
• protobuf - Generate protobuf types (requires ros-z/protobuf)

ros-z-codegen

• protobuf - Enable protobuf code generation support

ros-z-tests

• ros-msgs - Enable tests with ros-z-msgs dependency
• interop-tests - ROS interoperability tests (requires ros-msgs)