# ROS2 Client
This is a Rust native client library for [ROS2](https://docs.ros.org/en/galactic/index.html).
It does not link to [rcl](https://github.com/ros2/rcl),
[rclcpp](https://docs.ros2.org/galactic/api/rclcpp/index.html), or any non-Rust DDS library.
[RustDDS](https://github.com/jhelovuo/RustDDS) is used for communication.
## Architecture Ideas
The intetion is that this is a medium-level library between lower-level DDS and a higher-level library.
The (yet-to-be-written) higher-level library should provide an event loop, Actions, and possibly an async API. These are to be implemented as a separate crate on top of this one.
## Example: turtle_teleop
The included example program should be able to communicate with out-of-the-box ROS2 turtlesim example.
Install ROS2 and start the simulator by ` ros2 run turtlesim turtlesim_node`. Then run the `turtle_teleop` example to control the simulator.
Teleop example program currently has the following keyboard commands:
* Cursor keys: Move turtle
* `q` or `Ctrl-C`: quit
* `r`: reset simulator
* `p`: change pen color (for turtle1 only)
* `a`/`b` : spawn turtle1 / turtle2
* `A`/`B` : kill turtle1 / turtle2
* `1`/`2` : switch control between turtle1 / turtle2
## Example: ros2_service_server
Install ROS2. This has been tested to work against "Galactic" release, using either eProsima FastDDS or RTI Connext DDS (`rmw_connextdds`, not `rmw_connext_cpp`).
Start server: `cargo run --example=ros2_service_server`
In another terminal or computer, run a client: `ros2 run examples_rclpy_minimal_client client`
## Example: ros2_service_client
Similar to above.
Start server: `ros2 run examples_rclpy_minimal_service service`
Run client: `cargo run --example=ros2_service_client`
## Status
This is a work-in-progress.
## Related Work
* [ros2_rust](https://github.com/ros2-rust/ros2_rust) is closest(?) to an official ROS2 client library. It links to ROS2 `rcl` library written in C.
* [rclrust](https://github.com/rclrust/rclrust) is another ROS2 client library for Rust. It supports also ROS2 Services in addition to Topics. It links to ROS2 libraries, e.g. `rcl` and `rmw`.
* [rus2](https://github.com/marshalshi/rus2) exists, but appears to be inactive since September 2020.
## License
Copyright 2022 Atostek Oy
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
## Acknowledgements
This crate is developed and open-source licensed by [Atostek Oy](https://www.atostek.com/).