rosrust, and actionlib

Overview

Introduction

My name is Salvatore and I am a Development Engineer at 株式会社Rist.

About this article

This article is meant to be a quick and direct introduction to the actionlib support in rosrust, based on the examples of the rosrust repository.

rosrust

What is rosrust

rosrust is a Rust implementation of a ROS client library.
Being rosrust a Rust crate, it assumes an existing underlying Rust environment in order to be used.

Why it is needed

rosrust allows to interface code written in Rust to the standard ROS environment.

Installation

Environment

Software	Version
OS	Ubuntu 18.04.4 LTS (Bionic Beaver)
Python	Python 2.7.17
	Python 3.6.9 (Default)
ROS	ROS 1 (Melodic)
Rust	Rust 1.45.2 (d3fb005a3 2020-07-31)
rosrust	rosrust v0.9.3

For information on setting up a ROS 1 Melodic environment on a machine running Ubuntu, refer to the official documentation.

Rust

The installation of Rust is straight forward and all the needed packages will be located into the user home directory.

Proceed with the installation:

$ curl --proto '=https' --tlsv1.2 https://sh.rustup.rs -sSf | sh

Verify the installation:

$ rustc --version

For more details on the installation, or alternative platforms, refer to The Rust Programming Language book, or the official documentation.

rosrust

The rosrust crate is available at the official github repository.

To proceed with the installation, clone the official repository:

$ git clone https://github.com/adnanademovic/rosrust.git

Build the crate:
Note: in order to successfully build the rosrust crate, due to message dependencies, it is necessary to source the ROS installation path.

$ . /opt/ros/melodic/setup.bash
$ cargo build

At this point, the rosrust crate is available for use.

Verify the installation

To verify the correct installation of the rosrust crate, it is possible to run the examples provided by the crate itself.

To show a list of all available examples, run the following command from the root of the rosrust crate folder structure:

$ cargo run --example

Comprehensive list of available examples in the rosrust crate:

slb@salvatorepc: rosrust (master=) $ cargo run --example
error: "--example" takes one argument.
Available examples:
    access_image_message
    camera_subscriber
    client
    client_node
    example
    fibonacci_cancelling_client
    fibonacci_client
    fibonacci_multi_call_client
    fibonacci_server
    frequency_status
    function_task
    function_task_extra
    old_client
    old_service
    parameters
    publisher
    publisher_latch_demo
    publisher_node
    pubsub_loopback
    service
    service_node
    subscriber
    subscriber_node
    subscriber_with_ids

Next, it will be shown the simplest publisher/subscriber example in order to determine the correct behaviour of the ROS/rosrust environment.

Running the publisher/subscriber example

Considering the simplest example of the communication between a publisher and a subscriber on a common topic.

Shell 1: `roscore`

Launch roscore:

$ . /opt/ros/melodic/setup.bash
$ roscore

Shell 2: `publisher`

Launch the publisher:

$ . /opt/ros/melodic/setup.bash
$ cargo run --example publisher

Shell 3: `subscriber`

Launch the subscriber:

$ . /opt/ros/melodic/setup.bash
$ cargo run --example subscriber

Shell 4: `topics`

Show the nodes and the exchange of the messages on the specified topic:

$ . /opt/ros/melodic/setup.bash
$ rosnode list
$ rostopic list
$ rostopic info /chatter
$ rostopic echo /chatter

Terminals

Running the actionlib example

The actionlib example shows a fully functional integration with the ROS actionlib.

Shell 1: `roscore`

Launch roscore:

$ . /opt/ros/melodic/setup.bash
$ roscore

Shell 2: `fibonacci_server`

Launch the publisher:

$ . /opt/ros/melodic/setup.bash
$ cargo run --example fibonacci_server

Shell 3: `fibonacci_client`

Launch the subscriber:

$ . /opt/ros/melodic/setup.bash
$ cargo run --example fibonacci_client

Terminals

As shown earlier, there are a lot more examples available in the rosrust crate. Feel free to try them all!

References