ROS Turtlesim GUI using Docker

What is Docker?

Docker is a tool that enables us to run an application in an isolated environment called a container. Containers are lightweight and contain all dependencies required to run a particular application which frees us from the hassle of manual installation of dependencies. Containers can be easily be shared as they are independent of the host operating system. Shared containers work exactly the same on every machine with Docker installed.

Running ROS on Docker using Docker Image

1. Install Docker from here

2. Check if Docker properly install by running in Docker Terminal:

   docker run hello-world
   

3. To pull Turtlesim Docker Image run:

   docker pull yagneshde/ros_turtlesim:latest
   

4. To run the Docker Image run:

   docker images
   docker run -it <IMAGE ID> 
   

5. To create catkin workspace follow Step 6 of Running Turtlesim ROS Node on Docker (Manually)

Running Turtlesim ROS Node on Docker (Manually)

1. Install Docker from here

2. Check if Docker properly install by running in Docker Terminal:

   docker run hello-world
   

3. Now run:

   docker run --net=host --env="DISPLAY" -v "${PWD}:/myvol" --volume="$HOME/.Xauthority:/root/.Xauthority:rw" --name roslocal -it ros:melodic /bin/bash
   

This step will take some time so be patient and ensure internet connectivity.

Option	Description
--net=host	Connects the container to host network
--env="DISPLAY"	Passes environment variable which enables us to use GUI
-v "${PWD}:/myvol"	Mounts the current working directory of host machine at the time of starting the container. To access current working directory in the container navigate to myvol. Note: Make sure the name of the folder is unique, i.e. myvol should not clash with other folders in the container's root directory.
--volume	Allows us to mount a volume from local storage from the host machine
--name roslocal	Allows us to give roslocal as the name of the container. If not specified Docker gives a random name to it. Check using docker ps -a
-it	Allows us to use interactive mode
ros:melodic	Name of the Docker Image. See more here
/bin/bash	To get bash shell in the terminal

• Note:

  • To stop the Docker container use:

    docker ps 
    docker stop <CONTAINER ID>

  • To start Docker container use:

    docker ps -a
    docker start <CONTAINER ID>
    docker exec -it <CONTAINER NAME> bash

4. Installing Turtlesim:

   First update the container using

   apt-get update
   

   To install Turtlesim run:

   sudo apt-get install ros-melodic-turtlesim
   

5. To open another terminal for the same instance of roslocal container, run:

   docker exec -it roslocal bash
   

6. Creating catkin workspace:

   cd myvol
   mkdir -p ~/catkin_ws/src
   cd catkin_ws
   catkin_make

   Creating ROS package named ros_basics

   cd src
   catkin_create_pkg ros_basics

7. To source setup.bash open a new terminal of same instance of the container from step 5.

   sudo apt update
   sudo apt install vim -y
   cd
   vim .bashrc

   Now navigate to the bottom of the file and add the following:

   source /opt/ros/melodic/setup.bash
   source /myvol/catkin_ws/devel/setup.bash

   Press ESC and type :wq to save and exit vim.

8. To start ROS Master run:

   roscore

   To start turtlesim node run:

   rosrun turtlesim turtlesim_node

   To start turtlesim tele-operation run:

   rosrun turtlesim turtle_teleop_key

Running ROS Publisher and Subscriber Nodes

1. Clone the package into the created catkin workspace,catkin_ws

   cd /myvol/catkin_ws/src
   git clone https://github.com/yagdev99/TurtlesimDocker
   cd ..
   catkin_make

2. Starting ROS Master:

   roscore
   

3. To run talker.py open a new terminal of the same instance of the container and run:

   rosrun TurtlesimDocker talker.py
   

4. To run listener.py open a new terminal of the same instance of the container and run:

   rosrun TurtlesimDocker listener.py
   

You should now see messages being puslished by talker.py and displayed by listener.py

Resources

1. To learn more about Docker refer to Docker Docs
2. Docker vs. Virtual Machines: https://geekflare.com/docker-vs-virtual-machine/
3. Writing DockerFile: https://docs.docker.com/engine/reference/builder/