RoboND Catkin Workspace

Step into the ROS Kinetic Docker container by running

./run-nvidia.sh

This will open a shell as the ros user (password ros) and place you into the /workspace directory. In the background, an SSH server is started that allows you (or your IDE) to connect to the Docker container via port 2222. You can try it out by running

ssh ros@127.0.0.1 -p2222

from a different terminal.

Note that run-nvidia.sh makes use of the sunside/ros-gazebo-gpu:udacity-robond Docker image, because the original desktop-full ROS installation (via the base image) doesn't contain some required packages, such as

• ros-kinetic-gazebo-ros-control,
• ros-kinetic-effort-controllers,
• ros-kinetic-joint-state-controller etc.

You can either have the required image pulled automatically, or build it yourself from the provided Dockerfile by running

docker build --no-cache -t sunside/ros-gazebo-gpu:udacity-robond -f Dockerfile .

Dockerized building in CLion

To get a dockerized build going in CLion we have to apply some rocket science … sauce.

• First, we need to install the Docker plugin and configure it to talk to the local Docker daemon; after that, also connect to the Docker daemon in the Services toolbar.
• Next, we need to run an SSH server within the Docker container … yes, I know … and expose its port to the host. This is explained in Docker Plugin Integration and Using Docker with CLion; see the provided Dockerfile for how it actually plays out.
• We then create a Remote Host Toolchain that connects to the dockerized SSH server (as described in the above links).
• Now, we change the default CMake Configuration to apply some ROS specifics as hinted at in ROS Setup Tutorial.

Since we cannot just start CLion from the Catkin environment as described in the CLion documentation, we have to configure some CMake and environment variables manually. However, configuring the Generation path was not required, since we cannot point it to Catkins build dir without breaking things in various fantastic ways.

Anyway, here's what I added:

• CMake options:
  • -DCATKIN_DEVEL_PREFIX:PATH=/workspace/devel
  • -DCMAKE_PREFIX_PATH=/workspace/devel;/opt/ros/kinetic;/opt/ros/kinetic/share
• Environment:
  • ROS_VERSION=1
  • ROS_DISTRO=kinetic
  • ROS_MASTER_URI=http://localhost:11311
  • ROS_ROOT=/opt/ros/kinetic/share/ros
  • ROS_ETC_DIR=/opt/ros/kinetic/etc/ros
  • ROS_PACKAGE_PATH=/workspace/src:/opt/ros/kinetic/share
  • ROS_PYTHON_VERSION=2
  • ROSLISP_PACKAGE_DIRECTORIES=/workspace/devel/share/common-lisp
  • PYTHONPATH=/opt/ros/kinetic/lib/python2.7/dist-packages
  • LD_LIBRARY_PATH=/workspace/devel/lib:/opt/ros/kinetic/lib:/opt/ros/kinetic/lib/x86_64-linux-gnu:$LD_LIBRARY_PATH

The above variables were taken from the container by running env | grep -i ros and env | grep -i kinetic. When CLion is done trying to understand the environment, we can actually build the project(s) and introspect all referenced headers.

Setting up a Catkin workspace (once)

Ensure the src directory exists, then cd into it and call catkin_init_workspace to initiate a new Catkin workspace:

mkdir -p src && cd src
catkin_init_workspace

This should create a result similar to the following:

Creating symlink "/workspace/src/CMakeLists.txt" pointing to "/opt/ros/kinetic/share/catkin/cmake/toplevel.cmake"

If we run ls -l, we find that a symbolic link to Catkin's top-level CMakeLists.txt was created:

total 0
lrwxrwxrwx 1 ros ros 50 May 21 19:10 CMakeLists.txt -> /opt/ros/kinetic/share/catkin/cmake/toplevel.cmake

Building the workspace

Change back to the root directory of the repository (the one containing src/) and call

catkin_make

If we run ls -l again we will find, that the following directories exist:

• build: The CMake build directory
• devel: ROS and Catkin resources, such as setup.bash

Simple Arm

Ensure that all packages are installed as required:

rosdep install -i simple_arm

If a package is missing, this will ask you for permission to install it. Note that unless you run sudo apt update in the container at least once, these updates will fail. For this project, the required packages are included in the Dockerfile used to run th environment with.

Build the project via

catkin_make

then run roslaunch as described below to run the project:

source devel/setup.bash
roslaunch simple_arm robot_spawn.launch

If you encounter a warning

[WARN] [1590093853.282634, 0.000000]: Controller Spawner couldn't find the expected controller_manager ROS interface.

… that probably just means you started Gazebo for the first time in this Container and it takes a bit too long to do anything.

Fixing legacyModeNS errors for Kinetic

Originally, the code produced the following output:

[ERROR] [1590091780.648877316, 261.772000000]: GazeboRosControlPlugin missing <legacyModeNS> while using DefaultRobotHWSim, defaults to true.
This setting assumes you have an old package with an old implementation of DefaultRobotHWSim, where the robotNamespace is disregarded and absolute paths are used instead.
If you do not want to fix this issue in an old package just set <legacyModeNS> to true.

To fix, add the <legacyModeNS>true</legacyModeNS> attribute to the appropriate node of the .gazebo.xacro file that is affected. You can use the following command to pinpoint its location:

./src/simple_arm/urdf/simple_arm.gazebo.xacro

See the src/simple_arm/README.md for more information.