Building ROS 2 on Linux¶

System Requirements¶

Target platforms for Dashing Diademata are (see REP 2000):

• Tier 1: Ubuntu Linux - Bionic Beaver (18.04) 64-bit

Tier 3 platforms (not actively tested or supported) include:

• Debian Linux - Stretch (9)

• Fedora 30, see alternate instructions

• Arch Linux, see alternate instructions

System setup¶

sudo locale-gen en_US en_US.UTF-8
sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
export LANG=en_US.UTF-8

sudo apt update && sudo apt install -y \
  build-essential \
  cmake \
  git \
  python3-colcon-common-extensions \
  python3-lark-parser \
  python3-lxml \
  python3-numpy \
  python3-pip \
  python-rosdep \
  python3-vcstool \
  wget
# install some pip packages needed for testing
python3 -m pip install -U \
  argcomplete \
  flake8 \
  flake8-blind-except \
  flake8-builtins \
  flake8-class-newline \
  flake8-comprehensions \
  flake8-deprecated \
  flake8-docstrings \
  flake8-import-order \
  flake8-quotes \
  pytest-repeat \
  pytest-rerunfailures \
  pytest \
  pytest-cov \
  pytest-runner \
  setuptools
# install Fast-RTPS dependencies
sudo apt install --no-install-recommends -y \
  libasio-dev \
  libtinyxml2-dev

Get ROS 2 code¶

Create a workspace and clone all repos:

mkdir -p ~/ros2_ws/src
cd ~/ros2_ws
wget https://raw.githubusercontent.com/ros2/ros2/release-latest/ros2.repos
vcs import src < ros2.repos

Note: if you want to get all of the latest bug fixes then you can try the “tip” of development by replacing release-latest in the URL above with master. The release-latest is preferred by default because it goes through more rigorous testing on release than changes to master do. See also Maintaining a Source Checkout.

Install dependencies using rosdep¶

sudo rosdep init
rosdep update
rosdep install --from-paths src --ignore-src --rosdistro dashing -y --skip-keys "console_bridge fastcdr fastrtps libopensplice67 libopensplice69 rti-connext-dds-5.3.1 urdfdom_headers"

Install more DDS implementations (Optional)¶

ROS 2 builds on top of DDS. It is compatible with multiple DDS or RTPS (the DDS wire protocol) vendors. The repositories you downloaded for ROS 2 includes eProsima’s Fast RTPS, which is the only bundled vendor. If you would like to use one of the other vendors you will need to install their software separately before building. The ROS 2 build will automatically build support for vendors that have been installed and sourced correctly.

By default we include eProsima’s FastRTPS in the workspace and it is the default middleware. Detailed instructions for installing other DDS vendors are provided below.

sudo apt install libopensplice69  # from packages.ros.org/ros2/ubuntu

sudo apt install -q -y \
    rti-connext-dds-5.3.1  # from packages.ros.org/ros2/ubuntu

cd /opt/rti.com/rti_connext_dds-5.3.1/resource/scripts && source ./rtisetenv_x64Linux3gcc5.4.0.bash; cd -

export RTI_LICENSE_FILE=path/to/rti_license.dat

source ~/rti_connext_dds-5.3.1/resource/scripts/rtisetenv_x64Linux3gcc5.4.0.bash

Build the code in the workspace¶

Note: to build the ROS 1 bridge, read the ros1_bridge instructions.

More info on working with a ROS workspace can be found in this tutorial.

cd ~/ros2_ws/
colcon build --symlink-install

Note: if you are having trouble compiling all examples and this is preventing you from completing a successful build, you can use AMENT_IGNORE in the same manner as CATKIN_IGNORE to ignore the subtree or remove the folder from the workspace. Take for instance: you would like to avoid installing the large OpenCV library. Well then simply $ touch AMENT_IGNORE in the cam2image demo directory to leave it out of the build process.

Optionally install all packages into a combined directory (rather than each package in a separate subdirectory). On Windows due to limitations of the length of environment variables you should use this option when building workspaces with many (~ >> 100 packages).

Also, if you have already installed ROS2 from Debian make sure that you run the build command in a fresh environment. You may want to make sure that you do not have source /opt/ros/${ROS_DISTRO}/setup.bash in your .bashrc.

colcon build --symlink-install --merge-install

Afterwards source the local_setup.* from the install folder.

Try some examples¶

In one terminal, source the setup file and then run a talker:

. ~/ros2_ws/install/local_setup.bash
ros2 run demo_nodes_cpp talker

In another terminal source the setup file and then run a listener:

. ~/ros2_ws/install/local_setup.bash
ros2 run demo_nodes_py listener

You should see the talker saying that it’s Publishing messages and the listener saying I heard those messages. Hooray!

See the demos for other things to try.

Alternate compilers¶

Using a different compiler besides gcc to compile ROS 2 is easy. If you set the environment variables CC and CXX to executables for a working C and C++ compiler, respectively, and retrigger CMake configuration (by using --force-cmake-config or by deleting the packages you want to be affected), CMake will reconfigure and use the different compiler.

sudo apt install clang
export CC=clang
export CXX=clang++
colcon build --cmake-force-configure

Troubleshooting¶