ros-cross-compile 0.3.0

A tool to build ROS workspaces for various target architectures and platforms.

ROS2 Cross Compile

A tool to automate compiling ROS and ROS2 workspaces to non-native architectures.

:construction: ros_cross_compile relies on running emulated builds using QEmu, #69 tracks progress toward enabling cross-compilation.

Supported targets

This tool supports compiling a workspace for all combinations of the following:

• Architecture: armhf, aarch64
• ROS Distro
  • ROS: kinetic, melodic
  • ROS 2: dashing, eloquent
• OS: Ubuntu, Debian

Supported hosts

This tool officially supports running on the following host systems. Note that many others likely work, but these are being thoroughly tested.

• Ubuntu 18.04 Bionic Beaver
• OSX Mojave

Installation

Prerequisites

This tool requires that you have already installed

• Docker
  • Follow the instructions to add yourself to the docker group as well, so you can run containers as a non-root user
• Python 3.5 or higher

If you are using a Linux host, you must also install QEmu (Docker for OSX performs emulation automatically):

sudo apt-get install qemu-user-static

Installing ros_cross_compile

To install the stable release,

pip3 install ros_cross_compile

If you would like the latest nightly build, you can get it from Test PyPI

pip3 install --index-url https://test.pypi.org/simple/ ros_cross_compile

Usage

This script requires a sysroot directory containing the ROS 2 workspace, and the toolchain.

The following instructions explain how to create a sysroot directory.

Create the directory structure

mkdir -p sysroot/qemu-user-static
mkdir -p sysroot/ros_ws/src

Copy the QEMU Binaries

cp /usr/bin/qemu-*-static sysroot/qemu-user-static/

Prepare ros_ws

Use ROS or ROS 2 source installation guide to get the ROS repositories needed to cross compile.

Once you have the desired sources, copy them in the sysroot to use with the tool.

# Copy ros sources into the sysroot directory
cp -r <full_path_to_your_ros_ws>/src sysroot/ros_ws/src

Run the cross compilation script

In the end your sysroot directory should look like this:

sysroot/
 +-- qemu-user-static/
 |   +-- qemu-*-static
 +-- ros_ws/
     +-- src/
          |-- (ros packages)
          +-- ...

Then run the tool:

python3 -m ros_cross_compile \
  --sysroot-path /absolute/path/to/sysroot \
  --arch aarch64 \
  --os ubuntu

Custom setup script

Your ROS application may have build needs that aren't covered by rosdep install. If this is the case (for example you need to add extra apt repos), use the option --custom-setup-script to execute arbitrary code in the sysroot container.

The path provided may be absolute, or relative to the current directory.

Keep in mind

• It's up to the user to determine whether the script is compatible with chosen base platform
• Make sure to specify non-interactive versions of commands, for example apt-get install -y, or the script may hang waiting for input
• You cannot make any assumptions about the state of the apt cache, so run apt-get update before installing packages
• The script runs as root user in the container, so you don't need sudo

Below is an example script for an application that installs some custom Raspberry Pi libraries.

apt-get update
apt-get install -y software-properties-common

# Install Raspberry Pi library that we have not provided a rosdep rule for
add-apt-repository ppa:rpi-distro/ppa
apt-get install -y pigpio

Custom data directory

Your custom setup script (see preceding) may need some data that is not accessible within the sysroot creation environment. For example, you need custom rosdep rules files to find and install your dependencies. For this use case, you can use the option --custom-data-dir to point to an arbitrary path. The sysroot build copies this directory into the build environment, where it's available for use by your custom setup script at ./custom-data/.

Example:

Custom data directory (/arbitrary/local/directory)

/arbitrary/local/directory/
+-- my-data/
|   +-- something.txt

Setup Script (/path/to/custom-setup.sh)

#!/bin/bash
cat custom-data/something.txt

Tool invocation:

python3 -m ros_cross_compile \
  --sysroot-path /absolute/path/to/sysroot
  --arch aarch64 --os ubuntu \
  --custom-setup-script /path/to/custom-setup.sh \
  --custom-data-dir /arbitrary/local/directory

Now, during the sysroot creation process, you should see the contents of something.txt printed during the execution of the custom script.

NOTE: for trivial text files, as in the preceding example, you could have created those files fully within the --custom-setup-script. But for large or binary data such as precompiled libraries, this feature comes to the rescue.

Tutorial

For a new user, this section walks you through a representative use case, step by step.

This tutorial demonstrates how to cross-compile the File Talker tool against ROS2 Dashing, to run on an ARM64 Ubuntu system. You can generalize this workflow to any .repos file for your project.

NOTE: this tutorial assumes a Debian-based (including Ubuntu) Linux distribution as the host platform.

Creating a cross-compilation workspace

1. Create a directory for your workspace
   • mkdir cross_compile_ws
   • cd cross_compile_ws
2. Create a .repos file for vcs
   • file_talker.repos

   repositories:
     file_talker:
       type: git
       url: https://github.com/ros-tooling/file_talker.git
       version: master
   

3. Set up the sysroot environment for the cross-compiler to use
   • mkdir -p sysroot/qemu-user-static/
   • mkdir -p sysroot/ros_ws/src/
   • cp /usr/bin/qemu-*-static sysroot/qemu-user-static
   • vcs import ros_ws/src < file_talker.repos

Running the cross-compilation

python3 -m ros_cross_compile \
  --sysroot-path $(pwd) \
  --rosdistro dashing \
  --arch aarch64 \
  --os ubuntu

Here is a detailed look at the arguments passed to the script:

• --sysroot-path $(pwd)

Point the ros_cross_compile tool to the absolute path of the directory containing the sysroot directory created earlier. You could run the tool from any directory, but in this case the current working directory contains sysroot, hence $(pwd)

• --rosdistro dashing

You may specify both ROS and ROS2 distributions by name, for example, kinetic (ROS) or dashing (ROS 2). ros_cross_compile -h prints the supported distributions for this option

• --arch aarch64

Target the ARMv8 / ARM64 / aarch64 architecture (which are different names for the same thing). ros_cross_compile -h prints the supported architectures for this option.

• --os ubuntu

The target OS is Ubuntu - the tool chooses the OS version automatically based on the ROS Distro's target OS. In this case for ROS2 Dashing - 18.04 Bionic Beaver.

Outputs of the build

Run the following command

ls sysroot/ros_ws/

If the build succeeded, the directory looks like this:

ros_ws/
+-- src/
    |-- file_talker
+-- install_aarch64/
    |-- ...

The created directory install_aarch64 is the installation of your ROS workspace for your target architecture. You can verify this:

$ file ros_ws/install_aarch64/lib/file_talker/file_talker                                                               0s
ros_ws/install_aarch64/lib/file_talker/file_talker: ELF 64-bit LSB shared object, ARM aarch64, version 1 (GNU/Linux), dynamically linked, interpreter /lib/ld-, for GNU/Linux 3.7.0, BuildID[sha1]=02ede8a648dfa6b5b30c03d54c6d87fd9151389e, not stripped

Using the build on a target platform

Copy install_aarch64 onto the target system into a location of your choosing. It contains the binaries for your workspace.

If your workspace has any dependencies that are outside the source tree - that is, if rosdep had anything to install during the build - then you still need to install these dependencies on the target system.

# Run this on the target system, which must have rosdep already installed
# remember `rosdep init`, `rosdep update`, `apt-get update` if you need them
rosdep install --from-paths install_aarch64/share --ignore-src --rosdistro dashing -y

Now you may use the ROS installation as you would on any other system

source install_aarch64/setup.bash
ros2 run file_talker file_talker my_text_file.txt

License

This library is licensed under the Apache 2.0 License.

Build status

ROS 2 Release	Branch Name	Development	Source Debian Package	X86-64 Debian Package	ARM64 Debian Package	ARMHF Debian package
Latest	master		N/A	N/A	N/A	N/A
Dashing	dashing-devel				N/A	N/A