Snappy package for Robot Operating System tutorial

ROS what?

Robot Operating System (ROS) is a set of libraries, services, protocols, conventions, and tools to write robot software. It’s about seven years old now, free software, and a growing community, bringing Linux into the interesting field of robotics. They primarily target/support running on Ubuntu (current Indigo ROS release runs on 14.04 LTS on x86), but they also have some other experimental platforms like Ubuntu ARM and OS X.

ROS, meet Snappy

It appears that their use cases match Ubuntu Snappy’s vision really well: ROS apps usually target single-function devices which require absolutely robust deployments and upgrades, and while they of course require a solid operating system core they mostly implement their own build system and libraries, so they don’t make too many assumptions about the underlying OS layer.

So I went ahead and created a snapp package for the Turtle ROS tutorial, which automates all the setup and building. As this is a relatively complex and big project, it helped to uncover quite a number of bugs, of which the most important ones got fixed now. So while the building of the snap still has quite a number of workarounds, installing and running the snap is now reasonably clean.

Enough talk, how can I get it?

If you are interested in ROS, you can look at bzr branch lp:~snappy-dev/snappy-hub/ros-tutorials. This contains documentation and a script build.sh which builds the snapp package in a clean Ubuntu Vivid environment. I recommend a schroot for this so that you can simply do e. g.

$ schroot -c vivid ./build.sh

This will produce a /tmp/ros/ros-tutorial_0.2_<arch>.snap package. You can download a built amd64 snapp if you don’t want to build it yourself.

Installing and running

Then you can install this on your Snappy QEMU image or other installation and run the tutorial (again, see README.md for details):

yourhost$ ssh -o UserKnownHostsFile=/dev/null -p 8022 -R 6010:/tmp/.X11-unix/X0 ubuntu@localhost
  snappy$ scp <yourhostuser>@10.0.2.2:/tmp/ros/ros-tutorial_0.2_amd64.snap
  snappy$ sudo snappy install ros-tutorial_0.2_amd64.snap

You need to adjust <yourhostuser> accordingly; if you didn’t build yourself but downloaded the image, you might also need to adjust the host path where you put the .snap.

Finally, run it:

snappy$ ros-tutorial.rossnap roscore &
  snappy$ DISPLAY=localhost:10.0 ros-tutorial.rossnap rosrun turtlesim turtlesim_node &
  snappy$ ros-tutorial.rossnap rosrun turtlesim turtle_teleop_key

You might prefer ssh’ing in three times and running the commands in separate shells. Only turtlesim_node needs $DISPLAY (and is quite an exception — an usual robotics app of course wouldn’t!). Also, note that this requires ssh from at least Ubuntu 14.10 – if you are on 14.04 LTS, see README.md.

Enjoy!

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