ros2: start node with sudo rights
Hi,
as I have some nodes on a Raspi requiring access to the hardware, some of my nodes need to be started with sudo rights.
The easiest, but imho undesirable solution, is to open a shell with sudo -s and afterwards start the node. However, this is not really user-friendly. Is there a better solution for that? As mentioned in this post, launch-prefix may be used. However, this is a solution for ROS1. I gave it a try, and this results in errors. If I set the launch-prefix to either sudo or sudo -E, the following error occurs:
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [led_strip_node-1]: process started with pid [20011]
[led_strip_node-1] Traceback (most recent call last):
[led_strip_node-1] File "/home/pi/vehicle_workspace/install/vehicle_hardware/lib/vehicle_hardware/led_strip_node", line 33, in <module>
[led_strip_node-1] sys.exit(load_entry_point('vehicle-hardware', 'console_scripts', 'led_strip_node')())
[led_strip_node-1] File "/home/pi/vehicle_workspace/install/vehicle_hardware/lib/vehicle_hardware/led_strip_node", line 22, in importlib_load_entry_point
[led_strip_node-1] for entry_point in distribution(dist_name).entry_points
[led_strip_node-1] File "/home/pi/vehicle_workspace/env/lib/python3.7/site-packages/importlib_metadata/__init__.py", line 549, in distribution
[led_strip_node-1] return Distribution.from_name(distribution_name)
[led_strip_node-1] File "/home/pi/vehicle_workspace/env/lib/python3.7/site-packages/importlib_metadata/__init__.py", line 206, in from_name
[led_strip_node-1] raise PackageNotFoundError(name)
[led_strip_node-1] importlib_metadata.PackageNotFoundError: vehicle-hardware
[ERROR] [led_strip_node-1]: process has died [pid 20011, exit code 1, cmd 'sudo -E /home/pi/vehicle_workspace/install/vehicle_hardware/lib/vehicle_hardware/led_strip_node --ros-args'].
Thanks in advance! urczf
Wouldn't the 'best' solution be to make sure the user starting the ROS nodes has the access rights, instead of starting a whole node with
rootprivileges?What about writing a
udevrule which allows a certain group read/write access? And then make your$USERa member of that group.That's a very common approach which completely removes the need for running ROS nodes as
root(which from a security perspective is not a very nice thing to do).The questen is why do you need root rights, because it is not windows so you could solfe the problem buy adding you user to some groups.
Isn't this exactly what I wrote in my comment?
We need to access
/dev/memwhich is not possible with udev rules. By adding$USERto therootgroup would imply that by default I have alwayssurights, which is not what I want.Are these GPIOs you're trying to access? I remember similar questions but in a ROS 1 context and I believe the solution was to use
/dev/gpiomeminstead of/dev/memdirectly.As to your issue: it's likely the environment of your process is getting sanatised, leading to the
PYTHONPATHno longer containing the required packages.