ROS2 - ardupilot_sitl launch file to include a "out" parameter for Mavproxy

[tizianofiorenzani]

The ROS2 ardupilot_sitl launch file is currently setting the --out argument to mavproxy as default to localhost:14550. This PR allows to change the default output, in case for example we launch the node on a docker container and we want to connect to a Ground Station running on the host.

How to test:
We can follow the example provided in https://ardupilot.org/dev/docs/ros2-sitl.html and launch the sitl with:

ros2 launch ardupilot_sitl sitl_dds_udp.launch.py transport:=udp4 refs:=$(ros2 pkg prefix ardupilot_sitl)/share/ardupilot_sitl/config/dds_xrce_profile.xml synthetic_clock:=True wipe:=False model:=quad speedup:=1 slave:=0 instance:=0 defaults:=$(ros2 pkg prefix ardupilot_sitl)/share/ardupilot_sitl/config/default_params/copter.parm,$(ros2 pkg prefix ardupilot_sitl)/share/ardupilot_sitl/config/default_params/dds_udp.parm sim_address:=127.0.0.1 master:=tcp:127.0.0.1:5760 sitl:=127.0.0.1:5501

This should output something like:

which shows that, by default, the output is still localhost:14550

We can then add the option out:=udp:<any_ip_address>:<any_port>, and verify that the output to the launch file becomes:

We can then use either mavproxy or any GUI to connect to the UDP stream. In my case, I went from my Ubuntu Virtual Machine to my Windows host where I run QGCS:

[Ryanf55]

@srmainwaring - Do you know the context for why this was commented out earlier? I like this change.

[srmainwaring]

Do you know the context for why this was commented out earlier?

It's most likely an oversight from the original development. mavproxy.py will accept multiple --out parameters, however ROS 2 launch scripts do not. IIRC I fixed the single parameter --out parameter during development, did not find a solution for handling multiple --outs, and forgot to leave the one available that could be set.

@tizianofiorenzani thanks for your contribution. It's good to have this as available as an argument so will add my approval as well.

[khancyr]

should use a list as argument so you can add as much as you want .
That will be handly to remove the second --out too.

And it probably need default value to "127.0.0.1:14550 " in case nothing is passed to retain the current behavior

[srmainwaring]

And it probably need default value to "127.0.0.1:14550 " in case nothing is passed to retain the current behavior

That's already handled by the generate_launch_arguments method which supplies a default for a single --out param.

should use a list as argument so you can add as much as you want .

Yep. Could revisit the current launch methods in a follow up PR and apply this consistently. Will prob need to handle both list and single value as fallback to support existing usage.

[tizianofiorenzani]

I agree with the list of --out, in general you may want to pass more than one argument at a time. And yes, the localhost:14550 is default, so you don't need to add it. One option could be to have localhost anyway and add an external --out argument in case it was different

[peterbarker]

Commit list is bad.

[Ryanf55]

Commit list is bad.

When are we gonna get an automated github action for this

[srmainwaring]

@Ryanf55 can you please rebase and remove the merge commit.

[Ryanf55]

@Ryanf55 can you please rebase and remove the merge commit.

Done.

[peterbarker]

Merged, thanks

[rmackay9]

This is included in Copter-4.5.7-beta1 as part of PR #27919