Suggestion: Inject the remote's IP address into the script code

[fmauch]

Currently, we use the configured remote's IP address only for accessing the script_sender port. Our protocol specification from the client library requires two additional ports, the reverse port and the trajectory port.

The IP address of those get injected into the script code sent from the remote side, where it either gets automatically deduced from the interface that connects to the RTDE port if no particular address is passed in (see this line).

This complicates setup a bit, as users have to specify their remote PC's address twice. Once in the URCap installation and once when starting the client application. An example using the docker simulation:

docker run --rm -it -p 5900:5900 -p 6080:6080 -p 29999:29999 -p 30001:30001 -p 30004:30004 -p 30002:30002 universalrobots/ursim_e-series

This will bind the interfaces from URSim to localhost and therefore the default reverse IP used in the client library is 127.0.0.1. However, from inside the docker container this will not correspond to the host machine. For the reverse interface we want to connect to <host_ip>:50001 by default.

With saving the Installation remote's IP into the script code we can reuse that inside the actual script code instead of replacing it with the host ip on the remote side.

I'm not feeling completely happy with this, as this introduces a syntax dependency between the URCap and the client library, but it would definitely reduce the user's setup requirements.

Related issues from the drivers:

• Moveit with ursim Universal_Robots_ROS2_Driver#254
• Allow to set the reverse_ip manually, useful to run in a container Universal_Robots_ROS_Driver#268