core: MAVLink SYSID should match vehicle

[rmackay9]

Current behaviour

If the user changes the mavlink system id from the default, the BlueOS processes that publish to mavlink should use that same system id. I suspect the easiest way to do this is to have a user setting somewhere. Please note that extensions also need access to this system id somehow unless we want to force extension developers to always have a local setting.

Below is a screen shot of BlueOS 1.5.0-beta15 connected to a vehicle with SysID = 2

Expected or desired behaviour

BlueOS (and its extensions) should use the same system id as the vehicle

Prerequisites

• I have checked to make sure that a similar request has not already been filed or fixed.

[joaoantoniocardoso]

• 191 is mavlink-server, (hopefully) covered by this PR
  
• 194 is BlueOS backend services communicating via mavlink2rest (see MavlinkComm.py), or other services using mavlink2rest (see start-blueos-core). Both cases already use the env MAV_SYSTEM_ID, which makes me think we might not be passing this env forward.

[rmackay9]

@joaoantoniocardoso,

Thanks very much for this!

I've also noticed that @Williangalvani's NTRIP extension is using the 255 systemid (see Williangalvani/BlueOS-Ntrip-extension#3) but I will look into that further as well. Txs!

[rmackay9]

@joaoantoniocardoso,

BTW, I tried to change @Williangalvani's NTRIP extension to use the environment variables but as you've noticed, they don't seem to be being propagated to the Extensions (at least not this one). I printed out the full list of environment variables and it was only this

   GPG_KEY=A035C8C19219BA821ECEA86B64E628F8D684696D
   HOME=/root
   HOSTNAME=006a42bd1c15
   LANG=C.UTF-8
   PATH=/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
   PYTHON_SHA256=8d3ed8ec5c88c1c95f5e558612a725450d2452813ddad5e58fdb1a53b1209b78
   PYTHON_VERSION=3.11.14

[joaoantoniocardoso]

Yes, check it here: #3449

[joaoantoniocardoso]

@rmackay9, this PR adds a way of changing the MAV_SYSTEM_ID, which may be the last change to close this issue.