core: start-blueos-core: Allow MAV_SYSTEM_ID configuration via env vars

[joaoantoniocardoso]

This should allow us to set MAV_SYSTEM_ID via env var in /root/.config/blueos/bootstrap/startup.json.

Helps #3591

How to test

To test it:

1. Change SYSID_THISMAV parameter to 2
2. Add the following to your /root/.config/blueos/bootstrap/startup.json:

"environment": [
  "MAV_SYSTEM_ID=2"
]

Then, open MAVLink-Server UI (http://blueos-avahi.local:8080) and check the SYS ID:

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

This PR enhances the start-blueos-core bootstrap script to read an optional MAV_SYSTEM_ID from the environment and inject it into the startup JSON configuration during initialization.

File-Level Changes

Change	Details	Files
Enable MAV_SYSTEM_ID override via environment variable	Check for MAV_SYSTEM_ID in the shell environment Inject or replace the MAV_SYSTEM_ID field in the startup JSON Fallback to existing value when MAV_SYSTEM_ID is unset	core/start-blueos-core

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[sourcery-ai]

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[rmackay9]

Hi @joaoantoniocardoso,

Thanks very much for this! Does this mean that users will need to manually modify the "/root/.config/blueos/bootstrap/startup.json" file if they've modified the autopilot's MAV_SYSID parameter? Ideally this manual file change wouldn't be necessary because we know that BlueOS can see the autopilot's system id at least once the autopilot has started.

Of course, having anyway to resolve this problem, even if it's a manual file update is still a step forward so my comment above is not meant to be a blocker, just a question

[joaoantoniocardoso]

Hi @joaoantoniocardoso,

Thanks very much for this! Does this mean that users will need to manually modify the "/root/.config/blueos/bootstrap/startup.json" file if they've modified the autopilot's MAV_SYSID parameter? Ideally this manual file change wouldn't be necessary because we know that BlueOS can see the autopilot's system id at least once the autopilot has started.

Of course, having anyway to resolve this problem, even if it's a manual file update is still a step forward so my comment above is not meant to be a blocker, just a question

Unfortunately, yes.

The other approach I can think of is to make mavlink2rest, mavlink-server, and optionally extensions, dynamically learn the system id.

We could still use the environment variable to pass to extensions, in which case the kraken would have to learn it to inject it to each extension.

[rmackay9]

Hi @joaoantoniocardoso so I should add something like this at the bottom of the file?

[joaoantoniocardoso]

Hi @joaoantoniocardoso so I should add something like this at the bottom of the file?

As you can imagine, that change could be made into an API, called from the UI.

[rmackay9]

@joaoantoniocardoso,

So I tried to test this but I wasn't able to see a difference. I made the above shown change to the, "/root/.config/blueos/bootstrap/startup.json" file but I'm unsure how I can pull in the change from this PR to the BlueOS running on my RPI. I tried using the "BlueOS Version" screen in BlueOS but couldn't figure out what the "Remove repository" should be. I also looked around for the "/core/start-blueos-core" file but I couldn't find it. Please excuse my ignorace on this