Additional levels in DiagnosticStatus

[Timple]

@v4hn

On the other side when writing a driver, who can decide whether a laser scanner that fails to connect is a CRITICAL failure or just an ERROR?
When the scanner is used as an optional hardware add-on for navigation and I can still use the arms for all the manipulation tasks I want, I don’t want my system to report CRITICAL, because it leads to even more error blindness.

This is an important statement you make. If something is CRITICAL (or even ERROR) is not always up to the reporter.
In our system we have the velodyne driver complaining the velodyne is missing with an ERROR, which makes sense from the drive point of view.

But we know that in some states, the lidar is not even powered and thus this is normal behavior at this system state.

That’s why in the past we already proposed a DowngradeAnalyser.

I don’t have a strong opinion about the reported levels proposed here. But keep in mind that overriding these values in some manner might be just as important.