Arc - Make it possible to inspect shutdown reason from ShutdownEvent

[manovotn]

Fixes #16976

A simple way to expand ShutdownEvent so that users can inspect the cause of shutdown and differentiate between standard and non-standard.

@geoand is this at least close to what you meant? :)

[geoand]

That's what I had in mind!

[manovotn]

Also CCing @Ladicek and @mkouba who might have something to add.

[Ladicek]

Makes sense to me, but I'd rather not expose the enum publicly, as it's hard to extend. Really the only thing the user can figure out is a boolean value, so in my opinion, we should expose a single boolean-returning method (called e.g. isStandardShutdown or so). If we later need to expose more detailed information (e.g. which signal triggered that shutdown, or the exit code maybe), that becomes a bit easier in my opinion. WDYT?

[manovotn]

Really the only thing the user can figure out is a boolean value, so in my opinion, we should expose a single boolean-returning method

Yea, we could do that.

(e.g. which signal triggered that shutdown, or the exit code maybe)

From the code I don't think we can do this apart from native mode where we use SignalHandler and even then it is based on env property. Which is probably even more of a reason to just expose the boolean.

I'll adjust the PR in a while

[manovotn]

@Ladicek updated. User can now only get to a boolean value derived from ShutdownReason.

I should also note that I tested these changes with quickstarts as there is no way to add automated test for it.

[Ladicek]

LGTM.

SHUTDOWN_REASON shouldn't really be upper-case, as it's not a constant, but that's just nit-picking :-)

[manovotn]

SHUTDOWN_REASON shouldn't really be upper-case, as it's not a constant, but that's just nit-picking :-)

Damn, can't get that past you even on Friday :-D
Fixed now.