How to observe a dead loop.

[tttoad]

Problem Statement

func main(){
        // ....
	ctx, span := tracer.Start(
		ctx,
		"CollectorExporter-Example",
		trace.WithAttributes(commonAttrs...))
	defer span.End()
	for i := 0; i < 10; i++ {
		Work(ctx)
	}

	log.Printf("Done!")
}
func Work(ctx context.Context) {
	ctx, span := otel.Tracer("test-tracer").Start(ctx, "work")
	defer span.End()
	for i := 1; i < 10; i++ {
		// do something
		Work2(ctx)
	}
}

func Work2(ctx context.Context) {
	_, span := otel.Tracer("test-tracer").Start(ctx, "work2")
	defer span.End()
	for i := 1; i > 0; i++ {
		// do something
	}
}

If there's a bug in my code, it's a dead loop.
In this case the trace cannot find out where the program is looping.
Should a span timeout be added?
like Start(ctx,"name",Timeout(time.Minute )).

[MrAlias]

	for i := 1; i > 0; i++ {
		// do something
	}

What is "do something"? If it does not include return or break this loop will never terminate.

Without the function returning you will never have your defered function run.

If you want to see the progress of an unterminated loop you need to create and end a span each iteration of the loop.

[tttoad]

I mean how do I find out when my code never terminates?
Maybe add a timeout to automatically call the span.end() method when the Work2 function times out.

[dmathieu]

Add a timeout to the loop itself, so it can't never terminate ?

[tttoad]

Add a timeout to the loop itself, so it can't never terminate ?

Loop is just one possibility.Maybe it's a deadlock...
I'm not sure this is an issue that should be discovered by traces.
I had this problem, so I asked...
Other services send requests, but I don't see any span for my service...

[dmathieu]

If you have infinite and unchecked loops or deadlocks, you'll end up with CPU/memory being used for nothing, and a leak. That should be tracked and fixed in your code, I'm not sure traces should be handling it.

Profiling could be something that helps you there.

[tttoad]

I can't pinpoint the problem fast enough for the loop that won't terminate. ( Maybe the function is not being called, or not requested)
The problem was found to be more complex through Profiling.

timeout don't seem to be good.
In many cases, it is impossible to predict how long a function will run...