hold onto otel tracer, fixed tracer name

lisp/x/profiler/opentelemetry_annotator.go

@@ -11,17 +11,13 @@ import (
 	"go.opentelemetry.io/otel/trace"
 )
 
-const (
-	// ContextOpenTelemetryTracerKey looks up a parent tracer name from a context key.
-	ContextOpenTelemetryTracerKey = "otelParentTracer"
-)
-
 var _ lisp.Profiler = &otelAnnotator{}
 
 type otelAnnotator struct {
 	profiler
 	currentContext context.Context
 	currentSpan    trace.Span
+	tracer         trace.Tracer
 }
 
 func NewOpenTelemetryAnnotator(runtime *lisp.Runtime, parentContext context.Context, opts ...Option) *otelAnnotator {
@@ -30,6 +26,7 @@ func NewOpenTelemetryAnnotator(runtime *lisp.Runtime, parentContext context.Cont
 			runtime: runtime,
 		},
 		currentContext: parentContext,
+		tracer:         otel.GetTracerProvider().Tracer("elps"),
 	}
 	p.profiler.applyConfigs(opts...)
 	return p
@@ -50,21 +47,13 @@ func (p *otelAnnotator) Complete() error {
 	return nil
 }
 
-func contextTracer(ctx context.Context) trace.Tracer {
-	tracerName, ok := ctx.Value(ContextOpenTelemetryTracerKey).(string)
-	if !ok {
-		tracerName = "elps"
-	}
-	return otel.GetTracerProvider().Tracer(tracerName)
-}
-
 func (p *otelAnnotator) Start(fun *lisp.LVal) func() {
 	if p.skipTrace(fun) {
 		return func() {}
 	}
 	oldContext := p.currentContext
 	prettyLabel, funName := p.prettyFunName(fun)
-	p.currentContext, p.currentSpan = contextTracer(p.currentContext).Start(p.currentContext, prettyLabel)
+	p.currentContext, p.currentSpan = p.tracer.Start(p.currentContext, prettyLabel)
 	p.addCodeAttributes(fun, funName)
 	return func() {
 		p.currentSpan.End()