gtsocial-umbx

tracer.go (5098B)

---

 // Copyright The OpenTelemetry Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 package trace // import "go.opentelemetry.io/otel/sdk/trace"
 
 import (
 	"context"
 	"time"
 
 	"go.opentelemetry.io/otel/sdk/instrumentation"
 	"go.opentelemetry.io/otel/trace"
 )
 
 type tracer struct {
 	provider             *TracerProvider
 	instrumentationScope instrumentation.Scope
 }
 
 var _ trace.Tracer = &tracer{}
 
 // Start starts a Span and returns it along with a context containing it.
 //
 // The Span is created with the provided name and as a child of any existing
 // span context found in the passed context. The created Span will be
 // configured appropriately by any SpanOption passed.
 func (tr *tracer) Start(ctx context.Context, name string, options ...trace.SpanStartOption) (context.Context, trace.Span) {
 	config := trace.NewSpanStartConfig(options...)
 
 	if ctx == nil {
 		// Prevent trace.ContextWithSpan from panicking.
 		ctx = context.Background()
 	}
 
 	// For local spans created by this SDK, track child span count.
 	if p := trace.SpanFromContext(ctx); p != nil {
 		if sdkSpan, ok := p.(*recordingSpan); ok {
 			sdkSpan.addChild()
 		}
 	}
 
 	s := tr.newSpan(ctx, name, &config)
 	if rw, ok := s.(ReadWriteSpan); ok && s.IsRecording() {
 		sps := tr.provider.getSpanProcessors()
 		for _, sp := range sps {
 			sp.sp.OnStart(ctx, rw)
 		}
 	}
 	if rtt, ok := s.(runtimeTracer); ok {
 		ctx = rtt.runtimeTrace(ctx)
 	}
 
 	return trace.ContextWithSpan(ctx, s), s
 }
 
 type runtimeTracer interface {
 	// runtimeTrace starts a "runtime/trace".Task for the span and
 	// returns a context containing the task.
 	runtimeTrace(ctx context.Context) context.Context
 }
 
 // newSpan returns a new configured span.
 func (tr *tracer) newSpan(ctx context.Context, name string, config *trace.SpanConfig) trace.Span {
 	// If told explicitly to make this a new root use a zero value SpanContext
 	// as a parent which contains an invalid trace ID and is not remote.
 	var psc trace.SpanContext
 	if config.NewRoot() {
 		ctx = trace.ContextWithSpanContext(ctx, psc)
 	} else {
 		psc = trace.SpanContextFromContext(ctx)
 	}
 
 	// If there is a valid parent trace ID, use it to ensure the continuity of
 	// the trace. Always generate a new span ID so other components can rely
 	// on a unique span ID, even if the Span is non-recording.
 	var tid trace.TraceID
 	var sid trace.SpanID
 	if !psc.TraceID().IsValid() {
 		tid, sid = tr.provider.idGenerator.NewIDs(ctx)
 	} else {
 		tid = psc.TraceID()
 		sid = tr.provider.idGenerator.NewSpanID(ctx, tid)
 	}
 
 	samplingResult := tr.provider.sampler.ShouldSample(SamplingParameters{
 		ParentContext: ctx,
 		TraceID:       tid,
 		Name:          name,
 		Kind:          config.SpanKind(),
 		Attributes:    config.Attributes(),
 		Links:         config.Links(),
 	})
 
 	scc := trace.SpanContextConfig{
 		TraceID:    tid,
 		SpanID:     sid,
 		TraceState: samplingResult.Tracestate,
 	}
 	if isSampled(samplingResult) {
 		scc.TraceFlags = psc.TraceFlags() | trace.FlagsSampled
 	} else {
 		scc.TraceFlags = psc.TraceFlags() &^ trace.FlagsSampled
 	}
 	sc := trace.NewSpanContext(scc)
 
 	if !isRecording(samplingResult) {
 		return tr.newNonRecordingSpan(sc)
 	}
 	return tr.newRecordingSpan(psc, sc, name, samplingResult, config)
 }
 
 // newRecordingSpan returns a new configured recordingSpan.
 func (tr *tracer) newRecordingSpan(psc, sc trace.SpanContext, name string, sr SamplingResult, config *trace.SpanConfig) *recordingSpan {
 	startTime := config.Timestamp()
 	if startTime.IsZero() {
 		startTime = time.Now()
 	}
 
 	s := &recordingSpan{
 		// Do not pre-allocate the attributes slice here! Doing so will
 		// allocate memory that is likely never going to be used, or if used,
 		// will be over-sized. The default Go compiler has been tested to
 		// dynamically allocate needed space very well. Benchmarking has shown
 		// it to be more performant than what we can predetermine here,
 		// especially for the common use case of few to no added
 		// attributes.
 
 		parent:      psc,
 		spanContext: sc,
 		spanKind:    trace.ValidateSpanKind(config.SpanKind()),
 		name:        name,
 		startTime:   startTime,
 		events:      newEvictedQueue(tr.provider.spanLimits.EventCountLimit),
 		links:       newEvictedQueue(tr.provider.spanLimits.LinkCountLimit),
 		tracer:      tr,
 	}
 
 	for _, l := range config.Links() {
 		s.addLink(l)
 	}
 
 	s.SetAttributes(sr.Attributes...)
 	s.SetAttributes(config.Attributes()...)
 
 	return s
 }
 
 // newNonRecordingSpan returns a new configured nonRecordingSpan.
 func (tr *tracer) newNonRecordingSpan(sc trace.SpanContext) nonRecordingSpan {
 	return nonRecordingSpan{tracer: tr, sc: sc}
 }