/
context.go
56 lines (50 loc) · 1.97 KB
/
context.go
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// Unless explicitly stated otherwise all files in this repository are licensed
// under the Apache License Version 2.0.
// This product includes software developed at Datadog (https://www.datadoghq.com/).
// Copyright 2016 Datadog, Inc.
package tracer
import (
"context"
"github.com/DataDog/dd-trace-go/v2/internal"
"github.com/DataDog/dd-trace-go/v2/internal/contrib/options"
)
// ContextWithSpan returns a copy of the given context which includes the span s.
func ContextWithSpan(ctx context.Context, s *Span) context.Context {
if ctx == nil {
ctx = context.Background()
}
return context.WithValue(ctx, internal.ActiveSpanKey, s)
}
// SpanFromContext returns the span contained in the given context. A second return
// value indicates if a span was found in the context. If no span is found, a no-op
// span is returned.
func SpanFromContext(ctx context.Context) (*Span, bool) {
if ctx == nil {
return nil, false
}
v := ctx.Value(internal.ActiveSpanKey)
if s, ok := v.(*Span); ok {
return s, true
}
return nil, false
}
// StartSpanFromContext returns a new span with the given operation name and options. If a span
// is found in the context, it will be used as the parent of the resulting span. If the ChildOf
// option is passed, it will only be used as the parent if there is no span found in `ctx`.
func StartSpanFromContext(ctx context.Context, operationName string, opts ...StartSpanOption) (*Span, context.Context) {
// copy opts in case the caller reuses the slice in parallel
// we will add at least 1, at most 2 items
optsLocal := options.Expand(opts, 0, 2)
if ctx == nil {
// default to context.Background() to avoid panics on Go >= 1.15
ctx = context.Background()
} else if s, ok := SpanFromContext(ctx); ok {
optsLocal = append(optsLocal, ChildOf(s.Context()))
}
optsLocal = append(optsLocal, withContext(ctx))
s := StartSpan(operationName, optsLocal...)
if s != nil && s.pprofCtxActive != nil {
ctx = s.pprofCtxActive
}
return s, ContextWithSpan(ctx, s)
}