forked from lightstep/lightstep-tracer-go
/
propagation_ot.go
94 lines (85 loc) · 2.24 KB
/
propagation_ot.go
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package lightstep
import (
"strconv"
"strings"
opentracing "github.com/opentracing/opentracing-go"
)
const (
prefixTracerState = "ot-tracer-"
prefixBaggage = "ot-baggage-"
tracerStateFieldCount = 3
fieldNameTraceID = prefixTracerState + "traceid"
fieldNameSpanID = prefixTracerState + "spanid"
fieldNameSampled = prefixTracerState + "sampled"
)
type textMapPropagator struct{}
func (_ *textMapPropagator) Inject(
spanContext opentracing.SpanContext,
opaqueCarrier interface{},
) error {
sc, ok := spanContext.(SpanContext)
if !ok {
return opentracing.ErrInvalidSpanContext
}
carrier, ok := opaqueCarrier.(opentracing.TextMapWriter)
if !ok {
return opentracing.ErrInvalidCarrier
}
carrier.Set(fieldNameTraceID, strconv.FormatUint(sc.TraceID, 16))
carrier.Set(fieldNameSpanID, strconv.FormatUint(sc.SpanID, 16))
carrier.Set(fieldNameSampled, "true")
for k, v := range sc.Baggage {
carrier.Set(prefixBaggage+k, v)
}
return nil
}
func (_ *textMapPropagator) Extract(
opaqueCarrier interface{},
) (opentracing.SpanContext, error) {
carrier, ok := opaqueCarrier.(opentracing.TextMapReader)
if !ok {
return nil, opentracing.ErrInvalidCarrier
}
requiredFieldCount := 0
var traceID, spanID uint64
var err error
decodedBaggage := map[string]string{}
err = carrier.ForeachKey(func(k, v string) error {
switch strings.ToLower(k) {
case fieldNameTraceID:
traceID, err = strconv.ParseUint(v, 16, 64)
if err != nil {
return opentracing.ErrSpanContextCorrupted
}
requiredFieldCount++
case fieldNameSpanID:
spanID, err = strconv.ParseUint(v, 16, 64)
if err != nil {
return opentracing.ErrSpanContextCorrupted
}
requiredFieldCount++
case fieldNameSampled:
requiredFieldCount++
default:
lowercaseK := strings.ToLower(k)
if strings.HasPrefix(lowercaseK, prefixBaggage) {
decodedBaggage[strings.TrimPrefix(lowercaseK, prefixBaggage)] = v
}
}
return nil
})
if err != nil {
return nil, err
}
if requiredFieldCount < tracerStateFieldCount {
if requiredFieldCount == 0 {
return nil, opentracing.ErrSpanContextNotFound
}
return nil, opentracing.ErrSpanContextCorrupted
}
return SpanContext{
TraceID: traceID,
SpanID: spanID,
Baggage: decodedBaggage,
}, nil
}