micro/tracer/context.go

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// Package tracer provides an interface for distributed tracing
package tracer
import (
"context"
"github.com/unistack-org/micro/v3/metadata"
)
const (
traceIDKey = "Micro-Trace-Id"
spanIDKey = "Micro-Span-Id"
)
// FromContext returns a span from context
func FromContext(ctx context.Context) (traceID string, parentSpanID string, isFound bool) {
md, ok := metadata.FromIncomingContext(ctx)
if !ok {
return "", "", false
}
traceID, traceOk := md.Get(traceIDKey)
microID, microOk := md.Get("Micro-Id")
if !traceOk && !microOk {
isFound = false
return
}
if !traceOk {
traceID = microID
}
parentSpanID, ok = md.Get(spanIDKey)
return traceID, parentSpanID, ok
}
// NewContext saves the trace and span ids in the context
func NewContext(ctx context.Context, traceID, parentSpanID string) context.Context {
md, ok := metadata.FromContext(ctx)
if !ok {
md = metadata.New(2)
}
md.Set(traceIDKey, traceID)
md.Set(spanIDKey, parentSpanID)
return metadata.NewContext(ctx, md)
}