How to pass a opentracing.Span with the context through a gRPC call with go-micro

[djedjethai]

Hi,

How to pass an opentracing.Span id between two services(2 handlers) using a gRPC call, see:

// before sending
ct := opentracing.ContextWithSpan(ctx, sp)
fmt.Println(ct)
// you see the span-id is inside the context
.WithValue(type opentracing.contextKey, val 0de0a6cf7b8c66d1:0de0a6cf7b8c66d1:0000000000000000:1)

But then on the receiver handler

func (s *handler) Get(ctx context.Context, req *pb.GetRequest, res *pb.GetResponse) error {
sp = opentracing.SpanFromContext(ctx)
fmt.Println("with span: ", sp)
}
with span:  {}
// and even I println the ctx, the span-id is gone

The span identifier is gone... ?? How can I pass it ?

[Davincible]

Contexts are Go instances and cannot simply be send over a grpc call. You'd have to send the span separately from the context

[djedjethai]

Thanks for the Information @Davincible, I finally tried to add them to the body and it works.