can I trace sub called function with OpenCensus?

Question

I want to trace the whole project with Opencensus and Jaeger. I added HTTP trace in entry services and add stratspan in middleware surrounded whol my services and this two-span called and show on Jaeger. My problem is each service contain a lot of function and I want see a trace of all my functions but in this way not show overall service not shown each function. I don't like add per function add one stratspan. I use ctx context.Context entry all my function but not different!

Answer 1

There's really not many options for other than starting a span in each function you'd like to instrument:

func something(ctx context.Context) {
  ctx, span := trace.StartSpan(ctx, "something")
  defer span.End()
}

If your functions have a common call signature, or you can coalesce your function into a common call signature, you can write a wrapper. Examples of this can be seen in http "middleware".

Consider the http.Handler, you could write a decorator for your functions that handles the span lifecycle:

func WithTraced(handler http.Handler, opName string) http.Handler {
    return func(w http.ResponseWriter, r *http.Request) {
        ctx, span := trace.StartSpan(ctx, opName)
        defer span.End()
        handler.ServeHTTP(w, r.WithContext(ctx))

    }

}

A similar pattern could be applied by embedding structs.