Add request-id to different logs - best practice with context

[magvonim (magvonim lahim)]

I have a REST API written with gorilla/mux v1.7.3 in go1.13.
I’m the only one in the team “proficient” in Golang, so I really wanted someone to tell me what I’m about to do is fine, and is good/bad practice.

I have plenty of logs - requests, stdout, errors and dependencies (mongo, db, etc).
I want to stick the request-id to each one of them.

After some digging and researching - from what I understood the best practice is to do so with the context library.

So basically using a middleware to store the request-id in the context:

	id := uuid.New().String()
	ctx := goContext.WithValue(r.Context(), "request-id", id)
	r = r.WithContext(ctx)
	w.Header().Set("request-id", id)
	next.ServeHTTP(w, r)
	return

So in order to use this “request-id”, I really need to pass the context request- r.Context() to every function call?
This seems very hard to grasp.
So at the start of every request, declaring ctx := r.Context() and passing it around to all other methods.

From what I understood, this is good practice and I should do that. So following this step, now I need to extract the request-id from the context. So for example, a (very simplified) log would be:

func RequestInfo(ctx context.Context, msg string) {
	fmt.Println(fmt.Sprintf("%v", ctx.Value("request-id")), msg)
}

Is this fine? Basically I’ll be using ctx.Value(..) quite a lot. From what I see this shouldn’t cause performance issues since it doesn’t lock anything when extracting the value.