Should RequestID middleware also set x-Request-Id to response header?

[devbyP]

First of all, sorry for a noob question. From what I understand, the x-request-id header is use to correlate request with server log.
Now the RequestID middleware already use the x-request-id header from client if one is sent, so I assume the RequestID here is the same as x-request-id.

My problem is when the client is not send the header to the server,
the server generate one id but the client has no info on the newly generated id, how will I know which request is correlate to which log?

Now what I usually like do is I make another middleware to handle the header setting and use it after the RequestID middleware.
It make more sense to do it this way or, would it be better if the RequestID middleware do this?

Or maybe I completely misunderstand the purpose of this middleware?

[adilburaksen]

Your understanding is correct — and your instinct to add it as a separate middleware is the right approach.

The built-in RequestID middleware only sets the ID on the request context (accessible via middleware.GetReqID(r.Context())). It doesn't echo it back in the response header. This is intentional: the middleware just establishes the ID; what you do with it is your decision.

Adding it to the response is a one-liner you can stack right after RequestID:

r.Use(middleware.RequestID)
r.Use(func(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if reqID := middleware.GetReqID(r.Context()); reqID != "" {
            w.Header().Set("X-Request-Id", reqID)
        }
        next.ServeHTTP(w, r)
    })
})

This way:

• If the client sent X-Request-Id, RequestID reuses it and your middleware echoes it back.
• If the client didn't send it, RequestID generates a new one and your middleware ensures the client receives it in the response.

The client can then log/store the response X-Request-Id for any support or debugging correlation with your server logs. This pattern is standard in observability setups.