Rework servers load-balancer to use the WRR

Co-authored-by: Kevin Pollet <pollet.kevin@gmail.com>

pkg/middlewares/capture/capture.go

@@ -62,13 +62,13 @@ func FromContext(ctx context.Context) (Capture, error) {
 // Capture is the object populated by the capture middleware,
 // holding probes that allow to gather information about the request and response.
 type Capture struct {
-	rr *readCounter
-	rw responseWriter
+	rr  *readCounter
+	crw *captureResponseWriter
 }
 
 // NeedsReset returns whether the given http.ResponseWriter is the capture's probe.
 func (c *Capture) NeedsReset(rw http.ResponseWriter) bool {
-	return c.rw != rw
+	return c.crw.rw != rw
 }
 
 // Reset returns a new handler that renews the Capture's probes, and inserts
@@ -83,18 +83,18 @@ func (c *Capture) Reset(next http.Handler) http.Handler {
 			c.rr = readCounter
 			newReq.Body = readCounter
 		}
-		c.rw = newResponseWriter(rw)
+		c.crw = &captureResponseWriter{rw: rw}
 
-		next.ServeHTTP(c.rw, newReq)
+		next.ServeHTTP(c.crw, newReq)
 	})
 }
 
 func (c *Capture) ResponseSize() int64 {
-	return c.rw.Size()
+	return c.crw.Size()
 }
 
 func (c *Capture) StatusCode() int {
-	return c.rw.Status()
+	return c.crw.Status()
 }
 
 // RequestSize returns the size of the request's body if it applies,
@@ -123,22 +123,7 @@ func (r *readCounter) Close() error {
 	return r.source.Close()
 }
 
-var _ middlewares.Stateful = &responseWriterWithCloseNotify{}
-
-type responseWriter interface {
-	http.ResponseWriter
-	Size() int64
-	Status() int
-}
-
-func newResponseWriter(rw http.ResponseWriter) responseWriter {
-	capt := &captureResponseWriter{rw: rw}
-	if _, ok := rw.(http.CloseNotifier); !ok {
-		return capt
-	}
-
-	return &responseWriterWithCloseNotify{capt}
-}
+var _ middlewares.Stateful = &captureResponseWriter{}
 
 // captureResponseWriter is a wrapper of type http.ResponseWriter
 // that tracks response status and size.
@@ -189,13 +174,3 @@ func (crw *captureResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error)
 
 	return nil, nil, fmt.Errorf("not a hijacker: %T", crw.rw)
 }
-
-type responseWriterWithCloseNotify struct {
-	*captureResponseWriter
-}
-
-// CloseNotify returns a channel that receives at most a
-// single value (true) when the client connection has gone away.
-func (r *responseWriterWithCloseNotify) CloseNotify() <-chan bool {
-	return r.rw.(http.CloseNotifier).CloseNotify()
-}