account for streaming

proxy/internal/accesslog/middleware.go

@@ -32,6 +32,14 @@ func (l *Logger) Middleware(next http.Handler) http.Handler {
 			status:            http.StatusOK,
 		}
 
+		var bytesRead int64
+		if r.Body != nil {
+			r.Body = &bodyCounter{
+				ReadCloser: r.Body,
+				bytesRead:  &bytesRead,
+			}
+		}
+
 		// Resolve the source IP using trusted proxy configuration before passing
 		// the request on, as the proxy will modify forwarding headers.
 		sourceIp := extractSourceIP(r, l.trustedProxies)
@@ -53,10 +61,7 @@ func (l *Logger) Middleware(next http.Handler) http.Handler {
 			host = r.Host
 		}
 
-		bytesUpload := r.ContentLength
+		bytesUpload := bytesRead
-		if bytesUpload < 0 {
-			bytesUpload = 0
-		}
 		bytesDownload := sw.bytesWritten
 
 		entry := logEntry{

proxy/internal/accesslog/statuswriter.go

@@ -1,6 +1,8 @@
 package accesslog
 
 import (
+	"io"
+
 	"github.com/netbirdio/netbird/proxy/internal/responsewriter"
 )
 
@@ -23,3 +25,15 @@ func (w *statusWriter) Write(b []byte) (int, error) {
 	w.bytesWritten += int64(n)
 	return n, err
 }
+
+// bodyCounter wraps an io.ReadCloser and counts bytes read from the request body.
+type bodyCounter struct {
+	io.ReadCloser
+	bytesRead *int64
+}
+
+func (bc *bodyCounter) Read(p []byte) (int, error) {
+	n, err := bc.ReadCloser.Read(p)
+	*bc.bytesRead += int64(n)
+	return n, err
+}