make grpc proxy streaming work

proxy/mucp/mucp.go

@@ -398,7 +398,7 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 
 		// set address if available via routes or specific endpoint
 		if len(routes) > 0 {
-			addresses := toNodes(routes)
+			addresses = toNodes(routes)
 			opts = append(opts, client.WithAddress(addresses...))
 		}
 
@@ -489,6 +489,25 @@ func (p *Proxy) serveRequest(ctx context.Context, link client.Client, service, e
 	}
 	defer stream.Close()
 
+	// if we receive a grpc stream we have to refire the initial request
+	if c, ok := req.Codec().(codec.Codec); ok && c.String() == "grpc" {
+		// get the header from client
+		hdr := req.Header()
+		msg := &codec.Message{
+			Type:   codec.Request,
+			Header: hdr,
+			Body:   body,
+		}
+
+		// write the raw request
+		err = stream.Request().Codec().Write(msg, nil)
+		if err == io.EOF {
+			return nil
+		} else if err != nil {
+			return err
+		}
+	}
+
 	// create client request read loop if streaming
 	go readLoop(req, stream)