perf: Rest client allocs improvements (#2381)

* perf: Rest client allocs improvements

cmd/tools/rest/client.go

@@ -158,9 +158,9 @@ func (c *Client) invokeWithAuthRetry() ([]byte, error) {
 
 	doInvoke := func() ([]byte, error) {
 		var (
-			response *http.Response
-			body     []byte
-			err      error
+			response  *http.Response
+			innerBody []byte
+			innerErr  error
 		)
 
 		if c.request.Body != nil {
@@ -174,23 +174,23 @@ func (c *Client) invokeWithAuthRetry() ([]byte, error) {
 		restReq := c.request.URL.String()
 
 		// send request to server
-		if response, err = c.client.Do(c.request); err != nil {
-			return nil, fmt.Errorf("connection error %w", err)
+		if response, innerErr = c.client.Do(c.request); innerErr != nil {
+			return nil, fmt.Errorf("connection error %w", innerErr)
 		}
 		//goland:noinspection GoUnhandledErrorResult
 		defer response.Body.Close()
+		innerBody, innerErr = io.ReadAll(response.Body)
+		if innerErr != nil {
+			return nil, errs.Rest(response.StatusCode, innerErr.Error(), 0, "")
+		}
 
 		if response.StatusCode != http.StatusOK {
-			body2, err2 := io.ReadAll(response.Body)
-			if err2 != nil {
-				return nil, errs.Rest(response.StatusCode, err2.Error(), 0, "")
-			}
 
 			if response.StatusCode == http.StatusUnauthorized {
 				return nil, errs.New(errs.ErrAuthFailed, response.Status)
 			}
 
-			result := gjson.GetBytes(body2, "error")
+			result := gjson.GetBytes(innerBody, "error")
 
 			if response.StatusCode == http.StatusForbidden {
 				message := result.Get(Message).String()
@@ -206,16 +206,9 @@ func (c *Client) invokeWithAuthRetry() ([]byte, error) {
 			return nil, errs.Rest(response.StatusCode, "", 0, "")
 		}
 
-		// read response body
-		if body, err = io.ReadAll(response.Body); err != nil {
-			return nil, err
-		}
-		defer c.printRequestAndResponse(restReq, body)
+		defer c.printRequestAndResponse(restReq, innerBody)
 
-		if err != nil {
-			return nil, err
-		}
-		return body, nil
+		return innerBody, nil
 	}
 
 	body, err = doInvoke()

pkg/matrix/matrix.go

@@ -78,7 +78,6 @@ func (m *Matrix) Clone(with With) *Matrix {
 	clone.globalLabels = m.globalLabels
 	clone.exportOptions = m.exportOptions
 	clone.exportable = m.exportable
-	clone.displayMetrics = make(map[string]string)
 
 	if with.Instances {
 		clone.instances = make(map[string]*Instance, len(m.GetInstances()))
@@ -95,6 +94,7 @@ func (m *Matrix) Clone(with With) *Matrix {
 
 	if with.Metrics {
 		clone.metrics = make(map[string]*Metric, len(m.GetMetrics()))
+		clone.displayMetrics = make(map[string]string)
 		for key, metric := range m.GetMetrics() {
 			c := metric.Clone(with.Data)
 			clone.metrics[key] = c