fix: do not leak the response body on Client.Do() (#348)

CHANGELOG.md

@@ -61,6 +61,13 @@
 
 - Fix: handle empty array as nil when filling record defaults
   [#345](https://github.com/Kong/go-kong/pull/345)
+- Fix leaking response body from `Client.Do()`. From now on `kong.Response` does
+  not contain the `http.Response` field which was in fact leaking the implementation
+  detail. It now contains the response headers, status and status code.
+  If users want to get the response body they can still provide the `v` parameter
+  to `Do()` to get the body unmarshalled into it (or copied into it if an `io.Writer`
+  was to be provided).
+  [#348](https://github.com/Kong/go-kong/pull/348)
 
 ## [v0.43.0]
 

kong/client.go

@@ -240,44 +240,54 @@ func (c *Client) DoRAW(ctx context.Context, req *http.Request) (*http.Response,
 	return resp, err
 }
 
-// Do executes an HTTP request and returns a kong.Response
-func (c *Client) Do(ctx context.Context, req *http.Request,
+// Do executes an HTTP request and returns a Response.
+//
+// The caller can optionally provide v parameter, which when provided will contain
+// the response body. Do supports wither an io.Writer (which will contain the
+// response body verbatim) or anything else which the body should be unmarshalled
+// into.
+func (c *Client) Do(
+	ctx context.Context,
+	req *http.Request,
 	v interface{},
 ) (*Response, error) {
-	// TODO https://github.com/Kong/go-kong/issues/273 clear this lint ignore
-	resp, err := c.DoRAW(ctx, req) //nolint:bodyclose
+	resp, err := c.DoRAW(ctx, req)
 	if err != nil {
 		return nil, err
 	}
+	defer resp.Body.Close()
 
-	// log the response
-	err = c.logResponse(resp)
-	if err != nil {
+	if err = c.logResponse(resp); err != nil {
 		return nil, err
 	}
 
 	response := newResponse(resp)
 
-	// check for API errors
+	// Check for API errors.
+	// If an error status code was returned, then parse the body and create
+	// an API Error out of it.
 	if err = hasError(resp); err != nil {
 		return response, err
 	}
 
-	// response
 	if v != nil {
-		if writer, ok := v.(io.Writer); ok {
-			_, err = io.Copy(writer, resp.Body)
+		switch v := v.(type) {
+		case io.Writer:
+			_, err = io.Copy(v, resp.Body)
 			if err != nil {
-				return nil, err
+				return nil, fmt.Errorf("failed copying response body: %w", err)
 			}
-		} else {
+			return response, nil
+		default:
 			err = json.NewDecoder(resp.Body).Decode(v)
 			if err != nil {
-				return nil, err
+				return nil, fmt.Errorf("failed decoding response body: %w", err)
 			}
+			return response, nil
 		}
 	}
-	return response, err
+
+	return response, nil
 }
 
 // ErrorOrResponseError helps to handle the case where

kong/response.go

@@ -9,14 +9,20 @@ import (
 	"time"
 )
 
-// Response is a Kong Admin API response. It wraps http.Response.
+// Response is a Kong Admin API response.
+// It contains the response headers, status and status code.
 type Response struct {
-	*http.Response
-	// other Kong specific fields
+	Header     http.Header
+	Status     string
+	StatusCode int
 }
 
 func newResponse(res *http.Response) *Response {
-	return &Response{Response: res}
+	return &Response{
+		Header:     res.Header,
+		Status:     res.Status,
+		StatusCode: res.StatusCode,
+	}
 }
 
 func messageFromBody(b []byte) string {