client-go: extract warning headers from API responses

Kubernetes-commit: b1098bd0d53658bfb945e485683d543ab7dc73ba

rest/request.go

@@ -88,6 +88,8 @@ var noBackoff = &NoBackoff{}
 type Request struct {
 	c *RESTClient
 
+	warningHandler WarningHandler
+
 	rateLimiter flowcontrol.RateLimiter
 	backoff     BackoffManager
 	timeout     time.Duration
@@ -135,12 +137,13 @@ func NewRequest(c *RESTClient) *Request {
 	}
 
 	r := &Request{
-		c:           c,
-		rateLimiter: c.rateLimiter,
-		backoff:     backoff,
-		timeout:     timeout,
-		pathPrefix:  pathPrefix,
-		maxRetries:  10,
+		c:              c,
+		rateLimiter:    c.rateLimiter,
+		backoff:        backoff,
+		timeout:        timeout,
+		pathPrefix:     pathPrefix,
+		maxRetries:     10,
+		warningHandler: c.warningHandler,
 	}
 
 	switch {
@@ -218,6 +221,13 @@ func (r *Request) BackOff(manager BackoffManager) *Request {
 	return r
 }
 
+// WarningHandler sets the handler this client uses when warning headers are encountered.
+// If set to nil, this client will use the default warning handler (see SetDefaultWarningHandler).
+func (r *Request) WarningHandler(handler WarningHandler) *Request {
+	r.warningHandler = handler
+	return r
+}
+
 // Throttle receives a rate-limiter and sets or replaces an existing request limiter
 func (r *Request) Throttle(limiter flowcontrol.RateLimiter) *Request {
 	r.rateLimiter = limiter
@@ -692,6 +702,8 @@ func (r *Request) Watch(ctx context.Context) (watch.Interface, error) {
 		return nil, err
 	}
 
+	handleWarnings(resp.Header, r.warningHandler)
+
 	frameReader := framer.NewFrameReader(resp.Body)
 	watchEventDecoder := streaming.NewDecoder(frameReader, streamingSerializer)
 
@@ -764,6 +776,7 @@ func (r *Request) Stream(ctx context.Context) (io.ReadCloser, error) {
 
 	switch {
 	case (resp.StatusCode >= 200) && (resp.StatusCode < 300):
+		handleWarnings(resp.Header, r.warningHandler)
 		return resp.Body, nil
 
 	default:
@@ -1020,6 +1033,7 @@ func (r *Request) transformResponse(resp *http.Response, req *http.Request) Resu
 				body:        body,
 				contentType: contentType,
 				statusCode:  resp.StatusCode,
+				warnings:    handleWarnings(resp.Header, r.warningHandler),
 			}
 		}
 	}
@@ -1038,6 +1052,7 @@ func (r *Request) transformResponse(resp *http.Response, req *http.Request) Resu
 			statusCode:  resp.StatusCode,
 			decoder:     decoder,
 			err:         err,
+			warnings:    handleWarnings(resp.Header, r.warningHandler),
 		}
 	}
 
@@ -1046,6 +1061,7 @@ func (r *Request) transformResponse(resp *http.Response, req *http.Request) Resu
 		contentType: contentType,
 		statusCode:  resp.StatusCode,
 		decoder:     decoder,
+		warnings:    handleWarnings(resp.Header, r.warningHandler),
 	}
 }
 
@@ -1181,6 +1197,7 @@ func retryAfterSeconds(resp *http.Response) (int, bool) {
 // Result contains the result of calling Request.Do().
 type Result struct {
 	body        []byte
+	warnings    []net.WarningHeader
 	contentType string
 	err         error
 	statusCode  int
@@ -1294,6 +1311,11 @@ func (r Result) Error() error {
 	return r.err
 }
 
+// Warnings returns any warning headers received in the response
+func (r Result) Warnings() []net.WarningHeader {
+	return r.warnings
+}
+
 // NameMayNotBe specifies strings that cannot be used as names specified as path segments (like the REST API or etcd store)
 var NameMayNotBe = []string{".", ".."}