Fall back to JSON request encoding after CBOR 415.

If a client is configured to encode request bodies to CBOR, but the server does not support CBOR,
the server will respond with HTTP 415 (Unsupported Media Type). By feeding this response back to the
RESTClient, subsequent requests can fall back to JSON, which is assumed to be acceptable.

Kubernetes-commit: 1745dfdd154b1a838765e70b81c861c644bfcffe

rest/request.go

@@ -156,7 +156,7 @@ func NewRequest(c *RESTClient) *Request {
 		timeout = c.Client.Timeout
 	}
 
-	contentConfig := c.content
+	contentConfig := c.content.GetClientContentConfig()
 	contentTypeNotSet := len(contentConfig.ContentType) == 0
 	if contentTypeNotSet {
 		contentConfig.ContentType = "application/json"
@@ -188,7 +188,7 @@ func NewRequestWithClient(base *url.URL, versionedAPIPath string, content Client
 	return NewRequest(&RESTClient{
 		base:             base,
 		versionedAPIPath: versionedAPIPath,
-		content:          content,
+		content:          requestClientContentConfigProvider{base: content},
 		Client:           client,
 	})
 }
@@ -1235,6 +1235,9 @@ func (r *Request) request(ctx context.Context, fn func(*http.Request, *http.Resp
 		if req.ContentLength >= 0 && !(req.Body != nil && req.ContentLength == 0) {
 			metrics.RequestSize.Observe(ctx, r.verb, r.URL().Host, float64(req.ContentLength))
 		}
+		if resp != nil && resp.StatusCode == http.StatusUnsupportedMediaType {
+			r.c.content.UnsupportedMediaType(resp.Request.Header.Get("Content-Type"))
+		}
 		retry.After(ctx, r, resp, err)
 
 		done := func() bool {