chore: do not retry on HTTP 429 or HTTP 503

Related to #470

We prefer not to retry requests:
- If the ingress return a "bare" 429, as the backend was not able to respond anyway.
- If the ingress return a "bare" 503, to prevent possible self made ddos, and preventing a disaster recovery.

hcloud/client_handler_retry.go

@@ -69,11 +69,8 @@ func retryPolicy(resp *Response, err error) bool {
 			}
 		case errors.Is(err, ErrStatusCode):
 			switch resp.Response.StatusCode {
-			// 4xx errors
-			case http.StatusTooManyRequests:
-				return true
 			// 5xx errors
-			case http.StatusBadGateway, http.StatusServiceUnavailable, http.StatusGatewayTimeout:
+			case http.StatusBadGateway, http.StatusGatewayTimeout:
 				return true
 			}
 		case errors.As(err, &netErr):

hcloud/client_handler_retry_test.go

@@ -31,11 +31,11 @@ func TestRetryHandler(t *testing.T) {
 			},
 		},
 		{
-			name: "http 503 error recovery",
+			name: "http 502 error recovery",
 			wrapped: func(req *http.Request, _ any) (*Response, error) {
-				resp := fakeResponse(t, 503, "", false)
+				resp := fakeResponse(t, 502, "", false)
 				resp.Response.Request = req
-				return resp, fmt.Errorf("%w %d", ErrStatusCode, 503)
+				return resp, fmt.Errorf("%w %d", ErrStatusCode, 502)
 			},
 			recover: true,
 			want: func(t *testing.T, err error, retryCount int) {
@@ -44,14 +44,14 @@ func TestRetryHandler(t *testing.T) {
 			},
 		},
 		{
-			name: "http 503 error",
+			name: "http 502 error",
 			wrapped: func(req *http.Request, _ any) (*Response, error) {
-				resp := fakeResponse(t, 503, "", false)
+				resp := fakeResponse(t, 502, "", false)
 				resp.Response.Request = req
-				return resp, fmt.Errorf("%w %d", ErrStatusCode, 503)
+				return resp, fmt.Errorf("%w %d", ErrStatusCode, 502)
 			},
 			want: func(t *testing.T, err error, retryCount int) {
-				assert.EqualError(t, err, "server responded with status code 503")
+				assert.EqualError(t, err, "server responded with status code 502")
 				assert.Equal(t, 5, retryCount)
 			},
 		},

hcloud/hcloud.go

@@ -14,9 +14,7 @@ The following rules defines when a request can be retried:
 When the [http.Client] returned a network timeout error.
 
 When the API returned an HTTP error, with the status code:
-  - [http.StatusTooManyRequests]
   - [http.StatusBadGateway]
-  - [http.StatusServiceUnavailable]
   - [http.StatusGatewayTimeout]
 
 When the API returned an application error, with the code: