Update generic errors with the new http package codes

All of these errors are now part of the standard HTTP method. Formalize
those into our error types and remove duplication and unclear
separation.

Kubernetes-commit: d3be1ac92eb644e284915a55fe67942c33f88d4c

pkg/endpoints/apiserver_test.go

@@ -3749,7 +3749,7 @@ func TestCreateTimeout(t *testing.T) {
 	if err != nil {
 		t.Errorf("unexpected error: %v", err)
 	}
-	itemOut := expectApiStatus(t, "POST", server.URL+"/"+prefix+"/"+testGroupVersion.Group+"/"+testGroupVersion.Version+"/namespaces/default/foo?timeout=4ms", data, apierrs.StatusServerTimeout)
+	itemOut := expectApiStatus(t, "POST", server.URL+"/"+prefix+"/"+testGroupVersion.Group+"/"+testGroupVersion.Version+"/namespaces/default/foo?timeout=4ms", data, http.StatusGatewayTimeout)
 	if itemOut.Status != metav1.StatusFailure || itemOut.Reason != metav1.StatusReasonTimeout {
 		t.Errorf("Unexpected status %#v", itemOut)
 	}

pkg/endpoints/installer.go

@@ -511,7 +511,7 @@ func (a *APIInstaller) registerResourceHandlers(path string, storage rest.Storag
 	// http.StatusUnsupportedMediaType, http.StatusNotAcceptable,
 	// http.StatusBadRequest, http.StatusUnauthorized, http.StatusForbidden,
 	// http.StatusRequestTimeout, http.StatusConflict, http.StatusPreconditionFailed,
-	// 422 (StatusUnprocessableEntity), http.StatusInternalServerError,
+	// http.StatusUnprocessableEntity, http.StatusInternalServerError,
 	// http.StatusServiceUnavailable
 	// and api error codes
 	// Note that if we specify a versioned Status object here, we may need to

pkg/server/filters/maxinflight.go

@@ -123,5 +123,5 @@ func WithMaxInFlightLimit(
 func tooManyRequests(req *http.Request, w http.ResponseWriter) {
 	// Return a 429 status indicating "Too Many Requests"
 	w.Header().Set("Retry-After", retryAfter)
-	http.Error(w, "Too many requests, please try again later.", errors.StatusTooManyRequests)
+	http.Error(w, "Too many requests, please try again later.", http.StatusTooManyRequests)
 }