Unclear response output in case of timeout when requesting a subgraph

[LiageSTD]

At the moment, when using integrated timeouts for each subgraph, we can get a vague answer "Failed to fetch from Subgraph X". However, I would like to receive a clear answer that a timeout has occurred.
I suggest integrating a similar implementation in v2/loader.go.:

func (l *Loader) renderErrorsFailedToFetch(fetchItem *FetchItem, res *result, reason string) error {
	l.ctx.appendSubgraphErrors(res.err, NewSubgraphError(res.ds, fetchItem.ResponsePath, reason, res.statusCode))
	errorObject, err := astjson.ParseWithoutCache(l.renderSubgraphBaseError(res.ds, fetchItem.ResponsePath, reason))
	
	var errorObject *astjson.Value
	var err error
	
	if res.statusCode == 0 && reason == "" {
		errorObject, err = astjson.ParseWithoutCache(l.renderTimeoutFetchError(fetchItem, res))

	} else {
		errorObject, err = astjson.ParseWithoutCache(l.renderSubgraphBaseError(res.ds, fetchItem.ResponsePath, reason))
	}

	if err != nil {
		return err
	}
	l.setSubgraphStatusCode([]*astjson.Value{errorObject}, res.statusCode)
	astjson.AppendToArray(l.resolvable.errors, errorObject)
	return nil
}

func (l *Loader) renderTimeoutFetchError(fetchItem *FetchItem, res *result) string {
	path := ""
	switch f := fetchItem.Fetch.(type) {
	case *SingleFetch:
		path = getJsonReadyPath(f.Info.RootFields)
	case *EntityFetch:
		path = getJsonReadyPath(f.Info.RootFields)
	default:
		path = ""
	}
	return fmt.Sprintf(
		`{"path":[%s],
		 "extensions":{"code":"GlobalTimeoutError", "type":"GlobalTimeoutError", "classification":"GlobalTimeoutError"},
		  "locations": [],
		   "message":"GlobalTimeoutError"}`,
		 path,
		)
}

Or go to another level to allow developers to customize errors without changing the library code.

[mocksoul]

Or go to another level to allow developers to customize errors without changing the library code.

+1 to this
right now there is no way to produce custom errors

[endigma]

Hi @LiageSTD, we'll take a look at implementing this internally.