chore: simplify

tariff/ngeso.go

@@ -76,26 +76,23 @@ func (t *Ngeso) run(done chan error) {
 
 	// Data updated by ESO every half hour, but we only need data every hour to stay current.
 	for ; true; <-time.Tick(time.Hour) {
-		var carbonResponse ngeso.CarbonForecastResponse
-		if err := backoff.Retry(func() error {
-			var err error
-			carbonResponse, err = tReq.DoRequest(client)
-
-			// Consider whether errors.As would be more appropriate if this needs to start dealing with wrapped errors.
-			if se, ok := err.(request.StatusError); ok && se.HasStatus(http.StatusBadRequest) {
-				// Catch cases where we're sending completely incorrect data (usually the result of a bad region).
-				return backoff.Permanent(se)
+		res, err := backoff.RetryWithData(func() (ngeso.CarbonForecastResponse, error) {
+			res, err := tReq.DoRequest(client)
+			var se request.StatusError
+			if errors.As(err, &se) && se.HasStatus(http.StatusBadRequest) {
+				return nil, backoff.Permanent(se)
 			}
-			return err
-		}, bo); err != nil {
+			return res, err
+		}, bo)
+		if err != nil {
 			once.Do(func() { done <- err })
 
 			t.log.ERROR.Println(err)
 			continue
 		}
 
-		data := make(api.Rates, 0, len(carbonResponse.Results()))
-		for _, r := range carbonResponse.Results() {
+		data := make(api.Rates, 0, len(res.Results()))
+		for _, r := range res.Results() {
 			ar := api.Rate{
 				Start: r.ValidityStart.Time,
 				End:   r.ValidityEnd.Time,