package service import ( "context" "fmt" "time" ) func (mw metricsMiddleware) ChangeUserEmail(ctx context.Context, token string) (string, error) { var ( err error newEmail string ) defer func(begin time.Time) { lvs := []string{"method", "CommitEmailChange", "error", fmt.Sprint(err != nil)} mw.requestCount.With(lvs...).Add(1) mw.requestLatency.With(lvs...).Observe(time.Since(begin).Seconds()) }(time.Now()) newEmail, err = mw.Service.ChangeUserEmail(ctx, token) return newEmail, err }